JP7728537B2 - Polycyclic aromatic compounds - Google Patents

Description

The present invention relates to polycyclic aromatic compounds. In particular, the present invention relates to polycyclic aromatic compounds containing nitrogen and boron. The present invention also relates to materials for organic devices, organic electroluminescent devices, and display and lighting devices, each containing the polycyclic aromatic compounds.

Display devices using electroluminescent light-emitting elements have traditionally been the subject of extensive research due to their potential for power saving and thinning. Furthermore, organic electroluminescent devices made from organic materials have been actively investigated due to their ease of being lightweight and large. In particular, there has been active research into the development of organic materials with luminescent properties, such as blue, one of the three primary colors of light, and organic materials with charge transport capabilities for holes, electrons, etc. (potential to become semiconductors or superconductors), regardless of whether they are polymeric or low-molecular-weight compounds.

Organic electroluminescent devices have a structure consisting of a pair of electrodes consisting of an anode and a cathode, and one or more layers containing organic compounds placed between the pair of electrodes. Layers containing organic compounds include light-emitting layers and charge transport/injection layers that transport or inject charges such as holes and electrons, and a variety of organic materials suitable for these layers have been developed.

Among these, Patent Document 1 discloses that boron-containing polycyclic aromatic compounds are useful as materials for organic electroluminescent devices, etc. Organic electroluminescent devices containing these polycyclic aromatic compounds have been reported to have good external quantum efficiency.

Chinese Patent Application Publication No. 106467554

As described above, various materials have been developed for use in organic EL elements. However, in order to increase the options for materials for organic EL elements, it is desirable to develop materials made of compounds that are different from conventional ones.
An object of the present invention is to provide a novel compound useful as a material for organic devices such as organic EL devices.

The present inventors conducted extensive research to solve the above-mentioned problems and succeeded in producing a novel polycyclic aromatic compound with superior light-emitting properties among polycyclic aromatic compounds having a structure similar to that of the compound described in Patent Document 1. They also discovered that an excellent organic EL device can be obtained by constructing an organic EL device by disposing a layer containing this polycyclic aromatic compound between a pair of electrodes, thereby completing the present invention. Specifically, the present invention provides the following polycyclic aromatic compounds, as well as materials for organic devices containing the following polycyclic aromatic compounds.

<1> A polycyclic aromatic compound represented by the following formula (1):

In formula (1),
ring A, ring B, and ring C are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen atom of the aryl ring or heteroaryl ring in ring A, ring B, and ring C is optionally substituted;
Ring D is an aryl ring, a heteroaryl ring, or a cycloalkane ring, and at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring in Ring D is optionally substituted;
any one of —CH ₂ — in the cycloalkane ring in ring D may be replaced by —S—, —O— or >Si(—CH ₃ ) ₂ ;
An aryl ring, a heteroaryl ring, or a cycloalkane ring in each of rings A, B, C, and D may be condensed with at least one cycloalkane, at least one hydrogen atom in the cycloalkane may be substituted, and at least one —CH ₂ — in the cycloalkane may be substituted with —O—;
^Y1 is B, P, P=O, P=S, Al, Ga, As, Si—R, Ge—R, or Sn—R, and R in Si—R, Ge—R, and Sn—R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted alkyl, or an optionally substituted cycloalkyl,
X ¹ is a single bond, >O, >S, >Se, >N—R, >Si(—R) ₂ , >C(—R) ₂ , or >C═O, R in said >N—R, >Si(—R) ₂ , and >C(—R) ₂ each independently represents hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, two R in each of >Si(—R) ₂ and >C(—R) ₂ may be bonded to each other to form a ring, and R in said >N—R, >Si(—R) ₂ , and >C(—R) ₂ may be bonded to ring B and/or ring D via a linking group or a single bond,
X ² is >Si(-R) ₂ , >C(-R) ₂ , or >C=O, R in said >Si(-R) ₂ and >C(-R) ₂ each independently represents hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, two R in each of >Si(-R) ₂ and >C(-R) ₂ may be bonded to each other to form a ring, and R in said >Si(-R) ₂ and >C(-R) ₂ may be bonded to ring A and/or ring C via a linking group or a single bond,
At least one hydrogen atom in the compound represented by formula (1) may be substituted with cyano, halogen, or deuterium.

<2> The polycyclic aromatic compound according to <1>, wherein Y ¹ is B.
<3> The polycyclic aromatic compound according to <1> or <2>, wherein X ¹ is >O, >S, >N—R, or >C(—R) ₂ .
<4> The polycyclic aromatic compound according to any one of <1> to <3>, wherein X ² is >C(—R) ₂ .
<5> The polycyclic aromatic compound according to <4>, wherein X ² is C(—R) ₂ and R are each independently alkyl.
<6> The polycyclic aromatic compound according to any one of <1> to <5>, wherein at least one hydrogen atom of an aryl ring, a heteroaryl ring, or a cycloalkane ring in at least one selected from the group consisting of ring A, ring B, ring C, and ring D is substituted.

<7> The polycyclic aromatic compound according to <6>, in which at least one hydrogen atom of an aryl ring, a heteroaryl ring, or a cycloalkane ring in at least one selected from the group consisting of ring A, ring B, ring C, and ring D is substituted with a substituent represented by the following formula (tR):
In formula (tR), R ^a , R ^b , and R ^c each independently represent alkyl having 1 to 24 carbon atoms, and any —CH ₂ — in the alkyl may be replaced with —O—, and the group represented by formula (tR) replaces at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring at *.

<8> Ring A and ring B are each independently an optionally substituted benzene ring, an optionally substituted pyridine ring, an optionally substituted pyrimidine ring, an optionally substituted pyridazine ring, or an optionally substituted triazine ring,
The polycyclic aromatic compound according to any one of <1> to <7>, wherein the ring D is an optionally substituted benzene ring, an optionally substituted pyridine ring, an optionally substituted pyrimidine ring, an optionally substituted pyridazine ring, an optionally substituted triazine ring, or an optionally substituted tetrazine ring.
<9> The polycyclic aromatic compound according to <8>, in which the ring A, the ring B, and the ring D are each independently an optionally substituted benzene ring.

<10> The polycyclic aromatic compound according to any one of <1> to <9>, wherein Ring C is an aryl ring or heteroaryl ring represented by one formula selected from the group consisting of the following formulas (c1) to (c18):

In formulas (c1) to (c18),
* and # represent the bonding positions with ^Y1 and ^X2 ,
Either * or # may be bonded to either ^Y1 or ^X2 ,
L is >O, >S, >Se, >N—R, >Si(—R) ₂ , or >C(—R) ₂ , and R in the >N—R, >Si(—R) ₂ , and >C(—R) ₂ are each independently hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, or L may have an additional bond to form the following partial structure (A40);

In formula (A40), Me is methyl, X ⁴¹ is a single bond, >O, >S, >N—R, >C(—R) ₂ or >C═O, and is bonded to the same monocycle at the two * positions and to another monocycle at the ** position, R in >N—R and >C(—R) ₂ as X ⁴¹ is hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, and the two R in >C(—R) ₂ as X ⁴¹ may be bonded to each other to form a ring,
Each ^Z2 is independently N or C- ^R2 , and ^{each R2} in the C- ^R2 is independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, dialkylamino, diarylboryl (two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, or substituted silyl, in which at least one hydrogen may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl, and
Two R ^{2 s} in two adjacent Z ^{2 s} may be bonded to form a group represented by formula (A10);

In formula (A10), ^L is >N-R, >O, >Si(-R) or >S, R of the >N-R is _an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted alkyl or an optionally substituted cycloalkyl, _R of the >Si(-R) is a hydrogen atom, an optionally substituted aryl, an optionally substituted alkyl or an optionally substituted cycloalkyl, and they may be bonded to each other via a linking group, and at least one of R of >N-R as L and ^R of > ^Si (-R) as _L may be bonded to ^R in C- ^R as ^Z via a linking group or a single bond,
r is an integer from 1 to 4,
Each ^R is independently hydrogen, optionally substituted alkyl, or optionally substituted cycloalkyl, and any ^R may be bonded to any other ^R via a linking group or a single bond;
The group represented by formula (A10) is bonded to two adjacent atoms on the aryl ring, heteroaryl ring, or cycloalkane ring at the two * marks.

<11> The polycyclic aromatic compound according to <10>, wherein the C ring is an aryl ring or heteroaryl ring represented by a formula selected from the group consisting of formula (c1), formula (c2), formula (c3), formula (c4), formula (c5), formula (c8), and formula (c9).

<12> The polycyclic aromatic compound according to <1>, represented by formula (1-c1-8):
In the formula, Me is methyl and tBu is t-butyl.

<13> The polycyclic aromatic compound according to <1>, represented by formula (1-c2f-64) or formula (1-c2f-65);
In the formula, Me is methyl and tBu is t-butyl.

<14> The polycyclic aromatic compound according to <1>, represented by formula (1-n-3):
In the formula, Me is methyl and tBu is t-butyl.

<15> A material for an organic device, comprising the polycyclic aromatic compound according to any one of <1> to <14>.
<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 polycyclic aromatic compound according to any one of <1> to <14>.
<17> The organic electroluminescent device according to <16>, wherein the light-emitting layer contains a host and the polycyclic aromatic compound as a dopant.
<18> The organic electroluminescent device according to <17>, wherein the host is an anthracene-based compound, a fluorene-based compound, or a dibenzochrysene-based compound.

<19> A light-emitting device comprising a pair of electrodes consisting of an anode and a cathode, a light-emitting layer disposed between the pair of electrodes, and an electron injection layer and/or an electron transport layer disposed between the cathode and the light-emitting layer,
<14> An organic electroluminescent device, wherein the electron injection layer and/or the electron transport layer contains the polycyclic aromatic compound according to any one of <1> to <14>.
<20> A light-emitting device comprising a pair of electrodes consisting of an anode and a cathode, a light-emitting layer disposed between the pair of electrodes, and a hole injection layer and/or a hole transport layer disposed between the anode and the light-emitting layer,
<15> An organic electroluminescent device, wherein the hole injection layer and/or the hole transport layer contains the polycyclic aromatic compound according to any one of <1> to <14>.
<21> A display device comprising the organic electroluminescent device according to any one of <16> to <20>.
<22> A lighting device comprising the organic electroluminescent element according to any one of <16> to <20>.

The present invention provides novel polycyclic aromatic compounds that are useful as materials for organic devices such as organic electroluminescent devices. The polycyclic aromatic compounds of the present invention can be used in the manufacture of organic devices such as organic electroluminescent devices.

1 is a schematic cross-sectional view showing an example of an organic electroluminescent device. FIG. 1 is an energy level diagram showing the energy relationship between the host, assisting dopant, and emitting dopant of a TAF element using a common fluorescent dopant. 1 is an energy level diagram showing an example of the energy relationship between a host, an assisting dopant, and an emitting dopant in an organic electroluminescent element according to one embodiment of the present invention.

The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. 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 addition, in this specification, "hydrogen" in the description of structural formulas means "hydrogen atom (H)."
In this specification, the organic electroluminescent element may be referred to as an organic EL element.

In this specification, chemical structures and substituents are sometimes represented by the number of carbon atoms. However, when a chemical structure is substituted with a substituent, or when a substituent is further substituted with a substituent, the number of carbon atoms refers to the number of carbon atoms in the chemical structure or the substituent, and does not refer to the total number of carbon atoms in the chemical structure and the substituent, or the total number of carbon atoms in the substituent and the substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent B of carbon number Y" is substituted with "substituent A of carbon number X," and carbon number Y is not the total number of carbon atoms in substituents A and B. For example, "substituent B of carbon number Y substituted with substituent A" means that "substituent B of carbon number Y" is substituted with "substituent A (with no carbon number restriction)," and carbon number Y is not the total number of carbon atoms in substituents A and B.

1. Polycyclic aromatic compound The polycyclic aromatic compound of the present invention is represented by the following formula (1): The polycyclic aromatic compound of the present invention has a high luminescence quantum yield (PLQY), and in particular, compared to conventionally known polycyclic aromatic compounds, the polycyclic aromatic compound has a narrow emission half-width and excellent color purity due to the presence of a bridge (X ¹ ) between the B ring and the D ring.

In formula (1),
ring A, ring B, and ring C are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen atom of the aryl ring or heteroaryl ring in ring A, ring B, and ring C is optionally substituted;
Ring D is an aryl ring, a heteroaryl ring, or a cycloalkane ring, and at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring in Ring D may be substituted.

Here, as shown in formula (1), ring A is a ring that is directly bonded to ^Y1 , ^X2 , and N (nitrogen) at ring member atoms (atoms forming a ring structure) as a trivalent group, ring B is a ring that is directly bonded to ^Y1 , ^X1 , and N (nitrogen) at ring member atoms as a trivalent group, ring C is a ring that is directly bonded to ^Y1 and ^X2 at ring member atoms as a divalent group, and ring D is a ring that is directly bonded to ^X1 and N (nitrogen) at ring member atoms as a divalent group. Therefore, "at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring has been substituted" means that the ring has at least one substituent at a position other than the position bonded to any of ^Y1 , ^X1 , ^X2 , and N (nitrogen). The ring member atoms that are directly bonded to ^Y1 , ^X1 , ^X2 , and N (nitrogen) may be carbon atoms.

Furthermore, the above-mentioned aryl ring, heteroaryl ring, and cycloalkane ring may each be fused with at least one cycloalkane.

The "aryl ring" in rings A, B, C, and D of formula (1) can be, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 16 carbon atoms, more preferably an aryl ring having 6 to 12 carbon atoms, and particularly preferably an aryl ring having 6 to 10 carbon atoms.

Specific examples of "aryl rings" include monocyclic benzene rings, fused bicyclic naphthalene rings and indene rings, fused tricyclic anthracene rings, acenaphthylene rings, fluorene rings, phenalene rings, and phenanthrene rings, fused tetracyclic tricyclic triphenylene rings, pyrene rings, naphthacene rings, benzofluorene rings, and chrysene rings, and fused pentacyclic perylene rings and pentacene rings. Fluorene and benzofluorene rings also include structures in which fluorene and benzofluorene rings are spiro-bonded, respectively. It is also preferred that two of the two hydrogen atoms in the methylene groups of the fluorene and benzofluorene rings be replaced by methyl groups as the first substituent, as described below, to form dimethylfluorene and dimethylbenzofluorene rings.

The "heteroaryl ring" in rings A, B, C, and D of formula (1) is, for example, a heteroaryl ring having 2 to 30 carbon atoms, preferably a heteroaryl ring having 2 to 25 carbon atoms, more preferably a heteroaryl ring having 2 to 20 carbon atoms, even more preferably a heteroaryl ring having 2 to 15 carbon atoms, and particularly preferably a heteroaryl ring having 2 to 10 carbon atoms. Furthermore, "heteroaryl rings" include, for example, heterocyclic rings containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

Specific examples of "heteroaryl rings" include pyrrole rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, imidazole rings, oxadiazole rings, thiadiazole rings, triazole rings, tetrazole rings, pyrazole rings, pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, triazine rings, tetrazine rings, indole rings, isoindole rings, 1H-indazole rings, benzimidazole rings, and benzo a quinoxazole 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 9,10-dihydroacridine ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, an indolizine ring, an imidazopyridine ring (imidazo[1,2-a]pyridine ring, etc. ), a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, a naphthobenzofuran ring, a benzofurofuran ring, a benzofurobenzofuran ring (such as a benzofuro[3,2-b]benzofuran ring), a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a naphthobenzothiophene ring, a thienobenzothiophene ring, a benzothienobenzothiophene ring (such as a [1]-benzothieno[3,2-b][1]benzothiophene ring), a thienopyridine ring (such as a thieno[1,2-a]pyridine ring), a thienopyrimidine ring (such as a thieno[3,2-d]pyrimidine ring), a thienobenzofuran ring (such as a thieno[3,2-b]benzofuran ring), a benzophosphole ring, a dibenzophosphole ring, a benzophosphole oxide ring, a dibenzophosphole oxide ring, a furazan ring, a thianthrene ring, a selenophene ring, a xanthene ring, a thioxanthene ring, and an indenothiophene ring. The xanthene ring and thioxanthene ring also include structures in which a fluorene ring or a benzofluorene ring is spiro-bonded, respectively. In the fluorene ring, benzofluorene ring, xanthene ring, thioxanthene ring, indenothiophene ring, and 9,10-dihydroacridine ring, two of the two hydrogen atoms in each methylene ring may be substituted with methyl as the first substituent, as described below. Examples include a dimethylfluorene ring, a dimethylbenzofluorene ring, a dimethylindenothiophene ring (dimethyl-4H-indeno[1,2-b]thiophene ring), and a 9,10-dihydro-9,9-dimethylacridine ring.

Specific examples of the "cycloalkane ring" in ring D of formula (1) include a cyclopentane ring, a cyclohexane ring, and a cycloheptane ring.

Ring A is preferably an optionally substituted benzene ring, an optionally substituted pyridine ring, an optionally substituted pyrimidine ring, an optionally substituted pyridazine ring, or an optionally substituted triazine ring (1,2,3-triazine ring), more preferably an optionally substituted benzene ring.
Ring B is preferably an optionally substituted benzene ring, an optionally substituted pyridine ring, an optionally substituted pyrimidine ring, an optionally substituted pyridazine ring, or an optionally substituted triazine ring (1,2,3-triazine ring), more preferably an optionally substituted benzene ring.
Ring D is preferably an optionally substituted benzene ring, an optionally substituted pyridine ring, an optionally substituted pyrimidine ring, an optionally substituted pyridazine ring, an optionally substituted triazine ring (1,2,3-triazine ring or 1,2,4-triazine ring), or an optionally substituted tetrazine ring (1,2,3,4-tetrazine ring), more preferably an optionally substituted benzene ring.
Ring C is preferably an aryl ring or heteroaryl ring represented by one formula selected from the group consisting of formulas (c1) to (c16) below.

In formulae (c1) to (c18), * and # represent bonding positions to ^Y1 and ^X2 , and bonding to either ^Y1 or ^X2 may occur at either * or #. That is, the ring atom at the position of * may be directly bonded to ^Y1 and the ring atom at the position of # may be directly bonded to ^X2 , or the ring atom at the position of # may be directly bonded to ^Y1 and the ring atom at the position of * may be directly bonded to ^X2 .

In formulas (c1) to (c18), L is >O, >S, >Se, >N—R, >Si(—R) ₂ , or >C(—R) ₂ , and R in >N—R, >Si(—R) ₂ , and >C(—R) ₂ is each independently hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl. L is preferably >O, >S, >N—R, or >C(—R) ₂ , more preferably >O, >S, or >C(—CH ₃ ) ₂ , even more preferably >O or >S, and most preferably >S.

Alternatively, L may have an additional bond, forming the following partial structure (A40):

In formula (A40), Me is methyl, and ^X41 is a single bond, >O, >S, >N-R, >C(-R) ₂ , or >C=O, and is bonded to the same monocyclic ring at the two * positions and to another monocyclic ring at the ** position. The atoms on the ring bonded at the two * positions may be adjacent atoms (preferably carbon atoms). R in >N-R and >C(-R) ₂ as ^X41 is hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, and R in >N-R as ^X41 is preferably aryl, more preferably phenyl. R in >C(-R) ₂ as ^X41 is preferably independently hydrogen, alkyl, or aryl, more preferably alkyl or aryl, and even more preferably methyl. The two R in C(-R) ₂ may be bonded to each other to form a ring.

In formulas (c1) to (c18), each ^Z2 is independently N or C- _R2 , and each _R2 in C- _R2 is independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, dialkylamino, diarylboryl (the two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, or substituted silyl, and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl. In each of formulas (c1) to (c18), the number of ^Z2s that are N is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

In each of formulas (c1) to (c18), when there are a plurality of C- _R2s that are ^Z2 , it is preferable that 0 to 2 _R2s are groups other than hydrogen and the rest are hydrogen, and it is preferable that 0 to 1 _R2s are groups other than hydrogen and the rest are hydrogen.

Alternatively, two R ^{2 s} in two adjacent Z ^{2 s} may be bonded to form a group represented by formula (A10) described below.

