JP7722697B2 - Compound, composition, host material and organic light-emitting device - Google Patents

Description

The present invention relates to a compound useful as a host material, etc., a composition using the compound, and an organic light-emitting device.

Research and development of materials for organic light-emitting devices such as organic electroluminescent devices (organic EL devices) has been actively conducted. In particular, various attempts have been made to improve the properties of organic electroluminescent devices by developing and combining new electron transport materials, hole transport materials, light-emitting materials, host materials, etc. For example, mCBP and mCP, which have the following structures, have been widely recognized as useful host materials.

In addition to these compounds having a carbazole structure, compounds having both a carbazole structure and a dibenzofuran structure have also been proposed (Patent Documents 1 and 2).

US2020/0194685 WO2011/15859

However, even when conventional host materials are used, it is not always possible to provide light-emitting devices with excellent properties. For example, when combined with a delayed fluorescent material, even if a host material that is considered useful is used as is, it is often not possible to produce an organic light-emitting device with excellent properties. In particular, when used in organic electroluminescence devices, there is room for improvement in terms of driving voltage. For this reason, the inventors conducted research with the aim of improving the properties of organic light-emitting devices by providing an excellent host material.

After extensive research, the inventors discovered that the characteristics of organic light-emitting devices can be improved by using compounds with specific structures. The present invention was proposed based on this finding and specifically has the following configuration.

[1] A compound represented by the following general formula (1):
[In general formula (1),
X represents O or S;
R ¹ to R ⁶ each independently represent a hydrogen atom, a deuterium atom, an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group;
At least one of Z ¹ and Z ² is each independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
Z ¹ may be a substituted or unsubstituted carbazolyl group;
^Z2 may be a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group.
The carbazolyl group, the benzofurocarbazolyl group, and the benzothienocarbazolyl group are each groups bonded via a nitrogen atom constituting a carbazole ring.]
[2] The compound according to [1], wherein Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group.
[3] The compound according to [1], wherein Z ¹ is a substituted or unsubstituted carbazolyl group.
[4] The compound according to any one of [1] to [3], wherein Z ² is a substituted or unsubstituted dibenzofuryl group.
[5] The compound according to [4], wherein Z ² is a substituted or unsubstituted dibenzofuran-2-yl group.
[6] The compound according to any one of [1] to [3], wherein Z ² is a substituted or unsubstituted benzofurocarbazolyl group.
[7] The compound according to [1], [2], [4] or [5], wherein Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group, and Z ² is a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group.
[8] The compound according to [1] or [2], wherein Z ¹ and Z ² are each independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
[9] The compound according to [1] or [6], wherein Z ¹ is a substituted or unsubstituted carbazolyl group, and Z ² is a substituted or unsubstituted benzofurocarbazolyl group, or a substituted or unsubstituted benzothienocarbazolyl group.
[10] The compound according to any one of [1] to [9], wherein R ¹ to R ⁶ are hydrogen atoms.
[11] A host material containing the compound according to any one of [1] to [10].
[12] The host material according to [10], for use together with a delayed fluorescent material.
[13] A composition in which the compound according to any one of [1] to [10] is doped with a delayed fluorescent material.
[14] The composition according to [13], which is in the form of a film.
[15] The composition according to [13] or [14], wherein the delayed fluorescent material is a compound having a cyanobenzene structure in which one cyano group is substituted on a benzene ring.
[16] The composition according to [15], wherein the delayed fluorescent material has two or more kinds of substituted or unsubstituted carbazolyl groups bonded to a benzene ring in addition to the cyano group.
[17] The composition according to any one of [13] to [16], further comprising a fluorescent compound having a lower minimum excited singlet energy than the host material and the delayed fluorescent material.
[18] An organic light-emitting device having a layer made of the composition according to any one of [13] to [17].
[19] The organic light-emitting device according to [18], wherein the layer is composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, and halogen atoms.
[20] The organic light-emitting device according to [19], wherein the layer is composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms.
[21] The organic light-emitting device according to any one of [18] to [20], which is an organic electroluminescence device.
[22] The organic light-emitting element according to any one of [18] to [21], wherein the composition does not contain the fluorescent compound, and the largest component of light emitted from the element is light emitted from the delayed fluorescent material.
[23] The organic light-emitting device according to any one of [18] to [21], wherein the composition contains the fluorescent compound, and the largest component of the light emitted from the device is light emitted from the fluorescent compound.

