JP7624646B2 - Polycyclic aromatic compounds - Google Patents

Description

The present invention relates to a polycyclic aromatic compound. The present invention also relates to a polymer compound having a repeating unit of a structure derived from the above polycyclic aromatic compound. The present invention further relates to a material for an organic device, a material for a light-emitting layer, a composition for forming a light-emitting layer, which contains the above compound or the above polymer compound, an organic electroluminescent element, an organic field-effect transistor, or an organic thin-film solar cell, which contains the above compound and the polymer compound in the light-emitting layer, and a display device and a lighting device which include the above organic electroluminescent element.

Display devices using electroluminescent light-emitting elements have been extensively studied because they can be made thin and energy-efficient. Furthermore, organic electroluminescent elements (hereinafter sometimes referred to as "organic EL elements") made from organic materials have been actively studied because they can be easily made large and lightweight. In particular, there has been active research into the development of organic materials that have the luminescence properties of blue, one of the three primary colors of light, and organic materials that have the ability to transport charges such as holes and electrons, regardless of whether they are polymeric or low molecular weight compounds.

An organic EL element has a structure consisting of a pair of electrodes consisting of an anode and a cathode, and one or more layers containing an organic compound that are disposed between the pair of electrodes. Layers containing organic compounds include a light-emitting layer and a charge transport/injection layer that transports or injects charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

There are two main emission mechanisms for organic EL elements: fluorescent emission, which uses light emitted from an excited singlet state, and phosphorescent emission, which uses light emitted from an excited triplet state. General fluorescent materials have a low exciton utilization efficiency of approximately 25%, and even when triplet-triplet fusion (TTF: Triplet-Triplet Fusion, or triplet-triplet annihilation, TTA: Triplet-Triplet Annihilation) is used, the exciton utilization efficiency is only 62.5%. On the other hand, phosphorescent materials can sometimes achieve an exciton utilization efficiency of 100%, but it is difficult to achieve deep blue emission, and in addition, the wide width of the emission spectrum results in low color purity.

Compounds that can be used in organic EL elements include, for example, the compounds described in Patent Document 1 or Non-Patent Documents 1 to 4.

Patent No. 5669163

Nature 2012, 492, 234-238 Chemistry of Materials, 2016, 28 (15), pp 5400-5405 Nature Photonics, 2019, 13, 540-546 (https://doi.org/10.1038/s41566-019-0415-5) Advanced Optical Materials. 2019, 1900130

Professor Adachi Chihaya of Kyushu University proposed a donor-acceptor type (DA type) thermally activated delayed fluorescence (TADF) mechanism (see Non-Patent Document 1). DA type TADF compounds have a structure in which a donor structure and an acceptor structure are bonded directly or via a π or σ bond, and are compounds that absorb thermal energy, undergo reverse intersystem crossing from an excited triplet state to an excited singlet state, and radiatively deactivate from the excited singlet state to emit fluorescence (delayed fluorescence). By using such TADF compounds, the energy of triplet excitons can also be effectively used for fluorescent emission, so that the exciton utilization efficiency for emission has reached 100%. A characteristic of DA type TADF compounds is that they give a wide emission spectrum with low color purity due to their structure, but the speed of reverse intersystem crossing is extremely fast.

Professor Hatakeyama of Kwansei Gakuin University has also proposed molecular design of TADF-active compounds that utilize the multiple resonance effect (Non-Patent Document 3 and Patent Document 1). In molecular design that utilizes the multiple resonance effect, boron (electron-withdrawing) and nitrogen (electron-donating) are bonded to each other at the o-position. As a result, the HOMO and LUMO formed by each are strengthened and localized on the atom, resulting in separation of the HOMO and LUMO and TADF properties. The robust planar structure formed results in an emission spectrum with small Stokes shifts of the absorption and emission peaks and high color purity. On the other hand, the speed of reverse intersystem crossing is inferior to that of D-A type TADF compounds.

In the DA-TADF compound, an emission spectrum with high color purity can be realized by utilizing a DA structure with restricted structural change and rotation (Non-Patent Document 2). Based on a similar idea, compounds with narrow emission half-widths using an acceptor structure with a boron atom have been proposed (Patent Document 1, Non-Patent Documents 3 and 4), and the emission half-widths have been improved. On the other hand, even if a similar donor structure is used, a narrow emission half-width, a fast reverse intersystem crossing rate, and blue emission cannot be obtained (Non-Patent Document 4).
As described above, it is difficult to achieve all of a narrow emission half-width, high TADF activity, and blue emission, and there is room for improvement in optimizing the partial structure to achieve these.

The objective of the present invention is to provide a novel compound as a material for use in organic devices such as organic EL elements.

The inventors conducted extensive research to solve the above problems and discovered a novel combination of donor and acceptor structures. The present invention was proposed based on these findings, and specific examples of the present invention have the following configurations:

[1] A polycyclic aromatic compound represented by the following formula (1):

(In formula (1),
ring A, ring B, ring C and ring D are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen atom in these rings may be substituted;
Z ¹ and Z ² each independently represent -CH= or -N=, and hydrogen in -CH= may be substituted;
X ¹ to X ⁴ are each independently >O or >N—R ^1X , provided that they are not all >O, and R ^1X is aryl, heteroaryl, alkyl, or cycloalkyl;
At least one of R ^1X is a substituent represented by formula (A-1), (A-2), (A-3) or (A-4), and the wavy lines in formula (A-1), (A-2), (A-3) and (A-4) indicate the bonding position.
In formula (A-1), R ²¹ to R ²⁸ each independently represent a hydrogen atom, an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group, or a halogen atom, and adjacent two of R ²¹ to R ²⁸ may be bonded to each other to form a ring;
In formula (A-2), Y ¹ to Y ⁵ are each independently -CR ^1Y = or -N =, R ^1Y is hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and adjacent two R ^1Y may be bonded to each other to form a ring, with the proviso that when all of Y ¹ to Y ⁵ are -CR ^1Y =, at least one R ^1Y is fluorine, cyano, -BR ₂ , -CO-R, -SO ₂ -R, pyridyl, piperidyl, or pyrazinyl, or any two adjacent R ^1Y are bonded to each other to form a nitrogen-containing heteroaromatic ring, and R in said -BR ₂ , -CO-R, and -SO ₂ -R is aryl, heteroaryl, alkyl, or cycloalkyl,
In formula (A-3), W ¹ is >O, >S, >PR ^1W or a ring having a carbon as a spiro atom, R ^1W and R ³¹ to R ³⁸ each independently represent hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and any two adjacent groups among R ³¹ to R ³⁸ may be bonded to each other to form a ring;
In formula (A-4), ^W2 is >O, >S or >N- ^R2W , ^Y11 to ^Y13 are each independently ^-CR11Y = or -N=, ^R2W and ^R11Y are each independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, adjacent ^R2W and ^R11Y or two ^R11Ys may be bonded to each other to form a ring,
At least one selected from the group consisting of aryl rings and heteroaryl rings in the compound represented by formula (1) may be condensed with at least one cycloalkane, at least one hydrogen in the cycloalkane may be substituted, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;
At least one hydrogen atom in the compound represented by formula (1) may be substituted with a halogen atom or a deuterium atom.

[2] The polycyclic aromatic compound according to [1], represented by the following formula (2):

(In formula (2), R ¹ to R ¹⁴ are each independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), in which at least one hydrogen may be substituted with an aryl, heteroaryl, or alkyl, and two adjacent groups among R ³ to R ¹⁴ may be bonded to each other to form a ring;
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that all of them are not >O, R ^1X is an aryl having 6 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, an alkyl having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 8 carbon atoms, and at least one of R ^1X is a substituent represented by formula (A-1), (A-2), (A-3) or (A-4),
In formula (A-1), R ²¹ to R ²⁸ each independently represent a hydrogen atom, an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group, or a halogen atom, and adjacent two of R ²¹ to R ²⁸ may be bonded to each other to form a ring;
In formula (A-2), Y ¹ to Y ⁵ are each independently -CR ^1Y = or -N=, provided that at least one of Y ¹ to Y ⁵ is -N=, R ^1Y is hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and two adjacent R ^1Ys may be bonded to each other to form a ring;
In formula (A-3), W ¹ is >O, >S or a ring having a carbon as a spiro atom; R ³¹ to R ³⁸ each independently represent hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen; and adjacent two of R ³¹ to R ³⁸ may be bonded to each other to form a ring;
In formula (A-4), ^W2 is >O, >S or >N- ^R2W , ^Y11 to ^Y13 are each independently ^-CR11Y = or -N=, ^R2W and ^R11Y are each independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, adjacent ^R2W and ^R11Y or two ^R11Ys may be bonded to each other to form an aryl ring or a heteroaryl ring,
At least one selected from the group consisting of aryl rings and heteroaryl rings in the compound represented by formula (2) may be condensed with at least one cycloalkane, at least one hydrogen in the cycloalkane may be substituted, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;
At least one hydrogen atom in the compound represented by formula (2) may be substituted with a halogen atom or a deuterium atom.

[3] R ¹ to R ¹⁴ are each independently a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 2 to 30 carbon atoms, a diarylamino group (wherein the aryl group has 6 to 12 carbon atoms), an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms, in which at least one hydrogen atom may be substituted by an aryl group having 6 to 12 carbon atoms or an alkyl group having 1 to 8 carbon atoms;
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that all of them are not >O, R ^1X is an aryl having 6 to 12 carbon atoms or an alkyl having 1 to 8 carbon atoms, and at least one of R ^1X is a substituent represented by formula (A-1), (A-2), (A-3) or (A-4);
In formula (A-1), R ²¹ to R ²⁸ each independently represent a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 2 to 30 carbon atoms, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, or a halogen atom;
In formula (A-2), R ^1Y represents hydrogen, an aryl having 6 to 30 carbon atoms, a heteroaryl having 2 to 30 carbon atoms, an alkyl having 1 to 12 carbon atoms, a cycloalkyl having 3 to 20 carbon atoms, cyano, or halogen; two adjacent R ^1Ys may be bonded to each other to form an aromatic ring or heteroaromatic ring having 6 to 10 carbon atoms;
In formula (A-3), W ¹ is >O, >S, or a fluorene ring having a carbon atom as a spiro atom; R ³¹ to R ³⁸ each independently represent an aryl having 6 to 30 carbon atoms, a heteroaryl having 2 to 30 carbon atoms, an alkyl having 1 to 12 carbon atoms, a cycloalkyl having 3 to 20 carbon atoms, cyano, or halogen;
In formula (A-4), ^W2 is >O, >S or >N- ^R2W , ^Y11 to ^Y13 are each independently ^-CR11Y = or -N=, ^R2W and ^R11Y are each independently hydrogen, an aryl having 6 to 30 carbon atoms, a heteroaryl having 2 to 30 carbon atoms, an alkyl having 1 to 12 carbon atoms or a cycloalkyl having 3 to 20 carbon atoms, adjacent ^R2W and ^R11Y or two ^R11Ys may be bonded to each other to form a benzene ring or a pyridine ring,
At least one hydrogen atom in the compound represented by formula (2) may be substituted with a halogen atom or a deuterium atom.
The polycyclic aromatic compound according to [2].
[4] The polycyclic aromatic compound according to [2] or [3], wherein one or two of X ¹ to X ⁴ are >N-R ^{1X, in which R 1X} is a substituent represented by formula (A-1 ⁾ , (A-2), (A-3) or (A-4).
[5] The polycyclic aromatic compound according to any one of [2] to [4], wherein R ^1X is any one of the structures shown below, in which any hydrogen atom may be independently substituted with an alkyl group having 1 to 8 carbon atoms, deuterium, or fluorine, and in which the wavy line portion indicates a bonding position.

[6] X ¹ and X ² are both N-Ph, and X ³ and X ⁴ are each independently N-R ^1X , or
^X1 and ^X2 are each independently N- ^R1X , and ^X3 and ^X4 are both N-Ph;
Ph is phenyl;
The polycyclic aromatic compound according to [5], wherein the structures and binding positions of the multiple R ^1X's are the same as each other.
[7] The polycyclic aromatic compound according to any one of [1] to [6], wherein each of the halogens is fluorine.
[8] A polycyclic aromatic compound or a multimer thereof according to any one of [1] to [6], in which at least one hydrogen atom is substituted with a chlorine atom, a bromine atom, or an iodine atom.
[9] A polycyclic aromatic compound in which at least one hydrogen atom of the polycyclic aromatic compound or a multimer thereof according to any one of [1] to [7] is substituted with a substituent represented by formula (B):

In formula (B), R ⁴⁰ and R ⁴¹ are each independently an alkyl group or are bonded to each other to form an alkylene group, the total number of carbon atoms in R ⁴⁰ and R ⁴¹ is 2 to 10, and the wavy line portion is a bonding site.
[10] A polymer compound comprising a structure derived from the polycyclic aromatic compound according to any one of [1] to [9] as a repeating unit.
[11] The polymer compound according to [10], which contains, as a repeating unit, at least one structure derived from a compound selected from the group consisting of unsubstituted or optionally substituted triarylamine, unsubstituted or optionally substituted fluorene, unsubstituted or optionally substituted anthracene, unsubstituted or optionally substituted tetracene, unsubstituted or optionally substituted triazine, unsubstituted or optionally substituted carbazole, unsubstituted or optionally substituted tetraphenylsilane, unsubstituted or optionally substituted spirofluorene, unsubstituted or optionally substituted triphenylphosphine, unsubstituted or optionally substituted dibenzothiophene, and unsubstituted or optionally substituted dibenzofuran.
[12] A material for an organic device, comprising the polycyclic aromatic compound according to any one of [1] to [9], or the polymer compound according to [10] or [11].
[13] The material for an organic device according to [12], which is a material for an organic electroluminescent element, a material for an organic field effect transistor, or a material for an organic thin-film solar cell.
[14] A material for a light-emitting layer of an organic electroluminescent element, comprising the polycyclic aromatic compound according to any one of [1] to [9] or the polymer compound according to [10] or [11].
[15] An organic electroluminescent element, an organic field effect transistor, or an organic thin-film solar cell, comprising the polycyclic aromatic compound according to any one of [1] to [9], or the polymer compound according to [10] or [11].
[16] An organic electroluminescent device comprising a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes, the light-emitting layer containing the material for a light-emitting layer according to [14].
[17] The organic electroluminescent device according to [16], wherein the light-emitting layer contains at least one compound represented by the following formulas (H1) to (H5), or contains at least one polymer compound having a repeating unit derived from at least one of the following structures (H1) to (H5).

In formula (H1), L ¹ is an arylene having 6 to 24 carbon atoms, Z is C—H, C—R′, or N,
In formula (H2), L ² and L ³ each independently represent an aryl having 6 to 30 carbon atoms or a heteroaryl having 2 to 30 carbon atoms;
At least one hydrogen atom in the compound represented by each of the above formulas may be substituted with an alkyl group having 1 to 6 carbon atoms, a cyano group, a halogen atom, or a deuterium atom;
In formula (H3), J is >O, >S, >N-R', >C(-R') ₂ or >Si(-R') ₂ ;
Y is a single bond, >O, >S, >C(-R') ₂ or >Si(-R') ₂ ;
Z is C-H, C-R' or N;
In formula (H4), Z is C—H, C—R′ or N;
R' in the C-R', >N-R', >C(-R') ₂ or >Si(-R') ₂ is aryl, heteroaryl, alkyl or cycloalkyl;
In formula (H5),
R ¹⁰¹ to R ¹¹¹ are each independently a hydrogen atom or an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl group, at least one hydrogen atom in these substituents may be further substituted with an aryl, heteroaryl, diarylamino or alkyl group;
Adjacent groups among R ¹⁰¹ to R ¹¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the benzene ring to which they are bonded, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino or an alkyl, and at least one hydrogen atom in these rings may be further substituted with an aryl, a heteroaryl, a diarylamino or an alkyl;
At least one hydrogen atom in the compound represented by formula (H5) may be independently replaced with a halogen atom or a deuterium atom.
[18] The organic electroluminescent device according to [16] or [17], wherein the light-emitting layer contains at least one compound represented by any one of the following formulae (AD1), (AD2) and (AD3):

(In the formulae (AD1), (AD2) and (AD3),
Each M is independently at least one of a single bond, —O—, >N—Ar, and >_CAR;
J's are each independently an arylene having 6 to 18 carbon atoms, and the arylene is optionally substituted with phenyl, alkyl having 1 to 6 carbon atoms, and cycloalkyl having 3 to 12 carbon atoms;
Each Q is independently ═C(—H)— or ═N—;
Ar's each independently represent a hydrogen atom, an aryl having 6 to 18 carbon atoms, a heteroaryl having 6 to 18 carbon atoms, an alkyl having 1 to 6 carbon atoms, or a cycloalkyl having 3 to 12 carbon atoms, and at least one hydrogen atom in the aryl and heteroaryl may be substituted with a phenyl, an alkyl having 1 to 6 carbon atoms, or a cycloalkyl having 3 to 12 carbon atoms;
m is 1 or 2;
n is an integer from 2 to (6-m);
At least one hydrogen atom in the compounds represented by the above formulas may be substituted with a halogen or deuterium.
[19] A composition for forming a light-emitting layer, comprising at least one of the polycyclic aromatic compound according to any one of [1] to [9], or the polymer compound according to [10] or [11], and a solvent.
[20] The composition for forming a light-emitting layer according to [19], wherein the solvent contains an organic solvent having a boiling point of 150° C. or higher.
[21] The composition for forming an emission layer according to [19] or [20], wherein the solvent is a mixed solvent containing a good solvent and a poor solvent for at least one of the polycyclic aromatic compound or the polymer compound, and the boiling point of the good solvent is lower than the boiling point of the poor solvent.
[22] The composition for forming a light-emitting layer according to any one of [19] to [21], which contains at least one compound represented by formulae (H1) to (H5), or contains at least one polymer compound having a repeating unit derived from at least one of the structures represented by formulae (H1) to (H5).

In formula (H1), L ¹ is an arylene having 6 to 24 carbon atoms, Z is C—H, C—R′, or N,
In formula (H2), L ² and L ³ each independently represent an aryl having 6 to 30 carbon atoms or a heteroaryl having 2 to 30 carbon atoms;
At least one hydrogen atom in the compound represented by each of the above formulas may be substituted with an alkyl group having 1 to 6 carbon atoms, a cyano group, a halogen atom, or a deuterium atom;
In formula (H3), J is >O, >S, >N-R', >C(-R') ₂ or >Si(-R') ₂ ;
Y is a single bond, >O, >S, >C(-R') ₂ or >Si(-R') ₂ ;
Z is C-H, C-R' or N;
In formula (H4), Z is C—H, C—R′ or N;
R' in the C-R', >N-R', >C(-R') ₂ or >Si(-R') ₂ is aryl, heteroaryl, alkyl or cycloalkyl;
In formula (H5),
R ¹⁰¹ to R ¹¹¹ are each independently a hydrogen atom or an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl group, at least one hydrogen atom in these substituents may be further substituted with an aryl, heteroaryl, diarylamino or alkyl group;
adjacent groups among R ¹⁰¹ to R ¹¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the benzene ring to which they are bonded, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino or an alkyl, and at least one hydrogen atom in these rings may be further substituted with an aryl, a heteroaryl, a diarylamino or an alkyl;
At least one hydrogen atom in the compound represented by formula (H5) may be independently replaced with a halogen atom or a deuterium atom.
[23] An organic electroluminescent element comprising a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes, the light-emitting layer being formed from the composition for forming a light-emitting layer according to any one of [19] to [22].
[24] The organic electroluminescence device according to any one of [16] to [18] and [23], further comprising at least one layer selected from the group consisting of an electron transport layer and an electron injection layer disposed between the cathode and the light-emitting layer, wherein at least one of the electron transport layer and the electron injection layer contains at least one selected from the group consisting of borane derivatives, pyridine derivatives, fluoranthene derivatives, BO-based derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metal complexes.
[25] The organic electroluminescent device according to [24], wherein at least one of the electron transport layer and the electron injection layer further contains at least one selected from the group consisting of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal oxide, an alkali metal halide, an alkaline earth metal oxide, an alkaline earth metal halide, a rare earth metal oxide, a rare earth metal halide, an alkali metal organic complex, an alkaline earth metal organic complex, and a rare earth metal organic complex.
[26] A display device comprising the organic electroluminescent device according to any one of [16] to [18] and [23] to [25].
[27] A lighting device comprising the organic electroluminescent element according to any one of [16] to [18] and [23] to [25].

The present invention provides a novel polycyclic aromatic compound. The present invention also provides a novel polymer compound having a repeating unit of a structure derived from the above polycyclic aromatic compound. The polycyclic aromatic compound and polymer compound of the present invention are useful as organic device materials that can be used in the manufacture of organic devices such as organic electroluminescent elements, organic field effect transistors, or organic thin-film solar cells.

FIG. 1 is a schematic cross-sectional view showing an example of an organic EL element.

The present invention will be described in detail below. The following description of the components may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments.
As used herein, combinations of preferred aspects are more preferred aspects.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In this specification, "hydrogen" in the explanation of structural formulae means "hydrogen atom (H)".
In the present specification, a structure derived from a specific compound in describing a polymer compound refers to a structure that includes most of the structure of the compound and can be a repeating unit of the polymer compound. For example, a structural unit derived from the monomer in a polymer compound obtained by polymerizing a monomer having a structure in which any one hydrogen of the compound is substituted with a polymerizable group, or a structural unit derived from the reactive compound in the case where a polymer compound is formed by bonding different reactive groups to each other in a reactive compound in which any two or more hydrogens of the compound are independently substituted with reactive groups, can be mentioned.
As used herein, combinations of preferred aspects are more preferred aspects.

In this specification, the term "thermally activated delayed fluorescent substance" (TADF compound) refers to a compound that can absorb thermal energy, undergo reverse intersystem crossing from an excited triplet state to an excited singlet state, and then radiatively deactivate from the excited singlet state to emit delayed fluorescence. Here, the term "thermally activated delayed fluorescent substance" also includes those that undergo a higher-order triplet state during the excitation process from the excited triplet state to the excited singlet state. The light emission mechanism that emits fluorescence via higher triplet is called the FvHT (Fluorescence via Higher Triplet) mechanism, and is described in, for example, a paper by Monkman et al. of Durham University (NATURE COMMUNICATIONS, 7:13680, DOI: 10.1038/ncomms13680), a paper by Hosokai et al. of the National Institute of Advanced Industrial Science and Technology (Hosokai et al., Sci. Adv. 2017;3: e1603282), a paper by Sato et al. of Kyoto University (Scientific Reports, 7:4820, DOI:10.1038/s41598-017-05007-7), and a conference presentation by Sato et al. of Kyoto University (98th Annual Meeting of the Chemical Society of Japan, presentation number: 2I4-15, Mechanism of highly efficient light emission in organic electroluminescence using DABNA as an emitting molecule, Graduate School of Engineering, Kyoto University). In the present invention, when a sample containing a target compound is measured for its fluorescence lifetime at 300K, if a slow fluorescent component is observed, the target compound is determined to be a "thermally activated delayed fluorescent substance." Here, "slow fluorescent component" refers to a fluorescent component with a fluorescence lifetime of 0.1 μs or more. In contrast, the fluorescence emitted from an excited singlet state generated by direct transition from the ground singlet state usually has a fluorescence lifetime of 0.1 μs or less (e.g., 10 ns). In the following explanation, fluorescence with a lifetime of 0.1 μs or less is referred to as a "fast fluorescent component." The fluorescence emitted by the "thermally activated delayed fluorescent substance" used in the present invention may contain a fast fluorescent component as well as a slow fluorescent component.

The fluorescence lifetime can be measured, for example, using a fluorescence lifetime measuring device (manufactured by Hamamatsu Photonics KK, C11367-01).
In this specification, unless otherwise specified, "E _S1 " denotes the excited singlet energy level obtained from the intersection of a tangent passing through an inflection point on the short wavelength side of a fluorescence spectrum at 77K and a baseline, "E _T1 " denotes the excited triplet energy level obtained from the intersection of a tangent passing through an inflection point on the short wavelength side of a phosphorescence spectrum at 77K and a baseline, and "ΔE _ST " means the energy difference therebetween, i.e., the value calculated as E _S1 -E _T1 . ΔE _ST is 0.20 eV or less, preferably 0.15 eV or less, and more preferably 0.10 eV or less.
The term "phosphor" refers to a compound that can radiatively deactivate from an excited singlet state to emit fluorescence. The phosphor may be a normal phosphor in which only a fast fluorescent component is observed when the fluorescence lifetime is measured at 300K, or a delayed fluorescent material in which both a fast fluorescent component and a delayed fluorescent component are observed. The phosphor preferably has an excited singlet energy level determined from the shoulder on the short wavelength side of the peak of the fluorescence spectrum lower than that of the host compound as the first component and the thermally activated delayed fluorescent material as the second component.

In this specification, the term "emitter" refers to a compound that is contained in the light-emitting layer in an organic EL element and emits light that is finally extracted outside the element, and may be a plurality of compounds, or may have different emission wavelengths. In particular, the emitter used in the "TAF element" (TADF Assisting Fluorescence element) described later is called the "emitting dopant". The compound of the present invention can be used as an emitter, and in particular, in the TAF element, it can function as an emitting dopant or an "assisting dopant". The "thermally activated delayed phosphor" can function as an assisting dopant that assists the emission of the phosphor. In particular, in the TAF element, the assisting dopant performs reverse intersystem crossing of the electrons and holes received from the host from the excited triplet state to the excited singlet state following recombination on the assisting dopant, and transfers energy to the emitting dopant. In the following description, an organic electroluminescent element using a thermally activated delayed phosphor as an assisting dopant may be referred to as a "TAF element". In TAF elements, triplet excited energy is converted to singlet excited energy by reverse intersystem crossing in the thermally activated delayed phosphor, so that singlet excited energy can be efficiently supplied to the phosphor to assist in light emission. This results in high light emission efficiency.