Ring C is more preferably an aryl ring or heteroaryl ring represented by one formula selected from the group consisting of formula (c1), formula (c2), formula (c3), formula (c4), formula (c5), formula (c8), and formula (c9), even more preferably an aryl ring or heteroaryl ring represented by formula (c1) or formula (c2), and particularly preferably a benzene ring.

In formula (1), at least one hydrogen atom in the aryl ring, heteroaryl ring, or cycloalkane ring in each of rings A, B, C, and D may be substituted. It is preferable that at least one hydrogen atom in at least one aryl ring, heteroaryl ring, or cycloalkane ring selected from the group consisting of rings A, B, C, and D is substituted. It is more preferable that at least one hydrogen atom in the aryl ring or heteroaryl ring in each of rings A, B, and C is substituted, and it is even more preferable that one hydrogen atom in the aryl ring or heteroaryl ring in each of rings A, B, and C is substituted. At the same time, it is preferable that ring D is an aryl ring having at least one substituent or a heteroaryl ring having at least one substituent, and it is preferable that ring D is an aryl ring having one substituent or a heteroaryl ring having one substituent.

In formula (1), when at least one hydrogen atom in the aryl ring, heteroaryl ring, or cycloalkane ring in each of rings A, B, C, and D is substituted, the substituent may be selected from the group consisting of substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino (the two aryls may be bonded via a single bond or a linking group), substituted or unsubstituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino, substituted or unsubstituted dialkylamino, substituted or unsubstituted diarylboryl (the two aryls may be bonded via a single bond or a linking group), substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryloxy, substituted silyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted diarylphosphine, substituted or unsubstituted diarylphosphine oxide, and substituted or unsubstituted diarylphosphine sulfide. In particular, examples of substituents when two or three hydrogen atoms bonded to adjacent carbon atoms are substituted include groups represented by formula (A10) described below.

In this specification, the above substituents, "aryl," "heteroaryl," "diarylamino (the two aryls may be bonded via a single bond or a linking group)," "diheteroarylamino," "arylheteroarylamino," "dialkylamino," "diarylboryl (the two aryls may be bonded via a single bond or a linking group)," "alkyl," "cycloalkyl," "alkoxy," and "aryloxy," are referred to as first substituents. Furthermore, as explained in "substituted or unsubstituted," the substituent substituted on the first substituent is referred to as the second substituent.

When the above-mentioned substituents (first and second substituents) contain an aryl ring or heteroaryl ring, at least one selected from the group consisting of aryl rings and heteroaryl rings in the substituents may be fused with at least one cycloalkane.

Examples of "aryl" as the first substituent include the monovalent groups of the "aryl ring" described above, as well as biphenylyl, m-terphenylyl, o-terphenylyl, and p-terphenylyl. Specific examples of "aryl" as the first substituent include phenyl, which is a monocyclic ring; biphenylyl, which is a bicyclic ring; naphthyl (1-naphthyl or 2-naphthyl), which is a fused bicyclic ring; terphenylyl (m-terphenylyl, o-terphenylyl, or p-terphenylyl), which is a tricyclic ring; acenaphthylenyl, fluorenyl, phenalenyl, and phenanthrenyl, which are fused tricyclic rings; triphenylenyl, pyrenyl, naphthacenyl, and chrysenyl, which are fused tetracyclic rings; and perylenyl and pentacenyl, which are fused pentacyclic rings. Other examples include groups in which a fluorene ring or benzofluorene ring is spiro-bonded to a fluorenyl, and groups in which a fluorene ring or benzofluorene ring is spiro-bonded to a benzofluorenyl.

Furthermore, examples of the "heteroaryl" as the first substituent include the monovalent groups of the "heteroaryl ring" described above. Examples 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.

Specific examples of "heteroaryl" include pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnolinyl, and quinazolinyl. , quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thiophenyl, benzothiophenyl, isobenzothiophenyl, dibenzothiophenyl, naphthobenzothiophenyl, furazanyl, thianthrenyl, xanthenyl, and thioxanthenyl.

The "alkyl" as the first substituent may be either linear or branched, and examples include linear alkyls having 1 to 24 carbon atoms or branched alkyls having 3 to 24 carbon atoms. Alkyls having 1 to 18 carbon atoms (branched alkyls having 3 to 18 carbon atoms) are preferred, alkyls having 1 to 12 carbon atoms (branched alkyls having 3 to 12 carbon atoms) are more preferred, alkyls having 1 to 6 carbon atoms (branched alkyls having 3 to 6 carbon atoms) are even more preferred, and alkyls having 1 to 4 carbon atoms (branched alkyls having 3 to 4 carbon atoms) are particularly preferred.

Specific alkyl groups 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, and n-eicosyl.

Other examples include 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-ethyl-1-methylbutyl, 1,1,4-trimethylpentyl, 1,1,2-trimethylpropyl, 1,1-dimethyloctyl, 1,1-dimethylpentyl, 1,1-dimethylheptyl, 1,1,5-trimethylhexyl, 1-ethyl-1-methylhexyl, 1-ethyl-1,3-dimethylbutyl, 1,1,2,2-tetramethylpropyl, 1-butyl-1-methylpentyl, 1,1-diethylbutyl, 1-ethyl-1-methylpentyl, 1,1,3-trimethylbutyl, 1-propyl-1-methylpentyl, 1,1,2-trimethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, 1-propyl-1-methylbutyl, and 1,1-dimethylhexyl.

Also, examples of "cycloalkyl" as the first substituent include cycloalkyl having 3 to 12 carbon atoms. Preferred cycloalkyls are cycloalkyl having 3 to 10 carbon atoms. More preferred cycloalkyls are cycloalkyl having 3 to 8 carbon atoms. Even more preferred cycloalkyls are cycloalkyl having 3 to 6 carbon atoms.

Specific examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and alkyl (especially methyl) substituted derivatives of these having 1 to 5 carbon atoms, as well as norbornyl (bicyclo[2.2.1]heptyl), bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, and decahydroazulenyl.

In addition, by introducing a cycloalkyl into the polycyclic aromatic compound of the present invention, it is expected that the melting point and sublimation temperature will be lowered. This means that sublimation purification, which is almost essential as a method for purifying materials for organic devices such as organic EL elements, which require high purity, can be performed at relatively low temperatures, thereby avoiding thermal decomposition of the materials. The same is true for the vacuum deposition process, which is an effective means of producing organic devices such as organic EL elements. Because the process can be carried out at relatively low temperatures, thermal decomposition of the materials can be avoided, resulting in high-performance organic devices. Furthermore, because the introduction of a cycloalkyl improves solubility in organic solvents, it can also be applied to the production of elements using a coating process. However, the present invention is not particularly limited to these principles.

Examples of "alkoxy" as the first substituent include straight-chain alkoxy having 1 to 24 carbon atoms or branched-chain alkoxy having 3 to 24 carbon atoms. Alkoxy having 1 to 18 carbon atoms (branched-chain alkoxy having 3 to 18 carbon atoms) is preferred, alkoxy having 1 to 12 carbon atoms (branched-chain alkoxy having 3 to 12 carbon atoms) is more preferred, alkoxy having 1 to 6 carbon atoms (branched-chain alkoxy having 3 to 6 carbon atoms) is even more preferred, and alkoxy having 1 to 4 carbon atoms (branched-chain alkoxy having 3 to 4 carbon atoms) is particularly preferred.

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

Examples of "alkenyl" as the first substituent include unsaturated aliphatic hydrocarbon groups containing a double bond, such as vinyl, allyl, and butadienyl. The number of carbon atoms in the alkenyl is not particularly limited, but is typically in the range of 2 to 20.

Examples of "alkynyl" as the first substituent include unsaturated aliphatic hydrocarbon groups containing a triple bond, such as acetylenyl. The number of carbon atoms in the alkynyl is not particularly limited, but is typically in the range of 2 to 20.

For details about the "aryl" and "heteroaryl" in the first substituents "diarylamino," "diheteroarylamino," "arylheteroarylamino," "diarylboryl," "aryloxy," "arylsulfonyl," "diarylphosphine," "diarylphosphine oxide," and "diarylphosphine sulfide," the above-mentioned explanations of "aryl" and "heteroaryl" can be cited.

The two aryls in the "diarylamino" of the first substituent may be bonded via a single bond or a linking group (for example, >C(-R) ₂ , >O, >S, or >N-R). The two aryls in the "diarylboryl" of the first substituent may be bonded via a single bond or a linking group (for example, >C(-R) ₂ , >O, >S, or >N-R). Here, R in >C(-R) ₂ and >N-R is aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, or aryloxy (all of which are first substituents), and the first substituent may be further substituted with an aryl, heteroaryl, alkyl, or cycloalkyl (all of which are second substituents). Specific examples of these groups can be found in the descriptions of aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy, or aryloxy as the first substituent described above.

The alkyl in "dialkylamino" as the first substituent can be referenced from the explanation of "alkyl" above.

"Substituted silyl" includes silyl substituted with three substituents selected from the group consisting of alkyl, cycloalkyl, and aryl. Specific examples include trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, triarylsilyl, dialkylarylsilyl, and alkyldiarylsilyl.

"Trialkylsilyl" refers to a group in which three hydrogen atoms in an unsubstituted silyl group are each independently substituted with an alkyl, and the alkyl group can be any of the groups described above as the "alkyl" in the first substituent. Preferred alkyl groups for substitution are those having 1 to 5 carbon atoms, and specific examples include methyl, ethyl, propyl, i-propyl, butyl, sec-butyl, t-butyl, and t-amyl.

Specific trialkylsilyl groups include trimethylsilyl, triethylsilyl, tripropylsilyl, tri-i-propylsilyl, tributylsilyl, tri-sec-butylsilyl, tri-t-butylsilyl, tri-t-amylsilyl, ethyldimethylsilyl, propyldimethylsilyl, i-propyldimethylsilyl, butyldimethylsilyl, sec-butyldimethylsilyl, t-butyldimethylsilyl, t-amyldimethylsilyl, methyldiethylsilyl, propyldiethylsilyl, i-propyldiethylsilyl, and butyl Examples include methyldiethylsilyl, sec-butyldiethylsilyl, t-butyldiethylsilyl, t-amyldiethylsilyl, methyldipropylsilyl, ethyldipropylsilyl, butyldipropylsilyl, sec-butyldipropylsilyl, t-butyldipropylsilyl, t-amyldipropylsilyl, methyldi-i-propylsilyl, ethyldi-i-propylsilyl, butyldi-i-propylsilyl, sec-butyldi-i-propylsilyl, t-butyldi-i-propylsilyl, and t-amyldi-i-propylsilyl.

"Tricycloalkylsilyl" refers to an unsubstituted silyl group in which three hydrogen atoms are each independently replaced with a cycloalkyl. Examples of this cycloalkyl include the groups described above as "cycloalkyl" in the first substituent. Preferred cycloalkyl groups for substitution are those having 5 to 10 carbon atoms, such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, decahydronaphthalenyl, and decahydroazulenyl.

Specific examples of tricycloalkylsilyl include tricyclopentylsilyl and tricyclohexylsilyl.

Specific examples of dialkylcycloalkylsilyl substituted with two alkyls and one cycloalkyl, and alkyldicycloalkylsilyl substituted with one alkyl and two cycloalkyls, include silyl substituted with a group selected from the specific alkyls and cycloalkyls listed above.

Specific examples of dialkylarylsilyl substituted with two alkyls and one aryl, alkyldiarylsilyl substituted with one alkyl and two aryls, and triarylsilyl substituted with three aryls include silyl substituted with a group selected from the specific alkyls and aryls listed above. Specific examples of triarylsilyl include triphenylsilyl.

Examples of the second substituent include aryl, heteroaryl, alkyl, and cycloalkyl. Specific examples of these groups include the same groups as those described above for the aryl, heteroaryl, alkyl, and cycloalkyl groups as the first substituent.

The emission wavelength can be adjusted by the first substituent.
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 (tR) (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, carbamate, Preferred are zolyl, 3,6-dimethylcarbazolyl, 3,6-di-t-butylcarbazolyl and phenoxy, and more preferred are methyl, t-butyl, t-amyl, t-octyl, phenyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6-dimethylcarbazolyl and 3,6-di-t-butylcarbazolyl. From the viewpoint of ease of synthesis, 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" represents methyl, "tBu" represents t-butyl, "tAm" represents t-amyl, and "tOct" represents t-octyl, and * represents the bond position.

Tertiary alkyls (tR), some of the examples of which are given above, are particularly preferred as substituents. This is because such bulky substituents prevent inactivation due to aggregation of molecules and improve the luminescence quantum yield (PLQY). Tertiary alkyls can be represented by the following formula (tR):

In formula (tR), R ^a , R ^b , and R ^c each independently represent alkyl having 1 to 24 carbon atoms, and any —CH ₂ — in the alkyl may be replaced with —O—, and the group represented by formula (tR) replaces at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring at *.

The "alkyl having 1 to 24 carbon atoms" of R ^a , R ^b , and R ^c may be either a straight chain or a branched chain, and examples thereof include a straight chain alkyl having 1 to 24 carbon atoms or a branched chain alkyl having 3 to 24 carbon atoms, an alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms), an alkyl having 1 to 12 carbon atoms (branched chain alkyl having 3 to 12 carbon atoms), an alkyl having 1 to 6 carbon atoms (branched chain alkyl having 3 to 6 carbon atoms), and an alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms).

The total number of carbon atoms of R ^a , R ^b and R ^c in formula (tR) is preferably 3 to 20, and particularly preferably 3 to 10.

Specific examples of alkyl for R ^a , R ^b , and R ^c 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.

Examples of groups represented by formula (tR) include t-butyl, t-amyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-ethyl-1-methylbutyl, 1,1,3,3-tetramethylbutyl, 1,1,4-trimethylpentyl, 1,1,2-trimethylpropyl, 1,1-dimethyloctyl, 1,1-dimethylpentyl, 1,1-dimethylheptyl, 1,1,5-trimethylhexyl, 1-ethyl- Examples include 1-methylhexyl, 1-ethyl-1,3-dimethylbutyl, 1,1,2,2-tetramethylpropyl, 1-butyl-1-methylpentyl, 1,1-diethylbutyl, 1-ethyl-1-methylpentyl, 1,1,3-trimethylbutyl, 1-propyl-1-methylpentyl, 1,1,2-trimethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, 1-propyl-1-methylbutyl, and 1,1-dimethylhexyl groups. Of these, t-butyl and t-amyl are preferred.

Other preferred examples include diarylamino substituted with a group of formula (tR), carbazolyl substituted with a group of formula (tR), and benzocarbazolyl substituted with a group of formula (tR). Examples of the substitution of a group of formula (tR) on diarylamino, carbazolyl, and benzocarbazolyl include those in which some or all of the hydrogen atoms on the aryl ring or benzene ring in these groups are substituted with a group of formula (tR).

Furthermore, preferred examples of the substituent when a hydrogen atom of a nitrogen-containing heteroaryl ring such as a carbazole ring, a 9,10-dihydroacridine ring, or a 9,10-dihydro-9,9-dimethylacridine ring is substituted include substituents that form the above-mentioned partial structure (A40) together with the nitrogen atom in each ring.

As mentioned above, when two or three hydrogen atoms bonded to consecutive (adjacent) carbon atoms are substituted, the substituent may be a group represented by formula (A10) described below.

In formula (A10), ^L is >N-R, >O, >Si(-R) or > _S , R of >N-R is optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl or optionally substituted cycloalkyl, R of >Si(-R) is hydrogen, optionally substituted aryl, optionally substituted alkyl or optionally substituted cycloalkyl, and they may be bonded to each other via a linking group, and at least _one of R of >N-R which is L and R of > ^Si (-R) which is ^L may be bonded to at least one selected from the group consisting of ring A, ring B, ring C, ring D and ^R via a linking group or _a single bond,
r is an integer from 1 to 4,
Each ^R is independently hydrogen, optionally substituted alkyl, or optionally substituted cycloalkyl, and any ^R may be bonded to any other ^R via a linking group or a single bond;
The group represented by formula (A10) is bonded to two adjacent atoms on the aryl ring, heteroaryl ring, or cycloalkane ring at the two * marks.

When a compound represented by formula (1) contains a group represented by formula (A10), it preferably contains one or two such groups. The group represented by formula (A10) may be a substituent on any of rings A, B, C, and D, but is preferably a substituent on an aryl ring, heteroaryl ring, or cycloalkane ring on ring C.

The group represented by formula (A10) is bonded to two adjacent atoms on an aryl ring, heteroaryl ring, or cycloalkane ring via two * marks. The group represented by formula (A10) is preferably bonded to two adjacent atoms on an aryl ring, heteroaryl ring, or cycloalkane ring via two * marks. In this case, both adjacent atoms on the ring are preferably carbon atoms. A fused ring structure is formed when the group represented by formula (A10) is bonded to an aryl ring, heteroaryl ring, or cycloalkane ring. A compound represented by formula (1) having this fused ring structure has a more rigid structure. This rigidity is expected to suppress molecular vibration, improve EQE, increase molecular stability, and extend device life.

In formula (A10), ^L is >N-R, >O, >Si(-R) ₂ , or >S. By selecting the type of ^L in the group represented by formula (A10), it is possible to control the HOMO and LUMO of the compound of the present invention. When ^L is N-R, >O, or >S, the HOMO and LUMO become shallower, and when it is Si, the HOMO and LUMO become deeper. If the HOMO and LUMO become shallower, a TTF device using this is expected to have a longer life, higher efficiency, and lower driving voltage. On the other hand, if the HOMO and LUMO become deeper, the hole-trapping properties of the dopant are lost, and the driving voltage is expected to be significantly lowered.

R in >N-R, which is ^L in formula (A10), is optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl, or optionally substituted cycloalkyl. R in >Si(-R) ₂ , which is ^L in formula (A10), is hydrogen, optionally substituted aryl, optionally substituted alkyl, or optionally substituted cycloalkyl, and may be bonded to each other via a linking group. Furthermore, at least one of the R in >N-R and >Si(-R) ₂ may be bonded to at least one selected from the group consisting of ring A, ring B, ring C, ring D, and ^R via a linking group or a single bond. L is preferably >N-R, >O, or >S, more preferably >N-R or >O, and even more preferably >N-R.

When ^L is >N-R, R is preferably aryl optionally substituted with alkyl or cycloalkyl, heteroaryl optionally substituted with alkyl or cycloalkyl, alkyl or cycloalkyl, more preferably aryl optionally substituted with alkyl or cycloalkyl, or heteroaryl optionally substituted with alkyl or cycloalkyl, still more preferably aryl optionally substituted with alkyl or cycloalkyl, and particularly preferably phenyl optionally substituted with alkyl or cycloalkyl.

In formula (A10), r is an integer of 1 to 4, preferably 2 or 3, and more preferably 2.
In formula (A10), each ^R is independently hydrogen, an optionally substituted alkyl, or an optionally substituted cycloalkyl, and any ^R may be linked to any other ^R via a linking group or a single bond.

It is preferable that any two ^Rs are bonded to each other via a linking group or a single bond. Examples of the linking group include >O and >S. An example of the divalent group formed by bonding to each other is alkylene. At least one hydrogen atom in the alkylene may be substituted with an alkyl or cycloalkyl, and at least one (preferably one) -CH ₂ - in the alkylene may be substituted with -O- and -S-. The divalent group formed by bonding to each other is preferably a linear alkylene having 2 to 5 carbon atoms, more preferably a linear alkylene having 3 or 4 carbon atoms, and even more preferably a linear alkylene having 4 carbon atoms (-(CH ₂ ) ₄ -). It is particularly preferable that the linear alkylene having 4 carbon atoms (-(CH ₂ ) ₄ -) is unsubstituted.

When two ^Rs each bonded to adjacent carbon atoms are bonded to each other by a linking group or a single bond, the remaining ^Rs not involved in this bond are preferably each independently hydrogen or an optionally substituted alkyl, or bonded to R in ^Ls >N-R or >Si(-R) ₂ .