By using the compounds of the present invention, it is possible to provide organic light-emitting devices with excellent characteristics. For example, organic light-emitting devices using the compounds of the present invention include those with low driving voltages and long device lifetimes.

The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this specification, numerical ranges expressed using "to" refer to ranges that include the numerical values before and after "to" as the lower and upper limits. Furthermore, there are no particular limitations on the isotopes of hydrogen atoms present in the molecules of the compounds used in the present invention.

(Compound represented by general formula (1))
In the present invention, a compound represented by the following general formula (1) is used.
In general formula (1), X is O (oxygen atom) or S (sulfur atom). In one aspect of the present invention, X is O. In another aspect of the present invention, X is S.

In general formula (1), at least one of ^Z1 and ^Z2 is independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group. The benzofurocarbazolyl group and the benzothienocarbazolyl group are each a group bonded to a nitrogen atom constituting a carbazole ring skeleton.

In the present invention, the ring structure constituting the benzofurocarbazolyl group may be any of benzofuro[2,3-a]carbazole, benzofuro[3,2-a]carbazole, benzofuro[2,3-b]carbazole, benzofuro[3,2-b]carbazole, benzofuro[2,3-c]carbazole, and benzofuro[3,2-c]carbazole. These ring structures may or may not be fused with another ring. Preferably, they are fused with no other ring.
Preferred benzofurocarbazolyl groups include groups having any of the following structures, in which the hydrogen atoms may or may not be substituted. However, no other rings are fused to the following structures. The wavy lines indicate the bonding positions.

In the present invention, the ring structure constituting the benzothienocarbazolyl group may be any of benzothieno[2,3-a]carbazole, benzothieno[3,2-a]carbazole, benzothieno[2,3-b]carbazole, benzothieno[3,2-b]carbazole, benzothieno[2,3-c]carbazole, and benzothieno[3,2-c]carbazole. These ring structures may or may not be fused with another ring. Preferably, they are fused with no other ring.
Preferred benzothienocarbazolyl groups include groups having any of the following structures, in which the hydrogen atoms may or may not be substituted. However, no other rings are fused to the following structures. The wavy lines indicate the bonding positions.

The benzofurocarbazolyl group and benzothienocarbazolyl group which can be represented by ^Z1 and ^Z2 may be substituted. They may also be unsubstituted. When substituted, the substituent may be selected from the following substituent group A, the following substituent group B, the following substituent group C, the following substituent group D, or the following substituent group E. Preferred are substituents selected from the substituent group E. For example, they may be substituted with only an alkyl group, only an aryl group, or both an alkyl group and an aryl group.