The host, assisting dopant and emitting dopant used in the present invention preferably have energy levels that satisfy at least one of the following formulae (a) to (d), and more preferably satisfy all of the conditions.
|Ip(H)|≧|Ip(AD)| ...Formula (a)
In formula (a), Ip(H) represents the ionization potential of the host compound, and Ip(AD) represents the ionization potential of the assisting dopant.
|Ea(H)|≦|Ea(AD)| ...Formula (b)
In formula (b), Ea(H) represents the electron affinity of the host compound, and Ea(AD) represents the electron affinity of the assisting dopant.
|Eg(H)|≧|Eg(AD)|≧|Eg(ED)| ...Formula (c)
In formula (c), Eg(H) represents the energy difference between the ionization potential and the electron affinity of the host, Eg(AD) represents the energy difference between the ionization potential and the electron affinity of the assisting dopant, and Eg(ED) represents the energy difference between the ionization potential and the electron affinity of the emitting dopant.
E _T1 (H)≧E _T1 (AD)≧E _T1 (ED) ...Formula (d)
In formula (d), E _T1 (H) represents the energy of the excited triplet level of the host compound, E _T1 (AD) represents the energy of the excited triplet level of the assisting dopant, and E _T1 (ED) represents the energy of the excited triplet level of the emitting dopant.

On the other hand, it is preferable that the emitting dopant has an emission peak in the range of 440 to 590 nm in its fluorescence spectrum, with a full width at half maximum FWHM of 80 nm or less. For use as a blue light-emitting device, 450 to 475 nm is more preferable, and 455 to 465 nm is even more preferable. For use as a green light-emitting device, 490 to 590 nm is more preferable, and 510 to 550 nm is even more preferable. An emission peak with a full width at half maximum FWHM of 35 nm or less means that the color purity of the emitted light is high. Therefore, by using such a phosphor, an organic light-emitting device with good color can be realized.

In this specification, ionization potential (Ip) means the ionization potential (Ip) determined by photoelectron yield spectroscopy, energy gap (Eg) means the optical band gap determined from the intersection of the tangent of the absorption peak on the longest wavelength side of the spectrum determined by ultraviolet-visible absorption spectroscopy and the baseline, and electron affinity (Ea) means the electron affinity determined by subtracting Eg from Ip.

In this specification, as a measurement sample for measuring each energy level, when the target compound is a host compound or an assisting dopant, a single film (neat film, thickness: 50 nm) of the target compound formed on a glass substrate is used, and when the target compound is an emitting dopant, an inactive polymer film (e.g., a polymethyl methacrylate film. Other examples include polystyrene, Cytop, and Zeonex. Thickness: 10 μm, concentration of target compound: 1 mass%) formed on a glass substrate in which the target compound is dispersed is used. The thickness of the polymethyl methacrylate film in which the target compound is dispersed may be a thickness that provides sufficient strength for measuring the absorption spectrum, fluorescence spectrum, and phosphorescence spectrum, and may be thick when the strength is weak, and thin when the strength is strong. For the excitation light, the wavelength of the absorption peak obtained in the absorption spectrum is used, and each energy level is determined using data obtained from emission peaks that appear in the range of 400 to 500 nm for blue emission, 480 to 600 nm for green emission, and 580 to 700 nm for red emission among the emission peaks that appear in the fluorescence spectrum or phosphorescence spectrum. In addition, when the absorption peak and the emission peak are close to each other and the excitation light is mixed into the emission peak, the absorption peak or absorption shoulder on the shorter wavelength side may be used.
[1] The excited singlet energy level E _S1 obtained from the intersection of the tangent line on the short wavelength side of the peak of the fluorescence spectrum and the baseline
A measurement sample containing the target compound is irradiated with excitation light at 77 K to observe the fluorescence spectrum. A tangent line passing through the inflection point on the short wavelength side of the emission peak appearing in the fluorescence spectrum is drawn, and the excited singlet energy level E _S1 is calculated from the wavelength (B _Sh ) [nm] at the intersection point between the tangent line and the baseline using the following formula.
E _S1 [eV]=1240/B _Sh
[2] The excited triplet energy level E _T1 obtained from the intersection point between the tangent line on the short wavelength side of the peak of the phosphorescence spectrum and the baseline
A measurement sample containing the target compound is irradiated with excitation light at 77 K to observe the phosphorescence spectrum. A tangent line passing through the inflection point on the short wavelength side of the emission peak appearing in the phosphorescence spectrum is drawn, and the excited triplet energy level E _T1 is calculated from the wavelength (C _Sh ) [nm] at the intersection point between the tangent line and the baseline using the following formula.
E _T1 [eV]=1240/C _Sh

Here, because the emission widths of the fluorescence and phosphorescence spectra differ between DA (donor-acceptor) type TADF materials and MRE (Multi Resonance Effect) type compounds due to the robustness of the molecules, it is believed that even if the maximum emission wavelengths are the same, DA type TADF compounds have a wider range of molecular energy than MRE type compound molecules. In TAF elements, it is necessary to accurately estimate the energy transfer between each component and design the configuration, so the excited singlet energy level and excited triplet energy level are estimated from the short wavelength side of the spectrum.

In this specification, the reverse intersystem crossing rate refers to the rate of reverse intersystem crossing from excited triplet to excited singlet. The reverse intersystem crossing rate of the thermally activated delayed fluorescent substance can be calculated by transient fluorescence spectroscopy using the method described in Nat. Commun. 2015, 6, 8476. or Organic Electronics 2013, 14, 2721-2726. Specifically, the reverse intersystem crossing rate of the thermally activated delayed fluorescent substance is 10 ⁵ s ^-1 or more, preferably 10 ⁶ s ^-1 or more.

In this specification, the emission rate refers to the rate of transition from an excited singlet state to a ground state via fluorescence emission without going through a TADF process. The emission rate of the thermally activated delayed fluorescent substance can be calculated using the method described in Nat. Commun. 2015, 6, 8476. or Organic Electronics 2013, 14, 2721-2726, similarly to the reverse intersystem crossing rate. Specifically, the emission rate of the thermally activated delayed fluorescent substance is 10 ⁷ s ^-1 or more, preferably 10 ⁸ s ^-1 or more.

In this specification, the compounds of the present invention are described using terms such as HOMO/LUMO, energy gap, (lowest) excited singlet energy, and (lowest/highest) excited triplet energy, each of which has a prefix such as "partial", "localized", or "charge transfer transition". Some of these values are not values that can be obtained optically or electrochemically by measuring the compounds of the present invention, but values that can be obtained by molecular orbital calculations, and although there is a correlation with actual measurements (or it can be assumed that there is a correlation with actual measurements), the numerical values may not match. For ease of designing and verifying the molecular structure, the structures are decomposed into donor and acceptor structures, and calculations, measurements, and explanations are performed. Therefore, when explaining the partial structure of the acceptor or donor, only the acceptor structure or only the donor structure should be considered.

<<Polycyclic aromatic compound>>
The polycyclic aromatic compound of the present invention has a structure represented by formula (1) and thus has both a narrow emission half-width and a high TADF property.
The polycyclic aromatic compound of the present invention is a compound having a donor structure (D) and an acceptor structure (A), and having a robust cyclic structure having a heteroatom at least at the center or a structure utilizing a multiple resonance effect, It is a multiple resonance effect type delayed fluorescent material. By appropriately selecting the donor structure (D) and the acceptor structure (A), the high-order excited triplet energy level and the excited singlet energy level are brought closer to each other, resulting in high TADF properties. More specifically, the compound can have high luminous efficiency, a short delayed fluorescence lifetime, blue light emission, and a short emission half-width. It is speculated that when contained in the light-emitting layer as an emitter or assisting dopant, it can realize high external quantum efficiency and long lifetime.

The polycyclic aromatic compound of the present invention has a structure represented by formula (1), and thus achieves both an extremely narrow emission half-width and high TADF properties using LE transitions in the donor structure. The term "LE transitions" refers to local energy transitions between HOMO-LUMOs that exist on the same partial structure in a molecule. The LE state (locally excited state) refers to S1 when the S0-S1 transition, which is an LE transition, is observed. In general, the emission obtained by the "LE transition" is a spectrum having one or more emission peaks with a narrow half-width or overlapping them, and a clear vibration peak is often observed. On the other hand, the CT state (charge transfer state) refers to S1 when the S0-S1 transition, which is a CT transition, is observed. The "CT transitions" refer to energy transitions between HOMO-LUMOs that exist spatially separated on different partial structures in a molecule. In general, the emission obtained by the "CT transitions" is a spectrum having a wide emission peak with a half-width, and no clear vibration peak is observed.

In the present invention, it is important to control the high-order excited triplet energy (E _Tn ). In other words, by bringing the LUMO+n (partial structure A) level closer to the LUMO (main skeleton) level, S1 and Tn are brought closer together, and the upconversion from excited triplet to excited singlet by TADF can be accelerated. More specifically, the first is to accelerate the upconversion of T1 (CT) → Tn (LE) → S1 (CT), and the other is to accelerate the upconversion of T1 (LE) → Tn (CT) → S1 (LE). Specifically, E _S1 -E _T1 is preferably 0.20 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is preferably 0.20 eV or less, E _S1 -E _T1 is more preferably 0.15 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is more preferably 0.10 eV or less, and E _S1 -E _T1 is even more preferably 0.1 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is even more preferably 0.05 eV or less.
In particular, it is preferable that the energy level difference between S1 and T1 (E _S1 -E _T1 ) is 0.1 eV or less, and the energy level difference between S1 and T2 (|E _S1 -E _T2 |) or the energy level difference between S1 and T3 (|E _S1 -E _T3 |) is 0.05 eV or less, and further that S1 is in a locally excited state.

The polycyclic aromatic compound of the present invention is represented by formula (1).

In formula (1),
Ring A, ring B, ring C and ring D are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen atom in these rings may be substituted.
^Z1 and ^Z2 each independently represent -CH= or -N=, and the hydrogen in -CH= may be substituted.
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that all of them are not >O, R ^1X is aryl, heteroaryl, alkyl or cycloalkyl, and at least one of R ^1X is a substituent represented by formula (A-1), (A-2), (A-3) or (A-4).
In formula (A-1), R ²¹ to R ²⁸ each independently represent hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and adjacent two of R ²¹ to R ²⁸ may be bonded to each other to form a ring.
In formula (A-2), Y ¹ to Y ⁵ are each independently -CR ^1Y = or -N =, R ^1Y is hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and adjacent two R ^1Y may be bonded to each other to form a ring, with the proviso that when all of Y ¹ to Y ⁵ are -CR ^1Y =, at least one R ^1Y is fluorine, cyano, -BR ₂ , -CO-R, -SO ₂ -R, pyridyl, piperidyl, or pyrazinyl, or any two adjacent R ^1Y are bonded to each other to form a nitrogen-containing heteroaromatic ring, and R in -BR ₂ , -CO-R, and -SO ₂ -R is aryl, heteroaryl, alkyl, or cycloalkyl.
In formula (A-3), W ¹ is >O, >S, >PR ^1W or a ring having a carbon as a spiro atom, R ^1W and R ³¹ to R ³⁸ each independently represent hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and adjacent two of R ³¹ to R ³⁸ may be bonded to each other to form a ring.
In formula (A-4), ^W2 is >O, >S or >N- ^R2W , ^Y11 to ^Y13 are each independently ^-CR11Y = or -N=, ^R2W and ^R11Y are each independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, and adjacent ^R2W and ^R11Y or two ^R11Ys may be bonded to each other to form a ring.
The wavy lines in formulae (A-1), (A-2), (A-3) and (A-4) indicate the bonding positions.
At least one hydrogen atom in the compound represented by formula (1) may be substituted with a halogen or deuterium.

The polycyclic aromatic compound of the present invention has, in the structure represented by formula (1), an acceptor structure (A) as a substituent represented by formula (A-1), (A-2), (A-3) or (A-4), and a donor structure (D) as a portion other than the substituent represented by formula (A-1), (A-2), (A-3) or (A-4).
Adachi et al. of Kyushu University have clarified the characteristics required for a thermally activated delayed fluorescent compound having high TADF properties in a series of papers (Nature 2012, 492, 234-238, Science Advances, 2017:3, e1603282, Science Advances 2018:4, eaao6910). In addition to the characteristics described in these papers, that is, the HOMO localized on the donor and the LUMO localized on the acceptor, it is believed that the polycyclic aromatic compound of the present invention also has the characteristics of having a small ΔE _ST and a spin inversion process via a localized transition.

In formula (1), ring A, ring B, ring C, and ring D are each independently an aryl ring which may have a substituent or a heteroaryl ring which may have a substituent. In formula (1), ring A, ring B, ring C, and ring D are each preferably independently an aryl ring which may have a substituent. Ring A, ring B, ring C, and ring D are each preferably a benzene ring which may have a substituent.

Examples of "aryl rings" include aryl rings having 6 to 30 carbon atoms, preferably aryl rings having 6 to 16 carbon atoms, more preferably aryl rings having 6 to 12 carbon atoms, and particularly preferably aryl rings having 6 to 10 carbon atoms. Specific examples of "aryl rings" include a monocyclic benzene ring, a bicyclic ...

Examples of "heteroaryl rings" include heteroaryl rings having 2 to 30 carbon atoms, preferably heteroaryl rings having 2 to 25 carbon atoms, more preferably heteroaryl rings having 2 to 20 carbon atoms, even more preferably heteroaryl rings having 2 to 15 carbon atoms, and particularly preferably heteroaryl rings having 2 to 10 carbon atoms. Examples of "heteroaryl rings" include heterocycles containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms. The "heteroaryl ring" may contain a selenium atom.

Specific examples of the "heteroaryl ring" include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, an isoindole ring, a 1H-indazole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a 1H-benzo Examples of such rings include a triazole ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinazoline ring, a quinoxaline ring, a phthalazine ring, a naphthyridine ring, a purine ring, a pteridine ring, a carbazole ring, an acridine ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, an indolizine ring, a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a furazan ring, and a thianthrene ring.

At least one hydrogen atom in the above "aryl ring" or "heteroaryl ring" in ring A, ring B, ring C, and ring D may be substituted with a substituent. Examples of the substituent include aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group) (above, first substituent), and at least one hydrogen atom in the aryl, heteroaryl, and diarylamino may be substituted with aryl, heteroaryl, alkyl, or cycloalkyl (above, second substituent).

Examples of "aryl" (first substituent) include aryls having 6 to 30 carbon atoms, preferably aryls having 6 to 24 carbon atoms, more preferably aryls having 6 to 20 carbon atoms, even more preferably aryls having 6 to 16 carbon atoms, particularly preferably aryls having 6 to 12 carbon atoms, and most preferably aryls having 6 to 10 carbon atoms.

Specific examples of aryl include monocyclic aryl phenyl, bicyclic aryl (2-, 3-, 4-) biphenylyl, condensed bicyclic aryl (1-, 2-) naphthyl, tricyclic aryl terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl), condensed tricyclic aryl, Examples of the aryl include acenaphthylene-(1-,3-,4-,5-)yl, fluorene-(1-,2-,3-,4-,9-)yl, phenalene-(1-,2-)yl, (1-,2-,3-,4-,9-)phenanthryl, tetracyclic aryl quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenylyl), condensed tetracyclic aryl triphenylene-(1-,2-)yl, pyrene-(1-,2-,4-)yl, naphthacene-(1-,2-,5-)yl, condensed pentacyclic aryl perylene-(1-,2-,3-)yl, pentacene-(1-,2-,5-,6-)yl, etc.

The above explanation of "aryl" as the first substituent can also be applied to "aryl" in diarylamino, "aryl" in arylheteroarylamino, "aryl" in aryloxy, "aryl" in diarylboryl, and "aryl" as the second substituent as the first substituent.

Examples of "heteroaryl" (first substituent) include heteroaryls having 2 to 30 carbon atoms, preferably heteroaryls having 2 to 25 carbon atoms, more preferably heteroaryls having 2 to 20 carbon atoms, even more preferably heteroaryls having 2 to 15 carbon atoms, and particularly preferably heteroaryls having 2 to 10 carbon atoms. Examples of heteroaryls include heterocycles containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

Specific examples of heteroaryl include furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzo[b]thienyl, dibenzothienyl, indoaryl, and aryl. These include isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenoxathiinyl, thianthrenyl, and indolizinyl.

The above explanation of the "heteroaryl" as the first substituent can also be cited for the "heteroaryl" in diheteroarylamino and the "heteroaryl" in arylheteroarylamino as the first substituent. The above explanation of the "heteroaryl" as the first substituent can also be cited for the "heteroaryl" as the second substituent. In addition, the "heteroaryl" as the second substituent includes a group in which at least one hydrogen atom in the heteroaryl is substituted with an aryl such as phenyl (specific examples are the groups mentioned above) or an alkyl such as methyl (specific examples are the groups mentioned below). As an example, when the second substituent is a carbazolyl group, a carbazolyl group in which at least one hydrogen atom at the 9-position is substituted with an aryl such as phenyl or an alkyl such as methyl is also included in the heteroaryl as the second substituent.

The "alkyl" (first substituent) may be either linear or branched, and examples thereof include alkyl having 1 to 24 carbon atoms (branched chain alkyl having 3 to 24 carbon atoms), preferably alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms), more preferably alkyl having 1 to 12 carbon atoms (branched chain alkyl having 3 to 12 carbon atoms), even more preferably alkyl having 1 to 6 carbon atoms (branched chain alkyl having 3 to 6 carbon atoms), particularly preferably alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms), and most preferably methyl.

Specific examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, Examples include 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-eicosyl.

The above explanation of "alkyl" as the first substituent can also be applied to "alkyl" as the second substituent. The position at which the alkyl, which is the second substituent, substitutes the first substituent is not particularly limited, but the second or third position is preferred, and the second position is more preferred, based on the bonding position (1st position) of the first substituent to the ring (ring a, ring b, ring c, and ring d in formula (2)).

The "cycloalkyl" (first substituent) may be any of cycloalkyl consisting of one ring, cycloalkyl consisting of multiple rings, cycloalkyl containing a double bond that is not conjugated within the ring, and cycloalkyl containing a branch outside the ring. For example, cycloalkyl having 3 to 20 carbon atoms is included, cycloalkyl having 3 to 12 carbon atoms is preferred, cycloalkyl having 5 to 10 carbon atoms is more preferred, and cycloalkyl having 6 to 10 carbon atoms is even more preferred.

Specific examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, decahydronaphthyl, and adamantyl.

The above explanation of "cycloalkyl" as the first substituent can also be applied to "cycloalkyl" as the second substituent.

Examples of "alkoxy" (first substituent) include alkoxy having 1 to 24 carbon atoms (branched chain alkoxy having 3 to 24 carbon atoms), preferably alkoxy having 1 to 18 carbon atoms (branched chain alkoxy having 3 to 18 carbon atoms), more preferably alkoxy having 1 to 12 carbon atoms (branched chain alkoxy having 3 to 12 carbon atoms), even more preferably alkoxy having 1 to 6 carbon atoms (branched chain alkoxy having 3 to 6 carbon atoms), and particularly preferably alkoxy having 1 to 4 carbon atoms (branched chain alkoxy having 3 to 4 carbon atoms).

Specific examples of alkoxy include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy, t-butoxy, pentyloxy, hexyloxy, heptyloxy, and octyloxy.

The first substituent (including those substituted with the second substituent) is preferably a group represented by the following structural formula, and more preferably methyl, tertiary alkyl (t-butyl, t-amyl, t-octyl, etc.), phenyl, o-tolyl, p-tolyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl , 3,6-dimethylcarbazolyl, 3,6-di-t-butylcarbazolyl, and phenoxy, and more preferably methyl, t-butyl, t-amyl, t-octyl, phenyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, and bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6-dimethylcarbazolyl, and 3,6-di-t-butylcarbazolyl. From the viewpoint of ease of synthesis, a larger steric hindrance is preferred for selective synthesis, and specifically, t-butyl, t-amyl, t-octyl, o-tolyl, p-tolyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, 3,6-dimethylcarbazolyl, and 3,6-di-t-butylcarbazolyl are preferred.

In the structural formula below, "Me" is methyl, "tBu" is t-butyl, "tAm" is t-amyl, "tOct" is t-octyl, and * indicates the bond position.

In formula (1), ^Z1 and ^Z2 are each independently -CH= or -N=, and -CH= is preferred from the viewpoint of ease of synthesis and stability of the compound, and -N= is preferred from the viewpoint of a wide energy gap of the compound.
The hydrogen atom in the -CH= may be substituted, and examples of the substituent include the first substituent described above. In addition, at least one hydrogen atom in the first substituent may be substituted with the second substituent described above.

X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that not all of them are >O. At least one of X ¹ to X ⁴ is >N-R ^1X , which makes it easier to obtain a narrow emission half width. It is more preferable that all of X ¹ to X ⁴ are >N-R ^1X . In addition, from the viewpoint of a wide energy gap, it is preferable that at least one of X ¹ to X ⁴ is >O.

R ^1X is aryl, heteroaryl, alkyl or cycloalkyl, and at least one of R ^1X is a substituent represented by formula (A-1), (A-2), (A-3) or (A-4). For aryl, heteroaryl, alkyl or cycloalkyl, the respective explanations in the above first substituent can be cited. The wavy lines in formulas (A-1), (A-2), (A-3) and (A-4) indicate the bonding positions. The number of the substituents represented by formula (A-1), (A-2), (A-3) or (A-4) is 1 to 4, preferably 1 to 2. By at least one of R ^1X being a substituent represented by formula (A-1), (A-2), (A-3) or (A-4), good TADF properties can be obtained. At least one of R ^1X is preferably a substituent represented by formula (A-1), (A-2), or (A-3).

The polycyclic aromatic compound represented by formula (1) is preferably a polycyclic aromatic compound represented by formula (2).

In formula (2), R ¹ to R ¹⁴ are each independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), in which at least one hydrogen may be substituted with an aryl, heteroaryl, or alkyl, and two adjacent groups among R ³ to R ¹⁴ may be bonded to each other to form a ring.
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that all of them are not >O, R ^1X is an aryl having 6 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, an alkyl having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 8 carbon atoms, and at least one of R ^1X is a substituent represented by formula (A-1), (A-2), or (A-3).
In formula (A-1) of formula (2), R ²¹ to R ²⁸ each independently represent hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and adjacent two of R ²¹ to R ²⁸ may be bonded to each other to form a ring.
In formula (A-2) of formula (2), Y ¹ to Y ⁵ are each independently -CR ^1Y = or -N=, provided that at least one of Y ¹ to Y ⁵ is -N=, R ^1Y is hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and two adjacent R ^1Ys may be bonded to each other to form a ring.
In formula (A-3) of formula (2), W ¹ is >O, >S or a ring having a carbon as a spiro atom, and R ³¹ to R ³⁸ are each independently hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and any two adjacent groups among R ³¹ to R ³⁸ may be bonded to each other to form a ring.
In formula (A-4) of formula (2), ^W2 is >O, >S or >N- ^R2W , ^Y11 to ^Y13 are each independently ^-CR11Y = or -N=, ^R2W and ^R11Y are each independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, and adjacent ^R2W and ^R11Y or two ^R11Y may be bonded to each other to form an aryl ring or a heteroaryl ring.
At least one hydrogen atom in the compound represented by formula (2) may be substituted with a halogen atom or deuterium.

In formula (2), R ¹ to R ¹⁴ are each independently hydrogen or a substituent which is an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy or diarylboryl (two aryls may be bonded via a single bond or a linking group), and specifically, are as described in the "first substituent" above. In addition, in the "first substituent", adjacent substituents may be bonded to each other to form a ring structure. In addition, at least one hydrogen atom in the "first substituent" may be substituted with an aryl, heteroaryl, or alkyl, and the substituent bonded to the "first substituent" is as described in the "second substituent" above.

R ¹ is preferably hydrogen. R ² is preferably hydrogen. In formula (2), R ¹ and R ² are preferably both hydrogen. R ³ is preferably hydrogen. R ⁹ is preferably hydrogen. In formula (2), R ³ and R ⁹ are preferably both hydrogen. R ⁵ is preferably hydrogen. R ¹¹ is preferably hydrogen. In formula (2), R ⁵ and R ¹¹ are preferably both hydrogen. R ⁶ is preferably hydrogen. R ¹² is preferably hydrogen. In formula (2), R ⁶ and R ¹² are preferably both hydrogen. R ⁸ is preferably hydrogen. R ¹⁴ is preferably hydrogen. In formula (2), R ⁸ and R ¹⁴ are preferably both hydrogen.
In formula (2), it is preferable that R ¹ , R ² , R ³ , R ⁹ , R ⁵ , R ¹¹ , R ⁶ , R ¹² , R ⁸ and R ¹⁴ are all hydrogen.
In addition, among R ¹ to R ¹⁴ , it is preferable that all except R ⁴ and R ¹⁰ are hydrogen, or all except R ⁷ and R ¹³ are hydrogen, and it is more preferable that all except R ⁴ and R ¹⁰ are hydrogen. It is preferable that ^{R 4} and R ¹⁰ are diarylamine, alkyl, or cycloalkyl.
It is also preferred that R ¹ to R ¹⁴ are all hydrogen.

In formula (2), adjacent groups among R ³ to R ¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, the b ring, the c ring, or the d ring, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, an alkyl, a cycloalkyl, an alkoxy, an aryloxy, or a diarylboryl (two aryls may be bonded via a single bond or a linking group) (above, first substituents), and at least one hydrogen atom in these may be substituted with an aryl, a heteroaryl, an alkyl, or a cycloalkyl (above, second substituents). Examples of adjacent groups among R ³ to R ¹¹ include combinations of R ³ and R ⁴ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹² and R ¹³ , and R ¹³ and R ¹⁴ .

Formula (2) preferably contains a partial structure represented by the following formula (4-B2X4-0000).

Each X is independently O or N, and from the viewpoint of a narrow emission half width, at least one X is N, preferably three Xs are N, and more preferably all Xs are N. Also, from the viewpoint of a wide energy gap, it is preferable that at least one X is O.
The substitution position of the substituent represented by formula (A-1), (A-2), (A-3) or (A-4) on the above partial structure may be the position represented by R' below.

In addition, from a synthetic viewpoint, it is preferable that the substitution position of the substituent represented by formula (A-1), (A-2), (A-3) or (A-4) in the compound represented by formula (2) be a position that makes the entire structure symmetrical.