When two ^Rs each bonded to adjacent carbon atoms are bonded to each other by a linking group or a single bond, the remaining R not involved in this bond is an optionally substituted ^alkyl of 1 to 6 carbon atoms, more preferably an optionally substituted alkyl of 1 to 6 carbon atoms, even more preferably an unsubstituted alkyl of 1 to 6 carbon atoms, and most preferably methyl.
That is, a preferred example of the group represented by formula (A10) is a group represented by the following formula (A10-b).

In the formula, Me is methyl.

At least one of the Rs in >N-R and >Si(-R) ₂ which are ^Ls may be bonded to at least one selected from the group consisting of ring A, ring B, ring C, ring D and ^Rs via a linking group or a single bond. When ^Ls is >N-R, examples thereof include groups represented by any of the following formulas, and a group represented by formula (A10-b-1) is preferred.

In each formula, Me is methyl. In each formula, * is bonded to two or three consecutive (adjacent) atoms on any of the aryl, heteroaryl, or cycloalkane rings in rings A, B, C, and D.

For example, when a group represented by formula (A10) is contained in a C ring represented by one of formulae (c1) to (c18), two adjacent ^Z2s may be bonded to form a group represented by formula (A10). In particular, ^R2s bonded to adjacent carbon atoms may be bonded to form a group represented by formula (A10). Furthermore, at least one of the Rs in >N-R and >Si(-R) ₂ of ^Ls may be bonded to another ^Z2 via a linking group or a single bond.

At least one of the aryl and heteroaryl rings in rings A, B, C, and D, and the aryl and heteroaryl rings contained as the first and second substituents, may be fused with at least one cycloalkane.

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

Specific cycloalkanes include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, norbornane (bicyclo[2.2.1]heptane), bicyclo[1.1.0]butane, bicyclo[1.1.1]pentane, bicyclo[2.1.0]pentane, bicyclo[2.1.1]hexane, bicyclo[3.1.0]hexane, bicyclo[2.2.2]octane, adamantane, diamantane, decahydronaphthalene, and decahydroazulene, as well as alkyl (especially methyl), halogen (especially fluorine), and deuterium-substituted derivatives of these having 1 to 5 carbon atoms.

Among these, for example, structures in which at least one hydrogen atom is substituted on the α-carbon atom of the cycloalkane (the carbon atom adjacent to the carbon atom at the condensation site in a cycloalkyl fused to an aromatic ring or heteroaromatic ring) are preferred, structures in which two hydrogen atoms are substituted on the α-carbon atom are more preferred, and structures in which a total of four hydrogen atoms are substituted on the two α-carbon atoms are even more preferred. Examples of such substituents include alkyl (particularly methyl) substituents having 1 to 5 carbon atoms, halogen (particularly fluorine) substituents, and deuterium substituents.

The number of cycloalkanes fused to one aryl ring or heteroaryl ring is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. As an example of cycloalkanes fused to a ring that is a monovalent group, an example in which one or more cycloalkanes are fused to a benzene ring (phenyl) is shown below. * indicates the bonding position. Fused cycloalkanes such as those in formula (Cy-1-4) and formula (Cy-2-4) may also be fused together. This applies even if the fused ring (group) is an aromatic ring or heteroaromatic ring other than a benzene ring (phenyl), or even if the fused cycloalkane is a cycloalkane other than cyclopentane or cyclohexane.

At least one -CH ₂ - in a cycloalkane may be replaced with -O-. For example, an example in which one or more -CH ₂ - in a cycloalkane fused to a benzene ring (phenyl) are replaced with -O- is shown below. The same applies when the fused ring (group) is an aromatic ring or heteroaromatic ring other than a benzene ring (phenyl), or when the fused cycloalkane is a cycloalkane other than cyclopentane or cyclohexane.

At least one hydrogen atom in the cycloalkane may be substituted. Examples of such substituents include aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, dialkylamino, diarylboryl (the two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, substituted silyl, deuterium, cyano, or halogen. For details, see the description of the first substituent above. Among these substituents, alkyl (e.g., alkyl having 1 to 6 carbon atoms), cycloalkyl (e.g., cycloalkyl having 3 to 14 carbon atoms), halogen (e.g., fluorine), and deuterium are preferred. Furthermore, when cycloalkyl is substituted, it may be substituted in a manner that forms a spiro structure, an example of which is shown below.

Specific examples include those in which the first substituent is a diarylamino fused with a cycloalkane (fused to the aryl portion) or a carbazolyl fused with a cycloalkane (fused to the benzene ring portion).

In formula (1), ^Y1 is B, P, P=O, P=S, Al, Ga, As, Si-R, Ge-R or Sn-R, and R in Si-R, Ge-R or Sn-R is optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl or optionally substituted cycloalkyl. ^Y1 is preferably B, P, P=O or P=S, and more preferably B.

In formula (1), ^X1 is a single bond, >O, >S, >Se, >N-R, >Si(-R) ₂ , >C(-R) ₂ , or >C=O, and the Rs in >N-R, >Si(-R) ₂ , and >C(-R) ₂ are each independently hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, and the two Rs in each of >Si(-R) ₂ and >C(-R) ₂ may be bonded to each other to form a ring. ^X1 is preferably a single bond, >O, >S, >N-R, >C(-R) ₂ , or >C=O, more preferably >O, >S, >N-R, >C(-R) ₂ , or >C=O, even more preferably >O or >S, and particularly preferably >S. The R in >N-R for ^X1 is preferably aryl, more preferably phenyl. In X ¹ , R in >C(—R) ₂ is preferably independently hydrogen, alkyl or aryl, more preferably alkyl or aryl.

The R in ^X1 , >N-R, >Si(-R) ₂ , and >C(-R) ₂ , may be bonded to ring B and/or ring D via a linking group or a single bond. Here, the linking group is preferably -O-, -S-, or -C(-R) ₂ -. In addition, R in the above-mentioned "-C(-R) ₂ -" is hydrogen or alkyl.

As an example of a structure in which R of >N—R, which is ^X1 , is bonded to ring B or ring D via a linking group or a single bond, ^X1 may have one additional bond and may be the following partial structure (A20).

In formula (A20), Me is methyl, ^X11 is a single bond, >O, >S, >N-R, >C(-R) ₂ , or >C=O, and is bonded to one ring selected from ring B and ring D at the two * positions and to the other ring selected from ring B and ring D at the ** position. The atoms on the rings bonded at the two * positions may be adjacent atoms (preferably carbon atoms). R in >N-R and >C(-R) ² as _X11 is hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, and R in >N- ^R as X11 is preferably aryl, more preferably phenyl. R in >C(-R) ₂ as ^X11 is preferably independently hydrogen, alkyl, or aryl, more preferably alkyl or aryl, and even more preferably methyl. The two R in C(-R) ₂ may be bonded to each other to form a ring.

The partial structure represented by formula (A20) contains an N-C bond with a weak bond dissociation energy (BDE), but the presence of another bond that forms a ring promotes the reverse reaction (recombination reaction) even when the N-C bond is broken, making the compound having the partial structure represented by formula (A20) a more stable structure. Therefore, organic EL devices manufactured using compounds having the partial structure represented by formula (A20) are expected to have a longer device life.

^X2 is >Si(-R) ₂ , >C(-R) ₂ , or >C=O, and the Rs in >Si(-R) ₂ and >C(-R) ₂ are independently hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl, and the two Rs may be bonded to each other to form a ring. ^X2 is preferably >C(-R) ₂ . Each R in >C(-R)2, which is ^X2, is preferably independently hydrogen, alkyl, or aryl, more preferably alkyl or aryl, even more preferably alkyl, and particularly preferably both methyl. It is also preferable that _the two Rs in >C(-R) ₂ are bonded to each other to form a ring. For example, a structure in which both Rs in >C(-R) ₂ , which is ^X2 , are phenyl and are bonded via a single bond, > _CH2 , >C( _-CH3 ) ₂ , >O, >S, >NPh (Ph is phenyl), or >C=O is also preferred.

The R in ^X2 , >Si(-R) ₂ and >C(-R) ₂ , may be bonded to ring A and/or ring C via a linking group or a single bond. Here, the linking group is preferably -O-, -S-, or -C(-R) _2- . In addition, R in the "-C(-R) _2- " is hydrogen or alkyl. For example, ^X2 may be the following partial structure (A30).

Each R ^A is independently hydrogen, optionally substituted alkyl or optionally substituted cycloalkyl, and r is an integer of 0 to 2, and is bonded to one ring selected from ring A and ring C at the two * positions, and to the other ring selected from ring A and ring C at the ** position. R ^A is preferably hydrogen or methyl. The atoms on the rings bonded at the two * positions may be adjacent atoms (preferably carbon atoms).

As the partial structure represented by formula (A30), for example, a structure represented by the following formula (A31) is preferred.

In formula (A31), Me is methyl and is bonded to one ring selected from ring A and ring C at the two * positions and to the other ring selected from ring A and ring C at the ** position.

All or some of the hydrogen atoms in the polycyclic aromatic compound represented by formula (1) may be cyano, halogen, or deuterium. Examples include embodiments in which all or some of the hydrogen atoms in the aryl ring, heteroaryl ring, or cyclohexane ring contained in the structure are substituted with cyano, halogen, or deuterium; embodiments in which all or some of the hydrogen atoms in the first and second substituents are substituted with cyano, halogen, or deuterium; and embodiments in which at least one of the aryl ring and heteroaryl ring is fused with at least one cycloalkane and all or some of the hydrogen atoms in the cycloalkane are substituted with cyano, halogen, or deuterium (described above). The halogen atom is fluorine, chlorine, bromine, or iodine, preferably fluorine, chlorine, or bromine, and more preferably fluorine.

A preferred example of the polycyclic aromatic compound represented by formula (1) is a polycyclic aromatic compound represented by the following formula (2).

In formula (2),
Each Z ¹ is independently N or C-R ¹ , and each R ¹ in the C-R ¹ is independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, dialkylamino, diarylboryl (two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, or substituted silyl, in which at least one hydrogen may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl, and R Adjacent groups among ^{Z 1} may be bonded to each other to form an aryl ring or a heteroaryl ring together with ring a, ring b, or ring d, respectively, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, dialkylamino, diarylboryl (the two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, or substituted silyl, and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl, with the proviso that two R ² in two adjacent Z ¹ may be bonded to form a group represented by formula (A10).

X ¹ is a single bond, >O, >S, >Se, >N—R, >Si(—R) ₂ or >C(—R) ₂ , R in the >N—R, >Si(—R) ₂ and >C(—R) ₂ are independently hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, two Rs may be bonded to each other to form a ring, R in the >N—R, >Si(—R) ₂ and >C(—R) ₂ may be bonded to ring B and/or ring D via a linking group or a single bond, or X ¹ may be bonded to Z ¹ to form partial structure (A20),
^X2 is >Si(-R) ₂ or >C(-R) ₂ , R in said >Si(-R) ₂ and >C(-R) ₂ independently represents hydrogen, aryl, heteroaryl, alkyl or cycloalkyl, two R's may be bonded to each other to form a ring, and R in said >Si(-R) ₂ and >C(-R) ₂ may be bonded to ring A and/or ring C via a linking group or a single bond;
^Y1 is B, P, P=O, P=S, Al, Ga, As, Si—R, Ge—R, or Sn—R, and R in Si—R, Ge—R, and Sn—R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted alkyl, or an optionally substituted cycloalkyl,
Ring C is an aryl ring or heteroaryl ring represented by one formula selected from the group consisting of formulas (c1) to (c18).

In each of the ring a, ring b and ring d in formula (2), ^Z1 as N is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.
Furthermore, when there are a plurality of C-R ^1s as Z ¹ in each of ring a, ring b, and ring d in formula (2), it is preferable that 0 to 2 R ^1s are groups other than hydrogen and the rest are hydrogen, and it is preferable that 0 to 1 R ^1s are groups other than hydrogen and the rest are hydrogen.

The preferred ranges of X ¹ , X ² , Y ¹ and C ring in formula (2) are the same as the preferred ranges of X ¹ , X ² , Y ¹ and C ring in formula (1), respectively.
All or part of the hydrogen atoms in the polycyclic aromatic compound represented by formula (2) may be cyano, halogen, or deuterium.

Specific examples of polycyclic aromatic compounds represented by formula (1) include polycyclic aromatic compounds represented by any one of the following formulae: (1-c1), (1-c2f), (1-c2b), (1-c3f), (1-c3b), (1-c4f), (1-c4b), (1-c5f), (1-c8f), and (1-c9f).

In the above formula, each R ^a is independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino, substituted or unsubstituted dialkylamino, substituted or unsubstituted diarylboryl (the two aryls may be bonded via a single bond or a linking group), substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, or substituted silyl.
Preferably, each R ^a is independently hydrogen or unsubstituted alkyl.
The definitions and preferred ranges of ^X1 , ^X2 , and ^Y1 are the same as those in formula (1), and the definitions and preferred ranges of L and ^Z2 are the same as those in formulas (c1) to (c18).
All or a part of hydrogen atoms in the polycyclic aromatic compounds represented by formula (1-c1), formula (1-c2f), formula (1-c2b), formula (1-c3f), formula (1-c3b), formula (1-c4f), formula (1-c4b), formula (1-c5f), formula (1-c8f), and formula (1-c9f) may be cyano, halogen, or deuterium.

Further specific examples of the polycyclic aromatic compound represented by formula (1) of the present invention include the following compounds. In the structural formula below, "Me" represents methyl, "tBu" represents t-butyl, "tAm" represents t-amyl, and "D" represents deuterium. Note that the following structure is just one example.

The polycyclic aromatic compound of the present invention can be produced by the following procedure.

3. Method for producing polycyclic aromatic compounds represented by formula (1) Polycyclic aromatic compounds represented by formula (1) can be produced through the following steps: a first step of introducing a boron atom (Y) by a tandem boron-Friedel-Crafts reaction (sequential aromatic electrophilic substitution reaction, the same applies below) using boron triiodide or the like; a second step of producing an intermediate by reacting an organometallic compound such as an aryl Grignard reagent or aryllithium substituted with an alkenyl (e.g., isopropenyl) corresponding to the C ring moiety; and a third step of reacting this compound with an acid to cause a cyclization reaction to produce a polycyclic aromatic compound represented by formula (1). Note that the definitions of the symbols in the structural formulas in schemes (1) and (2) described below are the same as those in formula (1).

<First step and second step>
This process is explained using the following scheme (1). As shown below, an intermediate compound can be produced by performing a tandem boron-Friedel-Crafts reaction using boron triiodide or the like, followed by a reaction with an aryl Grignard reagent or aryllithium substituted with "-C(-Ra)=-Ra'(-Ra'')" to introduce a C ring moiety onto the boron atom. The precursor intermediate can be easily synthesized using a common amination reaction such as the Buchwald-Hartwig reaction.

In the above scheme (1), an example is shown in which boron triiodide is used in the tandem boron-Friedel-Crafts reaction in the first step, but other boron halide reagents such as boron trichloride, boron tribromide, or boron trifluoride-diethyl ether complex can also be used. Furthermore, to promote the tandem boron-Friedel-Crafts reaction in these reactions, a Lewis acid such as aluminum trichloride, gallium trichloride, or titanium tetrachloride can be added.

<3rd process>
The third step is a step of producing a polycyclic aromatic compound represented by formula (1) by subjecting the intermediate compound produced as described above to a Friedel-Crafts cyclization reaction in the presence of an acid catalyst. In this step, the polycyclic aromatic compound represented by formula (1) can be produced by a Friedel-Crafts reaction using an acid, particularly a Lewis acid such as Sc(OTf) ₃ , as shown in the following scheme (2).

Here, E/Z isomers exist at the double bond portion. However, in the above scheme (2), whether the intermediate compound is the E or Z isomer, the polycyclic aromatic compound represented by formula (1) is the same. Therefore, although the intermediate compounds in this specification are represented by the structural formula of only a single isomer, the double bond portion of the intermediate compound may be either the E or Z isomer, and may also be a mixture of the E and Z isomers in any ratio.

In schemes (1) and (2), the synthesis method when ^X2 in formula (1) is >C(—R) ₂ has been described. However, in other cases, the target polycyclic aromatic compound can also be obtained by similarly introducing a functional group that serves as a cyclization precursor in advance and then carrying out a cyclization reaction.

The Lewis acid used in the above scheme (2) may be a commonly known Lewis acid, for example, _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 , TiCl ₄ , TiBr ₄ , ZrCl ₄ , ZrBr ₄ , FeCl ₃ , FeBr ₃ , CoCl ₃ and CoBr ₃ .

The solvent used in the above scheme (2) can be any common organic solvent, including, for example, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, isomers of benzene, toluene, and xylene, and mixtures thereof; isomers of trimethylbenzene, and mixtures thereof; chlorobenzene, o-dichlorobenzene, benzotrifluoride, diethyl ether, methyl tertiary butyl ether, tetrahydrofuran (THF), dioxane, cyclopentyl methyl ether, diphenyl ether, cyclopentane, pentane, cyclohexane, hexane, octane, dodecane, and decalin; and mixtures of these in any ratio can also be used.

By appropriately selecting the above-mentioned production method and the raw materials used, it is possible to produce a polycyclic aromatic compound represented by formula (1) having substituents at the desired positions.

Furthermore, by using the above-mentioned production method, a compound having a reactive substituent, such as a halogen, a sulfonate ester such as trifluoromethanesulfonate ester, or a boronic acid or boronic acid ester, can be produced, and then a polycyclic aromatic compound represented by formula (1) having a substituent at a desired position can be produced using common reactions such as cross-coupling reactions such as Suzuki coupling, Negishi coupling, or Kumada coupling, Buchwald-Hartwig reaction, Ullmann reaction, halogen-metal exchange reaction using butyllithium, or Grignard reaction followed by metallation with an electrophilic reaction reagent.

Halogen-containing polycyclic aromatic compounds represented by formula (1) can be produced by using raw materials containing halogens, or by halogenating the polycyclic aromatic compounds and their multimers using commonly known reactions.

In addition, polycyclic aromatic compounds represented by formula (1) having a sulfonate ester such as trifluoromethanesulfonate ester can be produced by using a raw material having a sulfonate ester. Alternatively, they can be produced by reacting a compound produced using a raw material having an alkoxy group such as methoxy with a commonly known reagent such as boron tribromide or pyridine hydrochloride to convert the alkoxy group to a hydroxyl group, and then reacting the compound with an anhydride such as trifluoromethanesulfonic anhydride or a halide such as nonafluoro-1-butanesulfonyl fluoride.

In addition, the polycyclic aromatic compounds represented by formula (1) also include compounds in which at least some of the hydrogen atoms are substituted with deuterium, and such polycyclic aromatic compounds can also be produced in the same manner as above by using raw materials in which the desired positions are substituted with deuterium.

2. Organic Devices The polycyclic aromatic compound of the present invention can be used as a material for organic devices, such as organic electroluminescent devices, organic field-effect transistors, and organic thin-film solar cells.

2-1. Organic electroluminescent device
2-1-1. Structure of Organic Electroluminescent Device FIG. 1 is a schematic cross-sectional view showing an example of an organic EL device.
The organic EL element 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, a hole transport layer 104 provided on the hole injection layer 103, a light-emitting layer 105 provided on the hole transport layer 104, an electron transport layer 106 provided on the light-emitting layer 105, an electron injection layer 107 provided on the electron transport layer 106, and a cathode 108 provided on the electron injection layer 107.

The organic EL element 100 may be fabricated in the reverse order, for example, to have a substrate 101, a cathode 108 provided on the substrate 101, an electron injection layer 107 provided on the cathode 108, an electron transport layer 106 provided on the electron injection layer 107, an emissive layer 105 provided on the electron transport layer 106, a hole transport layer 104 provided on the emissive layer 105, a hole injection layer 103 provided on the hole transport layer 104, and an anode 102 provided on the hole injection layer 103.

Not all of the above layers are essential; the minimum structural unit is the anode 102, light-emitting layer 105, and cathode 108, with the hole injection layer 103, hole transport layer 104, electron transport layer 106, and electron injection layer 107 being optional layers. Furthermore, each of the above layers may consist of a single layer or multiple layers.