The "alkyl group" in this application may be linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched moieties may be present in combination. The number of carbon atoms in the alkyl group may be, for example, 1 or more, 2 or more, or 4 or more. The number of carbon atoms may be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. In one embodiment of the present invention, the alkyl group has 1 to 4 carbon atoms. In one embodiment of the present invention, the alkyl group is a methyl group. In one embodiment of the present invention, the alkyl group is an isopropyl group. In one embodiment of the present invention, the alkyl group is a tert-butyl group. When multiple alkyl groups are present in the molecule represented by general formula (1), these alkyl groups may be the same or different. In one embodiment of the present invention, all alkyl groups in the molecule represented by general formula (1) are the same. The number of alkyl groups in the molecule represented by general formula (1) can be 0 or more, 1 or more, 2 or more, 4 or more, or 8 or more. The number of alkyl groups in the molecule represented by general formula (1) may be 20 or less, 10 or less, 5 or less, or 3 or less. The number of alkyl groups in the molecule represented by general formula (1) may be 0. Note that the number of alkyl groups here includes the number of alkyl groups substituted with aryl groups. Furthermore, the alkyl groups may be optionally deuterated.
In the present application, an "optionally deuterated alkyl group" means that at least one hydrogen atom of the alkyl group may be substituted with a deuterium atom. All hydrogen atoms of the alkyl group may be substituted with deuterium atoms. For example, optionally deuterated methyl groups include _CH3 , _CDH2 , _CD2H , and _CD3 . The "optionally deuterated alkyl group" is preferably an alkyl group that is not deuterated at all or an alkyl group in which all hydrogen atoms are substituted with deuterium atoms. In one embodiment of the present invention, an alkyl group that is not deuterated at all is selected as the "optionally deuterated alkyl group." In one embodiment of the present invention, an alkyl group in which all hydrogen atoms are substituted with deuterium atoms is selected as the "optionally deuterated alkyl group." In one embodiment of the present invention, the "optionally deuterated alkyl group" is a non-deuterated methyl group [ _-CH3 ], a non-deuterated ethyl group [ _-CH2CH3 ], a non-deuterated isopropyl group [-CH( _CH3 ) ₂ ], a non-deuterated tert-butyl group [-C( _CH3 ) ₃ ], or a methyl group [ _-CD3 ] in which all hydrogen atoms are deuterated. In one embodiment of the present invention, the "optionally deuterated alkyl group" is a non-deuterated methyl group [ _-CH3 ] or a methyl group [ _-CD3 ] in which all hydrogen atoms are deuterated. In one embodiment of the present invention, at least one alkyl group in which at least one hydrogen atom is substituted with _a deuterium atom is present in the molecule represented by general formula (1).

The "aryl group" may be a monocyclic ring or a fused ring formed by condensing two or more rings. When the aryl group is a monocyclic ring, it is a phenyl group. When the fused ring is a fused ring, it is a group formed by condensing one or more rings to a phenyl group. The ring fused to the phenyl group may be any of an aromatic hydrocarbon ring, an aromatic heterocyclic ring, an aliphatic hydrocarbon ring, and an aliphatic heterocyclic ring, or a ring formed by condensing these. An aromatic hydrocarbon ring or an aromatic heterocyclic ring is preferred. An example of an aromatic hydrocarbon ring is a benzene ring. The benzene ring may be condensed with another benzene ring or may be condensed with a heterocyclic ring such as a pyridine ring. The aromatic heterocyclic ring refers to an aromatic ring containing a heteroatom as a ring skeleton-constituting atom, and is preferably a 5- to 7-membered ring; for example, a 5-membered ring or a 6-membered ring may be used. In one embodiment of the present invention, a furan ring, a thiophene ring, or a pyrrole ring may be used as the aromatic heterocyclic ring.
Specific examples of the ring constituting the aryl group include a benzene ring and a naphthalene ring. Specific examples of the aryl group include a phenyl group, a naphthalene-1-yl group, and a naphthalene-2-yl group. These specific groups may be substituted. The aryl group may also be deuterated.
As used herein, an "optionally deuterated aryl group" means that at least one hydrogen atom of the aryl group may be substituted with a deuterium atom. All hydrogen atoms of the aryl group may be substituted with deuterium atoms. For example, optionally deuterated phenyl groups include _C6H5 , _C6H4D , _{C6H3D2 , C6H2D3 , C6HD4} , _{and C6D5 .} The "optionally deuterated alkyl group" is preferably _a completely undeuterated aryl group or an aryl group in which all hydrogen atoms are substituted with deuterium atoms. In one embodiment of the present invention _{, an} aryl group _in which no deuterated aryl group is selected as the "optionally deuterated aryl group." In one embodiment of the present invention, an aryl group in which all hydrogen atoms are substituted with deuterium atoms is selected as the "optionally deuterated aryl group." In one embodiment of the present invention, an "optionally deuterated aryl group" is a non-deuterated phenyl group [-C ₆ H ₅ ], a non-deuterated naphthyl group [-C ₁₀ H ₇ ], a phenyl group in which all hydrogen atoms are deuterated [-C ₆ D ₅ ], or a naphthyl group in which all hydrogen atoms are deuterated [-C ₁₀ D ₇ ].
Specific examples of optionally substituted aryl groups are listed below. However, the aryl groups that can be employed in the present invention should not be construed as being limited by the following specific examples. In the following specific examples, * indicates a bonding position. Also, methyl groups are omitted. Therefore, Ar2 to Ar7 represent structures substituted with methyl groups.