<Substituent represented by formula (A-1), (A-2), (A-3) or (A-4): Acceptor structure (A)>

In formula (A-1), R ²¹ to R ²⁸ are each independently any one selected from the group consisting of hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, diarylboryl (two aryls may be bonded via a single bond or a linking group), cyano, and halogen, and are specifically similar to the description of the "first substituent" above. R ²¹ to R ²⁸ are each independently preferably hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, and R ²¹ to R ²⁸ are all preferably hydrogen. This is because a smaller molecular weight is preferable from the viewpoint of synthesis.
In addition, at least one hydrogen atom in the "first substituent" may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl, and the substituent bonded to the "first substituent" is similar to the description of the "second substituent" above. The wavy line in formula (A-1) indicates the bonding position.
In addition, two adjacent groups among R ²¹ to R ²⁸ may be bonded to each other to form a ring structure. The ring is preferably formed by linking with an alkylene having 2 to 5 carbon atoms. Examples of adjacent groups among R ²¹ to R ²⁸ include combinations of R ²¹ and R ²² , R ²² and R ²³ , R ²³ and R ²⁴ , R ²⁴ and R ²⁵ , R 25 and R ^{26 ,} R ²⁶ and R ²⁷ , R ²⁷ and R ²⁸ , and R ²⁸ and R ²¹ .

From the viewpoint of physical properties, it is preferable that the LUMO of the partial structure consisting of the substituents represented by formula (A-1) is close to the LUMO of the main skeleton (4-B2X4-0000), and when all of X are N (4-B2N4-0000), R ²¹ to R ²⁸ are preferably hydrogen.
Preferred examples of the substituent represented by formula (A-1) include the following. In the following structure, any hydrogen may be independently substituted with alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and among these, it is preferable that it is substituted with fluorine. The number of substitutions is not particularly limited, but is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

In formula (A-2), Y ¹ to Y ⁵ are each independently -CR ^1Y = or -N =. Each R ^1Y is independently any one selected from the group consisting of hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, diarylboryl (two aryls may be bonded via a single bond or a linking group), cyano, and halogen, and specifically, is similar to the description of the "first substituent" above. R ^1Y is preferably hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen.
However, when all of Y ¹ to Y ⁵ are -CR ^1Y =, at least one R ^1Y is fluorine, cyano, -BR ₂ , -CO-R, -SO ₂ -R, pyridyl, piperidinyl or pyrazinyl, or adjacent R ^1Y = are bonded to each other to form a nitrogen-containing heteroaromatic ring. Examples of the nitrogen-containing heteroaromatic ring include a pyrrole ring, an imidazole ring, a pyridine ring, a pyrazine ring and an isoxazole ring. R in the -BR ₂ , -CO-R and -SO ₂ -R is aryl, heteroaryl, alkyl or cycloalkyl, and specifically corresponds to the description of the "first substituent" above.
In addition, two adjacent R ^1Ys may be bonded to each other to form a ring. In this case, for example, R in -BR ₂ , -CO-R or -SO ₂ -R, C in -CR ^1Y , or adjacent substituents on the pyridyl, piperidinyl or pyrazinyl may be bonded to form a ring.
The wavy lines in (A-2) indicate the bond positions.

From the viewpoint of physical properties, it is preferable that the LUMO of the partial structure composed of the substituent represented by formula (A-2) is close to the LUMO of the main skeleton (4-B2X4-0000), and when all Xs are N (4-B2N4-0000), the following structure is preferable.
Preferred examples of the substituent represented by formula (A-2) include the following. In the following structure, any hydrogen may be independently substituted with alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and is preferably substituted with fluorine. The number of substitutions is not particularly limited, but is preferably 0 to 1, and more preferably 0.

In formula (A-3), W ¹ is >O, >S, >PR ^1W or a ring with a carbon as a spiro atom, and R ^1W and R ³¹ to R ³⁸ are each independently hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen, specifically as described in the "first substituent" above. In addition, adjacent two of R ³¹ to R ³⁸ may be bonded to each other to form a ring structure. Examples of adjacent groups among R ³¹ to R ³⁸ include combinations of R ³¹ and R ³² , R ³² and R ³³ , R ³³ and R ³⁴ , R 34 and R ³⁵ , R ³⁵ and R ³⁶ , R ³⁶ and ^{R 37 ,} and combinations of R ³⁷ , R ³⁸ , and R ²⁸ .
The ring having a carbon as a spiro atom is preferably a polycyclic ring, more preferably a polycyclic hydrocarbon ring, and further preferably a fluorene ring.
The wavy lines in (A-3) indicate the bond positions.

From the viewpoint of physical properties, it is preferable that the LUMO of the partial structure composed of the substituent represented by formula (A-3) is close to the LUMO of the main skeleton (4-B2X4-0000), and when all Xs are N (4-B2N4-0000), the following structure is preferable.
Preferred examples of the substituent represented by formula (A-3) include the following. In the following structure, any hydrogen may be independently substituted with alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and is preferably substituted with fluorine. The number of substitutions is not particularly limited, but is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

In formula (A-4), W ² is >O, >S or >N-R ^2W , and Y ¹¹ to Y ¹³ are each independently -CR ^11Y = or -N =, and R ^2W and R ^11Y are each independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, specifically as described in the "first substituent" above. Adjacent R ^2W and R ^11Y or two R ^11Y may be bonded to each other to form a ring structure. The ring structure is preferably an aryl ring or a heteroaryl ring, and more preferably contains a benzene ring or a pyridine ring. Among Y ¹¹ to Y ¹³ , it is preferable that Y ¹² and Y ¹³ are both -CR ^11Y =, and these two R ^11Y are bonded to each other to form a ring structure.

The wavy lines in (A-4) indicate the bond positions.
Preferred examples of the substituent represented by formula (A-4) include the following. In the following structure, any hydrogen may be independently substituted with alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and is preferably substituted with fluorine. The number of substitutions is not particularly limited, but is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

Examples of the substituents represented by formula (A-1), (A-2), (A-3) or (A-4) include the following. In the structures below, any hydrogen may be independently substituted with an alkyl group having 1 to 8 carbon atoms, deuterium or fluorine, and is preferably substituted with fluorine. The number of substitutions is not particularly limited, but is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

Of the above, preferred structures include the following:

<Substituents other than those represented by formula (A-1), (A-2), (A-3) or (A-4)>
Substituents other than those represented by formula (A-1), (A-2), (A-3) or (A-4) in the polycyclic aromatic compound represented by formula (2) play an important role in adjusting the energy of the donor structure (D). From a synthetic viewpoint, it is also preferable to have a substituent other than those represented by formula (A-1), (A-2), (A-3) or (A-4) at a position where the entire structure is symmetrical, and in this case, the number of substitutions is preferably 2 or 4. The number of substituents other than those represented by formula (A-1), (A-2), (A-3) or (A-4) in the compound represented by formula (2) is preferably 0 or 2, more preferably 0.
Substituents other than the substituents represented by formula (A-1), (A-2), (A-3) or (A-4) are preferably the first substituents described above. More specifically, it is sufficient to adjust the LUMO of the donor structure (D) and bring it closer to the LUMO of the acceptor structure (A), and from the viewpoint of the partial energy gap of the substituents other than the substituents represented by formula (A-1), (A-2), (A-3) or (A-4), unsubstituted or substituted phenyl, unsubstituted or substituted pyridyl, unsubstituted or substituted diphenylamino, unsubstituted or substituted alkyl having 1 to 12 carbon atoms, unsubstituted or substituted cycloalkyl having 3 to 12 carbon atoms are preferred, and phenyl, tolyl, xylyl, mesityl, pyridyl, methylpyridyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl and cyclohexyl are more preferred. From the viewpoint of ease of synthesis, phenyl, tolyl, xylyl, mesityl, methyl, butyl, cyclohexyl are preferred.

<Characteristics of polycyclic aromatic compounds having acceptor structure (A) and partial structure (D)>
The polycyclic aromatic compound of the present invention is a compound having a substituent represented by formula (A-1), (A-2), (A-3) or (A-4) as an acceptor structure (A) and a donor structure (D), and the partial HOMO and LUMO of the acceptor structure (A) and the partial structure (D), respectively, are HOMO (A), LUMO (A), HOMO (D) and LUMO (D), and it is preferable that LUMO (A) is shallower than LUMO (D) and close to LUMO (D). In addition, for high TADF activity, it is preferable that the high-order excited triplet energy (E _Tn ) is close to the lowest excited singlet energy (E _S1 ). It is almost difficult to actually measure the high-order excited triplet energy in an actual compound, and in reality, it is necessary to use a value obtained by molecular orbital calculation or to use a model compound. It is preferable that E _S1 -E _T1 is 0.20 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is 0.20 eV or less, more preferably that E _S1 -E _T1 is 0.15 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is 0.10 eV or less. It is even more preferable that E _S1 -E _T1 is 0.1 eV or less, |E _S1 -E _T2 | (or |E _S1 -E _T3 |) is 0.05 eV or less.

＜Other＞
At least one selected from the group consisting of aryl rings and heteroaryl rings in the polycyclic aromatic compound represented by formula (1) or (2) may be condensed with at least one cycloalkane, at least one hydrogen in the cycloalkane may be substituted, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-.

Examples of "cycloalkanes" include cycloalkanes with 3 to 24 carbon atoms, cycloalkanes with 3 to 20 carbon atoms, cycloalkanes with 3 to 16 carbon atoms, cycloalkanes with 3 to 14 carbon atoms, cycloalkanes with 5 to 10 carbon atoms, cycloalkanes with 5 to 8 carbon atoms, cycloalkanes with 5 to 6 carbon atoms, and cycloalkanes with 5 carbon atoms.

Specific examples of cycloalkanes include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, norbornene, bicyclo[1.0.1]butane, bicyclo[1.1.1]pentane, bicyclo[2.0.1]pentane, bicyclo[1.2.1]hexane, bicyclo[3.0.1]hexane, bicyclo[2.1.2]heptane, bicyclo[2.2.2]octane, adamantane, diamantane, decahydronaphthalene, and decahydroazulene, as well as alkyl (especially methyl) substituted, halogen (especially fluorine) substituted, and deuterium substituted derivatives of these having 1 to 5 carbon atoms.

Among these, for example, as shown in the structural formula below, a structure in which at least one hydrogen atom is substituted on the α-position carbon of a cycloalkane (in a cycloalkyl fused to an aryl ring or heteroaryl ring, the carbon atom adjacent to the fused carbon) is preferred, a structure in which two hydrogen atoms are substituted on the α-position carbon is more preferred, and a structure in which a total of four hydrogen atoms are substituted on the two α-position carbons is even more preferred. Examples of such a substituent include an alkyl (particularly methyl) substituent having 1 to 5 carbon atoms, a halogen (particularly fluorine) substituent, and a deuterium substituent.

上記部分構造（Ｂ）中、Ｒ^４０およびＲ^４１は、それぞれ独立にアルキルであるか、互いに結合してアルキレンとなっており、Ｒ^４０およびＲ^４１の合計炭素数は２～１０であり、波線部は他の構造との結合部位である。 Furthermore, a compound in which at least one hydrogen atom of the polycyclic aromatic compound represented by formula (1) is substituted with chlorine, bromine, or iodine can also be suitably used as the polycyclic aromatic compound of the present invention.
Furthermore, a compound in which at least one hydrogen of the polycyclic aromatic compound represented by formula (1) is substituted with the following partial structure (B) is also preferably used as a compound according to another embodiment of the present invention.

In the partial structure (B), R ⁴⁰ and R ⁴¹ are each independently an alkyl group or are bonded to each other to form an alkylene group, the total number of carbon atoms in R ⁴⁰ and R ⁴¹ is 2 to 10, and the wavy line portion is a bonding site to another structure.

The following are examples of the polycyclic aromatic compound of the present invention, but the present invention is not limited to these specific examples. In the following examples, Me represents methyl.

<Method of producing polycyclic aromatic compound>
The polycyclic aromatic compound of the present invention can basically produce an intermediate by bonding each ring structure to each other (first reaction), and then produce a final product by bonding each ring structure with a boron atom (second reaction). In the first reaction, for example, a general etherification reaction such as a nucleophilic substitution reaction or an Ullmann reaction, or a general amination reaction such as the Buchwald-Hartwig reaction can be used. In addition, in the second reaction, a tandem hetero Friedel-Crafts reaction (successive aromatic electrophilic substitution reactions, the same applies below) can be used. The symbols in the structural formulas in each of the following schemes have the same definition as those in formula (1) or formula (2).

The second reaction is a reaction for introducing boron atoms that bond each ring structure, as shown in the following scheme (1). First, the hydrogen atoms between ^X1 and ^X3 and between ^X2 and ^X4 are orthometalated with n-butyllithium, sec-butyllithium, t-butyllithium, or the like. Next, boron trichloride, boron tribromide, or the like is added to carry out lithium-boron metal exchange, and then a tandem boron-Friedel-Crafts reaction is carried out by adding a Bronsted base such as N,N-diisopropylethylamine to obtain the target product. In the second reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction.

In scheme (1), lithium was introduced to the desired position by ortho-metallation, but as in scheme (2) below, a halogen atom (Hal) can be introduced in advance to the desired position and lithium can be introduced to the desired position by halogen-metal exchange. This method is useful because it allows the synthesis of the target compound even in cases where ortho-metallation is not possible due to the influence of substituents.

By appropriately selecting the above-mentioned synthesis method and the raw materials to be used, it is possible to synthesize a polycyclic aromatic compound having substituents at desired positions, in which Y is boron, and X ¹ , X ² , X ³ and X ⁴ are each independently >O or >N-R.

Note that the tandem boron-Friedel-Crafts reaction may occur at different locations due to, for example, the rotation of the amino group in the intermediate, which may result in the production of by-products. In such cases, the desired polycyclic aromatic compound can be isolated from the mixture by chromatography, recrystallization, etc.

Orthometalation reagents used in the above scheme include, for example, alkyllithiums such as methyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium, and organic alkali compounds such as lithium diisopropylamide, lithium tetramethylpiperidide, lithium hexamethyldisilazide, and potassium hexamethyldisilazide.

The metal exchange reagent for metal-Y (boron) used in the above scheme includes boron halides such as boron trifluoride, trichloride, tribromide, and triiodide, amino halides of Y such as CIPN(NEt ₂ ) ₂ , alkoxyl compounds of Y, and aryloxyl compounds of Y.

Examples of Bronsted bases used in the above scheme include N,N-diisopropylethylamine, triethylamine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2,6-lutidine, sodium tetraphenylborate, potassium tetraphenylborate, triphenylborane, tetraphenylsilane, Ar ₄ BNa, Ar ₄ BK, Ar ₃ B, and Ar ₄ Si (wherein Ar is an aryl such as phenyl).

Lewis acids used in the above scheme include _AlCl3 , AlBr3, _AlF3 , _BF3.OEt2 , _BCl3 , _BBr3 , _GaCl3 , _GaBr3 , _InCl3 , _InBr3 , In(OTf) ₃ , SnCl4, _SnBr4 , AgOTf, _ScCl3 , Sc(OTf) ₃ , _ZnCl2 , _ZnBr2 , Zn(OTf) ₂ , _{MgCl2 , MgBr2} , Mg(OTf) ₂ , LiOTf _, NaOTf _, KOTf, Me3SiOTf, Cu(OTf) ₂ , _CuCl2 , _YCl3 , Y( _OTf ) ₃ , _TiCl4 , _TiBr4 , _ZrCl4 , _ZrBr4 , _FeCl3 , _FeBr3 , _CoCl3 , _CoBr3 , etc.

In the above scheme, a Brönsted base or Lewis acid may be used to promote the tandem hetero Friedel-Crafts reaction. However, when using boron halides such as boron trifluoride, trichloride, tribromide, and triiodide, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide are generated as the aromatic electrophilic substitution reaction proceeds, so it is effective to use a Brönsted base to capture the acid. On the other hand, when using boron amino halides and boron alkoxylates, amines and alcohols are generated as the aromatic electrophilic substitution reaction proceeds, so it is not necessary to use a Brönsted base in many cases, but since the amino and alkoxy groups have low elimination ability, it is effective to use a Lewis acid to promote their elimination.

The polycyclic aromatic compounds represented by formula (1) or (2) also include compounds in which at least some of the hydrogen atoms are replaced by cyano, halogen, or deuterium, and such compounds can be synthesized in the same manner as above by using raw materials in which the desired sites are cyanated, halogenated, or deuterium.

<<Polymer compounds with repeating units derived from polycyclic aromatic compounds>>
The polymer compound having a repeating unit derived from the polycyclic aromatic compound of the present invention has the same properties as the polycyclic aromatic compound of the present invention, and further has polymer properties, and is therefore suitable for forming a layer by coating when used as a material for an organic device, which will be described later.

The above-mentioned polymer compound of the present invention preferably contains a repeating unit derived from at least one compound selected from the group consisting of unsubstituted or substituted triarylamine, unsubstituted or substituted fluorene, unsubstituted or substituted anthracene, unsubstituted or substituted tetracene, unsubstituted or substituted triazine, unsubstituted or substituted carbazole, unsubstituted or substituted tetraphenylsilane, unsubstituted or substituted spirofluorene, unsubstituted or substituted triphenylphosphine, unsubstituted or substituted dibenzothiophene, and unsubstituted or substituted dibenzofuran. This repeating unit may be a repeating unit containing the structure represented by formula (1), or may be a repeating unit different from the repeating unit containing the structure represented by formula (1).
The polymer compound of the present invention having a repeating unit derived from a polycyclic aromatic compound can be synthesized by a known method using an aryl halide derivative and an arylboronic acid derivative as starting materials, or using an aryl halide derivative, an aryl halide derivative and an arylboronic acid derivative as starting materials, in an appropriate combination of Suzuki-Miyaura coupling, Kumada-Tamao-Corleau coupling, Negishi coupling, halogenation reaction, or boration reaction.

In the Suzuki-Miyaura coupling, the reactive functional groups of the halide and boronic acid derivative may be appropriately interchanged, and in the Kumada-Tamao-Corleau coupling and Negishi coupling, the functional groups involved in these reactions may be similarly interchanged. When converting to a Grignard reagent, the metallic magnesium and isopropyl Grignard reagent may be appropriately interchanged. The boronic acid ester may be used as is, or may be hydrolyzed with an acid to be used as a boronic acid. When used as a boronic acid ester, the alkyl of the ester portion may be an alkyl other than those exemplified.

Specific examples of palladium catalysts used in the reaction include tetrakis(triphenylphosphine)palladium(0): Pd(PPh ₃ ) ₄ , bis(triphenylphosphine)palladium(II) dichloride: PdCl ₂ (PPh ₃ ) ₂ , palladium(II) acetate: Pd(OAc) ₂ , tris(dibenzylideneacetone)dipalladium(0): Pd ₂ (dba) ₃ , tris(dibenzylideneacetone)dipalladium(0) chloroform complex: Pd ₂ (dba) _{3.CHCl 3} , bis(dibenzylideneacetone)palladium(0): Pd(dba) ₂ , and bis(tri-t-butylphosphino)palladium(0): Pd(t-Bu ₃ P) _{2 .} , [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II): Pd(dppf)Cl ₂ , [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (1:1): Pd(dppf)Cl ₂ ·CH ₂ Cl ₂ , PdCl ₂ {P(t-Bu) ₂ -(p-NMe ₂ -Ph)} ₂ : (A- ^ta Phos) ₂ PdCl ₂ , palladium bis(dibenzylidene), [1,3-bis(diphenylphosphino)propane]nickel(II) dichloride, PdCl ₂ [P(t-Bu) ₂ -(p-NMe ₂ -Ph)] ₂ : (A- ^ta Phos) ₂ PdCl ₂ (Pd-132: trademark; manufactured by Johnson Matthey).

In order to promote the reaction, a phosphine compound may be added to the palladium compound in some cases. Specific examples of the phosphine compound include tri(t-butyl)phosphine, tricyclohexylphosphine, 1-(N,N-dimethylaminomethyl)-2-(di-t-butylphosphino)ferrocene, 1-(N,N-dibutylaminomethyl)-2-(di-t-butylphosphino)ferrocene, 1-(methoxymethyl)-2-(di-t-butylphosphino)ferrocene, 1,1'-bis(di-t-butylphosphino)ferrocene, 2,2'-bis(di-t-butylphosphino)-1,1'-binaphthyl, 2-methoxy-2'-(di-t-butylphosphino)-1,1'-binaphthyl, and 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl.

Specific examples of bases used in the reaction include sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, barium hydroxide, sodium ethoxide, sodium t-butoxide, sodium acetate, potassium acetate, tripotassium phosphate, or potassium fluoride.

Specific examples of solvents used in the reaction include benzene, toluene, xylene, 1,2,4-trimethylbenzene, anisole, acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide, tetrahydrofuran, diethyl ether, t-butyl methyl ether, 1,4-dioxane, methanol, ethanol, t-butyl alcohol, cyclopentyl methyl ether or isopropyl alcohol, dimethoxyethane, 2-(2-methoxyethoxy)ethane, 2-(2-ethoxyethoxy)ethane, etc. These solvents can be selected appropriately and may be used alone or as a mixed solvent.

The base may also be added as an aqueous solution and the reaction may be carried out in a two-phase system. If the reaction is carried out in a two-phase system, a phase transfer catalyst such as a quaternary ammonium salt may be added as necessary.

When producing a polymer compound having a repeating unit derived from a polycyclic aromatic compound of the present invention, the compound may be produced in one step or in multiple steps. The compound may be produced by a batch polymerization method in which all raw materials are placed in a reaction vessel and then the reaction is started, a dropwise polymerization method in which raw materials are added dropwise to a reaction vessel, or a precipitation polymerization method in which the product precipitates as the reaction proceeds. These methods can be combined appropriately to synthesize the compound. For example, when synthesizing a polymer compound having a repeating unit derived from a polycyclic aromatic compound of the present invention in one step, the target product is obtained by adding a monomer having a polymerizable group bonded to a monomer unit (MU) and a monomer having a polymerizable group bonded to an end cap unit (EC) to a reaction vessel and then reacting the monomer. When synthesizing a polymer compound having a repeating unit derived from a polycyclic aromatic compound of the present invention in multiple steps, the target product is obtained by polymerizing a monomer having a polymerizable group bonded to a monomer unit (MU) to a target molecular weight, and then adding a monomer having a polymerizable group bonded to an end cap unit (EC) and reacting the monomer.

In addition, the primary structure of the polymer can be controlled by selecting the monomer polymerizable group. For example, as shown in 1) to 3) of the synthesis scheme (20), it is possible to synthesize a polymer compound having a random primary structure (synthetic scheme (20) 1), a polymer compound having a regular primary structure (synthetic scheme (20) 2 and 3), etc., and these can be used in appropriate combinations depending on the intended purpose.

A polymer compound containing a structure derived from the compound represented by formula (1) as a repeating unit may be produced by using, for example, a monomer in which a polymerizable group has been introduced into R ¹ to R ¹¹ in formula (1). The substituents as R ¹ to R ¹¹ into which a polymerizable group has been introduced are aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group) (above, first substituents), and at least one hydrogen atom in the aryl, heteroaryl, and diarylamino may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl (above, second substituents). A polymer compound having a repeating unit containing a structure represented by formula (1) may be produced by using a comonomer in addition to the monomer containing the structure represented by formula (1). More specifically, the comonomer that may be used in the production of the polymer compound may be any of the following into which a polymerizable group has been introduced: unsubstituted or optionally substituted benzene, unsubstituted or optionally substituted triazine, unsubstituted or optionally substituted anthracene, unsubstituted or optionally substituted triarylamine, unsubstituted or optionally substituted carbazole, unsubstituted or optionally substituted spirofluorene, unsubstituted or optionally substituted dibenzofuran, unsubstituted or optionally substituted dibenzothiophene, unsubstituted or optionally substituted tetraarylsilane, unsubstituted or optionally substituted triarylphosphine, unsubstituted or optionally substituted phenoxazine, unsubstituted or optionally substituted phenothiazine, unsubstituted or optionally substituted Examples of the acridan include an acridan which may be unsubstituted or substituted, an alkyl which may be unsubstituted or substituted, and a cycloalkyl which may be unsubstituted or substituted. Among these, a triarylamine which may be unsubstituted or substituted, a fluorene which may be unsubstituted or substituted, an anthracene which may be unsubstituted or substituted, a tetracene which may be unsubstituted or substituted, a triazine which may be unsubstituted or substituted, a carbazole which may be unsubstituted or substituted, a tetraphenylsilane which may be unsubstituted or substituted, a spirofluorene which may be unsubstituted or substituted, a triphenylphosphine which may be unsubstituted or substituted, a dibenzothiophene which may be unsubstituted or substituted, and a dibenzofuran which may be unsubstituted or substituted are preferred. From another viewpoint, benzene, biphenyl, terphenyl, triarylamine, triphenyltriazine, or carbazole are also preferred. In addition, it is more preferred that the benzene, biphenyl, terphenyl, triarylamine, triphenyltriazine, or carbazole has an alkyl having 1 to 24 carbon atoms or a cycloalkyl having 3 to 16 carbon atoms.

<<Materials for organic devices>>
The polycyclic aromatic compound of the present invention and the polymer compound having a repeating unit derived from the polycyclic aromatic compound of the present invention can each be used as a material for an organic device. In the following, any compound selected from the group consisting of the polycyclic aromatic compound of the present invention and the polymer compound having a repeating unit derived from the polycyclic aromatic compound of the present invention may be referred to as the compound of the present invention.
The compound of the present invention is a multiple resonance effect type thermally activated delayed fluorescent material having a donor (D) and an acceptor (A) having a specific structure, and has high luminous efficiency, a short delayed fluorescence lifetime, blue luminescence and a short emission half width, and is useful as a material for organic devices.
The organic device may be an organic electroluminescent device, an organic field effect transistor, an organic thin-film solar cell, etc. The compound of the present invention may be used to form a light-emitting layer in an organic electroluminescent device, and may be used to form an active layer in an organic field effect transistor or an organic thin-film solar cell.
The compound of the present invention is particularly preferably used in the light-emitting layer of an organic electroluminescent device.