The layers constituting an organic EL element may be configured in the above-mentioned "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport layer/electron injection layer/cathode" configuration, as well as "substrate/anode/hole transport layer/light-emitting layer/electron transport layer/electron injection layer/cathode," "substrate/anode/hole injection layer/light-emitting layer/electron transport layer/electron injection layer/cathode," "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron injection layer/cathode," "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron injection layer/cathode," or "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport" configuration. The configurations may be "transport layer/cathode", "substrate/anode/light-emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole transport layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole transport layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/hole injection layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/light-emitting layer/electron transport layer/cathode", or "substrate/anode/light-emitting layer/electron injection layer/cathode".

2-1-2. Light-emitting layer in organic electroluminescent device The polycyclic aromatic compound of the present invention is preferably used as a material for forming one or more organic layers in an organic electroluminescent device, and more preferably used as a material for forming a light-emitting layer.
The light-emitting layer 105 is a layer that 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 that forms the light-emitting layer 105 may be a compound that emits light when excited by the recombination of holes and electrons (a light-emitting compound), and is preferably a compound that can be formed into a stable thin film and that exhibits strong luminescence (fluorescence) efficiency in a solid state.
The polycyclic aromatic compound of the present invention can be used as a material for a light-emitting layer, and may be used as a dopant material or a host material.

Note that while there are cases in which an assisting dopant and an emitting dopant are used in combination as dopants, in this specification, when the term "dopant" is simply used, it refers to a light-emitting dopant used alone.

The light-emitting layer may consist of a single layer or multiple layers, each formed from light-emitting layer materials (host material, dopant material). The host material and dopant material may each be one type, or a combination of multiple types. The dopant material may be contained entirely or partially in the host material. As a doping method, the dopant material can be formed by co-evaporation with the host material, but it can also be mixed with the host material in advance and then vapor-deposited simultaneously.

The amount of host material used varies depending on the type of host material and can be determined based on the characteristics of the host material. The recommended amount of host material used is preferably 50 to 99.999% by mass, more preferably 80 to 99.95% by mass, and even more preferably 90 to 99.9% by mass, of the total light-emitting layer materials.

The amount of dopant material used varies depending on the type of dopant material and can be determined based on the characteristics of the dopant material. The recommended amount of dopant used is preferably 0.001 to 50% by mass of the total light-emitting layer material, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass. The above ranges are preferable in that they can prevent concentration quenching, for example.

Host Material Examples of the host material include fused ring derivatives of anthracene, pyrene, dibenzochrysene, fluorene, and the like, which have long been known as light-emitting bodies; bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives; tetraphenylbutadiene derivatives; cyclopentadiene derivatives; fluorene derivatives; benzofluorene derivatives; and dibenzochrysene-based compounds.

As the host material, for example, a compound represented by any one of the following formulas (H1), (H2), and (H3) can be used.

In formulae (H1), (H2), and (H3), L ¹ represents an arylene having 6 to 24 carbon atoms, a heteroarylene having 2 to 24 carbon atoms, a heteroarylenearylene having 6 to 24 carbon atoms, or 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, and 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 benzophenone ... 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 alkyl having 1 to 6 carbon atoms, cyano, halogen, or deuterium.

Preferred specific examples include compounds represented by any of the structural formulas listed below. In the structural formulas listed below, at least one hydrogen may be substituted with halogen, cyano, alkyl having 1 to 4 carbon atoms (e.g., methyl or t-butyl), phenyl, naphthyl, or the like.

<Anthracene-based compounds>
The anthracene-based compound as the host is, for example, a compound represented by the following formula (3-H).

In formula (3-H),
X and Ar ⁴ are each independently hydrogen, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted diarylamino, optionally substituted diheteroarylamino, optionally substituted arylheteroarylamino, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted arylthio or optionally substituted silyl, and all of X and Ar ⁴ are not hydrogen at the same time;
At least one hydrogen atom in the compound represented by formula (3-H) may be substituted with halogen, cyano, deuterium, or an optionally substituted heteroaryl.

The structure represented by formula (3-H) may also be used as a unit structure to form a polymer (preferably a dimer). In this case, for example, unit structures represented by formula (3-H) may be bonded to each other via X, where X may be a single bond, an arylene (such as phenylene, biphenylene, or naphthylene), or a heteroarylene (a divalent group such as a pyridine ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, benzocarbazole ring, or phenyl-substituted carbazole ring).

Details of the above aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, aryloxy, arylthio, and silyl are described in the preferred embodiments section below. Substituents for these include aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, aryloxy, arylthio, and silyl, and details of these are also described in the preferred embodiments section below.

Preferred embodiments of the above anthracene-based compounds are described below. The symbols in the following structures are defined as above.

In formula (3-H), each X is independently a group represented by formula (3-X1), formula (3-X2), or formula (3-X3), and the group represented by formula (3-X1), formula (3-X2), or formula (3-X3) is bonded to the anthracene ring of formula (3-H) at *. Preferably, no two Xs are simultaneously groups represented by formula (3-X3). More preferably, no two Xs are simultaneously groups represented by formula (3-X2).

The structure represented by formula (3-H) may also be used as a unit structure to form a polymer (preferably a dimer). In this case, for example, unit structures represented by formula (3-H) may be bonded to each other via X, where X may be a single bond, an arylene (such as phenylene, biphenylene, or naphthylene), or a heteroarylene (a divalent group such as a pyridine ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, benzocarbazole ring, or phenyl-substituted carbazole ring).

The naphthylene moieties in formula (3-X1) and formula (3-X2) may be fused with one benzene ring, resulting in the following fused structure:

Ar ¹ and Ar ² are each independently hydrogen, phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or a group represented by formula (A) (including carbazolyl, benzocarbazolyl, and phenyl-substituted carbazolyl). When Ar ¹ or Ar ² is a group represented by formula (A) described below, the group represented by formula (A) is bonded to the naphthalene ring in formula (3-X1) or formula (3-X2) at the *.

^Ar3 is phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or a group represented by formula (A) (including carbazolyl, benzocarbazolyl, and phenyl-substituted carbazolyl). When ^Ar3 is a group represented by formula (A), the group represented by formula (A) is bonded to the single bond represented by a straight line in formula (3-X3) at the *. In other words, the anthracene ring of formula (3-H) and the group represented by formula (A) are directly bonded.

Furthermore, ^Ar3 may have a substituent, and at least one hydrogen atom in ^Ar3 may be further substituted with alkyl having 1 to 4 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or a group represented by formula (A) (including carbazolyl and phenyl-substituted carbazolyl). When the substituent in ^Ar3 is a group represented by formula (A), the group represented by formula (A) is bonded to Ar3 in formula (3-X3) at the ^* .

Each Ar ⁴ is independently hydrogen, phenyl, biphenylyl, terphenylyl, naphthyl, or silyl substituted with alkyl having 1 to 4 carbon atoms (such as methyl, ethyl, t-butyl, etc.) and/or cycloalkyl having 5 to 10 carbon atoms.

Examples of alkyl groups having 1 to 4 carbon atoms that can be substituted on silyl include methyl, ethyl, propyl, i-propyl, butyl, sec-butyl, t-butyl, and cyclobutyl, and each of the three hydrogen atoms on the silyl is independently substituted with one of these alkyl groups.

Specific examples of "silyl substituted with alkyl having 1 to 4 carbon atoms" include trimethylsilyl, triethylsilyl, tripropylsilyl, tri-i-propylsilyl, tributylsilyl, tri-sec-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, propyldimethylsilyl, i-propyldimethylsilyl, butyldimethylsilyl, sec-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, propyldiethylsilyl, i-propyldiethylsilyl, butyldiethylsilyl, sec-butyldiethylsilyl, t-butyldiethylsilyl, methyldipropylsilyl, ethyldipropylsilyl, butyldipropylsilyl, sec-butyldipropylsilyl, t-butyldipropylsilyl, methyldi-i-propylsilyl, ethyldi-i-propylsilyl, butyldi-i-propylsilyl, sec-butyldi-i-propylsilyl, and t-butyldi-i-propylsilyl.

Cycloalkyls having 5 to 10 carbon atoms that substitute for silyl include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, norbornyl (bicyclo[2.2.1]heptyl), bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.2]octyl, adamantyl, decahydronaphthalenyl, and decahydroazulenyl, and three hydrogen atoms in the silyl are each independently replaced by one of these cycloalkyls.

Specific examples of "silyl substituted with cycloalkyl having 5 to 10 carbon atoms" include tricyclopentylsilyl and tricyclohexylsilyl.

Substituted silyls include dialkylcycloalkylsilyls, which are substituted with two alkyls and one cycloalkyl, and alkyldicycloalkylsilyls, which are substituted with one alkyl and two cycloalkyls. Specific examples of the alkyl and cycloalkyl substituents include the groups mentioned above.

In addition, hydrogen atoms in the chemical structure of the anthracene-based compound represented by formula (3-H) may be substituted with a group represented by formula (A). When substituted with a group represented by formula (A), the group represented by formula (A) replaces at least one hydrogen atom in the compound represented by formula (3-H) at the *.

The group represented by formula (A) is one of the substituents that the anthracene compound represented by formula (3-H) can have.

In formula (A), Y is —O—, —S— or >N—R ²⁹ , R ²¹ to R ²⁸ each independently represent hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted arylthio, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, optionally substituted amino, halogen, hydroxy, or cyano, adjacent groups among R ²¹ to R ²⁸ may bond to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring, and R ²⁹ is hydrogen or optionally substituted aryl.

The "alkyl" in the "optionally substituted alkyl" in R ^{to R} may be either a straight chain or a branched chain, and examples thereof include a straight chain alkyl having 1 to 24 carbon atoms or a branched chain alkyl having 3 to 24 carbon atoms. An alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms) is preferred, an alkyl having 1 to 12 carbon atoms (branched chain alkyl having 3 to 12 carbon atoms) is more preferred, an alkyl having 1 to 6 carbon atoms (branched chain alkyl having 3 to 6 carbon atoms) is even more preferred, and an alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms) is particularly preferred.

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.

Examples of the "cycloalkyl" in the "optionally substituted cycloalkyl" in R ^{to R} include cycloalkyl having 3 to 24 carbon atoms, cycloalkyl having 3 to 20 carbon atoms, cycloalkyl having 3 to 16 carbon atoms, cycloalkyl having 3 to 14 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, cycloalkyl having 5 to 8 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, and cycloalkyl having 5 carbon atoms.

Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and alkyl (especially methyl) substituted derivatives of these having 1 to 4 carbon atoms, as well as norbornyl (bicyclo[2.2.1]heptyl), bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, and decahydroazulenyl.

The "aryl" in the "optionally substituted aryl" in R ^{to R} is, for example, an aryl having 6 to 30 carbon atoms, 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" include phenyl, a monocyclic ring system; biphenylyl, a bicyclic ring system; naphthyl, a fused bicyclic ring system; terphenylyl (m-terphenylyl, o-terphenylyl, p-terphenylyl), a tricyclic ring system; acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, a fused tricyclic ring system; triphenylenyl, pyrenyl, naphthacenyl, a fused tetracyclic ring system; and perylenyl, pentacenyl, etc.

Examples of the "heteroaryl" in the "optionally substituted heteroaryl" in R ^{to R} include 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 pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, and cinnamyl. Examples include benzoyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, indolizinyl, furyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzo[b]thienyl, dibenzothienyl, furazanyl, oxadiazolyl, thianthrenyl, naphthobenzofuranyl, and naphthobenzothienyl.

Examples of the "alkoxy" in the "optionally substituted alkoxy" in R ^{to R} include straight-chain alkoxy having 1 to 24 carbon atoms or branched-chain alkoxy having 3 to 24 carbon atoms. Alkoxy having 1 to 18 carbon atoms (branched-chain alkoxy having 3 to 18 carbon atoms) is preferred, alkoxy having 1 to 12 carbon atoms (branched-chain alkoxy having 3 to 12 carbon atoms) is more preferred, alkoxy having 1 to 6 carbon atoms (branched-chain alkoxy having 3 to 6 carbon atoms) is even more preferred, and alkoxy having 1 to 4 carbon atoms (branched-chain alkoxy having 3 to 4 carbon atoms) is particularly preferred.

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

The "aryloxy" in the "optionally substituted aryloxy" in R ²¹ to R ²⁸ is a group in which the hydrogen of the -OH group is substituted with an aryl, and the aryl can be any of the groups described above as the "aryl" in R ²¹ to R ²⁸ .

The "arylthio" in the "optionally substituted arylthio" in R ²¹ to R ²⁸ is a group in which the hydrogen of the --SH group is substituted with an aryl, and the aryl can be any of the groups described above as the "aryl" in R ²¹ to R ²⁸ .

The "trialkylsilyl" in R ²¹ to R ²⁸ includes a group in which three hydrogen atoms in a silyl group are each independently substituted with an alkyl, and the alkyl can be quoted from the groups explained above as the "alkyl" in R ²¹ to R ^28. Preferred alkyl groups for substitution are alkyl groups having 1 to 4 carbon atoms, and specific examples include methyl, ethyl, propyl, i-propyl, butyl, sec-butyl, t-butyl, cyclobutyl, etc.

Specific examples of "trialkylsilyl" include trimethylsilyl, triethylsilyl, tripropylsilyl, tri-i-propylsilyl, tributylsilyl, tri-sec-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, propyldimethylsilyl, i-propyldimethylsilyl, butyldimethylsilyl, sec-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, propyldiethylsilyl, i-propyldiethylsilyl, butyldiethylsilyl, sec-butyldiethylsilyl, t-butyldiethylsilyl, methyldipropylsilyl, ethyldipropylsilyl, butyldipropylsilyl, sec-butyldipropylsilyl, t-butyldipropylsilyl, methyldi-i-propylsilyl, ethyldi-i-propylsilyl, butyldi-i-propylsilyl, sec-butyldi-i-propylsilyl, and t-butyldi-i-propylsilyl.

Examples of the "tricycloalkylsilyl" in R ²¹ to R ²⁸ include a group in which three hydrogen atoms in a silyl group are each independently substituted with a cycloalkyl, and examples of this cycloalkyl include the groups described above as the "cycloalkyl" in R ²¹ to R ^28. Preferred cycloalkyl groups for substitution are cycloalkyl groups having 5 to 10 carbon atoms, and specific examples include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, decahydronaphthalenyl, and decahydroazulenyl.

Specific examples of "tricycloalkylsilyl" include tricyclopentylsilyl and tricyclohexylsilyl.

Specific examples of dialkylcycloalkylsilyl substituted with two alkyls and one cycloalkyl, and alkyldicycloalkylsilyl substituted with one alkyl and two cycloalkyls, include silyl substituted with a group selected from the specific alkyls and cycloalkyls listed above.

The "substituted amino" in the "optionally substituted amino" in R ^{to R} includes, for example, amino in which two hydrogen atoms are substituted with aryl or heteroaryl. An amino in which two hydrogen atoms are substituted with aryl atoms is a diaryl-substituted amino, an amino in which two hydrogen atoms are substituted with heteroaryl atoms is a diheteroaryl-substituted amino, and an amino in which two hydrogen atoms are substituted with an aryl and a heteroaryl atom is an arylheteroaryl-substituted amino. The aryl and heteroaryl groups can be selected from the groups described above as "aryl" and "heteroaryl" in ^R to ^R.

Specific examples of "substituted amino" include diphenylamino, dinaphthylamino, phenylnaphthylamino, dipyridylamino, phenylpyridylamino, and naphthylpyridylamino.

The "halogen" in R ²¹ to R ²⁸ includes fluorine, chlorine, bromine and iodine.

Some of the groups explained as R ^{to R} may be substituted as described above, and in this case, the substituents include alkyl, cycloalkyl, aryl, or heteroaryl. The alkyl, cycloalkyl, aryl, or heteroaryl can refer to the groups explained as "alkyl,""cycloalkyl,""aryl," or "heteroaryl" in R ^to R ^above .

R ²⁹ in ">N-R ²⁹ " as Y is hydrogen or an optionally substituted aryl, and examples of this aryl include the groups described above as "aryl" in R ²¹ to R ²⁸ , and examples of the substituents include the groups described above as substituents for R ²¹ to R ²⁸ .

Adjacent groups among R ²¹ to R ²⁸ may be bonded to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring. The group represented by formula (A-1) below does not form a ring, and examples of the group represented by formulas (A-2) to (A-14) below include groups. At least one hydrogen atom in the group represented by any of formulas (A-1) to (A-14) may be substituted with alkyl, cycloalkyl, aryl, heteroaryl, alkoxy, aryloxy, arylthio, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, diaryl-substituted amino, diheteroaryl-substituted amino, arylheteroaryl-substituted amino, halogen, hydroxy, or cyano.

Examples of rings formed by bonding adjacent groups to each other include hydrocarbon rings such as cyclohexane rings, and examples of aryl and heteroaryl rings include the ring structures explained above for "aryl" and "heteroaryl" in R ^{to R} , and these rings are formed so as to be fused with one or two benzene rings in formula (A-1).

Examples of the group represented by formula (A) include groups represented by any of formulas (A-1) to (A-14), with groups represented by any of formulas (A-1) to (A-5) and formulas (A-12) to (A-14) being preferred, groups represented by any of formulas (A-1) to (A-4) being more preferred, groups represented by any of formulas (A-1), (A-3) and (A-4) being even more preferred, and groups represented by formula (A-1) being particularly preferred.

As described above, the group represented by formula (A) is bonded at * in formula (A) to the naphthalene ring in formula (3-X1) or formula (3-X2), the single bond in formula (3-X3), or Ar ³ in formula (3-X3), and is also substituted for at least one hydrogen in the compound represented by formula (3-H). Among these bonding forms, the bonding form to the naphthalene ring in formula (3-X1) or formula (3-X2), the single bond in formula (3-X3), and/or Ar ³ in formula (3-X3) is preferred.

Furthermore, in the structure of the group represented by formula (A), the naphthalene ring in formula (3-X1) or formula (3-X2), the single bond in formula (3-X3), the position at which Ar ³ in formula (3-X3) is bonded, and the position at which at least one hydrogen atom in the compound represented by formula (3-H) is substituted in the structure of the group represented by formula (A) may be any position in the structure of formula (A), and may be bonded, for example, to either of the two benzene rings in the structure of formula (A), to any ring formed by bonding adjacent groups among R ²¹ to R ²⁸ in the structure of formula (A), or to any position in R ²⁹ in “>N—R ²⁹ ” as Y in the structure of formula (A).

Examples of the group represented by formula (A) include the following groups: wherein Y and * are defined as above.

Furthermore, all or some of the hydrogen atoms in the chemical structure of the anthracene-based compound represented by formula (3-H) may be deuterium atoms.

The anthracene-based compound as the host may be, for example, a compound represented by the following formula (3-H-2).

In formula (3-H-2), Ar ^c is an optionally substituted aryl or an optionally substituted heteroaryl, R ^c is hydrogen, alkyl, or cycloalkyl, Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ¹⁵ , Ar ¹⁶ , Ar ¹⁷ , and Ar ¹⁸ are each independently hydrogen, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted diarylamino, an optionally substituted diheteroarylamino, an optionally substituted arylheteroarylamino, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted alkenyl, an optionally substituted alkoxy, an optionally substituted aryloxy, an optionally substituted arylthio, or an optionally substituted silyl, and at least one hydrogen in the compound represented by formula (1) may be replaced by halogen, cyano, or deuterium.

In formula (3-H-2), the definitions of "optionally substituted aryl," "optionally substituted heteroaryl," "optionally substituted diarylamino," "optionally substituted diheteroarylamino," "optionally substituted arylheteroarylamino," "optionally substituted alkyl," "optionally substituted cycloalkyl," "optionally substituted alkenyl," "optionally substituted alkoxy," "optionally substituted aryloxy," "optionally substituted arylthio," and "optionally substituted silyl" are the same as those in formula (3-H) above.

The "optionally substituted aryl" is preferably a group represented by any of the following formulas (1-X1) to (1-X7).

In formulas (1-X1) to (1-X7), * indicates a bonding position.
In formulas (1-X1) to (1-X3), Ar ²¹ , Ar ²² , and Ar ²³ each independently represent hydrogen, phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, anthracenyl, or a group represented by formula (A) described below.