When the benzofurocarbazolyl group and the benzothienocarbazolyl group are substituted with deuterium atoms, only the substituents bonded to the benzofurocarbazole ring or the benzothienocarbazole ring may be substituted with deuterium atoms, or all the hydrogen atoms present in the benzofurocarbazolyl group or the benzothienocarbazole ring may be substituted with deuterium atoms. For example, only the hydrogen atoms of the alkyl group bonded to the benzofurocarbazole ring or the benzothienocarbazole ring may be deuterated, or only the hydrogen atoms of the aryl group bonded to the benzofurocarbazole ring or the benzothienocarbazole ring may be deuterated. More specifically, the benzofurocarbazolyl group and the benzothienocarbazolyl group may be substituted with, for example, a deuterated methyl group ( _CD3 ) or a deuterated phenyl _group ( _C6D5 ).

In one embodiment of the present invention, only Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
In one embodiment of the present invention, only ^Z2 is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
In one embodiment of the present invention, ^Z1 and ^Z2 are both substituted or unsubstituted benzofurocarbazolyl groups or substituted or unsubstituted benzothienocarbazolyl groups. In one embodiment of the present invention, ^Z1 and ^Z2 are the same. In one embodiment of the present invention, ^Z1 and ^Z2 are different.
In one embodiment of the present invention, at least one of ^Z1 and ^Z2 is a substituted or unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, at least one ^{of Z1} and ^Z2 is a substituted benzofurocarbazolyl group. In one embodiment of the present invention, at least one of Z1 and ^Z2 is an unsubstituted benzofurocarbazolyl group.
In one embodiment of the present invention, at least one of ^Z1 and ^Z2 is a substituted or unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, at least one ^{of Z1} and ^Z2 is a substituted benzothienocarbazolyl group. In one embodiment of the present invention, at least one of Z1 and ^Z2 is an unsubstituted benzothienocarbazolyl group.

Specific examples of substituted or unsubstituted benzofurocarbazolyl groups and substituted or unsubstituted benzothienocarbazolyl groups that can be used for ^Z1 and ^Z2 are given below. However, what can be used in the present invention should not be construed as being limited by the following specific examples. In the following specific examples, * indicates the bonding position. Methyl groups are not shown. Therefore, D75 to D92 and D167 to D184 represent structures substituted with methyl groups.

In addition to the specific examples above, groups in which the methyl group (CH ₃ ) of D75 to D92 and D167 to D184 is replaced with deuterated CD ₃ are exemplified here as D75(m) to D92(m) and D167(m) to D184(m), respectively. Furthermore, groups in which the phenyl group (C ₆ H ₅ ) of D7 to D74 and D99 to D166 is replaced with deuterated C ₆ D ₅ are exemplified here as D7(p) to D74(p) and D99(p) to D166(p), respectively. Furthermore, groups in which all hydrogen atoms of D1 to D184 are deuterated are exemplified here as D1(D) to D184(D), respectively.