<<Organic electroluminescent device>>
The organic electroluminescent device has a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes. The organic electroluminescent device may have one or more organic layers in addition to the light-emitting layer. Examples of the organic layers include an electron transport layer, a hole transport layer, an electron injection layer, and a hole injection layer, and may further have other organic layers.
An example of the layer structure of an organic electroluminescent device having these organic layers is shown in Figure 1. In Figure 1, 101 denotes a substrate, 102 denotes an anode, 103 denotes a hole injection layer, 104 denotes a hole transport layer, 105 denotes a light emitting layer, 106 denotes an electron transport layer, 107 denotes an electron injection layer, and 108 denotes a cathode.

1. Light-emitting layer in organic electroluminescent element The light-emitting layer 105 emits light by recombining holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material for forming the light-emitting layer 105 may be a compound (light-emitting compound) that is excited by the recombination of holes and electrons to emit light, and is preferably a compound that can form a stable thin film shape and shows strong light-emitting (fluorescence) efficiency in a solid state. The light-emitting layer may be a single layer or multiple layers, each of which is formed from a material for the light-emitting layer (host material, dopant material). The host material and the dopant material may each be one type or a combination of multiple types. The dopant material may be contained in the entire host material or may be contained partially in the host material. As a doping method, the light-emitting layer may be formed by a co-evaporation method with the host material, but it may also be mixed with the host material in advance and then simultaneously evaporated. In addition, as described later, the light-emitting layer may also be formed by a wet film formation method using a light-emitting layer forming composition containing the host material and the dopant material.

The compound of the present invention can be preferably used as a material for forming the light-emitting layer of an organic electroluminescent device. The compound of the present invention can be used as an emitter or assisting dopant in the light-emitting layer to manufacture an organic electroluminescent device.

The light-emitting layer containing the compound of the present invention may contain a host compound. Here, the host compound may be one type or two or more types.
The light-emitting layer may be a single layer or a plurality of layers. The host compound, the thermally activated delayed phosphor, and other components described later may be contained in the same layer, or at least one component may be contained in each of the plurality of layers. The host compound and the thermally activated delayed phosphor contained in the light-emitting layer may be one type or a combination of a plurality of types. The assisting dopant and the emitting dopant may be entirely or partially contained in the host compound as a matrix. The light-emitting layer may be formed by a deposition method, or may be formed by a wet film-forming method in which a paint prepared by dissolving in an organic solvent is applied.

1-1. Host Compound The light-emitting layer containing the compound of the present invention may contain a host compound. Known host compounds can be used, for example, compounds having at least one of a carbazole ring and a furan ring, and among them, it is preferable to use a compound in which at least one of furanyl and carbazolyl is bonded to at least one of arylene and heteroarylene. Specific examples include mCP and mCBP.

The host compound may be, for example, a compound represented by any one of the following formulae (H1), (H2), (H3), (H4) and (H5).
These compounds may be polymer compounds having at least one structure selected from the group consisting of structures represented by the following formulae (H1), (H2), (H3), (H4), and (H5) as a repeating unit. The organic electroluminescent device of the present invention preferably contains at least one compound represented by the following formulae (H1) to (H5), or contains at least one polymer compound having at least one structure in the following formulae (H1) to (H5) as a repeating unit.

In formula (H1), L ¹ is an arylene having 6 to 24 carbon atoms, Z is C-H, C-R' or N, in formula (H2), L ² and L ³ are each independently an aryl having 6 to 30 carbon atoms or a heteroaryl having 2 to 30 carbon atoms, at least one hydrogen atom in the compound represented by each of the above formulae may be substituted with an alkyl having 1 to 6 carbon atoms, cyano, halogen or deuterium, in formula (H3), J is >O, >S, >N-R', >C(-R') ₂ or >Si(-R') ₂ , Y is a single bond, >O, >S, >C(-R') ₂ or >Si(-R') ₂ , Z is C-H, C-R' or N, in formula (H4), Z is C-H, C-R' or N, and the C-R', >N-R', >C(-R') R' in ₂ is aryl, heteroaryl, alkyl or cycloalkyl, and in formula (H5), R ¹⁰¹ to R ¹¹¹ are each independently hydrogen or a substituent which is aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl, at least _one hydrogen atom in these substituents may be further substituted with aryl, heteroaryl, diarylamino or alkyl, adjacent groups among R ¹⁰¹ to R ¹¹¹ may be bonded to each other to form an aryl ring or heteroaryl ring together with the benzene ring to which they are bonded, and at least one hydrogen atom in the formed ring may be substituted with aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl, at least one hydrogen atom in these may be further substituted with aryl, heteroaryl, diarylamino or alkyl, and at least one hydrogen atom in the compound represented by formula (H5) may each be independently substituted with halogen or deuterium.
As for R ¹⁰¹ to R ¹¹¹ in formula (H5), the above description of the first substituent and the second substituent substituting the first substituent can be cited.

As the host compound, a compound represented by any one of the following formulae (H-1), (H-2) and (H-3) can also be used.

In formulae (H-1), (H-2) and (H-3), L ¹ is an arylene having 6 to 24 carbon atoms, a heteroarylene having 2 to 24 carbon atoms, a heteroarylenearylene having 6 to 24 carbon atoms and an aryleneheteroarylenearylene having 6 to 24 carbon atoms, preferably an arylene having 6 to 16 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms, particularly preferably an arylene having 6 to 10 carbon atoms, and specific examples thereof include divalent groups such as a benzene ring, a biphenyl ring, a terphenyl ring and a fluorene ring. The heteroarylene is preferably a heteroarylene having 2 to 24 carbon atoms, more preferably a heteroarylene having 2 to 20 carbon atoms, still more preferably a heteroarylene having 2 to 15 carbon atoms, and particularly preferably a heteroarylene having 2 to 10 carbon atoms. Specific examples thereof include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, an isoindole ring, a 1H-indazole ring, a benzene ring, a phenyl ... and divalent groups such as a benzoimidazole ring, a benzoxazole ring, a benzothiazole ring, a 1H-benzotriazole ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinazoline ring, a quinoxaline ring, a phthalazine ring, a naphthyridine ring, a purine ring, a pteridine ring, a carbazole ring, an acridine ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, an indolizine ring, a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a furazan ring, an oxadiazole ring, and a thianthrene ring.
At least one hydrogen atom in the compounds represented by the above formulas may be substituted with an alkyl group having 1 to 6 carbon atoms, cyano, halogen or deuterium.

The host compound is preferably a compound represented by any of the structural formulas listed below. In the structural formulas listed below, at least one hydrogen may be substituted with a halogen, cyano, an alkyl having 1 to 4 carbon atoms (e.g., methyl or t-butyl), phenyl, naphthyl, or the like.

1-2. Phosphors (emitting dopants) in TAF elements
When the compound of the present invention is used as an assisting dopant, an emitting dopant may be used as an additional component in the light-emitting layer for the purpose of narrowing the half-width of the emission spectrum, improving the color tone, or extending the life.

The emitting dopant is not particularly limited, and known compounds can be used, and can be selected from various materials depending on the desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and chrysene, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, and tetraphenylbutadiene derivatives are available. conductors, cyclopentadiene derivatives, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives (JP Patent Publication No. 245087/1999), bisstyrylarylene derivatives (JP Patent Publication No. 247278/1990), diazaindacene derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives such as phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, and phenylisobenzofuran, Coumarin derivatives such as dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives, and 3-benzoxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, and rhodamine derivatives These include fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives, and benzofluorene derivatives.

As examples of dopant materials for each color of light emitted, blue to blue-green dopant materials include aromatic hydrocarbon compounds such as naphthalene, anthracene, phenanthrene, pyrene, triphenylene, perylene, fluorene, indene, and chrysene, and their derivatives, as well as furan, pyrrole, thiophene, silole, 9-silafluorene, 9,9'-spirobisilafluorene, benzothiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyrazine, naphthyridine, quinoxaline, pyrrolopyridine, and pyrrolopyridine. Examples include aromatic heterocyclic compounds and derivatives thereof such as lysine and thioxanthene, distyrylbenzene derivatives, tetraphenylbutadiene derivatives, stilbene derivatives, aldazine derivatives, coumarin derivatives, azole derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, and triazole, and metal complexes thereof, and aromatic amine derivatives such as N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine.

In addition, examples of green to yellow dopant materials include coumarin derivatives, phthalimide derivatives, naphthalimide derivatives, perinone derivatives, pyrrolopyrrole derivatives, cyclopentadiene derivatives, acridone derivatives, quinacridone derivatives, and naphthacene derivatives such as rubrene. Further, suitable examples include compounds in which a substituent that enables longer wavelengths, such as aryl, heteroaryl, arylvinyl, amino, or cyano, has been introduced into the compounds exemplified as the blue to blue-green dopant materials above.

Further, examples of orange to red dopant materials include naphthalimide derivatives such as bis(diisopropylphenyl)perylenetetracarboxylic acid imide, perinone derivatives, rare earth complexes such as Eu complexes with ligands such as acetylacetone, benzoylacetone and phenanthroline, 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran and its analogues, metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine, rhodamine compounds, deazaflavin derivatives, coumarin derivatives, quinacridone derivatives, phenoxazine derivatives, oxazine derivatives, quinazoline derivatives, pyrrolopyridine derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, phenoxazone derivatives and thiadiazolopyrene derivatives. Further, compounds in which a substituent that enables longer wavelengths, such as aryl, heteroaryl, arylvinyl, amino and cyano, is introduced into the compounds exemplified as the above blue to blue-green and green to yellow dopant materials, are also suitable examples.

Additional components may be appropriately selected from the compounds described in Chemical Industry, June 2004, page 13 and the references cited therein.

当該式中、Ａｒ^１は炭素数６～３０のアリールに由来するｍ価の基であり、Ａｒ^２およびＡｒ^３は、それぞれ独立して炭素数６～３０のアリールであるが、Ａｒ^１～Ａｒ^３の少なくとも１つはスチルベン構造を有し、Ａｒ^１～Ａｒ^３は置換されていてもよく、そして、ｍは１～４の整数である。 The amine having a stilbene structure is represented, for example, by the following formula.

In the formula, Ar ¹ is an m-valent group derived from an aryl having 6 to 30 carbon atoms, Ar ² and Ar ³ are each independently an aryl having 6 to 30 carbon atoms, at least one of Ar ¹ to Ar ³ has a stilbene structure, Ar ¹ to Ar ³ may be substituted, and m is an integer of 1 to 4.

当該式中、Ａｒ^２およびＡｒ^３は、それぞれ独立して炭素数６～３０のアリールであり、Ａｒ^２およびＡｒ^３は置換されていてもよい。 The amine having a stilbene structure is more preferably a diaminostilbene represented by the following formula.

In the formula, Ar ² and Ar ³ are each independently an aryl having 6 to 30 carbon atoms, and Ar ² and Ar ³ may be substituted.

Specific examples of aryls having 6 to 30 carbon atoms include benzene, naphthalene, acenaphthylene, fluorene, phenalene, phenanthrene, anthracene, fluoranthene, triphenylene, pyrene, chrysene, naphthacene, perylene, stilbene, distyrylbenzene, distyrylbiphenyl, and distyrylfluorene.

Specific examples of the amine having a stilbene structure include N,N,N',N'-tetra(4-biphenylyl)-4,4'-diaminostilbene, N,N,N',N'-tetra(1-naphthyl)-4,4'-diaminostilbene, N,N,N',N'-tetra(2-naphthyl)-4,4'-diaminostilbene, N,N'-di(2-naphthyl)-N,N'-diphenyl-4,4'-diaminostilbene, and N,N'-di(9-phenanthryl)-N,N'-diphenyl-4,4'-diaminostilbene. nyl-4,4'-diaminostilbene, 4,4'-bis[4"-bis(diphenylamino)styryl]-biphenyl, 1,4-bis[4'-bis(diphenylamino)styryl]-benzene, 2,7-bis[4'-bis(diphenylamino)styryl]-9,9-dimethylfluorene, 4,4'-bis(9-ethyl-3-carbazovinylene)-biphenyl, 4,4'-bis(9-phenyl-3-carbazovinylene)-biphenyl, and the like.
Furthermore, amines having a stilbene structure, such as those described in JP-A Nos. 2003-347056 and 2001-307884, may also be used.

Examples of perylene derivatives include 3,10-bis(2,6-dimethylphenyl)perylene, 3,10-bis(2,4,6-trimethylphenyl)perylene, 3,10-diphenylperylene, 3,4-diphenylperylene, 2,5,8,11-tetra-t-butylperylene, 3,4,9,10-tetraphenylperylene, 3-(1'-pyrenyl)-8,11-di(t-butyl)perylene, 3-(9'-anthryl)-8,11-di(t-butyl)perylene, and 3,3'-bis(8,11-di(t-butyl)perylenyl).
Also usable are perylene derivatives described in JP-A-11-97178, JP-A-2000-133457, JP-A-2000-26324, JP-A-2001-267079, JP-A-2001-267078, JP-A-2001-267076, JP-A-2000-34234, JP-A-2001-267075, and JP-A-2001-217077.

Compounds used as the third component of the present invention include compounds containing boron atoms, such as borane derivatives, dioxaboranaphthoanthracene (DOBNA) derivatives and multimers thereof, diazaboranaphthoanthracene (DABNA) derivatives and multimers thereof, oxazaboranaphthoanthracene (OABNA) derivatives and multimers thereof, oxaboranaphthoanthracene (OBNA) derivatives and multimers thereof, azaboranaphthoanthracene (ABNA) derivatives and multimers thereof, trioxaboradibenzopyrene derivatives and multimers thereof, dioxaazaborabenzopyrene derivatives and multimers thereof, oxadiazaborabenzopyrene derivatives and multimers thereof, etc.

Examples of the borane derivatives include 1,8-diphenyl-10-(dimesitylboryl)anthracene, 9-phenyl-10-(dimesitylboryl)anthracene, 4-(9'-anthryl)dimesitylborylnaphthalene, 4-(10'-phenyl-9'-anthryl)dimesitylborylnaphthalene, 9-(dimesitylboryl)anthracene, 9-(4'-biphenylyl)-10-(dimesitylboryl)anthracene, and 9-(4'-(N-carbazolyl)phenyl)-10-(dimesitylboryl)anthracene.
Furthermore, borane derivatives described in International Publication No. 2000/40586 and the like may also be used.

当該式中、Ａｒ^４は炭素数６～３０のアリールに由来するｎ価の基であり、Ａｒ^５およびＡｒ^６はそれぞれ独立して炭素数６～３０のアリールであり、Ａｒ^４～Ａｒ^６は置換されていてもよく、そして、ｎは１～４の整数である。 The aromatic amine derivative is represented, for example, by the following formula:

In the formula, Ar ⁴ is an n-valent group derived from an aryl having 6 to 30 carbon atoms, Ar ⁵ and Ar ⁶ are each independently an aryl having 6 to 30 carbon atoms, Ar ⁴ to Ar ⁶ are optionally substituted, and n is an integer of 1 to 4.

In particular, an aromatic amine derivative in which Ar ⁴ is a divalent group derived from anthracene, chrysene, fluorene, benzofluorene or pyrene, Ar ⁵ and Ar ⁶ are each independently an aryl having 6 to 30 carbon atoms, Ar ⁴ to Ar ⁶ may be substituted, and n is 2 is more preferable.

Specific examples of aryls having 6 to 30 carbon atoms include benzene, naphthalene, acenaphthylene, fluorene, phenalene, phenanthrene, anthracene, fluoranthene, triphenylene, pyrene, chrysene, naphthacene, perylene, and pentacene.

As aromatic amine derivatives, examples of chrysene derivatives include N,N,N',N'-tetraphenylchrysene-6,12-diamine, N,N,N',N'-tetra(p-tolyl)chrysene-6,12-diamine, N,N,N',N'-tetra(m-tolyl)chrysene-6,12-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl)chrysene-6,12-diamine, N,N,N',N'-tetra(naphthalene-2-yl)chrysene-6,12-diamine, N,N'-diphenyl Examples include -N,N'-di(p-tolyl)chrysene-6,12-diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)chrysene-6,12-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)chrysene-6,12-diamine, N,N'-diphenyl-N,N'-bis(4-t-butylphenyl)chrysene-6,12-diamine, and N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)chrysene-6,12-diamine.

Examples of pyrene-based compounds include N,N,N',N'-tetraphenylpyrene-1,6-diamine, N,N,N',N'-tetra(p-tolyl)pyrene-1,6-diamine, N,N,N',N'-tetra(m-tolyl)pyrene-1,6-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl)pyrene-1,6-diamine, N,N,N',N'-tetrakis(3,4-dimethylphenyl)pyrene-1,6-diamine, N,N'-diphenyl-N,N'-di(p-tolyl)pyrene-1,6-diamine, and N,N'-diphenyl-N,N'-bis(4-ethylphenyl)pyrene-1, 6-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)pyrene-1,6-diamine, N,N'-diphenyl-N,N'-bis(4-t-butylphenyl)pyrene-1,6-diamine, N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)pyrene-1,6-diamine, N,N,N',N'-tetrakis(3,4-dimethylphenyl)-3,8-diphenylpyrene-1,6-diamine, N,N,N,N-tetraphenylpyrene-1,8-diamine, N,N'-bis(biphenyl-4-yl)-N,N'-diphenylpyrene-1,8-diamine, N ¹ ,N ⁶ -diphenyl- ^{N 1} ,N ⁶ -bis-(4-trimethylsilanyl-phenyl)-1H,8H-pyrene-1,6-diamine and the like.
For example, specific examples include formulae (PYR1), (PYR2), (PYR3) and (PYR4).

Examples of anthracene-based compounds include N,N,N,N-tetraphenylanthracene-9,10-diamine, N,N,N',N'-tetra(p-tolyl)anthracene-9,10-diamine, N,N,N',N'-tetra(m-tolyl)anthracene-9,10-diamine, N,N,N',N'-tetrakis(4-isopropylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-di(p-tolyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-di(m-tolyl)anthracene-9,10 -diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)anthracene-9,10-diamine, N,N'-diphenyl-N,N'-bis(4-t-butylphenyl)anthracene-9,10-diamine, N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)anthracene-9,10-diamine, 2,6-di-t-butyl-N,N,N',N'-tetra(p-tolyl)anthracene-9,10-diamine 2,6-di-t-butyl-N,N'-diphenyl-N,N'-bis(4-isopropylphenyl)anthracene-9,10-diamine, 2,6-di-t-butyl-N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)anthracene-9,10-diamine, 2,6-dicyclohexyl-N,N'-bis(4-isopropylphenyl)-N,N'-di(p-tolyl)anthracene-9,10-diamine, 2,6-dicyclohexyl-N,N'-bis(4-isopropylphenyl)-N,N'-bis(4-t-butylphenyl)anthracene Examples include anthracene-9,10-diamine, 9,10-bis(4-diphenylamino-phenyl)anthracene, 9,10-bis(4-di(1-naphthylamino)phenyl)anthracene, 9,10-bis(4-di(2-naphthylamino)phenyl)anthracene, 10-di-p-tolylamino-9-(4-di-p-tolylamino-1-naphthyl)anthracene, 10-diphenylamino-9-(4-diphenylamino-1-naphthyl)anthracene, and 10-diphenylamino-9-(6-diphenylamino-2-naphthyl)anthracene.

Other examples include [4-(4-diphenylamino-phenyl)naphthalene-1-yl]-diphenylamine, [6-(4-diphenylamino-phenyl)naphthalene-2-yl]-diphenylamine, 4,4'-bis[4-diphenylaminonaphthalene-1-yl]biphenyl, 4,4'-bis[6-diphenylaminonaphthalene-2-yl]biphenyl, 4,4"-bis[4-diphenylaminonaphthalene-1-yl]-p-terphenyl, 4,4"-bis[6-diphenylaminonaphthalene-2-yl]-p-terphenyl, and indenocarbazole derivatives.
Furthermore, aromatic amine derivatives described in, for example, JP-A-2006-156888 may also be used.

The indenocarbazole derivative is a compound represented by the following formula (IDC1). Specific examples include compounds having the following partial structures (IDC11), (IDC12), and (IDC13). In the following formula (IDC1), Z is CR _A or N, π1 and π2 are each independently a substituted or unsubstituted aromatic hydrocarbon having 6 to 50 ring carbon atoms or a substituted or unsubstituted aromatic heterocycle having 5 to 50 ring carbon atoms, R _A , R _B, and R _C are hydrogen or any substituent, n and m are each independently an integer of 1 to 4, and two adjacent R _A , R _B , and R _C may be bonded to each other to form a substituted or unsubstituted ring structure. More specific examples include formulas (IDC121), (IDC131), (IDC132), (IDC133), and (IDC134).

The coumarin derivatives include coumarin-6, coumarin-334, and the like.
Furthermore, coumarin derivatives described in JP-A-2004-43646, JP-A-2001-76876, JP-A-6-298758, and the like may also be used.

また、特開2005-126399号公報、特開2005-097283号公報、特開2002-234892号公報、特開2001-220577号公報、特開2001-081090号公報、および特開2001-052869号公報などに記載されたピラン誘導体を用いてもよい。 Examples of the pyran derivative include the following DCM and DCJTB.

Furthermore, pyran derivatives described in JP-A-2005-126399, JP-A-2005-097283, JP-A-2002-234892, JP-A-2001-220577, JP-A-2001-081090, JP-A-2001-052869, and the like may also be used.

The phosphor used in the present invention is preferably a compound having a boron atom. Examples of compounds having a boron atom that can be used as phosphors include dioxaboranaphthoanthracene (DOBNA) derivatives and multimers thereof, diazaboranaphthoanthracene (DABNA) derivatives and multimers thereof, oxazaboranaphthoanthracene (OABNA) derivatives and multimers thereof, oxaboranaphthoanthracene (OBNA) derivatives and multimers thereof, and azaboranaphthoanthracene (ABNA) derivatives and multimers thereof.

The emitting dopant preferably contains at least one compound represented by the following formulae (ED1), (ED1′) and (ED2).

(In formula (ED1),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁹ , R ¹⁰ and R ¹¹ are each independently hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, aryloxy or diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further substituted with aryl, heteroaryl or alkyl, or adjacent groups among R ¹ to R ³ , R ⁴ to R ⁶ and R ⁹ to R ¹¹ may be bonded to each other to form an aryl ring or heteroaryl ring together with ring a, ring b or ring c, and the formed ring may be substituted with aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, aryloxy or diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further substituted with aryl, heteroaryl or alkyl,
X is >O or >N-R, and R and ^R13 of the >N-R are aryl, heteroaryl or alkyl, which may be substituted with aryl, heteroaryl or alkyl;
However, when X is an amino group, ^R2 cannot be an amino group.
and,
At least one hydrogen atom in the compound and structure represented by formula (ED1) may be replaced with cyano, halogen or deuterium.

(In formula (ED1′),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, aryloxy or diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further substituted with aryl, heteroaryl or alkyl, and R ¹ to R ³ , R ⁴ to R ⁷ , R ⁸ to R ¹⁰ and R ¹¹ to R Adjacent groups among ¹⁴ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, the b ring, the c ring or the d ring, and the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, an alkyl, a cycloalkyl, an alkoxy, an aryloxy or a diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further substituted with an aryl, a heteroaryl or an alkyl;
X is >O or >N-R, where R in >N-R is aryl, heteroaryl or alkyl, which may be substituted with aryl, heteroaryl or alkyl;
L is a single bond, >CR ₂ , >O, >S, or >N-R, and R in >CR ₂ and >N-R is each independently hydrogen, aryl, heteroaryl, diarylamino, alkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further substituted with an aryl, heteroaryl, or alkyl;
and,
At least one hydrogen atom in the compound and structure represented by formula (ED1') may be replaced with cyano, halogen, or deuterium.

(In formula (ED2),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, diarylboryl (two aryls may be bonded via a single bond or a linking group), arylthio, heteroarylthio or alkyl-substituted silyl, in which at least one hydrogen may be substituted with an aryl, heteroaryl or alkyl, and R ⁵ to R ⁷ and R ¹⁰ to R Adjacent groups among ¹² may be bonded to each other to form an aryl ring or a heteroaryl ring together with the b ring or the d ring, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino, an alkyl, a cycloalkyl, an alkoxy, an aryloxy, a heteroaryloxy, a diarylboryl (two aryls may be bonded via a single bond or a linking group), an arylthio, a heteroarylthio, or an alkyl-substituted silyl, and at least one hydrogen atom in these may be substituted with an aryl, a heteroaryl, or an alkyl,
X ¹ , X ² , X ³ and X ⁴ each independently represent >O, >N-R or >CR ₂ , R of the >N-R and R of the >CR ₂ are an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms or an alkyl having 1 to 6 carbon atoms, R of the >N-R and R of the >CR ₂ may be bonded to at least one of the ring a, ring b, ring c and ring d by -O-, -S-, -C(-R) ₂ - or a single bond, and R of the -C(-R) ₂ - is hydrogen or an alkyl having 1 to 6 carbon atoms,
However, among X ¹ , X ² , X ³ , and X ⁴ , the number of those that are >O is two or less;
and,
At least one hydrogen atom in the compound represented by formula (ED2) may be substituted with cyano, halogen or deuterium.
When X ¹ , X ² , X ³ and X ⁴ in formula (ED2) are >N-R, this R is preferably a substituent other than the substituents represented by formula (A-1), (A-2), (A-3) or (A-4) in formula (1).

More specifically, examples of compounds include those having structures represented by the following formulas (ED11) to (ED19), (ED21) to (ED28), (ED211), (ED212), (ED221) to (ED223), (ED231), (ED241), (ED242), (ED261) and (ED271).

At least one hydrogen atom in the structures represented by formulae (ED11) to (ED19), (ED21) to (ED28), (ED211), (ED212), (ED221) to (ED223), (ED231), (ED241), (ED242), (ED261) and (ED271) may be independently replaced with an aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, aryloxy or diarylboryl (two aryls may be bonded via a single bond or a linking group), which may be further replaced with an aryl, heteroaryl or alkyl. For the preferred ranges and specific examples of aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy or aryloxy, the corresponding descriptions in R ¹ to R ¹¹ of formula (1) can be referred to.
Furthermore, the phosphor that is the additional component is preferably a compound having at least one structure selected from the partial structure group B below, and more preferably a compound having a structure represented by formula (ED11) to (ED19), (ED21) to (ED27), (ED211), (ED212), (ED221) to (ED223), (ED231), (ED241), (ED242), (ED261) or (ED271), and having at least one structure selected from the partial structure group B bonded to a benzene ring (including a benzene ring that constitutes a condensed ring) in that structure.