In formulas (1-X4) to (1-X7), Ar ²⁴ , Ar ²⁵ , Ar ²⁶ , Ar ²⁷ and Ar ²⁸ each independently represent hydrogen, phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) described below.
In addition, any one or more hydrogen atoms in each of the groups represented by formulae (1-X1) to (1-X7) may be substituted with alkyl having 1 to 6 carbon atoms (preferably methyl or t-butyl).

Furthermore, preferred examples of "optionally substituted aryl" include terphenylyl (particularly m-terphenyl-5'-yl) which may be substituted with one or more substituents selected from the group consisting of phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenyl, and groups represented by formula (A) described below.

"Optionally substituted heteroaryl" also includes groups represented by formula (A) described below.

At least one hydrogen atom in the compound represented by formula (1) may be substituted with a halogen atom, cyano atom, or deuterium atom. In this case, "halogen" includes fluorine, chlorine, bromine, and iodine. In particular, compounds in which all hydrogen atoms in the compound represented by formula (1) have been substituted with deuterium atoms are preferred.

In formula (1), R ^c is hydrogen, alkyl, or cycloalkyl, preferably hydrogen, methyl, or t-butyl, and more preferably hydrogen.
In formula (1), it is preferable that at least two of Ar ¹¹ to Ar ¹⁸ are optionally substituted aryl or optionally substituted heteroaryl. That is, it is preferable that the anthracene compound represented by formula (1) has a structure in which at least three substituents selected from the group consisting of optionally substituted aryl and optionally substituted heteroaryl are bonded to an anthracene ring.

In the anthracene compound represented by formula (1), two of Ar ¹¹ to Ar ¹⁸ are optionally substituted aryl or optionally substituted heteroaryl, and the other six are hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, or optionally substituted alkoxy. That is, the anthracene compound represented by formula (1) more preferably has a structure in which three substituents selected from the group consisting of optionally substituted aryl and optionally substituted heteroaryl are bonded to the anthracene ring.

In the anthracene compound represented by formula (1), any two of Ar ¹¹ to Ar ¹⁸ are optionally substituted aryl or optionally substituted heteroaryl, and the other six are hydrogen, methyl, or t-butyl.

Furthermore, in formula (1), it is preferred that R ^c is hydrogen and any six of Ar ¹¹ to Ar ¹⁸ are hydrogen.

The anthracene compound represented by formula (1) is preferably an anthracene compound represented by the following formula (1A), (1B), (1C), (1D), or (1E).

In formula (1A), (1B), (1C), (1D) or (1E), Ar ^c ', Ar ¹¹ ', Ar ¹² ', Ar ¹³ ', Ar ¹⁴ ', Ar ¹⁵ ', Ar ¹⁷ ' and Ar ¹⁸ ' are each independently phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) described below, and at least one hydrogen atom in these groups may be substituted by phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) described below. When all of the hydrogen atoms of the methylene groups in fluorenyl and benzofluorenyl are substituted with phenyl, these phenyl groups may be bonded to each other via a single bond. Methyl or t-butyl may be bonded to the carbon atoms of the anthracene ring to which Ar ^c ', Ar ¹¹ ', Ar ¹² ', Ar ¹³ ', Ar ¹⁴ ', Ar ¹⁵ ', Ar ¹⁷ ', and Ar ¹⁸ ' are not bonded, instead of hydrogen.

When Ar ^c ', Ar ¹¹ ', Ar ¹² ', Ar ¹³ ', Ar ¹⁴ ', Ar ¹⁵ ', Ar ¹⁷ ', and Ar ¹⁸ ' are each substituted or unsubstituted phenyl or substituted or unsubstituted naphthyl, they are preferably groups represented by any of the above formulas (1-X1) to (1-X7).

It is more preferable that Ar ^c ', Ar ¹¹ ', Ar ¹² ', Ar ¹³ ', Ar ¹⁴ ', Ar ¹⁵ ', Ar ¹⁷ ', and Ar ¹⁸ ' are each independently phenyl, biphenylyl (particularly biphenyl-2-yl or biphenyl-4-yl), terphenylyl (particularly m-terphenyl-5'-yl), naphthyl, phenanthryl, fluorenyl, or a group represented by any one of formulas (A-1) to (A-4) described below, in which case at least one hydrogen atom in these groups may be substituted by phenyl, biphenylyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of formulas (A-1) to (A-4) described below.

Furthermore, at least one hydrogen atom in the compound represented by formula (1A), (1B), (1C), (1D), or (1E) may be substituted with a halogen, cyano, or deuterium.

The group represented by the above formula (A) will be described below.

In formula (A), Y is —O—, —S—, or >N—R ^29. Furthermore, in formula (A), R ²¹ to R ²⁸ each independently represent hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted arylthio, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, optionally substituted amino, halogen, hydroxy, or cyano, adjacent groups among R ²¹ to R ²⁸ may bond to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring, and R ²⁹ is hydrogen or optionally substituted aryl.
The group represented by formula (A) is a group obtained by removing one hydrogen atom from any position of formula (A), and * indicates the position.

The "alkyl" in the "optionally substituted alkyl" for R ²¹ to R ²⁸ in formula (A) may be either a straight chain or a branched chain, and examples thereof include a straight chain alkyl having 1 to 24 carbon atoms or a branched chain alkyl having 3 to 24 carbon atoms. An alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms) is preferred, an alkyl having 1 to 12 carbon atoms (branched chain alkyl having 3 to 12 carbon atoms) is more preferred, an alkyl having 1 to 6 carbon atoms (branched chain alkyl having 3 to 6 carbon atoms) is even more preferred, and an alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms) is particularly preferred.

Some of the groups explained as R ^{to R} in formula (A) may be substituted as described above, and in this case, examples of the substituent include alkyl, aryl, or heteroaryl. The alkyl, aryl, or heteroaryl can refer to the groups explained as "alkyl,""aryl," or "heteroaryl" in R ^to R ^above .

R ²⁹ in ">N-R ²⁹ " as Y in formula (A) is hydrogen or an aryl which may be substituted, and examples of this aryl include the groups described above as "aryl" in R ²¹ to R ²⁸ , and examples of the substituents include the groups described above as substituents for R ²¹ to R ²⁸ .

Adjacent groups among R ²¹ to R ²⁸ in formula (A) may bond to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring. The group represented by formula (A-1) below does not form a ring, and examples of the group represented by formula (A-2) to formula (A-11) below include groups. At least one hydrogen atom in the group represented by any of formulas (A-1) to (A-11) may be substituted with alkyl, aryl, heteroaryl, alkoxy, aryloxy, arylthio, trialkylsilyl, diaryl-substituted amino, diheteroaryl-substituted amino, arylheteroaryl-substituted amino, halogen, hydroxy, or cyano, and examples of these groups include those described above as the groups for R ²¹ to R ²⁸ .

Examples of rings formed by bonding adjacent groups to each other include hydrocarbon rings such as cyclohexane rings, and aryl and heteroaryl rings such as the ring structures explained above for "aryl" and "heteroaryl" in R ^{to R} , and these rings are formed so as to be fused with one or two benzene rings in formula (A-1).

Examples of the group represented by formula (A) include groups represented by any of the following formulas (A-1) to (A-11). A group represented by any of formulas (A-1) to (A-4) is preferred, a group represented by any of formulas (A-1), (A-3), and (A-4) is more preferred, and a group represented by formula (A-1) is even more preferred.

The group represented by formula (A) is a group obtained by removing one hydrogen atom from any position of formula (A), and * indicates that position. That is, the group represented by formula (A) may have any position as its bonding position. Among these, it is preferably a group that is directly bonded to (has a bond to) any carbon atom on the two benzene rings in the structure of formula (A), an atom on any ring formed by bonding adjacent groups among R ²¹ to R ²⁸ in the structure of formula (A), or N in ">N-R ²⁹ " as Y in the structure of formula (A).

It is preferable that Y in formula (A) and Y in each of formulas (A-1) to (A-11) is -O-.

Examples of the group represented by formula (A) include groups represented by the following formula: In the formula, Y and * have the same definitions as above, and Y is preferably —O—.

Particularly preferred anthracene compounds represented by formula (1) include anthracene compounds represented by the following formula (1Aa).

In formula (1Aa), Ar ^c ', Ar ¹⁴ ', and Ar ¹⁵ ' are each independently phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by any one of formulas (A-1) to (A-11), and at least one hydrogen atom in these groups may be substituted by phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by any one of formulas (A-1) to (A-11). When both hydrogen atoms of methylene groups in fluorenyl and benzofluorenyl are substituted by phenyl, these phenyl groups may be bonded to each other by a single bond. Furthermore, a carbon atom on the anthracene ring to which Ar ^c ', Ar ¹⁴ ', and Ar ¹⁵ ' are not bonded may be substituted with methyl or t-butyl in place of hydrogen. At least one hydrogen in the compound represented by formula (1Aa) may be substituted with halogen or cyano, and at least one hydrogen in the compound represented by formula (1Aa) is substituted with deuterium.

In formula (1Aa), Ar ^c ', Ar ¹⁴ ', and Ar ¹⁵ ' are preferably each independently phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of formulas (A-1) to (A-4) above, and at least one hydrogen atom in these groups may be substituted by phenyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of formulas (A-1) to (A-4).

In the compound represented by formula (1Aa), it is preferable that at least the hydrogen bonded to the carbon at the 10th position of the anthracene ring (the carbon to which Ar ^c ' is bonded is considered to be the 9th position) is substituted with deuterium. That is, the compound represented by formula (1Aa) is preferably a compound represented by the following formula (1Ab). In formula (1Ab), D is deuterium, and Ar ^c ', Ar ¹⁴ ', and Ar ¹⁵ ' are the same as defined in formula (1Aa). D in formula (1Ab) indicates that at least this position is deuterium, and any one or more other hydrogen atoms in formula (1Aa) may also be deuterium, and it is also preferable that all hydrogen atoms in formula (1Aa) are deuterium.

Specific examples of anthracene-based compounds include compounds represented by the following formulas (3-1) to (3-72). Note that in the structural formulas below, "Me" represents methyl, "D" represents deuterium, and "tBu" represents t-butyl.

Further, other specific examples of the anthracene-based compound include, for example, compounds represented by the following formulas (3-131-Y) to (3-179-Y), compounds represented by the following formulas (3-180-Y) to (3-182-Y), compounds represented by the following formulas (3-183-N), (3-184-Y) to (3-254-Y), (3-254-Y) to (3-269-Y), and compounds represented by the following formulas (3-500) to (3-557). In the compounds represented by the following formulae (3-131-Y) to (3-179-Y), the compounds represented by the following formulae (3-180-Y) to (3-182-Y), the following formula (3-183-N), the following formulae (3-184-Y) to (3-254-Y), the following formulae (3-254-Y) to (3-269-Y), and the following formulae (3-500) to (3-557), hydrogen atoms may be partially or completely substituted with deuterium. In the formulae, Y may be —O—, —S—, >N—R ²⁹ (R ²⁹ is as defined above), or >C(—R ³⁰ ) ₂ (R ³⁰ is an optionally linked aryl or alkyl), and R ²⁹ is, for example, phenyl, and R ³⁰ is, for example, methyl. For example, when Y is O, the formula (3-131-Y) becomes the formula (3-131-O), and when Y is -S- or >N-R ²⁹ , the formula becomes the formula (3-131-S) or the formula (3-131-N), respectively.

Among these compounds, formulas (3-131-Y) to (3-134-Y), (3-138-Y), (3-140-Y) to (3-143-Y), (3-150-Y), (3-153-Y) to (3-156-Y), (3-166-Y), (3-168-Y), (3-173-Y), (3-177-Y), (3-180-Y) to (3-183-N), (3-185-Y), and (3-19 Compounds represented by formula (3-0-Y), formula (3-223-Y), formula (3-241-Y), formula (3-250-Y), formula (3-252-Y) to formula (3-254-Y), formula (3-501), formula (3-507), formula (3-508), formula (3-509), formula (3-513), formula (3-514), formula (3-519), formula (3-521), formula (3-538) to formula (3-547), or formula (3-600) to (3-620) are preferred. Furthermore, Y is preferably -O-.

The anthracene compound represented by formula (3-H) can be produced by applying Suzuki coupling, Negishi coupling, or other known coupling reactions using starting materials: a compound having a reactive group at a desired position on the anthracene skeleton; and a compound having a reactive group in a partial structure such as X, ^Ar4 , or the structure of formula (A). Examples of reactive groups in these reactive compounds include halogens and boronic acids. Specific production methods can be found, for example, in paragraphs [0089] to [0175] of WO 2014/141725.

<Fluorene-based compounds>
The compound represented by formula (4-H) basically functions as a host.

In formula (4-H),
R ¹ to R ¹⁰ each independently represent hydrogen, aryl, heteroaryl (the heteroaryl may be bonded to the fluorene skeleton in formula (4-H) via a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, in which at least one hydrogen may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl;
Furthermore, ^R1 and ^R2 , ^R2 and ^R3 , ^R3 and ^R4 , ^R5 and ^R6 , ^R6 and ^R7 , R7 and ^{R8 ,} or ^R9 and ^R10 may each independently bond to form a fused ring or a spiro ring, in which at least one hydrogen atom in the formed ring may be substituted with an aryl, a heteroaryl (the heteroaryl may be bonded to the formed ring via a linking group), a diarylamino, a diheteroarylamino, an arylheteroarylamino, an alkyl, a cycloalkyl, an alkenyl, an alkoxy, or an aryloxy, in which at least one hydrogen atom in these rings may be substituted with an aryl, a heteroaryl, an alkyl, or a cycloalkyl;
At least one hydrogen atom in the compound represented by formula (4-H) may be substituted with halogen, cyano or deuterium.

For details of each group in the definition of formula (4-H), please refer to the explanation for the polycyclic aromatic compound of formula (1) above.

Examples of the alkenyl for R ¹ to R ¹⁰ include alkenyl having 2 to 30 carbon atoms, preferably alkenyl having 2 to 20 carbon atoms, more preferably alkenyl having 2 to 10 carbon atoms, still more preferably alkenyl having 2 to 6 carbon atoms, and particularly preferably alkenyl having 2 to 4 carbon atoms. Preferred alkenyl groups include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl.

Specific examples of heteroaryl include monovalent groups represented by removing any one hydrogen atom from a compound of formula (4-Ar1), formula (4-Ar2), formula (4-Ar3), formula (4-Ar4), or formula (4-Ar5) below.

In formula (4-Ar1) to formula (4-Ar5), Y ¹ 's are each independently O, S, or N—R, and R is phenyl, biphenylyl, naphthyl, anthracenyl, or hydrogen;
At least one hydrogen atom in the structures of formulae (4-Ar1) to (4-Ar5) may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, phenanthrenyl, methyl, ethyl, propyl, or butyl.

These heteroaryls may be bonded to the fluorene skeleton in formula (4-H) via a linking group. That is, the fluorene skeleton and the heteroaryl in formula (4-H) may be bonded directly or via a linking group. Examples of such linking groups include phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, _{-OCH2CH2- , -CH2CH2O- ,} and _{-OCH2CH2O- .}

In addition, in formula (4-H), ^R1 and ^R2 , ^R2 and ^R3 , ^R3 and ^R4 , ^R5 and ^R6 , ^R6 and ^R7 , or R7 and ^R8 may each independently bond to form a fused ring, and ^R9 and ^R10 may bond to form a spiro ring. The fused ring formed by ^{R1 to R8} is a ring fused to the benzene ring in formula (4-H) and is an aliphatic ring or an aromatic ring. Preferably, it is an aromatic ring, and examples of structures including a benzene ring in formula (4-H) include a naphthalene ring and a phenanthrene ring. The spiro ring formed by ^R9 and ^R10 is a ring spiro-bonded to the five-membered ring in formula (4-H) and is an aliphatic ring or an aromatic ring. Preferably, it is an aromatic ring, and examples of such structures include a fluorene ring.

The compound represented by formula (4-H) is preferably a compound represented by the following formula (4-H-1), formula (4-H-2), or formula (4-H-3), which is a compound in which R ¹ and R ² in formula (4-H) are bonded to form a condensed benzene ring, a compound in which R ³ and R ⁴ in formula (4-H) are bonded to form a condensed benzene ring, or a compound in formula (4-H) to which none of R ¹ to R ⁸ are bonded.

The definitions of R ¹ to R ¹⁰ in formulas (4-H-1), (4-H-2), and (4-H-3) are the same as the corresponding R ¹ to R ¹⁰ in formula (4-H), and the definitions of R ¹¹ to R ¹⁴ in formulas (4-H-1) and (4-H-2) are the same as the corresponding R ¹ to R ¹⁰ in formula (4-H).

The compound represented by formula (4-H) is more preferably a compound represented by the following formula (4-H-1A), formula (4-H-2A), or formula (4-H-3A), which is a compound in which R ⁹ and R ¹⁰ in formula (4-H-1), formula (4-H-1), or formula (4-H-3) are bonded to form a spiro-fluorene ring, respectively.

The definitions of R ² to R ⁷ in formulas (4-1A), (4-2A), and (4-3A) are the same as the corresponding R ² to R ⁷ in formulas (4-1), (4-2), and (4-3), and the definitions of R ¹¹ to R ¹⁴ in formulas (4-1A) and (4-2A) are the same as the corresponding R ¹¹ to R ¹⁴ in formulas (4-1) and (4-2).

Furthermore, all or some of the hydrogen atoms in the compound represented by formula (4-H) may be substituted with halogen, cyano, or deuterium.

More specific examples of the fluorene-based compound as the host of the present invention include compounds represented by the following structural formula: wherein "Me" represents methyl.

<Dibenzochrysene compounds>
The dibenzochrysene compound as the host is, for example, a compound represented by the following formula (5-H).

In formula (5-H),
R ¹ to R ¹⁶ each independently represent hydrogen, aryl, heteroaryl (the heteroaryl may be bonded to the dibenzochrysene skeleton in formula (5-H) via a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, in which at least one hydrogen may be substituted with aryl, heteroaryl, alkyl, or cycloalkyl;
Furthermore, adjacent groups among R ¹ to R ¹⁶ may be bonded to each other to form a fused ring, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl (the heteroaryl may be bonded to the formed ring via a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl;
At least one hydrogen atom in the compound represented by formula (5-H) may be substituted with halogen, cyano or deuterium.

For details of each group in the definition of formula (5-H), please refer to the explanation for the polycyclic aromatic compound of formula (1) above.

The alkenyl in the definition of formula (5-H) is, for example, an alkenyl having 2 to 30 carbon atoms, preferably an alkenyl having 2 to 20 carbon atoms, more preferably an alkenyl having 2 to 10 carbon atoms, even more preferably an alkenyl having 2 to 6 carbon atoms, and particularly preferably an alkenyl having 2 to 4 carbon atoms. Preferred alkenyls are vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl.

Specific examples of heteroaryl include monovalent groups represented by removing any one hydrogen atom from a compound of formula (5-Ar1), formula (5-Ar2), formula (5-Ar3), formula (5-Ar4), or formula (5-Ar5) below.

In formula (5-Ar1) to formula (5-Ar5), Y ¹ 's are each independently O, S, or N—R, and R is phenyl, biphenylyl, naphthyl, anthracenyl, or hydrogen;
At least one hydrogen atom in the structures of formulae (5-Ar1) to (5-Ar5) may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, phenanthrenyl, methyl, ethyl, propyl, or butyl.

These heteroaryls may be bonded to the dibenzochrysene skeleton in formula (5-H) via a linking group. That is, the dibenzochrysene skeleton and the heteroaryl in formula (5-H) may be bonded directly or via a linking group. Examples of such linking groups include phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, _{-OCH2CH2- , -CH2CH2O- ,} and _{-OCH2CH2O- .}

In the compound represented by formula (5-H), R ¹ , R ⁴ , R ⁵ , R ⁸ , R ⁹ , R ¹² , R ¹³ and R ¹⁶ are preferably hydrogen. In this case, it is preferable that R ² , R ³ , R ⁶ , R ⁷ , R ¹⁰ , R ¹¹ , R ¹⁴ and R ¹⁵ in formula (5-H) are each independently hydrogen, phenyl, biphenylyl, naphthyl, anthracenyl, phenanthrenyl, a monovalent group having a structure of formula (5-Ar1), formula (5-Ar2), formula (5-Ar3), formula (5-Ar4) or formula (5-Ar5) (the monovalent group having such a structure may be bonded to the dibenzochrysene skeleton in formula (5-H) via phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, —OCH ₂ CH ₂ —, —CH ₂ CH ₂ O— or —OCH ₂ CH ₂ O—), methyl, ethyl, propyl or butyl.

In the compound represented by formula (5-H), R ¹ , R ² , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹² , R ¹³ , R ¹⁵ and R ¹⁶ are more preferably hydrogen. In this case, at least one (preferably one or two, more preferably one) of R ³ , R ⁶ , R ¹¹ and R ¹⁴ in formula (5-H) is a single bond, phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, —OCH ₂ CH ₂ —, —CH ₂ CH ₂ O—, or a _monovalent group having the structure of formula (5-Ar1), (5-Ar2), (5-Ar3), (5-Ar4) or (5-Ar5) via —OCH ₂ CH 2 O—,
The other than the at least one (i.e., other than the position substituted by the monovalent group having the structure) is hydrogen, phenyl, biphenylyl, naphthyl, anthracenyl, methyl, ethyl, propyl, or butyl, and at least one hydrogen in these may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, methyl, ethyl, propyl, or butyl.

Furthermore, when a monovalent group having a structure represented by formula (5-Ar1) to formula (5-Ar5) is selected as R ² , R ³ , R ⁶ , R ⁷ , R ¹⁰ , R ¹¹ , R ¹⁴ and R ¹⁵ in formula (5-H), at least one hydrogen atom in the structure may be bonded to any one of R ¹ to R ¹⁶ in formula (5-H) to form a single bond.

More specific examples of dibenzochrysene compounds as hosts in the present invention include compounds represented by the following structural formulas: where "tBu" represents t-butyl.

The above-mentioned light-emitting layer materials (host material and dopant material) can also be used as light-emitting layer materials in the form of polymer compounds obtained by polymerizing a reactive compound substituted with a reactive substituent as a monomer, or a crosslinked polymer thereof, or a pendant-type polymer compound obtained by reacting a main-chain polymer with the reactive compound, or a crosslinked pendant-type polymer thereof. Regarding the reactive substituent in this case, the same explanation as for the polycyclic aromatic compound represented by formula (1) can be cited.
The uses of such polymer compounds and crosslinked polymers will be described in detail below.

<Examples of polymer host materials>

In formula (SPH-1),
Each MU is independently a divalent aromatic group, each EC is independently a monovalent aromatic group, two hydrogen atoms in MU are replaced with EC or MU, and k is an integer of 2 to 50,000.

More specifically,
Each MU is independently arylene, heteroarylene, diarylylenearylamino, diarylylenearylboryl, oxaborine-diyl, or azaborine-diyl;
each EC is independently hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, or aryloxy;
At least one hydrogen atom in MU and EC may be further substituted with aryl, heteroaryl, diarylamino, alkyl, and cycloalkyl;
k is an integer from 2 to 50,000.
k is preferably an integer of 20 to 50,000, and more preferably an integer of 100 to 50,000.

At least one hydrogen atom in MU and EC in formula (SPH-1) may be substituted with alkyl having 1 to 24 carbon atoms, cycloalkyl having 3 to 24 carbon atoms, halogen, or deuterium; further, any —CH ₂ — in the alkyl may be substituted with —O— or —Si(CH ₃ ) ₂ —; any —CH ₂ — in the alkyl except for the —CH ₂ — directly bonded to EC in formula (SPH-1) may be substituted with arylene having 6 to 24 carbon atoms; and any hydrogen atom in the alkyl may be substituted with fluorine.

Examples of MU include a divalent group represented by removing any two hydrogen atoms from any of the following compounds:

More specifically, examples include divalent groups represented by any of the following structures. In these, MU is bonded to another MU or EC at the *.

Examples of EC include monovalent groups represented by any of the following structures. In these, EC is bonded to MU at *.

From the viewpoints of solubility and film-forming properties, the compound represented by formula (SPH-1) preferably has 10 to 100% of the total number of MUs (k) in the molecule having alkyl groups with 1 to 24 carbon atoms, more preferably 30 to 100% of the total number of MUs (k) having alkyl groups with 1 to 18 carbon atoms (branched-chain alkyl groups with 3 to 18 carbon atoms), and even more preferably 50 to 100% of the total number of MUs (k) having alkyl groups with 1 to 12 carbon atoms (branched-chain alkyl groups with 3 to 12 carbon atoms). On the other hand, from the viewpoints of in-plane alignment and charge transport, preferably has 10 to 100% of the total number of MUs (k) in the molecule having alkyl groups with 7 to 24 carbon atoms, and even more preferably 30 to 100% of the total number of MUs (k) having alkyl groups with 7 to 24 carbon atoms.

The light-emitting layer in the organic electroluminescent device containing an assisting dopant and an emitting dopant may contain a host compound as a first component, an assisting dopant (compound) as a second component, and an emitting dopant (compound) as a third component.
The polycyclic aromatic compound of the present invention is also preferably used as an emitting dopant.
As the assisting dopant (compound), a thermally activated delayed fluorescent material can be used.

In the following description, an organic electroluminescent device using a thermally activated delayed fluorescent substance as an assisting dopant may be referred to as a "TAF device" (TADF Assisting Fluorescence device).
The "host compound" in the TAF element means a compound whose excited singlet energy level, determined from the shoulder on the short-wavelength side of the peak of the fluorescence spectrum, is higher than that of the thermally activated delayed fluorescent material as the second component and the emitting dopant as the third component.
The term "thermally activated delayed fluorescent substance" refers to a compound that can absorb thermal energy to 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. However, the term "thermally activated delayed fluorescent substance" also includes compounds that undergo a higher-order triplet state during the excitation process from the excited triplet state to the excited singlet state. Examples include 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 an academic 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 emissive 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 300 K, if a slow fluorescent component is observed, the target compound is determined to be a "thermally activated delayed fluorescent substance." Here, a slow fluorescent component refers to a component having a fluorescence lifetime of 0.1 μsec or longer. The fluorescence lifetime can be measured using, for example, a fluorescence lifetime measurement device (manufactured by Hamamatsu Photonics KK, C11367-01).
The polycyclic aromatic compound of the present invention can function as an emitting dopant, and the "thermally activated delayed fluorescent substance" can function as an assisting dopant that assists the emission of the polycyclic aromatic compound of the present invention.

Figure 2 shows the energy level diagram of the emitting layer of a TAF device using a common fluorescent dopant as the emitting dopant (ED). In the diagram, the ground state energy level of the host is E(1,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the host's fluorescence spectrum is E(1,S,Sh), the excited triplet energy level obtained from the shoulder on the short wavelength side of the host's phosphorescence spectrum is E(1,T,Sh), the ground state energy level of the assisting dopant, which is the second component, is E(2,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the assisting dopant, which is the second component, is E(2,S,Sh), and the excited triplet energy level obtained from the shoulder on the short wavelength side of the second component's phosphorescence spectrum is E(1,T,Sh). The excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the assisting dopant is E(2,T,Sh), the ground state energy level of the emitting dopant which is the third component is E(3,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the emitting dopant which is the third component is E(3,S,Sh), and the excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the emitting dopant which is the third component is E(3,T,Sh). In a TAF element, when a general fluorescent dopant is used as the emitting dopant (ED), energy upconverted by the assisting dopant is transferred to the excited singlet energy level E(3,S,Sh) of the emitting dopant and emits light. However, some of the excited triplet energy E(2,T,Sh) on the assisting dopant transfers to the excited triplet energy level E(3,T,Sh) of the emitting dopant, or intersystem crossing occurs on the emitting dopant from the excited singlet energy level E(3,S,Sh) to the excited triplet energy level E(3,T,Sh), followed by thermal decay to the ground state E(3,G). Due to this pathway, some of the energy is not used for light emission, resulting in wasted energy.

In contrast, in the organic electroluminescent device of this embodiment, the energy transferred from the assisting dopant to the emitting dopant can be efficiently utilized for light emission, thereby achieving high luminous efficiency. This is presumably due to the following luminescence mechanism.
A preferred energy relationship in the organic electroluminescent device of this embodiment is shown in Figure 3. In the organic electroluminescent device of this embodiment, the compound having a boron atom as the emitting dopant has a high excited triplet energy level E (3, T, Sh). Therefore, even if the excited singlet energy upconverted by the assisting dopant undergoes intersystem crossing to the excited triplet energy level E (3, T, Sh) in the emitting dopant, it is upconverted on the emitting dopant or recovered to the excited triplet energy level E (2, T, Sh) on the assisting dopant (thermally activated delayed fluorescent material). Therefore, the generated excited energy can be used for emission without waste. Furthermore, by dividing the upconversion and emission functions into two types of molecules that are each good at each, the residence time of high energy is reduced, and it is expected that the burden on the compound is reduced.
In this embodiment, known host compounds can be used, such as compounds having at least one of a carbazole ring and a furan ring. Among them, it is preferable to use a compound in which at least one of a furanyl group and a carbazolyl group is bonded to at least one of an arylene group and a heteroarylene group. Specific examples include mCP and mCBP.

From the viewpoint of promoting rather than inhibiting the generation of TADF in the emitting layer, the excited triplet energy level E(1,T,Sh) of the host compound, determined from the shoulder on the short-wavelength side of the peak in the phosphorescence spectrum, is preferably higher than the excited triplet energy levels E(2,T,Sh) and E(3,T,Sh) of the emitting dopant or assisting dopant having the highest excited triplet energy level in the emitting layer. Specifically, the excited triplet energy level E(1,T,Sh) of the host compound is preferably 0.01 eV or higher, more preferably 0.03 eV or higher, and even more preferably 0.1 eV or higher, compared to E(2,T,Sh) and E(3,T,Sh). Furthermore, a TADF-active compound may be used as the host compound.

The host compound can be, for example, a compound represented by any of the above formulas (H1), (H2), and (H3).

<Thermally activated delayed phosphor (assisting dopant)>
The thermally activated delayed fluorescent substance (TADF compound) used in the TAF element is preferably a donor-acceptor type thermally activated delayed fluorescent substance (DA type TADF compound) designed to localize the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) in the molecule 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 a LUMO orbital is localized in a thermally activated delayed fluorescent substance molecule, and the term "electron-accepting substituent" (acceptor) refers to a substituent or partial structure in which a HOMO orbital is localized in a thermally activated delayed fluorescent substance molecule.
Generally, thermally activated delayed fluorescent materials using donors or acceptors have large spin orbit coupling (SOC) due to their structure, and small exchange interaction between HOMO and LUMO, resulting in a small ΔE(ST), resulting in a very fast reverse intersystem crossing rate. On the other hand, thermally activated delayed fluorescent materials using donors or acceptors exhibit large structural relaxation in the excited state (in some molecules, the stable structures in the ground state and excited state are different, so when an external stimulus causes conversion from the ground state to the excited state, the structure then changes to the stable structure in the excited state), which gives a wide emission spectrum, and therefore may reduce color purity when used as a light-emitting material.

The thermally activated delayed fluorescent substance in the TAF element can be, for example, a compound in which a donor and an acceptor are bound directly or via a spacer. The donor and acceptor structures used in the thermally activated delayed fluorescent substance of the present invention can be, for example, the structures described in Chemistry of Materials, 2017, 29, 1946-1963. Examples of donor structures include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridinediamine, tetramethyl-dihydro-indenoacridine, and diphenyl-dihydrodibenzazasiline. Examples of 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, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorene dicarbonitrile, triphenyltriazine, pyrazine dicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridine dicarbonitrile, dibenzoquinoxaline dicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thianthrene tetraoxide, and tris(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence in the TAF element is preferably a compound having at least one partial structure selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenyl sulfone, triazole, oxadiazole, thiadiazole, and benzophenone.

The compound used as the second component of the light-emitting layer in a TAF element is preferably a thermally activated delayed phosphor whose emission spectrum at least partially overlaps with the absorption peak of the emitting dopant. Examples of compounds that can be used as the second component (thermally activated delayed phosphor) of the light-emitting layer in a TAF element are listed below. However, compounds that can be used as thermally activated delayed phosphors in a TAF element should not be interpreted as being limited to the examples below. In the formula below, Me represents methyl, t-Bu represents t-butyl, Ph represents phenyl, and the wavy lines represent bonding positions.

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

In the above formulas (AD1), (AD2) and (AD3),
Each M is independently a single bond, -O-, >N-Ar, or >CAR _. From the viewpoint of the depth of the HOMO and the height of the excited singlet and triplet energy levels of the partial structure to be formed, a single bond, -O-, or >N-Ar is preferred. Each J is a spacer structure separating the donor partial structure and the acceptor partial structure. Each J is independently an arylene having 6 to 18 carbon atoms. From the viewpoint of the magnitude of conjugation exuding from the donor partial structure and the acceptor partial structure, an arylene having 6 to 12 carbon atoms is preferred. More specific examples include phenylene, methylphenylene, and dimethylphenylene. Each Q is independently ═C(—H)— or ═N—. From the viewpoint of the shallowness of the LUMO and the height of the excited singlet and triplet energy levels of the partial structure to be formed, ═N— is preferred. Each Ar is 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. 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, Ar is 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 1 to (6-m), and from the viewpoint of steric hindrance, n is 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 in this embodiment 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.

The compound used as the second component in this embodiment may be a donor-acceptor type TADF compound represented by D-A, in which one donor D and one acceptor A are bonded via a direct bond or a linking group; however, a compound having a structure represented by the following formula (DAD1), in which multiple donors D are bonded to one acceptor A via a direct bond or a linking group, is preferred because it will result in better properties for the organic electroluminescent device.
(D ¹ -L ¹ )n-A ¹ (DAD1)
Formula (DAD1) includes compounds represented by the following formula (DAD2).
D ² -L ² -A ² -L ³ -D ³ (DAD2)
In formula (DAD1) and formula (DAD2), ^D1 , ^D2 , and ^D3 each independently represent a donor group. The donor group may have the donor structure described above. ^A1 and ^A2 each independently represent an acceptor group. The acceptor group may have the acceptor structure described above. ^L1 , ^L2 , and ^L3 each independently represent a single bond or a conjugated linking group. The conjugated linking group is a spacer structure separating the donor group and the acceptor group, and is preferably an arylene having 6 to 18 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms. It is more preferable that ^L1 , ^L2 , and ^L3 each independently represent phenylene, methylphenylene, or dimethylphenylene. In formula (DAD1), n represents an integer of 2 or more and not exceeding the maximum number of groups that ^A1 can substitute. For example, n may be selected within the range of 2 to 10, or within the range of 2 to 6. When n is 2, the compound is represented by formula (DAD2). The n D ^1s may be the same or different, and the n L ^1s may be the same or different. Preferred specific examples of the compounds represented by formula (DAD1) and formula (DAD2) include 2PXZ-TAZ and the following compounds, but the second component that can be employed in the present invention is not limited to these compounds.

In this embodiment, the light-emitting layer may be composed of a single layer or multiple layers. The host compound, thermally activated delayed phosphor, and polycyclic aromatic compound of the present invention may be contained in the same layer, or multiple layers may contain at least one component each. The light-emitting layer may contain one or more types of host compound, thermally activated delayed phosphor, and polycyclic aromatic compound of the present invention. The assisting dopant and emitting dopant may be contained entirely or partially in the host compound matrix. The light-emitting layer doped with the assisting dopant and emitting dopant can be formed by a method of forming a film by ternary co-evaporation of the host compound, assisting dopant, and emitting dopant; a method of premixing the host compound, assisting dopant, and emitting dopant and then simultaneously evaporating them; or a wet film-forming method in which an emitting layer-forming composition (paint) prepared by dissolving the host compound, assisting dopant, and emitting dopant in an organic solvent is applied.

The amount of host compound used varies depending on the type of host compound, and can be determined based on the properties of the host compound. The recommended amount of host compound used is preferably 40 to 99.999% by mass of the total light-emitting layer materials, more preferably 50 to 99.99% by mass, and even more preferably 60 to 99.9% by mass. The above ranges are preferable in terms of, for example, efficient charge transport and efficient energy transfer to the dopant.

The amount of assisting dopant (thermally activated delayed phosphor) used varies depending on the type of assisting dopant, and can be determined based on the characteristics of the assisting dopant. The amount of assisting dopant used is preferably 1 to 60% by mass of the total material for the light-emitting layer, more preferably 2 to 50% by mass, and even more preferably 5 to 30% by mass. The above ranges are preferable, for example, because they allow energy to be transferred efficiently to the emitting dopant.

The amount of emitting dopant (a compound containing boron atoms) used varies depending on the type of emitting dopant and can be determined based on the characteristics of that emitting dopant. The recommended amount of emitting dopant used is preferably 0.001 to 30% by mass of the total emitting layer material, more preferably 0.01 to 20% by mass, and even more preferably 0.1 to 10% by mass. The above ranges are preferable in that they can prevent concentration quenching, for example.

A low concentration of the emitting dopant is preferable in terms of preventing concentration quenching. A high concentration of the assisting dopant is preferable in terms of the efficiency of the thermally activated delayed fluorescence mechanism. Furthermore, from the perspective of the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant, it is preferable that the concentration of the emitting dopant be lower than the amount of the assisting dopant.

2-1-3. Substrate in Organic Electroluminescent Device The substrate 101 is a support for the organic EL element 100 and is typically made of quartz, glass, metal, plastic, or the like. The substrate 101 is formed into a plate, film, or sheet shape depending on the purpose, and examples include glass plates, metal plates, metal foils, plastic films, and plastic sheets. Glass plates and plates made of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. For glass substrates, soda-lime glass or alkali-free glass is used, and the thickness should be sufficient to maintain mechanical strength, e.g., 0.2 mm or more. The upper limit of the thickness is, for example, 2 mm or less, preferably 1 mm or less. Regarding the glass material, alkali-free glass is preferred because fewer ions are eluted from the glass. However, commercially available soda-lime glass coated with a barrier coating such as _SiO2 can also be used. Furthermore, in order to improve the gas barrier properties of the substrate 101, a gas barrier film such as a dense silicon oxide film may be provided on at least one side thereof, and it is particularly preferable to provide a gas barrier film when a synthetic resin plate, film or sheet with poor gas barrier properties is used as the substrate 101.

The anode 102 plays a role in injecting holes into the light-emitting layer 105. If a hole injection layer 103 and/or a hole transport layer 104 is 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. Inorganic compounds include, for example, 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. Organic compounds include, for example, polythiophenes such as poly(3-methylthiophene), and conductive polymers such as polypyrrole and polyaniline. Other materials that can be appropriately selected from those used as anodes in organic EL elements can also be used.

The resistance of the transparent electrode is not limited as long as it can supply enough current to light the light-emitting element, but low resistance is desirable from the perspective 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 substrates of around 10 Ω/□ are now available, 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 depending on the resistance value, but it is usually between 50 and 300 nm.

2-1-5. Hole Injection Layer and Hole Transport Layer in Organic Electroluminescent Device The hole injection layer 103 serves to efficiently inject holes migrating from the anode 102 into the light-emitting layer 105 or the hole transport layer 104. The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 via 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 or mixing one or more hole injection/transport materials, or by a mixture of a hole injection/transport material and a polymer binder. Alternatively, an inorganic salt such as iron (III) chloride may be added to the hole injection/transport material to form a layer.

A 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. It is desirable for the material to have high hole injection efficiency and efficiently transport the injected holes. To achieve this, it is preferable for the material to have a low ionization potential, high hole mobility, excellent stability, and be less likely to generate impurities that can become traps during production or use.

As materials for forming the hole injection layer 103 and the hole transport layer 104, any compound can be selected from compounds conventionally used as charge transport materials for holes in photoconductive materials, p-type semiconductors, and known compounds used in hole injection layers and hole transport layers of organic EL elements. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (4,4',4"-tris(N-carbazolyl)triphenylamine, polymers having an aromatic tertiary amino group 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, heterocyclic compounds such as benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (for example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile), porphyrin derivatives, and polysilanes. As polymers, polycarbonates, styrene derivatives, polyvinylcarbazole, polysilanes, and the like having the above-mentioned monomers in their side chains are preferred, but there are no particular limitations on the type of polymer as long as it is a compound that can form a thin film required for producing a light-emitting element, can inject holes from the anode, and can transport holes.