Substructure group B:

Assisting dopant (thermally activated delayed phosphor)
An assisting dopant (thermally activated delayed fluorescent substance: TADF compound) that can be used when the compound of the present invention is used as an emitting dopant (ED) in a TAF element is preferably a donor-acceptor type TADF compound (D-A type TADF compound) designed to localize the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) in a molecule by using an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor, thereby causing efficient reverse intersystem crossing.
In this specification, the term "electron-donating substituent" (donor) refers to a substituent or partial structure in which the HOMO orbital is localized in the TADF compound molecule, and the term "electron-accepting substituent" (acceptor) refers to a substituent or partial structure in which the LUMO orbital is localized in the TADF compound molecule.
In general, TADF compounds using donors or acceptors have a large spin orbit coupling (SOC) due to their structure, a small exchange interaction between HOMO and LUMO, and a small ΔE _ST , so that they can obtain a very fast reverse intersystem crossing rate. On the other hand, TADF compounds using donors or acceptors have a large structural relaxation in the excited state (in some molecules, the stable structures are different between the ground state and the excited state, so when an external stimulus causes a conversion from the ground state to the excited state, the structure is subsequently changed to the stable structure in the excited state), and therefore give a wide emission spectrum, so that there is a possibility that the color purity will be reduced if they are used as a light-emitting material.

When the compound of the present invention is used as an ED in a TAF element, a thermally activated delayed fluorescent substance (TADF compound) that can be used may be, for example, a compound in which a donor and an acceptor are bound directly or via a spacer. As the donor and acceptor structures used in the thermally activated delayed fluorescent substance, for example, the structures described in Chemistry of Materials, 2017, 29, 1946-1963 can be used. Examples of the donor structure include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butyl)phenylamine, (diphenylamino)phenyldiphenylbenzenediamine, dimethyltetraphenyldihydroacridinediamine, tetramethyldihydroindenoacridine, and diphenyldihydrodibenzoazasiline. Acceptor structures include sulfonyldibenzene, benzophenone, phenylenebis(phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthracenone, anthracenedione, cycloheptabipyridine, fluorene dicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thianthrene tetraoxide, and tris(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence of the present invention is preferably a compound having at least one selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole, and benzophenone as a partial structure.

The compound used as the assisting dopant in the light-emitting layer of the present invention is preferably a thermally activated delayed phosphor whose emission spectrum at least partially overlaps with the absorption peak of the emitting dopant. Below, examples of compounds that can be used as the assisting dopant in the light-emitting layer of the present invention are given. However, the compounds that can be used as the assisting dopant in the present invention are not limited to the following example compounds, and in the following formula, Me represents methyl, tBu represents t-butyl, Ph represents phenyl, and the wavy line represents the bond position.

Furthermore, a compound represented by any one of the following formulae (AD1), (AD2) and (AD3) can also be used as a thermally activated delayed phosphor.

In formulae (AD1), (AD2) and (AD3),
M is each independently a single bond, -O-, >N-Ar or > _CAR2 , and is preferably a single bond, -O- or >N-Ar from the viewpoint of the depth of the HOMO of the partial structure to be formed and the height of the excited singlet energy level and the excited triplet energy level. J is a spacer structure separating the donor partial structure and the acceptor partial structure, and is each independently an arylene having 6 to 18 carbon atoms, and is preferably an arylene having 6 to 12 carbon atoms from the viewpoint of the magnitude of the conjugation exuded from the donor partial structure and the acceptor partial structure. More specifically, phenylene, methylphenylene and dimethylphenylene are included. Q is each independently =C(-H)- or =N-, and is preferably =N- from the viewpoint of the shallowness of the LUMO of the partial structure to be formed and the height of the excited singlet energy level and the excited triplet energy level. Ar are each independently hydrogen, an aryl having 6 to 24 carbon atoms, a heteroaryl having 2 to 24 carbon atoms, an alkyl having 1 to 12 carbon atoms, or a cycloalkyl having 3 to 18 carbon atoms, and from the viewpoint of the HOMO depth and the height of the excited singlet energy level and the excited triplet energy level of the partial structure to be formed, preferably hydrogen, an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 14 carbon atoms, an alkyl having 1 to 4 carbon atoms, or a cycloalkyl having 6 to 10 carbon atoms, more preferably hydrogen, phenyl, tolyl, xylyl, mesityl, biphenyl, pyridyl, bipyridyl, triazyl, carbazolyl, dimethylcarbazolyl, di-tert-butylcarbazolyl, benzimidazole, or phenylbenzimidazole, and even more preferably hydrogen, phenyl, or carbazolyl. m is 1 or 2. n is an integer of 2 to (6-m), and from the viewpoint of steric hindrance, preferably an integer of 4 to (6-m). Furthermore, at least one hydrogen atom in the compounds represented by the above formulas may be substituted with a halogen or deuterium.

More specifically, the compounds used as the second component of the light-emitting layer of the present invention are preferably 4CzBN, 4CzBN-Ph, 5CzBN, 3Cz2DPhCzBN, 4CzIPN, 2PXZ-TAZ, Cz-TRZ3, BDPCC-TPTA, MA-TA, PA-TA, FA-TA, PXZ-TRZ, DMAC-TRZ, BCzT, DCzTrz, DDCzTRz, spiroAC-TRZ, Ac-HPM, Ac-PPM, Ac-MPM, TCzTrz, TmCzTrz and DCzmCzTrz.

2. Electron Injection Layer and Electron Transport Layer in Organic Electroluminescent Device The electron injection layer 107 plays a role of efficiently injecting electrons moving from the cathode 108 into the light emitting layer 105 or the electron transport layer 106. The electron transport layer 106 plays a role of efficiently transporting electrons injected from the cathode 108 or electrons injected from the cathode 108 via the electron injection layer 107 to the light emitting layer 105. The electron transport layer 106 and the electron injection layer 107 are each formed by laminating and mixing one or more types of electron transport/injection materials. The electron transport layer 106 and the electron injection layer 107 may be formed from a mixture of an electron transport/injection material and a polymer binder.

The electron injection/transport layer is a layer that is responsible for injecting electrons from the cathode and transporting the electrons. It is desirable for the electron injection layer to have a high electron injection efficiency and efficiently transport the injected electrons. For this purpose, it is preferable for the material to have a large electron affinity, a large electron mobility, and excellent stability, and to be a material that is unlikely to generate impurities that become traps during manufacture and use. However, when considering the balance between the transport of holes and electrons, if the material mainly plays a role in efficiently preventing holes from the anode from flowing to the cathode without recombining, even if the electron transport ability is not that high, it has the effect of improving the luminous efficiency equivalent to a material with a high electron transport ability. Therefore, the electron injection/transport layer in this embodiment may also include the function of a layer that can efficiently block the movement of holes.

The material (electron transport material) forming the electron transport layer 106 or the electron injection layer 107 can be arbitrarily selected from compounds conventionally used as electron transfer compounds in photoconductive materials and known compounds used in the electron injection layer and electron transport layer of organic EL elements.

Materials used in the electron transport layer or electron injection layer preferably contain at least one selected from compounds consisting of aromatic rings or heteroaromatic rings composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon, and phosphorus, pyrrole derivatives and their condensed ring derivatives, and metal complexes having electron-accepting nitrogen. Specific examples include condensed ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives such as 4,4'-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, naphthalimide derivatives, quinone derivatives such as anthraquinone and diphenoquinone, phosphine oxide derivatives, arylnitrile derivatives, and indole derivatives. Metal complexes having electron-accepting nitrogen include, for example, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. These materials can be used alone or in combination with different materials.

Specific examples of other electron transfer compounds include borane derivatives, pyridine derivatives, naphthalene derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (such as 1,3-bis[(4-t-butylphenyl)1,3,4-oxadiazolyl]phenylene), thiophene derivatives, triazole derivatives (such as N-naphthyl-2,5-diphenyl-1,3,4-triazole), thiadiazole derivatives, metal complexes of oxine derivatives, quinolinol metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, Examples of such derivatives include pyrazine derivatives, benzoquinoline derivatives (such as 2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spirobifluorene), imidazopyridine derivatives, benzimidazole derivatives (such as tris(N-phenylbenzimidazol-2-yl)benzene), benzoxazole derivatives, thiazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (such as 1,3-bis(4'-(2,2':6'2"-terpyridinyl))benzene), naphthyridine derivatives (such as bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide), aldazine derivatives, pyrimidine derivatives, arylnitrile derivatives, indole derivatives, phosphine oxide derivatives, bisstyryl derivatives, silole derivatives, and azoline derivatives.

Metal complexes having an electron-accepting nitrogen can also be used, such as quinolinol metal complexes, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

The above materials can be used alone or in combination with other materials.

Among the above-mentioned materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO-based derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metal complexes are preferred.

<Borane derivatives>
The borane derivative is, for example, a compound represented by the following formula (ETM-1), and is disclosed in detail in JP-A-2007-27587.

In formula (ETM-1), R ¹¹ and R ¹² each independently represent at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, R ¹³ to R ¹⁶ each independently represent optionally substituted alkyl or optionally substituted aryl, X represents optionally substituted arylene, Y represents optionally substituted aryl having 16 or less carbon atoms, substituted boryl, or optionally substituted carbazolyl, and n each independently represents an integer of 0 to 3. In addition, examples of the substituent in the case of "optionally substituted" or "substituted" include aryl, heteroaryl, alkyl, and the like.

Among the compounds represented by formula (ETM-1), compounds represented by the following formula (ETM-1-1) and compounds represented by the following formula (ETM-1-2) are preferred.

In formula (ETM-1-1), R ¹¹ and R ¹² are each independently at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, R ¹³ to R ¹⁶ are each independently at least one of optionally substituted alkyl or optionally substituted aryl, R ²¹ and R ²² are each independently at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, X ¹ is an optionally substituted arylene having 20 or less carbon atoms, n is each independently an integer of 0 to 3, and m is each independently an integer of 0 to 4. In addition, examples of the substituent in the case of "optionally substituted" or "substituted" include aryl, heteroaryl, and alkyl.

In formula (ETM-1-2), R ¹¹ and R ¹² each independently represent at least one of hydrogen, alkyl, optionally substituted aryl, substituted silyl, optionally substituted nitrogen-containing heterocycle, or cyano, R ¹³ to R ¹⁶ each independently represent an optionally substituted alkyl or an optionally substituted aryl, X ¹ represents an optionally substituted arylene having 20 or less carbon atoms, and each n represents independently an integer of 0 to 3. In addition, examples of the substituent in the case of "optionally substituted" or "substituted" include aryl, heteroaryl, and alkyl.

（各式中、Ｒ^ａは、それぞれ独立してアルキル又は置換されていてもよいフェニルであり、＊は結合位置を表す。） Specific examples of ^X1 include divalent groups represented by the following formulae (X-1) to (X-9).

(In each formula, each R ^a is independently alkyl or optionally substituted phenyl, and * represents the bonding position.)

Specific examples of the borane derivative include the following:

This borane derivative can be produced using known raw materials and known synthesis methods.

<Pyridine derivatives>
The pyridine derivative is, for example, a compound represented by the following formula (ETM-2), and is preferably a compound represented by formula (ETM-2-1) or (ETM-2-2).

φ is an n-valent aryl ring (preferably an n-valent benzene ring, naphthalene ring, anthracene ring, fluorene ring, benzofluorene ring, phenalene ring, phenanthrene ring, or triphenylene ring), and n is an integer from 1 to 4.

In formula (ETM-2-1), R ¹¹ to R ¹⁸ are each independently hydrogen, alkyl (preferably alkyl having 1 to 24 carbon atoms), cycloalkyl (preferably cycloalkyl having 3 to 12 carbon atoms) or aryl (preferably aryl having 6 to 30 carbon atoms).

In formula (ETM-2-2), R ¹¹ and R ¹² each independently represent hydrogen, alkyl (preferably alkyl having 1 to 24 carbon atoms), cycloalkyl (preferably cycloalkyl having 3 to 12 carbon atoms) or aryl (preferably aryl having 6 to 30 carbon atoms), and R ¹¹ and R ¹² may be bonded to form a ring.

In each formula, the "pyridine-based substituent" is any one of the following formulae (Py-1) to (Py-15) (in the formulae, * indicates a bonding position), and each pyridine-based substituent may be independently substituted with an alkyl having 1 to 4 carbon atoms. In addition, the pyridine-based substituent may be bonded to the φ, anthracene ring, or fluorene ring in each formula via a phenylene group or naphthylene group.

The pyridine-based substituent is any one of the formulae (Py-1) to (Py-15), and among these, any one of the following formulae (Py-21) to (Py-44) (in the formulae, * represents a bonding position) is preferable.

At least one hydrogen in each pyridine derivative may be replaced with deuterium, and one of the two "pyridine-based substituents" in formula (ETM-2-1) and formula (ETM-2-2) may be replaced with an aryl.

The "alkyl" in R ¹¹ to R ¹⁸ may be either linear or branched, and examples thereof include linear alkyl having 1 to 24 carbon atoms or branched alkyl having 3 to 24 carbon atoms. A preferred "alkyl" is an alkyl having 1 to 18 carbon atoms (branched alkyl having 3 to 18 carbon atoms). A more preferred "alkyl" is an alkyl having 1 to 12 carbon atoms (branched alkyl having 3 to 12 carbon atoms). An even more preferred "alkyl" is an alkyl having 1 to 6 carbon atoms (branched alkyl having 3 to 6 carbon atoms). An especially preferred "alkyl" is an alkyl having 1 to 4 carbon atoms (branched alkyl having 3 to 4 carbon atoms).

Specific examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2 -Ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-eicosyl, etc.

The above description of alkyl can be used for the alkyl having 1 to 4 carbon atoms that substitutes the pyridine-based substituent.

The "cycloalkyl" in R ¹¹ to R ¹⁸ includes, for example, cycloalkyl having 3 to 12 carbon atoms. A preferred "cycloalkyl" is cycloalkyl having 3 to 10 carbon atoms. A more preferred "cycloalkyl" is cycloalkyl having 3 to 8 carbon atoms. An even more preferred "cycloalkyl" is cycloalkyl having 3 to 6 carbon atoms.
Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, and dimethylcyclohexyl.

As the "aryl" in R ¹¹ to R ¹⁸ , the preferred aryl is an aryl having 6 to 30 carbon atoms, the more preferred aryl is an aryl having 6 to 18 carbon atoms, the further more preferred aryl is an aryl having 6 to 14 carbon atoms, and the most preferred aryl is an aryl having 6 to 12 carbon atoms.

Specific examples of "aryls having 6 to 30 carbon atoms" include monocyclic aryls such as phenyl, fused bicyclic aryls such as (1-, 2-)naphthyl, fused tricyclic aryls such as acenaphthylene-(1-, 3-, 4-, 5-)yl, fluorene-(1-, 2-, 3-, 4-, 9-)yl, phenalene-(1-, 2-)yl, and (1-, 2-, 3-, 4-, 9-)phenanthryl, fused tetracyclic aryls such as triphenylene-(1-, 2-)yl, pyrene-(1-, 2-, 4-)yl, and naphthacene-(1-, 2-, 5-)yl, and fused pentacyclic aryls such as perylene-(1-, 2-, 3-)yl and pentacene-(1-, 2-, 5-, 6-)yl.

Preferred "aryl having 6 to 30 carbon atoms" include phenyl, naphthyl, phenanthryl, chrysenyl, and triphenylenyl, more preferably phenyl, 1-naphthyl, 2-naphthyl, and phenanthryl, and particularly preferably phenyl, 1-naphthyl, and 2-naphthyl.

In formula (ETM-2-2), R ¹¹ and R ¹² may be bonded to form a ring, and as a result, cyclobutane, cyclopentane, cyclopentene, cyclopentadiene, cyclohexane, fluorene, indene, or the like may be spiro-bonded to the five-membered ring of the fluorene skeleton.

Specific examples of the pyridine derivative include the following:

This pyridine derivative can be produced using known raw materials and known synthesis methods.

<Fluoranthene Derivatives>
The fluoranthene derivative is, for example, a compound represented by the following formula (ETM-3), and is disclosed in detail in WO 2010/134352.

In formula (ETM-3), X ¹² to X ²¹ each represent hydrogen, halogen, linear, branched or cyclic alkyl, linear, branched or cyclic alkoxy, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, where the substituent in the case of substitution is aryl, heteroaryl, alkyl, etc.

Specific examples of the fluoranthene derivative include the following:

<BO derivatives>
The BO derivative is, for example, a polycyclic aromatic compound represented by the following formula (ETM-4) or a polymer of a polycyclic aromatic compound having a plurality of structures represented by the following formula (ETM-4).

R ¹ to R ¹¹ are each independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), in which at least one hydrogen may be substituted with an aryl, heteroaryl, or alkyl.

Adjacent groups among R ¹ to R ¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the ring a, ring b, or ring c, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, or alkyl.

In addition, at least one hydrogen atom in the compound or structure represented by formula (ETM-4) may be replaced with a halogen or deuterium.

For an explanation of the substituents and ring formation form in formula (ETM-4), as well as the multimer formed by combining multiple structures of formula (ETM-4), the explanations of the polycyclic aromatic compounds and their multimers represented by formula (1) and formula (2) may be cited.

Specific examples of the BO derivative include the following:

This BO derivative can be produced using known raw materials and known synthesis methods.

<Anthracene derivatives>
One example of the anthracene derivative is a compound represented by the following formula (ETM-5-1).

Each Ar is independently a divalent benzene or naphthalene, and each of R ¹ to R ⁴ is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

Each Ar can be independently selected from divalent benzene or naphthalene, and the two Ars may be different or the same, but are preferably the same from the viewpoint of ease of synthesis of the anthracene derivative. Ar bonds with pyridine to form a "moiety consisting of Ar and pyridine", and this moiety is bonded to anthracene as a group represented by any one of the following formulas (Py-1) to (Py-12).

Among these groups, a group represented by any one of formulas (Py-1) to (Py-9) is preferred, and a group represented by any one of formulas (Py-1) to (Py-6) is more preferred. The two "moieties consisting of Ar and pyridine" bonded to anthracene may have the same or different structures, but from the viewpoint of ease of synthesis of anthracene derivatives, it is preferable that they have the same structure. However, from the viewpoint of element characteristics, it is preferable that the structures of the two "moieties consisting of Ar and pyridine" be the same or different.

The alkyl having 1 to 6 carbon atoms in R ¹ to R ⁴ may be either a straight chain or a branched chain. That is, it is a straight chain alkyl having 1 to 6 carbon atoms or a branched chain alkyl having 3 to 6 carbon atoms. It is more preferably an alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms). Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, and 2-ethylbutyl, and methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, or t-butyl is preferred, and methyl, ethyl, or t-butyl is more preferred.

Specific examples of the cycloalkyl having 3 to 6 carbon atoms for R ¹ to R ⁴ include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, and dimethylcyclohexyl.

The aryl having 6 to 20 carbon atoms for R ¹ to R ⁴ is preferably an aryl having 6 to 16 carbon atoms, more preferably an aryl having 6 to 12 carbon atoms, and particularly preferably an aryl having 6 to 10 carbon atoms.

Specific examples of "aryl having 6 to 20 carbon atoms" include monocyclic aryls such as phenyl, (o-, m-, p-) tolyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-) xylyl, mesityl (2,4,6-trimethylphenyl), (o-, m-, p-) cumenyl, bicyclic aryls such as (2-, 3-, 4-) biphenylyl, condensed bicyclic aryls such as (1-, 2-) naphthyl, tricyclic aryls such as terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3 ... terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl), fused tricyclic aryls anthracene-(1-,2-,9-)yl, acenaphthylene-(1-,3-,4-,5-)yl, fluorene-(1-,2-,3-,4-,9-)yl, phenalene-(1-,2-)yl, (1-,2-,3-,4-,9-)phenanthryl, fused tetracyclic aryls triphenylene-(1-,2-)yl, pyrene-(1-,2-,4-)yl, tetracene-(1-,2-,5-)yl, fused pentacyclic aryls perylene-(1-,2-,3-)yl, etc.

Preferred "aryl having 6 to 20 carbon atoms" is phenyl, biphenylyl, terphenylyl, or naphthyl, more preferably phenyl, biphenylyl, 1-naphthyl, 2-naphthyl, or m-terphenyl-5'-yl, even more preferably phenyl, biphenylyl, 1-naphthyl, or 2-naphthyl, and most preferably phenyl.

One example of the anthracene derivative is a compound represented by the following formula (ETM-5-2).

Each Ar ¹ is independently a single bond, or a divalent benzene, naphthalene, anthracene, fluorene, or phenalene.

Each Ar ² is independently an aryl having 6 to 20 carbon atoms, and the same explanation as for "aryl having 6 to 20 carbon atoms" in formula (ETM-5-1) can be cited. An aryl having 6 to 16 carbon atoms is preferable, an aryl having 6 to 12 carbon atoms is more preferable, and an aryl having 6 to 10 carbon atoms is particularly preferable. Specific examples include phenyl, biphenylyl, naphthyl, terphenylyl, anthracenyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthryl, triphenylenyl, pyrenyl, tetracenyl, perylenyl, etc.

R ¹ to R ⁴ each independently represent hydrogen, alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 20 carbon atoms, and the same explanation as in formula (ETM-5-1) can be cited.

Specific examples of these anthracene derivatives include the following:

These anthracene derivatives can be produced using known raw materials and known synthesis methods.

<Benzofluorene derivatives>
The benzofluorene derivative is, for example, a compound represented by the following formula (ETM-6).

Each Ar ¹ is independently an aryl having 6 to 20 carbon atoms, and the same explanation as for "aryl having 6 to 20 carbon atoms" in formula (ETM-5-1) can be cited. An aryl having 6 to 16 carbon atoms is preferable, an aryl having 6 to 12 carbon atoms is more preferable, and an aryl having 6 to 10 carbon atoms is particularly preferable. Specific examples include phenyl, biphenylyl, naphthyl, terphenylyl, anthracenyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthryl, triphenylenyl, pyrenyl, tetracenyl, perylenyl, etc.

Each Ar ² is independently hydrogen, an alkyl (preferably an alkyl having 1 to 24 carbon atoms), a cycloalkyl (preferably a cycloalkyl having 3 to 12 carbon atoms) or an aryl (preferably an aryl having 6 to 30 carbon atoms), and two Ar ² may be bonded to form a ring.

The "alkyl" in ^Ar2 may be either linear or branched, and examples thereof include linear alkyl having 1 to 24 carbon atoms or branched alkyl having 3 to 24 carbon atoms. A preferred "alkyl" is an alkyl having 1 to 18 carbon atoms (branched alkyl having 3 to 18 carbon atoms). A more preferred "alkyl" is an alkyl having 1 to 12 carbon atoms (branched alkyl having 3 to 12 carbon atoms). An even more preferred "alkyl" is an alkyl having 1 to 6 carbon atoms (branched alkyl having 3 to 6 carbon atoms). An especially preferred "alkyl" is an alkyl having 1 to 4 carbon atoms (branched alkyl having 3 to 4 carbon atoms). Specific examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, and the like.

The "cycloalkyl" in ^Ar2 includes, for example, cycloalkyl having 3 to 12 carbon atoms. A preferred "cycloalkyl" is cycloalkyl having 3 to 10 carbon atoms. A more preferred "cycloalkyl" is cycloalkyl having 3 to 8 carbon atoms. An even more preferred "cycloalkyl" is cycloalkyl having 3 to 6 carbon atoms. Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, and dimethylcyclohexyl.

As the "aryl" in ^Ar2 , a preferable aryl is an aryl having 6 to 30 carbon atoms, a more preferable aryl is an aryl having 6 to 18 carbon atoms, an even more preferable aryl is an aryl having 6 to 14 carbon atoms, and an especially preferable aryl is an aryl having 6 to 12 carbon atoms.

Specific examples of "aryl having 6 to 30 carbon atoms" include phenyl, naphthyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthryl, triphenylenyl, pyrenyl, naphthacenyl, perylenyl, pentacenyl, etc.

Two ^Ar2 may be bonded to form a ring, and as a result, cyclobutane, cyclopentane, cyclopentene, cyclopentadiene, cyclohexane, fluorene, indene, or the like may be spiro-bonded to the five-membered ring of the fluorene skeleton.

Specific examples of the benzofluorene derivative include the following:

This benzofluorene derivative can be produced using known raw materials and known synthesis methods.

<Phosphine oxide derivatives>
The phosphine oxide derivative is, for example, a compound represented by the following formula (ETM-7-1). Details are also described in WO 2013/079217 and WO 2013/079678.

^R5 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 5 to 20 carbon atoms;
R ⁶ is CN, a substituted or unsubstituted alkyl having 1 to 20 carbon atoms, a heteroalkyl having 1 to 20 carbon atoms, an aryl having 6 to 20 carbon atoms, a heteroaryl having 5 to 20 carbon atoms, an alkoxy having 1 to 20 carbon atoms, or an aryloxy having 6 to 20 carbon atoms;
R ⁷ and R ⁸ are each independently a substituted or unsubstituted aryl having 6 to 20 carbon atoms or a heteroaryl having 5 to 20 carbon atoms;
^R9 is oxygen or sulfur;
j is 0 or 1, k is 0 or 1, r is an integer of 0 to 4, and q is an integer of 1 to 3.
When substituted, the substituent may be an aryl, heteroaryl, or alkyl.

The phosphine oxide derivative may be, for example, a compound represented by the following formula (ETM-7-2).

R ¹ to R ³ may be the same or different and are selected from hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, alkoxy, alkylthio, aryl ether, aryl thioether, aryl, heterocyclic group, halogen, cyano, aldehyde, carbonyl, carboxyl, amino, nitro, silyl, and a fused ring formed between adjacent substituents.

Ar ¹ may be the same or different and is arylene or heteroarylene. Ar ² may be the same or different and is aryl or heteroaryl. However, at least one of Ar ¹ and Ar ² has a substituent or forms a condensed ring with the adjacent substituent. n is an integer of 0 to 3, when n is 0, there is no unsaturated structural portion, and when n is 3, R ¹ does not exist.