It is also known that the conductivity of organic semiconductors is strongly affected by their doping. Such organic semiconductor matrix materials are composed of compounds with good electron donating or accepting properties. Strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known for doping with electron donating substances (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes through 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. Known matrix materials with hole-transporting properties include benzidine derivatives (e.g., TPD), starburst amine derivatives (e.g., TDATA), and certain metal phthalocyanines (e.g., zinc phthalocyanine (ZnPc)) (see JP 2005-167175 A).
The polycyclic aromatic compound of the present invention may be used as a material for forming a hole injection layer or a material for forming a hole transport layer.

2-1-6. Electron Blocking Layer in Organic Electroluminescent Devices An electron blocking layer may be provided between the hole injection/transport layer and the light-emitting layer to prevent diffusion of electrons from the light-emitting layer. The electron blocking layer may be formed from a compound represented by any of the above formulas (H1), (H2), and (H3).
The polycyclic aromatic compound of the present invention may be used as a material for forming an electron blocking layer.

2-1-7. 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 or mixing one or more electron transport/injection materials, or by a mixture of an electron transport/injection material and a polymer binder.

The electron injection/transport layer is a layer that is responsible for the injection and transport of electrons from the cathode. It is desirable for the electron injection/transport layer to have high electron injection efficiency and efficiently transport the injected electrons. To achieve this, it is preferable for the material to have high electron affinity, high electron mobility, and excellent stability, and to be less likely to generate impurities that act as traps during manufacture and use. However, when considering the balance between hole and electron transport, if a material's primary function is to efficiently block holes from the anode from flowing toward the cathode without recombining, then even if its electron transport capacity is not that high, it can still have the same effect of improving luminous efficiency as a material with high electron transport capacity. Therefore, the electron injection/transport layer in this embodiment may also function as 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 selected from compounds conventionally used as electron transport compounds in photoconductive materials and known compounds used in the electron injection layers and electron transport layers of organic EL devices.

Materials used in the electron transport layer or electron injection layer preferably contain at least one selected from compounds consisting of aromatic or heteroaromatic rings composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon, and phosphorus; pyrrole derivatives and their fused ring derivatives; and metal complexes having electron-accepting nitrogen. Specific examples include fused ring aromatic derivatives such as naphthalene and anthracene; styryl aromatic derivatives such as 4,4'-bis(diphenylethenyl)biphenyl; perinone derivatives; coumarin derivatives; naphthalimide derivatives; quinone derivatives such as anthraquinone and diphenoquinone; phosphorus oxide derivatives; arylnitrile derivatives; and indole derivatives. Examples of metal complexes having electron-accepting nitrogen include 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 other materials.

Specific examples of other electron transport compounds include pyridine derivatives, naphthalene derivatives, fluoranthene derivatives, BO-based derivatives, anthracene 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-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoxazole derivatives, and the like. Examples of such compounds include quinolin derivatives (such as 2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spirobifluorene), imidazopyridine derivatives, borane 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, phosphorus oxide derivatives, bisstyryl derivatives, silole derivatives, and azoline derivatives.

Metal complexes having an electron-accepting nitrogen atom 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 materials mentioned above, 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, quinolinol-based metal complexes, thiazole derivatives, benzothiazole derivatives, silole derivatives, and azoline derivatives are preferred.

The polycyclic aromatic compound of the present invention may be used as a material for forming an electron injection layer or an electron transport layer.

The electron transport layer or electron injection layer may further contain a substance capable of reducing the material forming the electron transport layer or electron injection layer. A variety of substances can be used as this reducing substance, as long as they have a certain level of reducing ability. For example, at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, rare earth metal oxides, rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, and rare earth metal organic complexes can be suitably 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). Substances with a work function of 2.9 eV or less are particularly preferred. Among these, alkali metals K, Rb, or Cs are more preferred, with Rb or Cs being even more preferred, and Cs being the most preferred. These alkali metals have particularly high reducing power, and adding relatively small amounts to the materials forming the electron transport layer or electron injection layer can improve the luminance and extend the life of organic EL devices. Combinations of two or more of these alkali metals are also preferred as reducing substances with a work function of 2.9 eV or less, and combinations containing Cs, such as Cs and Na, Cs and K, Cs and Rb, or Cs, Na and K, are particularly preferred. By including Cs, the reducing ability can be efficiently exerted, and adding it to the material that forms the electron transport layer or electron injection layer can improve the luminance and extend the life of the organic EL element.

2-1-8. Cathode in Organic Electroluminescent Device The cathode 108 serves to inject electrons into the light-emitting layer 105 via the electron injection layer 107 and the electron transport layer 106 .

The material for the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but the same materials as those for the anode 102 can be used. Among these, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium, and magnesium, or alloys thereof (e.g., magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys such as lithium fluoride/aluminum alloys), are preferred. To increase electron injection efficiency and improve device performance, 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 address this issue, a known method is to dope the organic layer with trace amounts of lithium, cesium, or magnesium to create a highly stable electrode. Other dopants that can be used include, but are not limited to, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide, and cesium oxide.

Furthermore, for electrode protection, 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. There are no particular restrictions on the method for producing these electrodes, as long as electrical conductivity can be achieved, and methods such as resistance heating, electron beam evaporation, sputtering, ion plating, and coating can be used.

2-1-9. Binders that may be used in each layer The materials used in the hole injection layer, hole transport layer, light-emitting layer, electron transport layer, and electron injection layer described above can be used alone to form each layer, but they can also be used as a polymer binder by being dispersed in a solvent-soluble resin such as polyvinyl chloride, polycarbonate, polystyrene, poly(N-vinylcarbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate resin, ABS resin, or polyurethane resin, or a curable resin such as phenol resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, or silicone resin.

2-1-10. Method for Fabricating Organic Electroluminescent Devices Each layer constituting an organic EL device can be formed by forming the materials constituting each layer into a thin film using methods such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, inkjet printing, spin coating, casting, and coating. The thickness of each layer thus formed is not particularly limited and can be set appropriately depending on the properties of the material, but is typically in the range of 2 nm to 5,000 nm. Film thickness can typically be measured using a quartz crystal oscillator film thickness measuring device. When forming a thin film using vapor deposition, the vapor deposition conditions vary depending on the type of material, the desired crystalline structure and association structure of the film, and other factors. The vapor deposition conditions are generally set appropriately within the following range: boat heating temperature +50 to +400°C, vacuum level ^10-6 to ^10-3 Pa, vapor deposition rate 0.01 to 50 nm/sec, substrate temperature -150 to +300°C, and film thickness in the range of 2 nm to 5 μm.

Next, as an example of a method for fabricating an organic EL device, we will explain a method for fabricating an organic EL device consisting of an anode, hole injection layer, hole transport layer, emissive layer composed of a host material and a dopant material, electron transport layer, electron injection layer, and cathode. A thin film of anode material is formed on a suitable substrate by vapor deposition or other methods to form an anode, and then thin films of hole injection layer and hole transport layer are formed on the anode. A thin film of host material and dopant material is co-deposited on top of this to form an emissive layer. An electron transport layer and electron injection layer are then formed on top of this emissive layer, and a thin film of cathode material is then formed by vapor deposition or other methods to form the cathode, thereby obtaining the desired organic EL device. It should be noted that the above-described organic EL device can also be fabricated in the reverse order: cathode, electron injection layer, electron transport layer, emissive layer, hole transport layer, hole injection layer, and anode.

When applying a DC voltage to the organic EL element obtained in this way, the anode should be set to + polarity and the cathode to - polarity. When a voltage of approximately 2 to 40 V is applied, light emission can be observed from the transparent or semi-transparent electrode side (anode or cathode, or both). This organic EL element also emits light when a pulse current or AC current is applied. The AC waveform applied can be any waveform.

2-1-11. Application Examples of Organic Electroluminescent Devices Organic EL devices can also be used in display devices, lighting devices, and the like.
A display device or lighting device including an organic EL element can be manufactured by a known method, such as by connecting the organic EL element to a known driving device, and can be driven appropriately using a known driving method such as DC driving, pulse driving, or AC driving.

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

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

In the segment type, 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 and backlights for liquid crystal display devices (see, for example, JP 2003-257621 A, JP 2003-277741 A, and JP 2004-119211 A). Backlights are primarily used to improve the visibility of non-self-luminous display devices, and are used in liquid crystal display devices, clocks, audio equipment, automotive panels, display boards, signs, and the like. In particular, for backlights for liquid crystal display devices, particularly those used in personal computers where thinning is an issue, traditional methods use fluorescent lamps and light guide plates, making thinning difficult. Considering this, backlights using organic EL elements are characterized by their thinness and light weight.

2-2. Other Organic Devices The polycyclic aromatic compound according to the present invention can be used to produce organic field effect transistors or organic thin-film solar cells, in addition to the organic electroluminescent devices described above.

An organic field-effect transistor is a transistor that controls current using an electric field generated by voltage input. In addition to source and drain electrodes, it has a gate 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 and drain electrodes can be blocked at will, allowing current to be controlled. Field-effect transistors are easier to miniaturize than simple transistors (bipolar transistors), and are often used as elements in integrated circuits.

The organic field-effect transistor generally has a structure in which 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 device structure include the following structures.
(1) Substrate/gate electrode/insulating layer/source electrode/drain electrode/organic semiconductor active layer (2) Substrate/gate electrode/insulating layer/organic semiconductor active layer/source electrode/drain electrode (3) Substrate/organic semiconductor active layer/source electrode/drain electrode/insulating layer/gate electrode (4) Substrate/source electrode/drain electrode/organic semiconductor active layer/insulating layer/gate electrode An organic field effect transistor configured in this manner can be used as a pixel driving switching element for active matrix driven 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 layered 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 of the present invention can be used as a material for the hole transport layer, p-type semiconductor layer, n-type semiconductor layer, or electron transport layer, depending on its physical properties. The polycyclic aromatic compound of the present invention can function as a hole transport material or electron transport material in an organic thin-film solar cell. In addition to the above, the organic thin-film solar cell may also include a hole blocking layer, electron blocking layer, electron injection layer, hole injection layer, smoothing layer, etc. as appropriate. Known materials used in organic thin-film solar cells can be selected and combined as appropriate for use in the organic thin-film solar cell.

3. Wavelength Converting Material The polycyclic aromatic compound of the present invention can be used as a wavelength converting material.
Currently, the application of color conversion-based multicolor technology to liquid crystal displays, organic electroluminescence (EL) displays, lighting, and other applications is being actively investigated. Color conversion refers to the wavelength conversion of light emitted from an illuminant to light of a longer wavelength, such as converting ultraviolet or blue light to green or red light. By forming a film of a wavelength conversion material with this color conversion function and combining it with, for example, a blue light source, it is possible to extract the three primary colors of blue, green, and red from the blue light source, i.e., white light. By combining such a blue light source with a wavelength conversion film with color conversion function as a light source unit, and combining it with a liquid crystal driver and color filters, a full-color display can be fabricated. Furthermore, if the liquid crystal driver is not required, the white light source can be used as is, for example, as a white light source for LED lighting. Furthermore, by using a blue organic EL element as a light source and combining it with a wavelength conversion film that converts blue light to green and red light, it is possible to fabricate a full-color EL display without using a metal mask. Furthermore, by using blue micro-LEDs as a light source in combination with wavelength conversion films that convert blue light into green and red light, it becomes possible to create low-cost full-color micro-LED displays.

The polycyclic aromatic compound of the present invention can be used as this wavelength converting material. By using a wavelength converting material containing the polycyclic aromatic compound of the present invention, light from a light source or light-emitting element that generates ultraviolet light or a shorter wavelength blue light can be converted into blue light or green light with high color purity suitable for use in display devices (display devices using organic EL elements and liquid crystal display devices). The converted color can be adjusted by appropriately selecting the substituents of the polycyclic aromatic compound of the present invention, the binder resin used in the wavelength converting composition described below, and the like. The wavelength converting material can be prepared as a wavelength converting composition containing the polycyclic aromatic compound of the present invention. Furthermore, this wavelength converting composition may be used to form a wavelength conversion film.

The wavelength-converting composition may contain, in addition to the polycyclic aromatic compound of the present invention, a binder resin, other additives, and a solvent. Examples of binder resins that can be used include those described in paragraphs [0173] to [0176] of WO 2016/190283. Examples of other additives that can be used include compounds described in paragraphs [0177] to [0181] of WO 2016/190283. For solvents, please refer to the descriptions of the solvents contained in the light-emitting layer-forming composition described above.

The wavelength conversion film includes a wavelength converting layer formed by curing a wavelength converting composition. Known film formation methods can be referred to as a method for producing a wavelength converting layer from a wavelength converting composition. The wavelength conversion film may consist solely of a wavelength converting layer formed from a composition containing the polycyclic aromatic compound of the present invention, or may also include other wavelength converting layers (for example, a wavelength converting layer that converts blue light into green light or red light, or a wavelength converting layer that converts blue light or green light into red light). The wavelength conversion film may further include a substrate layer and a barrier layer to prevent deterioration of the color conversion layer due to oxygen, moisture, or heat.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

Synthesis Example (1):
Synthesis of compound (1-c1-8)

Step 1: Under a nitrogen atmosphere, compound (T-1) (6.24 g) (manufactured by Combi-Bloc), compound (T-2) (10.0 g), sodium tert-butoxide (4.22 g), dichlorobis(di-t-butyl(4-dimethylaminophenyl)phosphino)palladium (Pd-132, 0.21 g) as a palladium catalyst, and xylene (100 ml) were placed in a reactor and heated to reflux for 3 hours. After the reaction mixture was cooled to room temperature, the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (T-3) (11.17 g; 86%).

Step 2: Under a nitrogen atmosphere, compound (T-3) (11.17 g), boron triiodide (19.70 g), dodecane (1.37 ml), and o-dichlorobenzene (ODCB) (112 ml) were placed in a reactor and heated with stirring at 150°C for 3 hours. After cooling, a THF solution of (T-4) (8.38 g) was added dropwise and stirred overnight. The reaction mixture was poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by Florisil chromatography (toluene) and recrystallized from heptane to obtain compound (T-5) (10.01 g; 64%).

Step 3: Under a nitrogen atmosphere, compound (T-5) (10.01 g), tris(trifluoromethanesulfonate)scandium(III) (7.93 g), and 1,2-dichloroethane (100 ml) were placed in a reactor and heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and then poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (heptane/toluene). Further purification by recrystallization from heptane yielded compound (1-c1-8) (1.31; 13%).

HRMS m/z 625.3922 (calcd C ₄₃ H ₅₂ BNS, 625.3914).

Synthesis of (T-2)
It was synthesized based on the method described in Tertrahedron 68 (2012) 7063-7069.

Synthesis of (T-4)
(T-4) was synthesized from (T-6) purchased from Aurora Building Blocks according to the above route.

Synthesis Example (2):
Synthesis of compound (1-c2f-64)

Step 1: Under a nitrogen atmosphere, compound (T-1) (7.5 g) (manufactured by Combi-Bloc), compound (T-10) (11.43 g), sodium tert-butoxide (5.07 g), dichlorobis(di-t-butyl(4-dimethylaminophenyl)phosphino)palladium (Pd-132, 0.23 g) as a palladium catalyst, and xylene (110 ml) were placed in a reactor and heated to reflux for 3 hours. After the reaction mixture was cooled to room temperature, the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (T-11) (11.29 g; 75%).

Step 2: Under a nitrogen atmosphere, compound (T-11) (11.29 g), boron triiodide (20.67 g), dodecane (1.45 ml), and o-dichlorobenzene (ODCB) (120 ml) were placed in a reactor and heated with stirring at 150°C for 3 hours. After cooling, a THF solution of (T-12) (10.56 g) was added dropwise and stirred overnight. The reaction mixture was poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by Florisil chromatography (toluene) and recrystallized from heptane to obtain compound (T-13) (9.84 g; 56%).

Step 3: Under a nitrogen atmosphere, compound (T-13) (9.84 g), tris(trifluoromethanesulfonate)scandium(III) (7.27 g), and 1,2-dichloroethane (100 ml) were placed in a reactor and heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and then poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (heptane/toluene). Further purification by recrystallization from heptane yielded compound (1-c2f-64) (0.98 g; 10%).

HRMS m/z 665.3849 (calcd C ₄₃ H ₅₂ BNOS, 665.3863).

Synthesis of (T-10)
It was synthesized based on the method described in Journal of Organic Chemistry, 82(19), 10523-10536; 2017.

Synthesis Example (3):
Synthesis of compound (1-c2f-65)

Step 1: Under a nitrogen atmosphere, compound (T-1) (7.0 g) (manufactured by Combi-Bloc), compound (T-14) (10.08 g), sodium tert-butoxide (4.73 g), dichlorobis(di-t-butyl(4-dimethylaminophenyl)phosphino)palladium (Pd-132, 0.24 g) as a palladium catalyst, and xylene (100 ml) were placed in a reactor and heated to reflux for 3 hours. After the reaction mixture was cooled to room temperature, the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. This solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (T-15) (9.59 g; 71%).

Step 2: Under a nitrogen atmosphere, compound (T-15) (9.59 g), boron triiodide (18.24 g), dodecane (1.27 ml), and o-dichlorobenzene (ODCB) (110 ml) were placed in a reactor and heated with stirring at 150°C for 3 hours. After cooling, a THF solution of (T-12) (7.75 g) was added dropwise and stirred overnight. The reaction mixture was poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by Florisil chromatography (toluene) and recrystallized from heptane to obtain compound (T-16) (8.93 g; 59%).

Step 3: Under a nitrogen atmosphere, compound (T-16) (8.93 g), tris(trifluoromethanesulfonate)scandium(III) (6.76 g), and 1,2-dichloroethane (100 ml) were placed in a reactor and heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and then poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (heptane/toluene). Further purification by recrystallization from heptane yielded compound (1-c2f-65) (0.98 g; 11%).

HRMS m/z 649.3930 (calcd C ₄₃ H ₅₂ BNS, 649.3914).

Synthesis of (T-14)
Synthesis, 47(21), 3347-3353; 2015.

Synthesis of (T-12)
(T-12) was synthesized according to the above route.

Synthesis Example (4):
Synthesis of Compound (1-n-3) The compound was synthesized in the same manner as in Synthesis Example (1), except that (T-2) was changed to (T-17).

Step 1: Under a nitrogen atmosphere, compound (T-1) (6.24 g) (manufactured by Combi-Bloc), compound (T-17) (10.0 g), sodium tert-butoxide (4.22 g), dichlorobis(di-t-butyl(4-dimethylaminophenyl)phosphino)palladium (Pd-132, 0.21 g) as a palladium catalyst, and xylene (100 ml) were placed in a reactor and heated to reflux for 3 hours. After the reaction mixture was cooled to room temperature, the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. This solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (T-18) (7.00 g; 72%).

Step 2: Under a nitrogen atmosphere, compound (T-18) (7.00 g), boron triiodide (13.00 g), dodecane (1.00 ml), and o-dichlorobenzene (ODCB) (80 ml) were placed in a reactor and heated with stirring at 150°C for 3 hours. After cooling, a THF solution of (T-4) (5.5 g) was added dropwise and stirred overnight. The reaction mixture was poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by Florisil chromatography (toluene) and recrystallized from heptane to obtain compound (T-19) (9.02 g; 83%).

Step 3: Under a nitrogen atmosphere, compound (T-19) (9.02 g), tris(trifluoromethanesulfonate)scandium(III) (7.10 g), and 1,2-dichloroethane (100 ml) were placed in a reactor and heated to reflux for 24 hours. The reaction mixture was cooled to room temperature and then poured into water, and the aqueous layer was extracted with toluene. The combined organic layers were washed with water and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (heptane/toluene). Further purification by recrystallization from heptane yielded compound (1-n-3) (1.03; 29%).

HRMS m/z 515.3734 (calcd C ₃₇ H ₅₂ BN, 515.3723).