Among these substituents, alkyl refers to saturated aliphatic hydrocarbon groups such as methyl, ethyl, propyl, and butyl, which may be unsubstituted or substituted. If substituted, there is no particular limit to the substituent, and examples include alkyl, aryl, and heterocyclic groups, which is also the case in the following descriptions. In addition, the number of carbon atoms in the alkyl is not particularly limited, but is usually in the range of 1 to 20 from the standpoint of ease of availability and cost.

Cycloalkyl refers to a saturated alicyclic hydrocarbon group, such as cyclopropyl, cyclohexyl, norbornyl, or adamantyl, which may be unsubstituted or substituted. The number of carbon atoms in the alkyl portion is not particularly limited, but is usually in the range of 3 to 20.

Also, aralkyl refers to an aromatic hydrocarbon group via an aliphatic hydrocarbon such as benzyl or phenylethyl, and both the aliphatic and aromatic hydrocarbons may be unsubstituted or substituted. The number of carbon atoms in the aliphatic portion is not particularly limited, but is usually in the range of 1 to 20.

Alkenyl refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as vinyl, allyl, or butadienyl, which may be unsubstituted or substituted. The number of carbon atoms in an alkenyl is not particularly limited, but is usually in the range of 2 to 20.

Cycloalkenyl refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as cyclopentenyl, cyclopentadienyl, or cyclohexene, which may be unsubstituted or substituted.

Alkynyl refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as acetylenyl, which may be unsubstituted or substituted. The number of carbon atoms in alkynyl is not particularly limited, but is usually in the range of 2 to 20.

Alkoxy refers to an aliphatic hydrocarbon group, such as methoxy, that is bonded via an ether bond, and the aliphatic hydrocarbon group may be unsubstituted or substituted. The number of carbon atoms in the alkoxy is not particularly limited, but is usually in the range of 1 to 20.

Alkylthio is an alkoxy group in which the oxygen atom in the ether bond has been replaced with a sulfur atom.

The aryl ether group refers to an aromatic hydrocarbon group, such as phenoxy, that is bonded via an ether bond, and the aromatic hydrocarbon group may be unsubstituted or substituted. The number of carbon atoms in the aryl ether group is not particularly limited, but is usually in the range of 6 to 40.

An aryl thioether group is an aryl ether group in which the oxygen atom of the ether bond is replaced with a sulfur atom.

Also, aryl refers to an aromatic hydrocarbon group such as phenyl, naphthyl, biphenylyl, phenanthryl, terphenyl, or pyrenyl. Aryl may be unsubstituted or substituted. The number of carbon atoms in aryl is not particularly limited, but is usually in the range of 6 to 40.

Heterocyclic groups refer to cyclic structural groups having atoms other than carbon, such as furanyl, thienyl, oxazolyl, pyridyl, quinolinyl, and carbazolyl, which may be unsubstituted or substituted. The number of carbon atoms in the heterocyclic group is not particularly limited, but is usually in the range of 2 to 30.

Halogen refers to fluorine, chlorine, bromine, and iodine.

Aldehydes, carbonyls, and aminos can also include those substituted with aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, heterocycles, etc.

In addition, the aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and heterocycles may be unsubstituted or substituted.

Silyl refers to a silicon compound group such as trimethylsilyl, which may be unsubstituted or substituted. The number of carbon atoms in silyl is not particularly limited, but is usually in the range of 3 to 20. The number of silicon atoms is usually 1 to 6.

The fused ring formed between adjacent substituents is, for example, a conjugated or non-conjugated fused ring formed between Ar ¹ and R ² , Ar ¹ and R ³ , Ar ² and R ² , Ar ² and R ³ , R ² and R ³ , Ar ¹ and Ar ² , etc. Here, when n is 1, two R ^1s may form a conjugated or non-conjugated fused ring. These fused rings may contain a nitrogen, oxygen, or sulfur atom in the ring structure, or may be fused with another ring.

Specific examples of the phosphine oxide derivative include the following:

This phosphine oxide derivative can be produced using known raw materials and known synthesis methods.

<Pyrimidine derivatives>
The pyrimidine derivative is, for example, a compound represented by the following formula (ETM-8), preferably a compound represented by the following formula (ETM-8-1). Details are also described in WO 2011/021689.

Each Ar is independently an optionally substituted aryl or an optionally substituted heteroaryl. n is an integer from 1 to 4, preferably an integer from 1 to 3, and more preferably 2 or 3.

The "aryl" in "optionally substituted aryl" includes, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 24 carbon atoms, more preferably aryl having 6 to 20 carbon atoms, and even more preferably aryl having 6 to 12 carbon atoms.

Specific examples of "aryl" include monocyclic aryl phenyl, bicyclic aryl (2-, 3-, 4-) biphenylyl, condensed bicyclic aryl (1-, 2-) naphthyl, tricyclic aryl terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl), condensed tricyclic aryl Examples of the aryl include acenaphthylene-(1-,3-,4-,5-)yl, fluorene-(1-,2-,3-,4-,9-)yl, phenalene-(1-,2-)yl, (1-,2-,3-,4-,9-)phenanthryl, tetracyclic aryl quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenylyl), condensed tetracyclic aryl triphenylene-(1-,2-)yl, pyrene-(1-,2-,4-)yl, naphthacene-(1-,2-,5-)yl, condensed pentacyclic aryl perylene-(1-,2-,3-)yl, pentacene-(1-,2-,5-,6-)yl, etc.

The "heteroaryl" in "optionally substituted heteroaryl" includes, for example, heteroaryl having 2 to 30 carbon atoms, preferably heteroaryl having 2 to 25 carbon atoms, more preferably heteroaryl having 2 to 20 carbon atoms, still more preferably heteroaryl having 2 to 15 carbon atoms, and particularly preferably heteroaryl having 2 to 10 carbon atoms. In addition, examples of heteroaryl include heterocycles containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

Specific examples of heteroaryl include furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, isobenzofuranyl, benzo[b]thienyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenoxathiinyl, thianthrenyl, and indolizinyl.

The above aryl and heteroaryl may be substituted, for example, by the above aryl or heteroaryl, respectively.

Specific examples of the pyrimidine derivative include the following:

This pyrimidine derivative can be produced using known raw materials and known synthesis methods.

<Aryl nitrile derivatives>
The arylnitrile derivative is, for example, a compound represented by the following formula (ETM-9), or a multimer in which a plurality of such compounds are bonded together via single bonds, etc. Details are described in the specification of U.S. Patent Application Publication No. 2014/0197386.

From the viewpoint of fast electron transportability, Ar _ni preferably has a large number of carbon atoms, and from the viewpoint of high T1, Ar _{ni preferably has a small number of carbon atoms. Specifically, Ar ni} preferably has a high T1 when used in a layer adjacent to the light-emitting layer, and is an aryl having 6 to 20 carbon atoms, preferably an aryl having 6 to 14 carbon atoms, and more preferably an aryl having 6 to 10 carbon atoms. Furthermore, the number of substitutions n of the nitrile is preferably large from the viewpoint of high T1, and is preferably small from the viewpoint of high S1. Specifically, the number of substitutions n of the nitrile is an integer of 1 to 4, preferably an integer of 1 to 3, more preferably an integer of 1 to 2, and even more preferably 1.

Each Ar is independently an aryl which may be substituted, or a heteroaryl which may be substituted. From the viewpoint of high S1 and high T1, it is preferable that the heteroaryl has donor properties, and since it is used as an electron transport layer, it is preferable that there are few heteroaryl donors. From the viewpoint of charge transport, it is preferable that the aryl or heteroaryl has a large number of carbon atoms, and it is preferable that it has many substituents. Specifically, the number of substitutions m of Ar is an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 1 to 2.

The "aryl" in "optionally substituted aryl" includes, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 24 carbon atoms, more preferably aryl having 6 to 20 carbon atoms, and even more preferably aryl having 6 to 12 carbon atoms.

Specific examples of "aryl" include monocyclic aryl phenyl, bicyclic aryl (2-, 3-, 4-) biphenylyl, condensed bicyclic aryl (1-, 2-) naphthyl, tricyclic aryl terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl), condensed tricyclic aryl Examples of aryl include acenaphthylene-(1-,3-,4-,5-)yl, fluorene-(1-,2-,3-,4-,9-)yl, phenalene-(1-,2-)yl, (1-,2-,3-,4-,9-)phenanthryl, tetracyclic aryl quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenylyl), condensed tetracyclic aryl triphenylene-(1-,2-)yl, pyrene-(1-,2-,4-)yl, naphthacene-(1-,2-,5-)yl, condensed pentacyclic aryl perylene-(1-,2-,3-)yl, pentacene-(1-,2-,5-,6-)yl, etc.

The "heteroaryl" in "optionally substituted heteroaryl" includes, for example, heteroaryl having 2 to 30 carbon atoms, preferably heteroaryl having 2 to 25 carbon atoms, more preferably heteroaryl having 2 to 20 carbon atoms, even more preferably heteroaryl having 2 to 15 carbon atoms, and particularly preferably heteroaryl having 2 to 10 carbon atoms. In addition, examples of heteroaryl include heterocycles containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

Specific examples of heteroaryl include furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, isobenzofuranyl, benzo[b]thienyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenoxathiinyl, thianthrenyl, and indolizinyl.

The above aryl and heteroaryl may be substituted, for example, by the above aryl or heteroaryl, respectively.

The arylnitrile derivative may be a polymer in which a plurality of compounds represented by formula (ETM-9) are bonded together by single bonds or the like. In this case, in addition to single bonds, the compounds may be bonded together by aryl rings (preferably polyvalent benzene rings, naphthalene rings, anthracene rings, fluorene rings, benzofluorene rings, phenalene rings, phenanthrene rings, or triphenylene rings).

Specific examples of the arylnitrile derivative include the following compounds:

This arylnitrile derivative can be produced using known raw materials and known synthesis methods.

<Triazine derivatives>
The triazine derivative is, for example, a compound represented by the following formula (ETM-10), preferably a compound represented by the following formula (ETM-10-1), the details of which are described in U.S. Patent Publication No. 2011/0156013.

Each Ar is independently an optionally substituted aryl or an optionally substituted heteroaryl. n is an integer from 1 to 3, preferably 2 or 3.

The "aryl" in "optionally substituted aryl" includes, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 24 carbon atoms, more preferably aryl having 6 to 20 carbon atoms, and even more preferably aryl having 6 to 12 carbon atoms.

Specific examples of "aryl" include monocyclic aryl phenyl, bicyclic aryl (2-, 3-, 4-) biphenylyl, condensed bicyclic aryl (1-, 2-) naphthyl, tricyclic aryl terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl), condensed tricyclic aryl Examples of the aryl include acenaphthylene-(1-,3-,4-,5-)yl, fluorene-(1-,2-,3-,4-,9-)yl, phenalene-(1-,2-)yl, (1-,2-,3-,4-,9-)phenanthryl, tetracyclic aryl quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenylyl), condensed tetracyclic aryl triphenylene-(1-,2-)yl, pyrene-(1-,2-,4-)yl, naphthacene-(1-,2-,5-)yl, condensed pentacyclic aryl perylene-(1-,2-,3-)yl, pentacene-(1-,2-,5-,6-)yl, etc.

The "heteroaryl" in "optionally substituted heteroaryl" includes, for example, heteroaryl having 2 to 30 carbon atoms, preferably heteroaryl having 2 to 25 carbon atoms, more preferably heteroaryl having 2 to 20 carbon atoms, still more preferably heteroaryl having 2 to 15 carbon atoms, and particularly preferably heteroaryl having 2 to 10 carbon atoms. In addition, examples of heteroaryl include heterocycles containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

Specific examples of heteroaryl include furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, isobenzofuranyl, benzo[b]thienyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenoxathiinyl, thianthrenyl, and indolizinyl.

The above aryl and heteroaryl may be substituted, for example, by the above aryl or heteroaryl, respectively.

Specific examples of triazine derivatives include the following:

This triazine derivative can be produced using known raw materials and known synthesis methods.

<Benzimidazole Derivatives>
The benzimidazole derivative is, for example, a compound represented by the following formula (ETM-11).

φ is an n-valent aryl ring (preferably an n-valent benzene ring, naphthalene ring, anthracene ring, fluorene ring, benzofluorene ring, phenalene ring, phenanthrene ring, or triphenylene ring), n is an integer from 1 to 4, and the "benzoimidazole-based substituent" is a "pyridine-based substituent" in formulas (ETM-2), (ETM-2-1), and (ETM-2-2) in which the pyridyl group is replaced with benzoimidazolyl, and at least one hydrogen in the benzimidazole derivative may be replaced with deuterium.

R ¹¹ in the benzimidazolyl is hydrogen, alkyl having 1 to 24 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, or aryl having 6 to 30 carbon atoms, and the explanation of R ¹¹ in formulae (ETM-2-1) and (ETM-2-2) can be cited.

It is further preferred that φ is an anthracene ring or a fluorene ring, and in this case, the structure of formula (ETM-2-1) or formula (ETM-2-2) can be cited, and R ¹¹ to R ¹⁸ in each formula can be cited from those described in formula (ETM-2-1) or formula (ETM-2-2). In addition, in formula (ETM-2-1) or formula (ETM-2-2), two pyridine-based substituents are described in a form in which they are bonded, but when these are replaced with benzimidazole-based substituents, both pyridine-based substituents may be replaced with benzimidazole-based substituents (i.e., n=2), or any one of the pyridine-based substituents may be replaced with a benzimidazole-based substituent and the other pyridine-based substituent may be replaced with R ¹¹ to R ¹⁸ (i.e., n=1). Furthermore, for example, at least one of R ¹¹ to R ¹⁸ in formula (ETM-2-1) may be replaced with a benzimidazole-based substituent, and the “pyridine-based substituent” may be replaced with R ¹¹ to R ¹⁸ .

Specific examples of benzimidazole derivatives include 1-phenyl-2-(4-(10-phenylanthracen-9-yl)phenyl)-1H-benzo[d]imidazole, 2-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole, 2-(3-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole, 5-(10-(naphthalen-2-yl)anthracen-9-yl)-1,2-diphenyl-1H-benzo[d]imidazole, 1 -(4-(10-(naphthalene-2-yl)anthracen-9-yl)phenyl)-2-phenyl-1H-benzo[d]imidazole, 2-(4-(9,10-di(naphthalene-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole, 1-(4-(9,10-di(naphthalene-2-yl)anthracen-2-yl)phenyl)-2-phenyl-1H-benzo[d]imidazole, 5-(9,10-di(naphthalene-2-yl)anthracen-2-yl)-1,2-diphenyl-1H-benzo[d]imidazole, etc.

Benzimidazole derivatives can be produced using known raw materials and known synthesis methods.

<Phenanthroline derivatives>
The phenanthroline derivative is, for example, a compound represented by the following formula (ETM-12) or formula (ETM-12-1), the details of which are described in WO 2006/021982.

φ is an n-valent aryl ring (preferably an n-valent benzene ring, naphthalene ring, anthracene ring, fluorene ring, benzofluorene ring, phenalene ring, phenanthrene ring, or triphenylene ring), and n is an integer from 1 to 4.

R ¹¹ to R ¹⁸ in each formula are each independently hydrogen, alkyl (preferably alkyl having 1 to 24 carbon atoms), cycloalkyl (preferably cycloalkyl having 3 to 12 carbon atoms) or aryl (preferably aryl having 6 to 30 carbon atoms). In addition, in formula (ETM-12-1), any of R ¹¹ to R ¹⁸ is bonded to φ which is an aryl ring.

At least one hydrogen in each phenanthroline derivative may be replaced with deuterium.

The alkyl, cycloalkyl and aryl in R ¹¹ to R ¹⁸ can be explained with reference to the explanation of R ¹¹ to R ¹⁸ in formula (ETM-2). In addition to the above, φ can be, for example, the following structural formula: In the structural formula, each R is independently hydrogen, methyl, ethyl, isopropyl, cyclohexyl, phenyl, 1-naphthyl, 2-naphthyl, biphenylyl or terphenylyl, and * indicates a bonding position.

Specific examples of this phenanthroline derivative include 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 9,10-di(1,10-phenanthroline-2-yl)anthracene, 2,6-di(1,10-phenanthroline-5-yl)pyridine, 1,3,5-tri(1,10-phenanthroline-5-yl)benzene, 9,9'-difluoro-bi(1,10-phenanthroline-5-yl), bathocuproine, and 1,3-bis(2-phenyl-1,10-phenanthroline-9-yl)benzene.

This phenanthroline derivative can be produced using known raw materials and known synthesis methods.

<Quinolinol metal complexes>
The quinolinol metal complex is, for example, a compound represented by the following formula (ETM-13).

In the formula, R ¹ to R ⁶ are each independently hydrogen, fluorine, alkyl, aralkyl, alkenyl, cyano, alkoxy or aryl; M is Li, Al, Ga, Be or Zn; and n is an integer of 1 to 3.

Specific examples of quinolinol-based metal complexes include 8-quinolinol lithium, tris(8-quinolinolato)aluminum, tris(4-methyl-8-quinolinolato)aluminum, tris(5-methyl-8-quinolinolato)aluminum, tris(3,4-dimethyl-8-quinolinolato)aluminum, tris(4,5-dimethyl-8-quinolinolato)aluminum, tris(4,6-dimethyl-8-quinolinolato)aluminum, and bis( 2-methyl-8-quinolinolate)(phenolate)aluminum, bis(2-methyl-8-quinolinolate)(2-methylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(3-methylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(4-methylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2-phenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(phenolate)aluminum linolinate)(3-phenylphenolate)aluminum, bis(2-methyl-8-quinolinate)(4-phenylphenolate)aluminum, bis(2-methyl-8-quinolinate)(2,3-dimethylphenolate)aluminum, bis(2-methyl-8-quinolinate)(2,6-dimethylphenolate)aluminum, bis(2-methyl-8-quinolinate)(3,4-dimethylphenolate)aluminum, bis(2-methyl bis(2-methyl-8-quinolinolate)(3,5-dimethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(3,5-di-t-butylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,6-diphenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,4,6-triphenylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(2,4,6-trimethylphenolate)aluminum bis(2-methyl-8-quinolinolate)(2,4,5,6-tetramethylphenolate)aluminum, bis(2-methyl-8-quinolinolate)(1-naphtholate)aluminum, bis(2-methyl-8-quinolinolate)(2-naphtholate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(2-phenylphenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(3-phenylphenolate)aluminum phenylphenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(4-phenylphenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(3,5-dimethylphenolate)aluminum, bis(2,4-dimethyl-8-quinolinolate)(3,5-di-t-butylphenolate)aluminum, bis(2-methyl-8-quinolinolate)aluminum-μ-oxo-bis(2-methyl-8-quinolinolate) ) aluminum, bis(2,4-dimethyl-8-quinolinolato)aluminum-μ-oxo-bis(2,4-dimethyl-8-quinolinolato)aluminum, bis(2-methyl-4-ethyl-8-quinolinolato)aluminum-μ-oxo-bis(2-methyl-4-ethyl-8-quinolinolato)aluminum, bis(2-methyl-4-methoxy-8-quinolinolato)aluminum-μ-oxo-bis(2-methyl-4-methoxy-8-quinolinolato)aluminum linolinate) aluminum, bis(2-methyl-5-cyano-8-quinolinate) aluminum-μ-oxo-bis(2-methyl-5-cyano-8-quinolinate) aluminum, bis(2-methyl-5-trifluoromethyl-8-quinolinate) aluminum-μ-oxo-bis(2-methyl-5-trifluoromethyl-8-quinolinate) aluminum, bis(10-hydroxybenzo[h]quinoline) beryllium, etc.

This quinolinol metal complex can be produced using known raw materials and known synthesis methods.

<Reducing Substance>
At least one of the electron transport layer and the electron injection layer may contain a substance capable of reducing the material forming the electron transport layer or the electron injection layer. As the reducing substance, various substances may be used as long as they have a certain degree of reducing ability, and for example, at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, oxides of alkali metals, halides of alkali metals, oxides of alkaline earth metals, halides of alkaline earth metals, oxides of rare earth metals, halides of rare earth metals, organic complexes of alkali metals, organic complexes of alkaline earth metals, and organic complexes of rare earth metals may be preferably used.

Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (2.28 eV), Rb (2.16 eV), or Cs (1.95 eV), and alkaline earth metals such as Ca (2.9 eV), Sr (2.0-2.5 eV), or Ba (2.52 eV), with those with a work function of 2.9 eV or less being particularly preferred. Of these, more preferred reducing substances are the alkali metals K, Rb, or Cs, more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and by adding a relatively small amount to the material forming the electron transport layer or electron injection layer, the luminance of the organic EL element can be improved and the lifespan can be extended. In addition, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more of these alkali metals is also preferred, and in particular, a combination containing Cs, such as a combination of Cs and Na, Cs and K, Cs and Rb, or Cs, Na and K, is preferred. By containing Cs, the reducing ability can be efficiently exerted, and by adding it to the material forming the electron transport layer or electron injection layer, the luminance of the organic EL element can be improved and the life can be extended.

3. Cathode in Organic Electroluminescent Device The cathode 108 plays a role in injecting electrons into the light-emitting layer 105 via the electron injection layer 107 and the electron transport layer 106 .

The material for forming the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but the same material as the material for forming the anode 102 can be used. Among them, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium, and magnesium, or alloys thereof (magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy such as lithium fluoride/aluminum, etc.), etc. are preferred. In order to increase the electron injection efficiency and improve the device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low work function metals are effective. However, these low work function metals are generally unstable in air. To improve this point, for example, a method is known in which a trace amount of lithium, cesium, or magnesium is doped into the organic layer to use a highly stable electrode. Other dopants that can be used include inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide, and cesium oxide. However, they are not limited to these.

Furthermore, preferred examples include laminating metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, as well as inorganic materials such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, and hydrocarbon polymer compounds, in order to protect the electrodes. There are no particular limitations on the method of producing these electrodes, and they can be produced by resistance heating, electron beam deposition, sputtering, ion plating, coating, or the like, as long as electrical conductivity can be obtained.

4. Hole injection layer and hole transport layer in organic electroluminescence device The hole injection layer 103 plays a role of efficiently injecting holes moving from the anode 102 into the light emitting layer 105 or the hole transport layer 104. The hole transport layer 104 plays a role of efficiently transporting holes injected from the anode 102 or holes injected from the anode 102 through the hole injection layer 103 to the light emitting layer 105. The hole injection layer 103 and the hole transport layer 104 are each formed by laminating and mixing one or more types of hole injection/transport materials, or by a mixture of a hole injection/transport material and a polymer binder. Alternatively, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injection/transport material.

The hole injection/transport material must be able to efficiently inject and transport holes from the positive electrode between electrodes to which an electric field is applied, and it is desirable for the hole injection efficiency to be high and for the injected holes to be efficiently transported. For this purpose, it is preferable for the material to have a small ionization potential, a large hole mobility, and excellent stability, and to be unlikely to generate impurities that act as traps during manufacture and use.

As the materials for forming the hole injection layer 103 and the hole transport layer 104, any one can be selected from compounds conventionally used as charge transport materials for holes in photoconductive materials, p-type semiconductors, and known materials used in hole injection layers and hole transport layers of organic electroluminescent devices. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (polymers having an aromatic tertiary amino in the main chain or side chain, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine, N ⁴ ,N ^{4 '} -diphenyl-N ⁴ ,N ^{4 '} -Bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N ⁴ ,N ⁴ ,N ⁴ ',N ^{4 '} -tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine, triphenylamine derivatives such as 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives ( For example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile, heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. As for polymers, polycarbonates and styrene derivatives having the above-mentioned monomers in their side chains, polyvinylcarbazole, polysilanes, etc. are preferred, but there are no particular limitations on the type of compound as long as it is a compound that can form a thin film required for fabricating a light-emitting device, can inject holes from the anode, and can transport holes.

It is also known that the electrical conductivity of organic semiconductors is strongly influenced by their doping. Such organic semiconductor matrix substances consist of compounds with good electron donating or accepting properties. For doping with electron donating substances, strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known (see, for example, the literature "M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998)" and the literature "J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)"). These generate so-called holes by an electron transfer process in an electron-donating base material (hole-transporting material). The conductivity of the base material varies considerably depending on the number and mobility of the holes. Matrix materials with hole-transporting properties are known, for example, as benzidine derivatives (such as TPD) or starburst amine derivatives (such as TDATA), or as certain metal phthalocyanines (especially zinc phthalocyanine ZnPc) (JP 2005-167175 A).

5. Anode in Organic Electroluminescent Device The anode 102 plays a role in injecting holes into the light-emitting layer 105. When the hole injection layer 103 and/or the hole transport layer 104 are provided between the anode 102 and the light-emitting layer 105, holes are injected into the light-emitting layer 105 via these layers.

Materials for forming the anode 102 include inorganic and organic compounds. Examples of inorganic compounds include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO), etc.), metal halides (copper iodide, etc.), copper sulfide, carbon black, ITO glass, and Nesa glass. Examples of organic compounds include polythiophenes such as poly(3-methylthiophene), polypyrrole, polyaniline, and other conductive polymers. In addition, materials that are used as anodes in organic electroluminescent elements can be appropriately selected and used.

The resistance of the transparent electrode is not limited as long as it can supply sufficient current to light the light-emitting element, but a low resistance is desirable from the viewpoint of the power consumption of the light-emitting element. For example, an ITO substrate of 300 Ω/□ or less will function as an element electrode, but since it is now possible to supply substrates of around 10 Ω/□, it is particularly desirable to use a low resistance product of, for example, 100 to 5 Ω/□, preferably 50 to 5 Ω/□. The thickness of the ITO can be selected arbitrarily according to the resistance value, but it is usually used in the range of 50 to 300 nm.