Synthesis of (T-17) Fischer indole synthesis was used.

By appropriately changing the raw material compounds, other compounds of the present invention can be synthesized using methods similar to the above synthesis examples.

<Evaluation methods for basic physical properties>
Sample Preparation : 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 the form of a thin film. Furthermore, when evaluating in the form of a thin film, depending on the manner in which the compound to be evaluated will be used in an organic EL device, the compound to be evaluated may be evaluated as a thin film of only the compound to be evaluated, or as a thin film of the compound to be evaluated dispersed in an appropriate matrix material. Here, a thin film obtained by vapor-depositing only the compound to be evaluated is referred to as a "single film," and a thin film obtained by applying and drying a coating liquid containing the compound to be evaluated and a matrix material is referred to as a "coated film."

Commercially available PMMA (polymethyl methacrylate) or similar 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) using spin coating to prepare the sample.

When the matrix material is a host compound, a thin film sample is prepared as follows.
A transparent quartz support substrate (10 mm x 10 mm x 1.0 mm) was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Choshu Sangyo Co., Ltd.), and a molybdenum vapor deposition boat containing the host compound and a molybdenum vapor deposition boat containing the dopant material were installed. The vacuum chamber was then reduced in pressure to 5 x ¹⁰ Pa. Next, the vapor deposition boat containing the host compound and the vapor deposition boat containing the dopant material were simultaneously heated, 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 vapor 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 properties is measured using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation, UV-2600). The fluorescence spectrum or phosphorescence spectrum of the sample is measured using a spectrofluorometer (Hitachi High-Tech Corporation, F-7000).

To measure fluorescence spectra, the sample is excited at room temperature with an appropriate excitation wavelength and photoluminescence is measured. To measure phosphorescence spectra, an attached cooling unit is used to measure the sample while immersed in liquid nitrogen (temperature 77 K). To observe phosphorescence spectra, an optical chopper is 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.

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

Next, we will describe the evaluation of the basic physical properties of the polycyclic aromatic compounds of the present invention.

Evaluation of Fluorescence Lifetime (Delayed Fluorescence) The fluorescence lifetime was measured at 300 K using a fluorescence lifetime measurement device (Hamamatsu Photonics K.K., 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 fluorescence lifetime measurements of typical organic EL materials that emit fluorescence at room temperature, slow emission components involving triplet components derived from phosphorescence are rarely observed due to thermal deactivation of the triplet components. If a slow emission component is observed in the compound being evaluated, this 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 method as Eg = 1240/A.

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

The resulting 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 77 K using the second absorption peak from the long wavelength side of the absorption spectrum as excitation light, and the excited singlet energy level E(S, Sh) is determined from the shoulder on the short wavelength side of the peak of the fluorescence spectrum.
Furthermore, for a film of the target compound formed on a glass substrate, the phosphorescence spectrum is observed at 77 K using the second absorption peak from the long wavelength side of the absorption spectrum as excitation light, 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 (E _T ), and a small ΔEST, and therefore is 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 the emission spectrum, etc. For these evaluation items, values at appropriate emission luminance can be used.

The quantum efficiency of light-emitting elements can be divided into internal quantum efficiency and external quantum efficiency. Internal quantum efficiency indicates the rate at which external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting element is converted purely into photons. On the other hand, external quantum efficiency is calculated based on the amount of these photons that are emitted outside the light-emitting element. Since 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 outside the light-emitting element, the external quantum efficiency is lower than the internal quantum efficiency.

The spectral radiance (emission spectrum) and external quantum efficiency were measured as follows. The device was lit by applying voltage using an Advantest R6144 voltage/current generator. The spectral radiance in the visible light region was measured perpendicular to the light-emitting surface using a TOPCON SR-3AR spectroradiometer. Assuming the light-emitting surface is a perfectly diffusing surface, the measured spectral radiance value for each wavelength component was divided by the wavelength energy and multiplied by π to determine the number of photons at each wavelength. The number of photons was then integrated over the entire observed wavelength range to determine the total number of photons emitted from the device. The applied current value divided by the elementary charge is defined as the number of carriers injected into the device, and the total number of photons emitted from the device divided by the number of carriers injected into the device is the external quantum efficiency. The half-width of the emission spectrum is calculated as the width between the wavelengths above and below where the intensity is 50% of the maximum emission wavelength.

Next, we will describe the fabrication and evaluation of organic EL devices using the polycyclic aromatic compounds of the present invention.

Structure of Organic EL Devices Organic EL devices having the following device structure A and device structure B were produced using the polycyclic aromatic compound of the present invention.

[Element Configuration A]
The reference constituent materials for each layer are shown in Table 1 below. Further improvement in characteristics can be expected by replacing at least one of the hole transport layer material, electron blocking layer material, light-emitting layer host material, light-emitting layer dopant material, and electron transport layer material in this configuration with the polycyclic aromatic compound of the present invention. The film thickness and constituent materials of each layer can be appropriately changed depending on the basic physical properties of the polycyclic aromatic compound of the present invention.

The material composition of each layer in the organic EL device according to Example (A-1) is shown in Table 1.

In Table 1, "HI" is N ⁴ ,N ^4' -diphenyl-N ⁴ ,N ^4' -bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4,4'-diamine, "HAT-CN" is 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile, "HT-1" is N-([1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine[1,1'-biphenyl]-4-amine, and "HT-2" is N,N-bis(4-(dibenzo[b,d] "BH" is 2-(10-phenylanthracen-9-yl)dibenzo[b,d]furan, "ET-1" is 9,9'-(5-(6-(1,1'-biphenyl)-4-yl)-2-phenylpyrimidin-4-yl)-1,3-phenylene]bis(9H-carbazole), and "ET-2" is 2-ethyl-1-(4-(10-phenylanthracen-9-yl)phenyl)-1H-benzo[d]imidazole. The chemical structures are shown below together with "Liq."

A 26 mm x 28 mm x 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) on which an ITO film was formed to a thickness of 180 nm by sputtering and then polished to 150 nm was used as the transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition device (manufactured by Showa Vacuum Co., Ltd.), and molybdenum vapor deposition boats containing HI, HAT-CN, HT-1, HT-2, BH, compound (1-c1-8), ET-1, and ET-2, and aluminum nitride vapor deposition boats containing Liq, LiF, and aluminum, respectively, were attached.

The following layers are sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber is depressurized to 5 x ^10-4 Pa. First, HI is heated and vapor-deposited to a thickness of 40 nm. Next, HAT-CN is heated and vapor-deposited to a thickness of 5 nm. Next, HT-1 is heated and vapor-deposited to a thickness of 45 nm. Next, HT-2 is heated and vapor-deposited to a thickness of 10 nm, forming a hole layer consisting of four layers. Next, BH and compound (1-c1-8) are simultaneously heated and vapor-deposited to a thickness of 25 nm to form an emissive layer. The vapor deposition rate is adjusted so that the mass ratio of BH to compound (1-c1-8) is approximately 97:3. Next, ET-1 is heated and vapor-deposited to a thickness of 5 nm. Next, ET-2 and Liq are simultaneously heated and vapor-deposited to a thickness of 25 nm to form an electron layer consisting of two layers. The vapor deposition rate is adjusted so that the mass ratio of ET-2 to Liq is approximately 50:50. The deposition rate for each layer is 0.01 to 1 nm/sec. LiF is then heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec to a thickness of 1 nm, and then aluminum is heated and deposited to a thickness of 100 nm to form a cathode, thereby obtaining an organic EL device.

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 the emission spectrum, etc. For these evaluation items, values at an emission of 1000 cd/ ^m2 can be used, for example.

The quantum efficiency of light-emitting elements can be divided into internal quantum efficiency and external quantum efficiency. Internal quantum efficiency indicates the rate at which external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting element is converted purely into photons. On the other hand, external quantum efficiency is calculated based on the amount of these photons that are emitted outside the light-emitting element. Since 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 outside the light-emitting element, the external quantum efficiency is lower than the internal quantum efficiency.

The spectral radiance (emission spectrum) and external quantum efficiency were measured as follows. Using an Advantest voltage/current generator R6144, a voltage was applied to the device to achieve a luminance of 1000 cd/ ^m² , causing the device to emit light. Using a TOPCON SR-3AR spectroradiometer, the spectral radiance in the visible light region was measured perpendicular to the light-emitting surface. Assuming that the light-emitting surface is a perfectly diffusing 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. The number of photons was then integrated over the entire observed wavelength range to obtain the total number of photons emitted from the device. The applied current value was divided by the elementary charge to obtain the number of carriers injected into the device, and the total number of photons emitted from the device divided by the number of carriers injected into the device was obtained to obtain the external quantum efficiency. The half-width of the emission spectrum was calculated as the width between the wavelengths above and below the maximum emission wavelength at which the intensity was 50%.

When a DC voltage was applied to the ITO electrode as the anode and the LiF/aluminum electrode as the cathode, and the characteristics were measured at 1000 cd/ ^m² emission, the external quantum efficiency was 6.9%. Furthermore, when the device was continuously driven at the voltage required for 1000 cd/ ^m² emission, the time during which 95% or more of the initial brightness was maintained was measured and was found to be 189 hours.

[Element configuration B]
The reference constituent materials for each layer are shown in Table 2 below. Further improvement in characteristics can be expected by replacing at least one of the hole transport layer material, electron blocking layer material, light-emitting layer host material, light-emitting layer dopant material, and electron transport layer material in this configuration with the polycyclic aromatic compound of the present invention. The film thickness and constituent materials of each layer can be appropriately changed depending on the basic physical properties of the polycyclic aromatic compound of the present invention.

In Table 2, "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, "TSPO1" is diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide, and "2PXZ-TAZ" is 10,10'-((4-phenyl-4H-1,2,4-triazole-3,5-diyl)bis(4,1-phenylene))bis(10H-phenoxazine). The chemical structures are shown below.

<Example B-1>
<Device Configuration B: Device Using mCBP as the Host Compound, 2PXZ-TAZ as the Assisting Dopant, and Compound (1-c1-8) as the Emitting Dopant>
A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) on which a 200 nm thick ITO film was formed by sputtering and polished to 50 nm was used as a transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Choshu Sangyo Co., Ltd.), and tantalum vapor deposition boats containing NPD, TcTa, mCP, mCBP, 2PXZ-TAZ, compound (1-c1-8), and TSPO1, and aluminum nitride vapor deposition boats containing LiF and aluminum were attached.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 5×10 ⁻⁴ Pa. First, NPD was heated and vapor-deposited to a thickness of 40 nm. Next, TcTa was heated and vapor-deposited to a thickness of 15 nm to form a two-layer hole injection/transport layer. Next, mCP was heated and vapor-deposited to a thickness of 15 nm to form an electron blocking layer. Next, mCBP as the host, 2PXZ-TAZ as the assisting dopant, and compound (1-c1-8) as the emitting dopant were simultaneously heated and co-deposited to a thickness of 20 nm to form an emitting layer. The vapor deposition rate was adjusted so that the mass ratio of the host, assisting dopant, and emitting dopant was approximately 90:9:1. Next, TSPO1 was heated and vapor-deposited to a thickness of 30 nm to form an electron transport layer. The vapor deposition rate for each of the above layers was 0.01 to 1 nm/sec. Thereafter, LiF was heated and evaporated at a deposition rate of 0.01 to 0.1 nm/sec to a thickness of 1 nm, and then aluminum was heated and evaporated at a deposition rate of 100 nm to a thickness of 100 nm to form a cathode, thereby obtaining an organic EL device.

A DC voltage was applied to the ITO electrode as the anode and the LiF/aluminum electrode as the cathode, and the characteristics at 100 cd/ ^m² emission were measured, resulting in an external quantum efficiency of 22.2%.Furthermore, the device was continuously driven at the voltage required for 100 cd/ ^m² emission, and the time during which 90% or more of the initial brightness was maintained was measured and found to be 92 hours.

Device configuration A is characterized by its ability to maintain high brightness for a long period of time, while device configuration B is characterized by its ability to achieve high external quantum efficiency.

<Evaluation of vapor-deposited organic EL elements>
Organic EL elements according to Examples G-1, G-2, Comparative Examples CG-1, GX-1, GX-2, BX-1, and CB-1 were prepared, and the emission wavelength, half-width, driving voltage, external quantum efficiency, and LT50 (the time required to reach 250 cd/ ^m2 when continuously driven at a current density at an initial luminance of 500 cd/ ^m2 ) at a luminance of 500 cd/ ^m2 were measured.

In Table 3, the chemical structures of "HATCN", "TBB", "TcTa", "4CzIPN", "T2T", "TPBi", "BCC-TPTA", "FIrpic", and "Liq" are shown below.

<Example G-1>
A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) was used as a transparent support substrate. This transparent support substrate was formed by sputtering a 200 nm thick ITO film and polishing it to 50 nm. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Vacuum Co., Ltd.), and molybdenum vapor deposition boats containing HATCN, TBB, TcTa, 4CzIPN, compound (1-c1-8), T2T, TPBi, and Liq, and tungsten vapor deposition boats containing LiF and aluminum were attached.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 5 × 10 ^-4 Pa, and first, HATCN was heated and vapor-deposited to a thickness of 5 nm to form a hole injection layer. Next, TBB was heated and vapor-deposited to a thickness of 65 nm, and then TcTa was heated and vapor-deposited to a thickness of 10 nm to form a two-layer hole transport layer. Next, TcTa, 4CzIPN, and compound (1-c1-8) were simultaneously heated and vapor-deposited to a thickness of 30 nm to form an emitting layer. The vapor deposition rate was adjusted so that the mass ratio of TcTa, 4CzIPN, and compound (1-c1-8) was approximately 85:14:1. Next, T2T was heated and vapor-deposited to a thickness of 10 nm, and then TPBi and Liq were heated and vapor-deposited to a thickness of 40 nm to form a two-layer electron transport layer. The vapor deposition rate was adjusted so that the mass ratio of TPBi to Liq was approximately 70:30. The deposition rate of each layer was 0.01 to 1 nm/sec. Then, LiF was heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec to form a film thickness of 1 nm, and then aluminum was heated and deposited to form a film thickness of 100 nm to form a cathode, thereby obtaining an organic EL device. At this time, the deposition rate of aluminum was adjusted to be 1 to 10 nm/sec.

<Comparative Example CG-1, Example G-2, Example GX-1, Example GX-2, Example BX-1, and Comparative Example CB-1>
The assisting dopant 4CzIPN and the dopant compound (1-c1-8) and their mixing ratios in Example G-1 were changed to the assisting dopants, dopants, and mixing ratios shown in Table 3 to fabricate each device.

The evaluation results for each element are shown in Table 4.

In comparison with Comparative Example CG-1, Examples G-1 and G-2 exhibited higher efficiency and longer device life.
By changing the device configuration of Example G-1, it is possible to realize devices using exciplex and assisting dopants as in Examples GX-1 and GX-2.
By changing the dopant in Example GX-1, it is possible to realize a blue light-emitting element as in Example BX-1.
Example BX-1 exhibited higher efficiency, smaller half-width and longer device life than Comparative Example CB-1.

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 (18)

A polycyclic aromatic compound represented by the following formula (1):
In formula (1),
ring A and ring B each independently represent an optionally substituted benzene ring;
Ring C is an optionally substituted benzene ring or an optionally substituted benzothiophene ring,
Ring D is an optionally substituted benzene ring or an optionally substituted cyclohexane ring,
Y1 is B ^,
X1 is >O or >S ^;
X2 is >C(-R) ₂ , ^where R in >C(-R) ₂ is alkyl having 1 to 6 carbon atoms;
All or part of the hydrogen atoms in the compound represented by formula (1) may be deuterium atoms. A polycyclic aromatic compound represented by the following formula (1):
In formula (1),
ring A and ring B each independently represent an optionally substituted benzene ring;
Ring C is an optionally substituted benzene ring or an optionally substituted benzothiophene ring,
Ring D is an optionally substituted benzene ring or an optionally substituted cyclohexane ring,
Y ¹ is B,
X ¹ is >Si(-R) ₂ and the >Si(—R) ₂ each R is independently hydrogen, aryl, heteroaryl, alkyl, or cycloalkyl; >Si(—R) ₂ two R's may be bonded to each other to form a ring;
X ² HA > C (-R) ₂ and >C(-R) ₂ R is alkyl having 1 to 6 carbon atoms,
All or part of the hydrogen atoms in the compound represented by formula (1) may be deuterium atoms. 3. The polycyclic aromatic compound according to claim 1, wherein at least one hydrogen atom of a benzene ring, a benzothiophene ring, or a cyclohexane ring in at least one ring selected from the group consisting of ring A, ring B, ring C, and ring D is substituted. The polycyclic aromatic compound according to claim 3, wherein at least one hydrogen atom of a benzene ring, a benzothiophene ring, or a cyclohexane ring in at least one ring selected from the group consisting of ring A, ring B, ring C, and ring D is substituted with a substituent represented by the following formula (tR):
In formula (tR), R ^a , R ^b , and R ^c each independently represent alkyl having 1 to 24 carbon atoms, and any —CH ₂ — in the alkyl may be replaced with —O—, and the group represented by formula (tR) replaces at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring at *. A polycyclic aromatic compound represented by the following formula (1):
In formula (1),
ring A and ring B each independently represent an optionally substituted benzene ring;
Ring C is an optionally substituted benzene ring or an optionally substituted benzothiophene ring,
Ring D is an optionally substituted benzene ring or an optionally substituted cyclohexane ring,
At least one of the benzene ring, benzothiophene ring, and cyclohexane ring in at least one selected from the group consisting of ring A, ring B, ring C, and ring D is represented by the following formula (tR):
(In formula (tR), R ^a , R ^b , and R ^c are each independently alkyl having 1 to 24 carbon atoms, and any —CH ₂ - may be substituted with -O-, and the group represented by formula (tR) replaces at least one hydrogen atom of the aryl ring, heteroaryl ring, or cycloalkane ring at *.
Y ¹ is B,
X ¹ is a single bond,
X ² HA > C (-R) ₂ and >C(-R) ₂ R is alkyl having 1 to 6 carbon atoms,
All or part of the hydrogen atoms in the compound represented by formula (1) may be deuterium atoms. 6. The polycyclic aromatic compound according to claim 1, wherein ring D is an optionally substituted benzene ring. A polycyclic aromatic compound represented by formula (1-c1-8):
In the formula, Me is methyl and tBu is t-butyl. A polycyclic aromatic compound represented by formula (1-c2f-64) or formula (1-c2f-65);
In the formula, Me is methyl and tBu is t-butyl. A polycyclic aromatic compound represented by formula (1-n-3):
In the formula, Me is methyl and tBu is t-butyl. A polycyclic aromatic compound represented by formula (1-c1-65):
In the formula, Me is methyl. A material for an organic device, comprising the polycyclic aromatic compound according to any one of claims 1 to 10 . a pair of electrodes consisting of an anode and a cathode, and a light-emitting layer disposed between the pair of electrodes;
An organic electroluminescent device, wherein the light-emitting layer contains the polycyclic aromatic compound according to any one of claims 1 to 10 . The organic electroluminescent device according to claim 12 , wherein the light-emitting layer comprises a host and the polycyclic aromatic compound as a dopant. The organic electroluminescent device according to claim 13 , wherein the host is an anthracene-based compound, a fluorene-based compound, or a dibenzochrysene-based compound. a pair of electrodes consisting of an anode and a cathode, a light-emitting layer disposed between the pair of electrodes, and an electron injection layer and/or an electron transport layer disposed between the cathode and the light-emitting layer;
An organic electroluminescent device, wherein the electron injection layer and/or the electron transport layer contains the polycyclic aromatic compound according to any one of claims 1 to 10 . a pair of electrodes consisting of an anode and a cathode, a light-emitting layer disposed between the pair of electrodes, and a hole injection layer and/or a hole transport layer disposed between the anode and the light-emitting layer;
An organic electroluminescent device, wherein the hole injection layer and/or the hole transport layer contains the polycyclic aromatic compound according to any one of claims 1 to 10 . A display device comprising the organic electroluminescent device according to any one of claims 12 to 16 . A lighting device comprising the organic electroluminescent element according to any one of claims 12 to 16 .