6. Substrate in organic electroluminescent element The substrate 101 is a support for the organic electroluminescent element 100, and is usually made of quartz, glass, metal, plastic, etc. The substrate 101 is formed into a plate, film, or sheet shape depending on the purpose, and for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, etc. are used. Among them, a glass plate and a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, polysulfone, etc. are preferable. For a glass substrate, soda lime glass or alkali-free glass is used, and the thickness is sufficient to maintain mechanical strength, so that it is sufficient to be, for example, 0.2 mm or more. The upper limit of the thickness is, for example, 2 mm or less, preferably 1 mm or less. As for the material of the glass, it is better to have fewer ions eluted from the glass, so alkali-free glass is preferable, but soda lime glass with a barrier coat such as SiO ₂ is also commercially available, and this can be used. In addition, in order to improve the gas barrier properties, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one side, and it is preferable to provide a gas barrier film, especially when a synthetic resin plate, film or sheet with poor gas barrier properties is used as the substrate 101.

7. Electron Blocking Layer in Organic Electroluminescent Device An electron blocking layer for preventing diffusion of electrons and/or excitons from the light-emitting layer may be provided between the hole injection/transport layer and the light-emitting layer. The electron blocking layer may be formed using a compound represented by any one of the above formulas (H1), (H2) and (H3).

8. Method for Producing Organic Electroluminescent Device Each layer constituting an organic electroluminescent device can be formed by forming the material to be each layer into a thin film by a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, spin coating or casting, coating, etc. The thickness of each layer thus formed is not particularly limited and can be set appropriately according to the properties of the material, but is usually in the range of 2 nm to 5000 nm. The thickness can usually be measured with a quartz crystal oscillation type film thickness measuring device, etc. When forming a thin film using a vapor deposition method, the vapor deposition conditions vary depending on the type of material, the intended crystal structure and association structure of the film, etc. The vapor deposition conditions are generally preferably set appropriately in the range of a heating temperature of the vapor deposition crucible of +50 to +400°C, a vacuum degree of 10 ^-6 to 10 ^-3 Pa, a vapor deposition rate of 0.01 to 50 nm/sec, a substrate temperature of -150 to +300°C, and a film thickness of 2 nm to 5 μm.

Next, as an example of a method for producing an organic electroluminescent device, we will explain a method for producing an organic electroluminescent device consisting of an anode/hole injection layer/hole transport layer/light-emitting layer containing a host compound, a thermally activated delayed phosphor, and a compound having a boron atom/electron transport layer/electron injection layer/cathode.

8-1. Vapor Deposition Method After forming a thin film of an anode material on a suitable substrate by vapor deposition or the like to prepare an anode, a thin film of a hole injection layer and a hole transport layer is formed on the anode. A host compound, a thermally activated delayed phosphor, and a compound having a boron atom are co-deposited on the anode to form a thin film as a light-emitting layer, an electron transport layer and an electron injection layer are formed on the light-emitting layer, and a thin film of a cathode material is further formed by vapor deposition or the like to prepare a cathode, thereby obtaining a desired organic electroluminescence element. In the preparation of the above-mentioned organic electroluminescence element, the preparation order can be reversed to prepare the cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, and anode in that order.

8-2. Wet Film Formation Method In the case of the composition for forming a light emitting layer, a film is formed by using a wet film formation method.

In the wet film formation method, a coating film is generally formed through a coating process of coating a substrate with a composition for forming a light-emitting layer and a drying process of removing the solvent from the coated composition for forming a light-emitting layer. Depending on the difference in the coating process, a method using a spin coater is called a spin coat method, a method using a slit coater is called a slit coat method, a method using a plate is called a gravure, offset, reverse offset, or flexographic printing method, a method using an inkjet printer is called an inkjet method, and a method spraying in a mist form is called a spray method. The drying process includes air drying, heating, and drying under reduced pressure. The drying process may be performed only once, or may be performed multiple times using different methods or conditions. In addition, different methods may be used in combination, such as baking under reduced pressure.
That is, the organic electroluminescent device of the present invention is also preferably an organic electroluminescent device having a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes and formed from the composition for forming a light-emitting layer of the present invention.

A wet film formation method is a film formation method that uses a solution, and examples of this include some printing methods (inkjet methods), spin coating methods or casting methods, and coating methods. Unlike vacuum deposition methods, wet film formation methods do not require expensive vacuum deposition equipment, and can form films under atmospheric pressure. In addition, wet film formation methods allow for large area production and continuous production, which leads to reduced manufacturing costs.

On the other hand, compared to the vacuum deposition method, wet deposition methods are difficult to layer. When using wet deposition methods to create layered films, it is necessary to prevent the lower layer from being dissolved by the composition of the upper layer, and therefore compositions with controlled solubility, crosslinking of the lower layer, and orthogonal solvents (solvents that are not mutually soluble) are used. However, even with these techniques, it can be difficult to use wet deposition methods to apply all films.

Therefore, a common method for producing organic EL elements is to use wet deposition methods for only a few layers and vacuum deposition for the rest.

For example, the procedure for producing an organic EL element by partially applying a wet film formation method will be described below.
(Step 1) Formation of an anode by a vacuum deposition method (Step 2) Formation of a hole injection layer by a wet deposition method (Step 3) Formation of a hole transport layer by a wet deposition method (Step 4) Formation of an emission layer-forming composition containing a host compound, a thermally activated delayed phosphor, and a compound having a boron atom by a wet deposition method (Step 5) Formation of an electron transport layer by a vacuum deposition method (Step 6) Formation of an electron injection layer by a vacuum deposition method (Step 7) Formation of a cathode by a vacuum deposition method By going through these steps, an organic EL element consisting of an anode/hole injection layer/hole transport layer/emission layer consisting of a host material and a dopant material/electron transport layer/electron injection layer/cathode is obtained.

8-3. Organic Solvent The compound of the present invention can be dissolved in a solvent and used as a composition for forming a light-emitting layer.
The composition for forming a light-emitting layer of the present invention contains at least one compound of the present invention and a solvent.
In addition, it is preferable that the composition for forming a light-emitting layer of the present invention contains at least one compound represented by formulas (H1) to (H5), or contains at least one polymer compound having a repeating unit derived from at least one of the structures represented by formulas (H1) to (H5).
The composition for forming a light-emitting layer of the present invention may further contain other components such as an emitting dopant, an assistant dopant, etc., which are used as additional components of the light-emitting layer.
For example, the composition for forming a light-emitting layer of the present invention preferably contains at least one compound represented by any one of the above formulas (AD1), (AD2) and (AD3).
The composition for forming a light-emitting layer of the present invention preferably contains at least one organic solvent as the solvent. By controlling the evaporation rate of the organic solvent during film formation, it is possible to control and improve the film-forming properties, the presence or absence of defects in the coating film, the surface roughness, and the smoothness. In addition, during film formation using the inkjet method, it is possible to control the meniscus stability at the pinhole of the inkjet head, and control and improve the ejection properties. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, it is possible to improve the electrical properties, light-emitting properties, efficiency, and life of an organic EL element having a light-emitting layer obtained from the composition for forming a light-emitting layer.

8-3-1. Physical properties of organic solvent The composition for forming a light-emitting layer of the present invention preferably contains an organic solvent having a boiling point of 130° C. or higher, more preferably contains an organic solvent having a boiling point of 140° C. or higher, and even more preferably contains an organic solvent having a boiling point of 150° C. or higher as the solvent. The upper limit of the boiling point of the organic solvent is preferably 300° C. or lower, more preferably 270° C. or lower, and even more preferably 250° C. or lower. If the boiling point is higher than 130° C., it is preferable from the viewpoint of inkjet dischargeability. If the boiling point is lower than 300° C., it is preferable from the viewpoint of defects, surface roughness, residual solvent, and smoothness of the coating film. From the viewpoint of good inkjet dischargeability, film-forming property, smoothness, and low residual solvent, it is more preferable that the solvent contains two or more organic solvents. On the other hand, in some cases, the composition may be in a solid state by removing the solvent from the composition for forming a light-emitting layer, taking into consideration transportability and the like.

In addition, the solvent is a mixed solvent containing a good solvent (GS) and a poor solvent (PS) for at least one of the compound of the present invention or the polymer compound of the present invention, and it is preferable that the boiling point (BP _GS ) of the good solvent (GS) is lower than the boiling point (BP _PS ) of the poor solvent (PS).
By adding a poor solvent with a high boiling point, the good solvent with a low boiling point volatilizes first during film formation, increasing the concentration of the components in the composition and the concentration of the poor solvent, promoting rapid film formation. This results in a coating film with few defects, small surface roughness, and high smoothness.
The difference (S GS -S PS ) between the solubility (S _GS , %) of the compound of the present invention or at least one of the polymer compounds of the present invention in a good solvent (GS) and the solubility (S _PS , _{%) of the compound of the present invention or at least one of the polymer compounds of the present invention in a poor solvent (PS )} is preferably 1% or more, more preferably 3% or more, and even more preferably 5% or more.
The difference (BP _PS -BP _GS ) between the boiling point (BP _GS ) of the good solvent (GS) and the boiling point (BP _PS ) of the poor solvent (PS) is preferably 10°C or more, more preferably 30°C or more, and even more preferably 50°C or more.

Furthermore, the solvent includes a good solvent (GS) and a poor solvent (PS) for the compound represented by formula (1), formula (H1), formula (H2), formula (H3) or formula (H4), and a combination in which the boiling point (BP GS ) of the good solvent (GS) is lower than the boiling point (BP _PS ) of the poor solvent ( _PS ) is particularly preferred.
By adding a poor solvent with a high boiling point, the good solvent with a low boiling point volatilizes first during film formation, increasing the concentration of the components in the composition and the concentration of the poor solvent, promoting rapid film formation. This results in a coating film with few defects, small surface roughness, and high smoothness.

The difference (S _{GS -S PS} ) between the solubility (S GS ) of the compound represented by formula (1), (H1), (H2), (H3), (H4) or (H5) in the good solvent (GS) and the solubility (S _PS ) of the compound represented by formula (1), (H1), (H2), (H3), (H4) or (H5) in the poor _solvent ( _PS ) is preferably 1% or more, more preferably 3% or more, and even more preferably 5% or more. The difference in boiling point (BP _PS -BP _GS ) is preferably 10°C or more, more preferably 30°C or more, and even more preferably 50°C or more.

After the film is formed, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, or heating. When heating is performed, from the viewpoint of improving the coating film-forming properties, it is preferable to perform the heating at a temperature of the glass transition temperature (Tg) of the first component +30°C or lower. From the viewpoint of reducing residual solvent, it is preferable to heat at a temperature of the glass transition point (Tg) of the first component -30°C or higher. Even if the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is sufficiently removed because the film is thin. Also, drying may be performed multiple times at different temperatures, and multiple drying methods may be used in combination.

8-3-2. Specific examples of organic solvents Examples of organic solvents used in the composition for forming a light-emitting layer include alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, monocyclic ketone solvents, solvents having a diester skeleton, and fluorine-containing solvents. Specific examples include pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, hexane-2-ol, heptan-2-ol, octan-2-ol, decan-2-ol, dodecan-2-ol, cyclohexanol, α-terpineol, β-terpineol, γ-terpineol, δ-terpineol, terpineol (mixture), ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol ethyl ... ether, diethylene glycol isopropyl methyl ether, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, ethylene glycol monophenyl ether, triethylene glycol monomethyl ether, diethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, polyethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, p-xylene, m-xylene, o-xylene, 2,6-lutidine, 2-fluoro-m-xylene, 3-fluoro-o-xylene, 2-chlorobenzotrifluoride, cumene, toluene, 2-chloro-6-fluorotoluene, 2-fluoroanisole, anisole, 2,3-Dimethylpyrazine, Bromobenzene, 4-Fluoroanisole, 3-Fluoroanisole, 3-Trifluoromethylanisole, Mesitylene, 1,2,4-Trimethylbenzene, t-Butylbenzene, 2-Methylanisole, Phenetole, Benzodioxole, 4-Methylanisole, s-Butylbenzene, 3-Methylanisole, 4-Fluoro-3-methylanisole, Cymene, 1,2,3-Trimethylbenzene, 1,2-Dichlorobenzene, 2-Fluorobenzonitrile, 4-Fluoroveratrol, 2,6-Dimethylanisole, n-Butylbenzene, 3-Fluorobenzonitrile, Decalin (Decahydronaphthalene), Neopentylbenzene, 2,5-Dimethylanisole, 2,4-Dimethylanisole, Benzonitrile, 3,5-Dimethylanisole, Diphenyl ether, 1-Fluoro-3,5-dimethoxybenzene, Methyl benzoate, Isopentylbenzene, 3,4-Dimethylanisole , o-tolunitrile, n-amylbenzene, veratrole, 1,2,3,4-tetrahydronaphthalene, ethyl benzoate, n-hexylbenzene, propyl benzoate, cyclohexylbenzene, 1-methylnaphthalene, butyl benzoate, 2-methylbiphenyl, 3-phenoxytoluene, 2,2'-bitolyl, dodecylbenzene, dipentylbenzene, tetramethylbenzene, trimethoxybenzene, trimethoxytoluene, 2,3-dihydrobenzofuran, 1-methyl-4-(propoxymethyl)benzene, 1-methyl-4-(butyloxymethyl)benzene, 1-methyl-4-(pentyloxymethyl)benzene, 1-methyl-4-(hexyloxymethyl)benzene, 1-methyl-4-(heptyloxymethyl)benzene, benzyl butyl ether, benzyl pentyl ether, benzyl hexyl ether, benzyl heptyl ether, benzyl octyl ether, etc., but are not limited thereto. In addition, the solvent may be used alone or may be mixed.

9. Application Examples of Organic Electroluminescent Devices The present invention can also be applied to a display device including an organic electroluminescent device or a lighting device including an organic electroluminescent device.
The display device of the present invention or the lighting device of the present invention comprises the organic electroluminescent element of the present invention.
A display device or lighting device including an organic electroluminescent element can be manufactured by a known method, for example by connecting the organic electroluminescent element according to this embodiment to a known driving device, and can be driven appropriately using a known driving method such as DC driving, pulse driving, or AC driving.

Display devices include, for example, panel displays such as color flat panel displays, and flexible displays such as flexible color organic electroluminescent (EL) displays (see, for example, JP-A-10-335066, JP-A-2003-321546, JP-A-2004-281086, etc.). Display methods include, for example, matrix and/or segment methods. Note that matrix display and segment display may coexist in the same panel.

In a matrix, the pixels for display are arranged two-dimensionally, such as in a grid or mosaic pattern, and a collection of pixels displays characters and images. The shape and size of the pixels are determined by the application. For example, square pixels with sides of 300 μm or less are usually used to display images and characters on computers, monitors, and televisions, and pixels with sides on the order of mm are used for large displays such as display panels. For monochrome display, pixels of the same color can be arranged, but for color display, red, green, and blue pixels are displayed side by side. In this case, there are typically delta types and stripe types. The driving method for this matrix can be either line sequential driving method or active matrix. Line sequential driving has the advantage of being simpler in structure, but when considering operating characteristics, active matrix may be superior, so it is necessary to use it according to the application.

In the segment method, a pattern is formed to display predetermined information, and a specific area is illuminated. Examples include the time and temperature displays on digital clocks and thermometers, the operating status displays on audio equipment and induction cookers, and panel displays on automobiles.

Examples of lighting devices include lighting devices for indoor lighting, backlights for liquid crystal display devices, etc. (see, for example, JP 2003-257621 A, JP 2003-277741 A, JP 2004-119211 A, etc.). Backlights are mainly used for the purpose of improving the visibility of non-self-luminous display devices, and are used in liquid crystal display devices, clocks, audio devices, automobile panels, display boards, signs, etc. In particular, for liquid crystal display devices, particularly backlights for personal computers, where thinning is an issue, it is difficult to make them thin because conventional methods are made up of fluorescent lamps and light guide plates, so the backlights using the light-emitting elements according to this embodiment are characterized by their thinness and light weight.

<<Other organic devices>>
The compound of the present invention can be used for producing the organic electroluminescent device described above, as well as an organic field effect transistor or an organic thin-film solar cell.

An organic field-effect transistor is a transistor that controls current by generating an electric field through voltage input, and has a gate electrode in addition to a source electrode and a drain electrode. When a voltage is applied to the gate electrode, an electric field is generated, and the flow of electrons (or holes) between the source electrode and drain electrode can be arbitrarily blocked to control the current. Field-effect transistors are easier to miniaturize than simple transistors (bipolar transistors), and are often used as elements in integrated circuits.

The structure of an organic field effect transistor may be such that a source electrode and a drain electrode are provided in contact with an organic semiconductor active layer formed using the polycyclic aromatic compound according to the present invention, and a gate electrode is provided sandwiching an insulating layer (dielectric layer) in contact with the organic semiconductor active layer. Examples of the element structure include the following structure.
(1) Substrate/gate electrode/insulator layer/source electrode/drain electrode/organic semiconductor active layer (2) Substrate/gate electrode/insulator layer/organic semiconductor active layer/source electrode/drain electrode (3) Substrate/organic semiconductor active layer/source electrode/drain electrode/insulator layer/gate electrode (4) Substrate/source electrode/drain electrode/organic semiconductor active layer/insulator layer/gate electrode An organic field effect transistor configured in this manner can be used as a pixel driving switching element for active matrix driving liquid crystal displays and organic electroluminescence displays.

An organic thin-film solar cell has a structure in which an anode such as ITO, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a cathode are laminated on a transparent substrate such as glass. The photoelectric conversion layer has a p-type semiconductor layer on the anode side and an n-type semiconductor layer on the cathode side. The polycyclic aromatic compound according to the present invention can be used as a material for a hole transport layer, a p-type semiconductor layer, an n-type semiconductor layer, and an electron transport layer depending on its physical properties. The polycyclic aromatic compound according to the present invention can function as a hole transport material or an electron transport material in an organic thin-film solar cell. In addition to the above, the organic thin-film solar cell may appropriately include a hole blocking layer, an electron blocking layer, an electron injection layer, a hole injection layer, a smoothing layer, and the like. For the organic thin-film solar cell, known materials used in organic thin-film solar cells can be appropriately selected and combined for use.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Below, synthesis examples of the compounds used in the examples are shown.

Synthesis Example 1: Synthesis of Compound (1-1)

A 1.6M t-butyllithium pentane solution (7.6ml) was added to a flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro-N ¹ -(naphthalene-1-yl)-N ³ ,N ³ -diphenylbenzene-1,3-diamine) (2.75g, 3.0mmol) and t-butylbenzene (400ml) under nitrogen atmosphere while cooling in an ice bath. After the dropwise addition, the temperature was raised to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13ml, 12mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath and N,N-diisopropylethylamine (7.70ml, 45mmol) was added. After stirring at room temperature until the heat generation subsided, the mixture was heated to 120° C. and stirred for 1.5 hours. The reaction solution was then distilled off under reduced pressure at 60° C. to obtain a crude product. The crude product obtained was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under reduced pressure of 1×10 ⁻⁴ mmHg to obtain 1.12 g of compound (1-1).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.84 (s, 1H), 6.11-6.16 (m, 4H), 6.75 (d, 2H), 6.83 (d, 2H), 7.22 (t, 2H), 7.32 -7.46 (m, 20H), 7.60 (d, 2H), 8.01 (d, 2H), 8.07 (d, 2H), 9.30 (d, 2H), 10.50 (s, 1H).

Synthesis Example 2: Synthesis of Compound (1-9)

A 1.6M t-butyllithium pentane solution (7.6ml) was added to a flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro- ^{N 1} -(1,2-dihydroacenaphthylene-5-yl)-N ³ ,N ³ -diphenylbenzene-1,3-diamine) (2.90g, 3.0mmol) and t-butylbenzene (400ml) under nitrogen atmosphere while cooling in an ice bath. After the dropwise addition, the temperature was raised to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13ml, 12mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath and N,N-diisopropylethylamine (7.70ml, 45mmol) was added. After stirring at room temperature until the heat generation subsided, the mixture was heated to 120° C. and stirred for 1.5 hours. The reaction solution was then distilled off under reduced pressure at 60° C. to obtain a crude product. The crude product obtained was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under reduced pressure of 1×10 ⁻⁴ mmHg to obtain 1.23 g of compound (1-9).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ=3.51-3.52 (m, 8H), 5.84 (s, 1H), 6.12-6.16 (m, 4H), 6.56 (d, 2H), 6.81 (d, 2H), 7.25-7.48 (m, 24H), 9.31 (d, 2H), 10.51 (s, 1H).

Synthesis Example 3: Synthesis of compound (1-49)

A flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro-N ³ ,N ³ -diphenyl-N ¹ -(pyrimidin-5-yl)benzene-1,3-diamine) (2.46 g, 3.0 mmol) and t-butylbenzene (400 ml) was cooled in an ice bath under a nitrogen atmosphere, and 1.6 M t-butyllithium pentane solution (7.6 ml) was added. After the dropwise addition was completed, the temperature was raised to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13 ml, 12 mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath, and N,N-diisopropylethylamine (7.70 ml, 45 mmol) was added. After stirring at room temperature until the heat generation subsided, the mixture was heated to 120° C. and stirred for 1.5 hours. The reaction solution was then distilled off under reduced pressure at 60° C. to obtain a crude product. The crude product obtained was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under reduced pressure of 1×10 ⁻⁴ mmHg to obtain 0.34 g of compound (1-49).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.98 (s, 1H), 6.18 (d, 2H), 6.27 (d, 2H), 6.85 (d, 2H), 7.32-7.46 (m, 16H), 8.58 (s, 4H), 8.90 (s, 2H), 9.28 (d, 2H), 10.51 (s, 1H).

Synthesis Example 4: Synthesis of compound (1-79)

A flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro-N ¹ -(dibenzo[b,d]furan-2-yl)-N ³ ,N ³ ,N ⁵ ,N ⁵ -tetraphenylbenzene-1,3,5-triamine) (3.83 g, 3.0 mmol) and t-butylbenzene (400 ml) was charged with 1.6 M t-butyllithium pentane solution (7.6 ml) while cooling in an ice bath under a nitrogen atmosphere. After the dropwise addition, the mixture was heated to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13 ml, 12 mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath, and N,N-diisopropylethylamine (7.70 ml, 45 mmol) was added. After stirring at room temperature until the heat generation subsided, the mixture was heated to 120° C. and stirred for 1.5 hours. The reaction solution was then distilled off under reduced pressure at 60° C. to obtain a crude product. The crude product obtained was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under reduced pressure of 1×10 ⁻⁴ mmHg to obtain 0.66 g of compound (1-79).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.70 (s, 2H), 5.77 (s, 2H), 5.85 (s, 1H), 6.59 (d, 2H), 6.86-6.93 (m, 14H), 7.11 (dd, 8H) ), 7.29-7.45 (m, 20H), 7.55 (d, 2H), 7.84 (d, 2H), 7.95 (d, 2H), 9.31 (d, 2H), 10.51 (s, 1H).

Synthesis Example 5: Synthesis of compound (1-116)

To a flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro- ^{N 1} -(dibenzo[b,d]thiophen-1-yl)-5-(methyl-d)-N ³ -(3-(methyl-d)phenyl)-N ³ -phenylbenzene-1,3-diamine) (3.09 g, 3.0 mmol) and t-butylbenzene (400 ml), 1.6 M t-butyllithium pentane solution (7.6 ml) was added under a nitrogen atmosphere while cooling in an ice bath. After completion of the dropwise addition, the temperature was raised to 60°C and the mixture was stirred for 2 hours, after which components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C and boron tribromide (1.13 ml, 12 mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath, and N,N-diisopropylethylamine (7.70 ml, 45 mmol) was added. After stirring at room temperature until the heat generation subsided, the temperature was raised to 120° C. and the mixture was heated and stirred for 1.5 hours. Thereafter, the reaction solution was distilled off under reduced pressure at 60° C. to obtain a crude product. The obtained crude product was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice with o-dichlorobenzene, and then purified by sublimation at 440° C. under a reduced pressure of 1×10 ⁻⁴ mmHg to obtain 1.15 g of compound (1-116).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 2.11 (s, 6H), 2.13 (s, 6H), 5.86 (s, 1H), 6.03 (s, 2H), 6.06 (s, 2H), 6.78 (s, 2H), 7.05 (d, 2H) ), 7.30-7.40 (m, 12H), 7.47-7.54 (m, 8H), 7.92 (d, 2H), 8.45 (d, 2H), 9.29 (d, 2H), 10.52 (s, 1H).

Synthesis Example 6: Synthesis of compound (1-374)

A flask containing N ¹ ,N ¹ '-(1,3-phenylene)bis(2-chloro-N ³ ,N ³ -diphenyl-N ¹ -(pyrimidin-4-yl)benzene-1,3-diamine) (2.07 g, 3.0 mmol) and t-butylbenzene (400 ml) was cooled in an ice bath under a nitrogen atmosphere, and 1.6 M t-butyllithium pentane solution (7.6 ml) was added. After the dropwise addition, the mixture was heated to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13 ml, 12 mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. The mixture was then cooled again in an ice bath, and N,N-diisopropylethylamine (7.70 ml, 45 mmol) was added. After stirring at room temperature until the heat generation subsided, the mixture was heated to 120° C. and stirred for 1.5 hours. The reaction solution was then distilled off under reduced pressure at 60° C. to obtain a crude product. The crude product obtained was washed with acetonitrile, methanol, and toluene in that order, and purified by silica gel column chromatography (eluent: toluene), after which the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under reduced pressure of 1×10 ⁻⁴ mmHg to obtain 0.26 g of compound (1-374).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.97 (s, 1H), 6.11 (d, 1H), 6.32-6.33 (m, 2H), 6.42 (d, 2H), 6.51 (d, 1H), 6.83 (d, 1H), 7.03 (d, 1H), 7.25 (t, 1H), 7.32 (d, 2H), 7.39-7.53 (m, 8H), 8.34 (d, 2H), 8.40 (d, 2H), 9.31 (d, 1H), 9.46 (d, 1H), 10.62 (s, 1H).

Synthesis Example 7: Synthesis of compound (1-734)

A flask containing N,N'-((1,3-phenylenebis(oxy))bis(2-chloro-3,1-phenylene))bis(N-phenylpyrimidin-4-amine) (1.84 g, 3.0 mmol) and t-butylbenzene (400 ml) was cooled in an ice bath under a nitrogen atmosphere, and 1.6 M t-butyllithium pentane solution (7.6 ml) was added. After the dropwise addition was completed, the temperature was raised to 60°C and stirred for 2 hours, and then components with a boiling point lower than that of t-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -50°C, and boron tribromide (1.13 ml, 12 mmol) was added, and the mixture was heated to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled again in an ice bath, and N,N-diisopropylethylamine (7.70 ml, 45 mmol) was added. The mixture was stirred at room temperature until the heat generation subsided, and then heated to 120°C and stirred for 1.5 hours. Thereafter, the reaction solution was distilled off under reduced pressure at 60° C. to obtain a crude product. The obtained crude product was washed with acetonitrile, methanol, and toluene in this order, and purified by silica gel column chromatography (eluent: toluene), and then the crude product was recrystallized twice from o-dichlorobenzene, and then purified by sublimation at 440° C. under a reduced pressure of 1×10 ⁻⁴ mmHg to obtain 0.21 g of compound (1-734).

The structure of the compound obtained was confirmed by NMR spectroscopy.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 6.29 (s, 1H), 6.44-6.45 (m, 4H), 6.53 (d, 2H), 6.82 (d, 2H), 7.36-7.37 (m, 4H), 7.44 (t, 2H), 8.34 (s, 2H), 8.41 (d, 2H), 9.28 (d, 2H), 10.74 (s, 1H).

<Evaluation method of basic physical properties>
Preparation of Samples When evaluating the absorption and emission characteristics (fluorescence and phosphorescence) of a compound to be evaluated, the compound to be evaluated may be dissolved in a solvent and evaluated in the solvent, or in a thin film state. Furthermore, when evaluating in a thin film state, depending on the manner of use of the compound to be evaluated in an organic EL device, the compound to be evaluated may be evaluated as a thin film only, or as a thin film dispersed in an appropriate matrix material. Here, a thin film obtained by vapor-depositing only the compound to be evaluated is called a "single film," and a thin film obtained by applying a coating liquid containing the compound to be evaluated and a matrix material and drying it is called a "coating film."

Commercially available PMMA (polymethyl methacrylate) can be used as the matrix material. In this example, PMMA and the compound to be evaluated are dissolved in toluene, and then a thin film is formed on a transparent quartz support substrate (10 mm x 10 mm) by spin coating to prepare a sample.

Furthermore, a thin film sample in which the matrix material is a host compound is prepared as follows.
A transparent support substrate made of quartz (10 mm x 10 mm x 1.0 mm) was fixed to a substrate holder of a commercially available deposition apparatus (manufactured by Choshu Sangyo Co., Ltd.), a molybdenum deposition boat containing a host compound and a molybdenum deposition boat containing a dopant material were attached, and the vacuum chamber was then reduced in pressure to 5 x 10 ^-4 Pa. Next, the deposition boat containing the host compound and the deposition boat containing the dopant material were heated simultaneously, and the host compound and the dopant material were co-deposited to an appropriate film thickness to form a mixed thin film (sample) of the host compound and the dopant material. Here, the deposition rate was controlled according to the set mass ratio of the host compound and the dopant material.

The absorption spectrum of the sample for evaluation of absorption and emission characteristics is measured using an ultraviolet-visible-near infrared spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). The fluorescence spectrum or phosphorescence spectrum of the sample is measured using a spectrofluorophotometer (F-7000, manufactured by Hitachi High-Tech Corporation).

For measuring the fluorescence spectrum, the sample is excited with an appropriate excitation wavelength at room temperature and photoluminescence is measured. For measuring the phosphorescence spectrum, the sample is immersed in liquid nitrogen (temperature 77 K) using an attached cooling unit. To observe the phosphorescence spectrum, an optical chopper was used to adjust the delay time between irradiation with excitation light and the start of measurement. The sample is excited with an appropriate excitation wavelength and photoluminescence is measured.

The fluorescence quantum yield (PLQY) is also measured using an absolute PL quantum yield measurement device (Hamamatsu Photonics K.K., C9920-02G).

Evaluation of Fluorescence Lifetime (Delayed Fluorescence) The fluorescence lifetime was measured at 300K using a fluorescence lifetime measuring device (Hamamatsu Photonics Co., Ltd., C11367-01). Specifically, light-emitting components with fast and slow fluorescence lifetimes were observed at the maximum emission wavelength measured at an appropriate excitation wavelength. In the measurement of the fluorescence lifetime of a typical organic EL material that emits fluorescence at room temperature, slow emission components involving triplet components derived from phosphorescence are rarely observed due to the deactivation of triplet components by heat. If a slow emission component is observed in the compound to be evaluated, it indicates that triplet energy with a long excitation lifetime has been transferred to singlet energy by thermal activation and observed as delayed fluorescence.

Calculation of Energy Gap (Eg) The energy gap (Eg) is calculated from the long wavelength end A (nm) of the absorption spectrum obtained by the above-mentioned method as Eg = 1240/A.

Measurement of ionization potential (Ip) A transparent support substrate (28 mm x 26 mm x 0.7 mm) on which ITO (indium tin oxide) has been vapor-deposited is fixed to the substrate holder of a commercially available vapor deposition device (manufactured by Choshu Sangyo Co., Ltd.), a molybdenum vapor deposition boat containing the target compound is attached, and the vacuum chamber is then reduced in pressure to 5 x 10 ^-4 Pa. Next, the vapor deposition boat is heated to evaporate the target compound, forming a film of the target compound alone (neat film).

The obtained single film is used as a sample, and the ionization potential of the target compound is measured using a photoelectron spectrometer (Sumitomo Heavy Industries, Ltd. PYS-201).

Calculation of Electron Affinity (Ea) The electron affinity can be estimated from the difference between the ionization potential measured by the above-mentioned method and the energy gap calculated by the above-mentioned method.

Measurement of excited singlet energy level E(S,Sh) and excited triplet energy level E(T,Sh) For a single film of the target compound formed on a glass substrate, the fluorescence spectrum is observed at 77K using excitation light with a peak on the long wavelength side so that the fluorescence peaks of the absorption spectrum do not overlap, and the excited singlet energy level E(S,Sh) is obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum.
In addition, a phosphorescence spectrum of a single film of the target compound formed on a glass substrate is observed at 77 K using nm excitation light with a peak on the long wavelength side such that the fluorescence peak of the absorption spectrum does not overlap, and the excited triplet energy level E(T,Sh) is determined from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum.

<Evaluation of Organic EL Device>
As described above, the compound of the present invention is characterized by an appropriate energy gap (Eg), a high triplet excitation energy ( _ET ) and a small _ΔEST , and is therefore expected to be applicable to, for example, an emitting layer and a charge transport layer, and is particularly expected to be applicable to an emitting layer.

Evaluation items and evaluation method Evaluation items include driving voltage (V), emission wavelength (nm), CIE chromaticity (x, y), external quantum efficiency (%), maximum wavelength (nm) and half-width (nm) of emission spectrum, etc. For these evaluation items, values at appropriate emission luminance can be used.

The quantum efficiency of a light-emitting element can be classified into internal quantum efficiency and external quantum efficiency. The internal quantum efficiency indicates the proportion of external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting element that is converted purely into photons. On the other hand, the external quantum efficiency is calculated based on the amount of these photons that are emitted to the outside of the light-emitting element. Some of the photons generated in the light-emitting layer are absorbed or continue to be reflected inside the light-emitting element, and are not emitted to the outside of the light-emitting element, so the external quantum efficiency is lower than the internal quantum efficiency.

The method for measuring the spectral radiance (emission spectrum) and external quantum efficiency is as follows. The element was made to emit light by applying a voltage using an Advantest voltage/current generator R6144. The spectral radiance in the visible light region was measured from the direction perpendicular to the light-emitting surface using a TOPCON spectroradiometer SR-3AR. Assuming that the light-emitting surface is a perfect diffusion surface, the measured spectral radiance value of each wavelength component was divided by the wavelength energy and multiplied by π to obtain the number of photons at each wavelength. Next, the number of photons was integrated over the entire observed wavelength range to obtain the total number of photons emitted from the element. The value obtained by dividing the applied current value by the elementary charge was determined as the number of carriers injected into the element, and the value obtained by dividing the total number of photons emitted from the element by the number of carriers injected into the element was determined as the external quantum efficiency (EQE). The half-width (FWHM) of the emission spectrum was calculated as the width between the wavelengths above and below which the intensity was 50%, centered on the maximum emission wavelength (EL wavelength).

[1] Preparation and Evaluation of Organic EL Device In this example, an organic EL device was prepared according to the structure described in Adv. Mater. 2016, 28, 2777-2781. The layer structure of the prepared organic EL device, as well as the device characteristics at 100 cd/ ^m2 and LT90 (the time to reach 90 cd/ ^m2 when continuously driven at a current density with an initial luminance of 100 cd/ ^m2 ) are summarized in Table 1.

In Table 1, "NPD" is N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, "TcTa" is 4,4',4"-tris(N-carbazolyl)triphenylamine, "mCP" is 1,3-bis(N-carbazolyl)benzene, "mCBP" is 3,3'-bis(N-carbazolyl)-1,1'-biphenyl, "BPy-TP2" is 2,7-di([2,2'-bipyridine]-5-yl)triphenylene, "2CzBN" is 3,4-dicarbazolylbenzonitrile, and (DOBNA1) is 3,11-di-o-tolyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene.

Example 1: Element using compound (1-1) as a dopant Each thin film was laminated by vacuum deposition at a vacuum degree of 5×10 ⁻⁴ Pa on a glass substrate (26 mm×28 mm×0.7 mm) on which an anode made of ITO (indium tin oxide) with a thickness of 50 nm was formed.
First, NPD was evaporated on ITO to a thickness of 40 nm, and TcTa was evaporated on the NPD to a thickness of 15 nm to form a hole injection transport layer consisting of two layers. Subsequently, mCP was evaporated to a thickness of 15 nm to form an electron blocking layer. Next, compound DOBNA1 as a host and compound (1-1) as a dopant were co-evaporated from different evaporation sources to form a light-emitting layer having a thickness of 20 nm. At this time, the mass ratio of the host and the emitting dopant was set to 99:1. Next, 2CzBN was evaporated to a thickness of 10 nm to form a hole blocking layer. Subsequently, BPy-TP2 was evaporated to a thickness of 20 nm to form an electron transport layer. Subsequently, LiF was evaporated to a thickness of 1 nm, and aluminum was evaporated on the LiF to a thickness of 100 nm to form a cathode, and an organic EL device was obtained.

Examples 1 to 7 and Comparative Example 1
Compound (1-1) was changed to compound (1-9), compound (1-49), compound (1-79), compound (116), compound (1-374) and compound (1-734), respectively, to give Examples 2 to 7. Compound (1-1) was also changed to compound (ED28) to give Comparative Example 1. EL elements were obtained using the same procedures and configurations as in Example 1, except for changing the compound.

Comparing the evaluation results of Examples 1 to 7 and Comparative Example 1 in Table 1, it can be seen that the compounds of the present invention having specific substituents have a long lifetime even when differences in emission wavelengths are taken into account.

[2] Preparation of TAF element

In Table 2, "TSPO1" is diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide. The chemical structure is shown below.

Example 8
<Configuration A: Element in which the host compound is mCBP, the assisting dopant is 2PXZ-TAZ, and the emitting dopant is compound (1-1)>
A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) on which an ITO film having a thickness of 200 nm was formed by sputtering and polished to 50 nm was used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available deposition device (manufactured by Choshu Sangyo Co., Ltd.), and a tantalum deposition boat containing NPD, TcTa, mCP, mCBP, 2PXZ-TAZ, compound (1-1), and TSPO1, and an aluminum nitride deposition boat containing LiF and aluminum were attached.

The following layers are sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber is depressurized to 5×10 ⁻⁴ Pa, and NPD is heated and evaporated to a thickness of 40 nm, and then TcTa is heated and evaporated to a thickness of 15 nm to form a two-layer hole injection transport layer. Next, mCP is heated and evaporated to a thickness of 15 nm to form an electron blocking layer. Next, mCBP as a host, 2PXZ-TAZ as an assisting dopant, and compound (1-1) as an emitting dopant are simultaneously heated and co-evaporated to a thickness of 20 nm to form a light-emitting layer. The evaporation rate is adjusted so that the mass ratio of the host, assisting dopant, and emitting dopant is approximately 90:9:1. Next, TSPO1 is heated and evaporated to a thickness of 30 nm to form an electron transport layer. The evaporation rate of each of the above layers is 0.01 to 1 nm/sec. Thereafter, LiF is heated and evaporated at a deposition rate of 0.01 to 0.1 nm/sec to a thickness of 1 nm, and then aluminum is heated and evaporated to a thickness of 100 nm to form a cathode, thereby obtaining an organic EL element. At this time, the evaporation rate of aluminum is adjusted to 1 nm to 10 nm/sec.

<Example 9>
<Configuration A: Element in which the host compound is mCBP, the assisting dopant is compound (1-1), and the emitting dopant is compound (ED28)>
An EL element can be obtained using the same procedure and structure as in Example 5, except that the assisting dopant is changed to compound (1-1) and the emitting dopant is changed to compound (ED28).

Example 10
<Configuration A: Element in which the host compound is mCBP, the assisting dopant is compound (1-9), and the emitting dopant is compound (ED28)>
An EL element can be obtained using the same procedure and structure as in Example 5, except that the assisting dopant is changed to compound (1-9) and the emitting dopant is changed to compound (ED28).

Example 11
<Configuration A: Element in which the host compound is mCBP, the assisting dopant is compound (1-49), and the emitting dopant is compound (ED28)>
An EL element can be obtained using the same procedure and structure as in Example 5, except that the assisting dopant is changed to compound (1-49) and the emitting dopant is changed to compound (ED28).

REFERENCE SIGNS LIST 100 Organic electroluminescent element 101 Substrate 102 Anode 103 Hole injection layer 104 Hole transport layer 105 Light-emitting layer 106 Electron transport layer 107 Electron injection layer 108 Cathode

Claims (26)

A polycyclic aromatic compound represented by the following formula (1):
(In formula (1),
ring A, ring B, ring C and ring D are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen atom in these rings may be substituted;
Z ¹ and Z ² each independently represent -CH= or -N=, and hydrogen in -CH= may be substituted;
X ¹ to X ⁴ are each independently >O or >N—R ^1X , provided that they are not all >O, and R ^1X is aryl, heteroaryl, alkyl, or cycloalkyl;
At least one of R ^1X is any one of the structures shown below, in which any hydrogen atom may be independently substituted with an alkyl group having 1 to 8 carbon atoms, deuterium, or fluorine, and in the structures shown below, the wavy line indicates a bonding position.
At least one selected from the group consisting of aryl rings and heteroaryl rings in the compound represented by formula (1) may be condensed with at least one cycloalkane, at least one hydrogen in the cycloalkane may be substituted, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;
At least one hydrogen atom in the compound represented by formula (1) may be substituted with a halogen atom or a deuterium atom. The polycyclic aromatic compound according to claim 1, represented by the following formula (2):
(In formula (2), R ¹ to R ¹⁴ are each independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, or diarylboryl (two aryls may be bonded via a single bond or a linking group), in which at least one hydrogen may be substituted with an aryl, heteroaryl, or alkyl, and two adjacent groups among R ³ to R ¹⁴ may be bonded to each other to form a ring;
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that not all of them are >O, R ^1X is an aryl having 6 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, an alkyl having 1 to 20 carbon atoms, or a cycloalkyl having 3 to 8 carbon atoms, and at least one of R ^1X is any of the structures shown below, in which any hydrogen atom may be independently substituted with an alkyl having 1 to 8 carbon atoms, deuterium, or fluorine, and in which the wavy line indicates a bonding position,
At least one selected from the group consisting of aryl rings and heteroaryl rings in the compound represented by formula (2) may be condensed with at least one cycloalkane, at least one hydrogen in the cycloalkane may be substituted, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;
At least one hydrogen atom in the compound represented by formula (2) may be substituted with a halogen atom or a deuterium atom. R ¹ to R ¹⁴ are each independently a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 2 to 30 carbon atoms, a diarylamino group (wherein the aryl group has 6 to 12 carbon atoms), an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms, in which at least one hydrogen atom may be substituted by an aryl group having 6 to 12 carbon atoms or an alkyl group having 1 to 8 carbon atoms;
X ¹ to X ⁴ are each independently >O or >N-R ^1X , provided that not all of them are >O, R ^1X is an aryl having 6 to 12 carbon atoms or an alkyl having 1 to 8 carbon atoms, and at least one of R ^1X has any of the structures shown below, in which any hydrogen atom may be independently substituted with an alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and in which the wavy line indicates the bonding position,
At least one hydrogen atom in the compound represented by formula (2) may be substituted with a halogen atom or a deuterium atom.
The polycyclic aromatic compound according to claim 2. The polycyclic aromatic compound according to claim 2 or 3, wherein one or two of X ¹ to X ⁴ are >N-R ^1X , in which R ^1X has any of the structures shown below ;
In the above structures, any hydrogen may be independently substituted with alkyl having 1 to 8 carbon atoms, deuterium or fluorine, and in the structures below, the wavy lines indicate the bonding positions. X ¹ and X ² are both N-Ph, and X ³ and X ⁴ are each independently N-R ^1X ; or
^X1 and ^X2 are each independently N- ^R1X , and ^X3 and ^X4 are both N-Ph;
Ph is phenyl;
The polycyclic aromatic compound according to any one of claims 1 to 4 , wherein the structures and bonding positions of the multiple R ^1X's are the same as each other. The polycyclic aromatic compound according to any one of claims 1 to 5, wherein each of the halogens is fluorine. The polycyclic aromatic compound according to any one of claims 1 to 5 , wherein at least one hydrogen atom is substituted with chlorine, bromine, or iodine. 8. The polycyclic aromatic compound according to claim 1, wherein at least one hydrogen atom of the polycyclic aromatic compound is substituted with a substituent represented by formula (B).
(In formula (B), R ⁴⁰ and R ⁴¹ are each independently an alkyl group or are bonded to each other to form an alkylene group, the total number of carbon atoms in R ⁴⁰ and R ⁴¹ is 2 to 10, and the wavy line portion is a bonding site.) A polymer compound comprising a structure derived from the polycyclic aromatic compound according to any one of claims 1 to 8 as a repeating unit. The polymer compound according to claim 9, comprising, as a repeating unit, at least one structure derived from a compound selected from the group consisting of unsubstituted or optionally substituted triarylamine, unsubstituted or optionally substituted fluorene, unsubstituted or optionally substituted anthracene, unsubstituted or optionally substituted tetracene, unsubstituted or optionally substituted triazine, unsubstituted or optionally substituted carbazole, unsubstituted or optionally substituted tetraphenylsilane, unsubstituted or optionally substituted spirofluorene, unsubstituted or optionally substituted triphenylphosphine, unsubstituted or optionally substituted dibenzothiophene, and unsubstituted or optionally substituted dibenzofuran. A material for an organic device, comprising the polycyclic aromatic compound according to any one of claims 1 to 8 , or the polymer compound according to claim 9 or 10 . The material for an organic device according to claim 11 , which is a material for an organic electroluminescent element, a material for an organic field effect transistor, or a material for an organic thin-film solar cell. A material for a light-emitting layer of an organic electroluminescent device, comprising the polycyclic aromatic compound according to any one of claims 1 to 8 or the polymer compound according to claim 9 or 10 . 11. An organic electroluminescence element, an organic field effect transistor, or an organic thin-film solar cell, comprising the polycyclic aromatic compound according to any one of claims 1 to 8 , or the polymer compound according to claim 9 or 10 . 14. An organic electroluminescence device comprising a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes, the light-emitting layer comprising the material for a light-emitting layer according to claim 13 . The organic electroluminescent device according to claim 15, wherein the light-emitting layer contains at least one compound represented by the following formulas (H1) to (H5), or contains at least one polymer compound having a repeating unit derived from at least one of the following structures ( H1 ) to (H5).
In formula (H1), L ¹ is an arylene having 6 to 24 carbon atoms, Z is C—H, C—R′, or N,
In formula (H2), L ² and L ³ each independently represent an aryl having 6 to 30 carbon atoms or a heteroaryl having 2 to 30 carbon atoms;
At least one hydrogen atom in the compound represented by each of the above formulas may be substituted with an alkyl group having 1 to 6 carbon atoms, a cyano group, a halogen atom, or a deuterium atom;
In formula (H3), J is >O, >S, >N-R', >C(-R') ₂ or >Si(-R') ₂ ;
Y is a single bond, >O, >S, >C(-R') ₂ or >Si(-R') ₂ ;
Z is C-H, C-R' or N;
In formula (H4), Z is C—H, C—R′ or N;
R' in the C-R', >N-R', >C(-R') ₂ or >Si(-R') ₂ is aryl, heteroaryl, alkyl or cycloalkyl;
In formula (H5),
R ¹⁰¹ to R ¹¹¹ are each independently a hydrogen atom or an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl group, at least one hydrogen atom in these substituents may be further substituted with an aryl, heteroaryl, diarylamino or alkyl group;
Adjacent groups among R ¹⁰¹ to R ¹¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the benzene ring to which they are bonded, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino or an alkyl, and at least one hydrogen atom in these rings may be further substituted with an aryl, a heteroaryl, a diarylamino or an alkyl;
At least one hydrogen atom in the compound represented by formula (H5) may be independently replaced with a halogen atom or a deuterium atom. The organic electroluminescent device according to claim 15 or 16 , wherein the light-emitting layer contains at least one compound represented by any one of the following formulas (AD1), (AD2) and (AD3):
(In the formulae (AD1), (AD2) and (AD3),
Each M is independently at least one of a single bond, —O—, >N—Ar, and >_CAR;
J's are each independently an arylene having 6 to 18 carbon atoms, and the arylene is optionally substituted with phenyl, alkyl having 1 to 6 carbon atoms, and cycloalkyl having 3 to 12 carbon atoms;
Each Q is independently ═C(—H)— or ═N—;
Ar's each independently represent a hydrogen atom, an aryl having 6 to 18 carbon atoms, a heteroaryl having 6 to 18 carbon atoms, an alkyl having 1 to 6 carbon atoms, or a cycloalkyl having 3 to 12 carbon atoms, and at least one hydrogen atom in the aryl and heteroaryl may be substituted with a phenyl, an alkyl having 1 to 6 carbon atoms, or a cycloalkyl having 3 to 12 carbon atoms;
m is 1 or 2;
n is an integer from 2 to (6-m);
At least one hydrogen atom in the compounds represented by the above formulas may be substituted with a halogen or deuterium. A composition for forming a light-emitting layer, comprising at least one of the polycyclic aromatic compound according to any one of claims 1 to 8 or the polymer compound according to claim 9 or 10 , and a solvent. The composition for forming a light-emitting layer according to claim 18 , comprising, as the solvent, an organic solvent having a boiling point of 150° C. or higher. 20. The composition for forming an emission layer according to claim 18 or 19, wherein the solvent is a mixed solvent containing a good solvent and a poor solvent for at least one of the polycyclic aromatic compound or the polymer compound, and the boiling point of the good solvent is lower than the boiling point of the poor solvent. The composition for forming a light-emitting layer according to any one of claims 18 to 20, comprising at least one compound represented by formulas (H1) to (H5), or at least one polymer compound having a repeating unit derived from at least one of the structures represented by formulas (H1 ) to (H5).
In formula (H1), L ¹ is an arylene having 6 to 24 carbon atoms, Z is C—H, C—R′, or N,
In formula (H2), L ² and L ³ each independently represent an aryl having 6 to 30 carbon atoms or a heteroaryl having 2 to 30 carbon atoms;
At least one hydrogen atom in the compound represented by each of the above formulas may be substituted with an alkyl group having 1 to 6 carbon atoms, a cyano group, a halogen atom, or a deuterium atom;
In formula (H3), J is >O, >S, >N-R', >C(-R') ₂ or >Si(-R') ₂ ;
Y is a single bond, >O, >S, >C(-R') ₂ or >Si(-R') ₂ ;
Z is C-H, C-R' or N;
In formula (H4), Z is C—H, C—R′ or N;
R' in the C-R', >N-R', >C(-R') ₂ or >Si(-R') ₂ is aryl, heteroaryl, alkyl or cycloalkyl;
In formula (H5),
R ¹⁰¹ to R ¹¹¹ are each independently a hydrogen atom or an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or alkyl group, at least one hydrogen atom in these substituents may be further substituted with an aryl, heteroaryl, diarylamino or alkyl group;
adjacent groups among R ¹⁰¹ to R ¹¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the benzene ring to which they are bonded, and at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl, a diarylamino, a diheteroarylamino, an arylheteroarylamino or an alkyl, and at least one hydrogen atom in these rings may be further substituted with an aryl, a heteroaryl, a diarylamino or an alkyl;
At least one hydrogen atom in the compound represented by formula (H5) may be independently replaced with a halogen atom or a deuterium atom. An organic electroluminescent device comprising a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes, the light-emitting layer being formed from the composition for forming a light-emitting layer according to any one of claims 18 to 21 . The organic electroluminescence device according to any one of claims 15 to 17 and claim 22, further comprising at least one layer selected from the group consisting of an electron transport layer and an electron injection layer disposed between the cathode and the light emitting layer, and at least one of the electron transport layer and the electron injection layer contains at least one selected from the group consisting of a borane derivative, a pyridine derivative, a fluoranthene derivative, a BO-based derivative, an anthracene derivative, a benzofluorene derivative, a phosphine oxide derivative, a pyrimidine derivative, an arylnitrile derivative, a triazine derivative, a benzimidazole derivative, a phenanthroline derivative , and a quinolinol-based metal complex. 24. The organic electroluminescent device according to claim 23, wherein at least one of the electron transport layer and the electron injection layer further contains at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, oxides of alkali metals, halides of alkali metals, oxides of alkaline earth metals, halides of alkaline earth metals, oxides of rare earth metals, halides of rare earth metals, organic complexes of alkali metals, organic complexes of alkaline earth metals , and organic complexes of rare earth metals. A display device comprising the organic electroluminescent device according to any one of claims 15 to 17 and claims 22 to 24 . A lighting device comprising the organic electroluminescent device according to any one of claims 15 to 17 and claims 22 to 24 .