When ^Z2 in general formula (1) is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group, ^Z1 may be a substituted or unsubstituted carbazolyl group. The carbazolyl group here is a group bonded via a nitrogen atom constituting the carbazole ring skeleton. In addition, one or both of the two benzene rings constituting the carbazolyl group here may be fused with a benzene ring or a hydrocarbon ring. It is preferable that the two benzene rings constituting the carbazolyl group are not fused with another ring.
The carbazolyl group that ^Z1 can take may be substituted. It may be unsubstituted. When substituted, the substituent may be selected from the following substituent group A, the following substituent group B, the following substituent group C, the following substituent group D, or the following substituent group E. Preferred are substituents selected from the following substituent group E. For example, it may be substituted with only an alkyl group, only an aryl group, or both an alkyl group and an aryl group. For the description and preferred ranges of the alkyl group and the aryl group, please refer to the description and preferred ranges of the alkyl group and the aryl group that are the substituents of the benzofurocarbazolyl group and the benzothienocarbazolyl group.
In one aspect of the present invention, Z ¹ is an unsubstituted carbazolyl group. In one aspect of the present invention, Z ¹ is a substituted carbazolyl group. In one aspect of the present invention, Z ¹ is an alkyl-substituted carbazolyl group. In one aspect of the present invention, Z ¹ is an aryl-substituted carbazolyl group. In one aspect of the present invention, Z ¹ is a phenyl-substituted carbazolyl group.

Specific examples of substituted or unsubstituted carbazolyl groups that can be used for ^Z1 are listed below. However, those that can be used in the present invention should not be construed as being limited by the following specific examples. In the following specific examples, * indicates the bonding position. Also, methyl groups are omitted. Therefore, C2, C3, C5, and C7 to C9 represent structures substituted with methyl groups.

In addition to the specific examples above, groups in which all hydrogen atoms of C2, C3, C5, and C7-C12 alkyl groups have been replaced with deuterated groups are exemplified here as C2(m), C3(m), C5(m), and C7(m)-C12(m), respectively. Furthermore, groups in which a C4- _C6 phenyl group ( _C6H5 ) has been replaced with a deuterated _C6D5 are exemplified here as C4( _p )-C6(p), respectively. Furthermore, groups in which all hydrogen atoms of C1-C12 have been deuterated are exemplified here as C1(D)-C12(D), respectively.

When Z ¹ in general formula (1) is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group, Z ² may be a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group. The dibenzofuryl group and dibenzothienyl group referred to here may be groups bonded at any position on each benzene ring. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzofuran-1-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzofuran-2-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzofuran-3-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzofuran-4-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzothiophen-1-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzothiophen-2-yl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzothiophen-3-yl group.In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted dibenzothiophen-4-yl group.

The dibenzofuryl group and dibenzothienyl group that can be represented by ^Z2 may be substituted. They may also be unsubstituted. If substituted, the substituent may be selected from the following substituent group A, the following substituent group B, the following substituent group C, the following substituent group D, or the following substituent group E. Preferred are substituents selected from the following substituent group E. For example, they may be substituted with only an alkyl group, only an aryl group, or both an alkyl group and an aryl group. For the description and preferred ranges of the alkyl group and the aryl group, please refer to the description and preferred ranges of the alkyl group and the aryl group that are the substituents of the benzofurocarbazolyl group and the benzothienocarbazolyl group.
In one aspect of the present invention, ^Z2 is an unsubstituted dibenzofuryl group. In one aspect of the present invention, ^Z2 is a substituted dibenzofuryl group. In one aspect of the present invention, ^Z2 is an alkyl-substituted dibenzofuryl group. In one aspect of the present invention, ^Z2 is an aryl-substituted dibenzofuryl group. In one aspect of the present invention, ^Z2 is a phenyl-substituted dibenzofuryl group. In one aspect of the present invention, ^Z2 is an unsubstituted dibenzothienyl group. In one aspect of the present invention, ^Z2 is a substituted dibenzothienyl group. In one aspect of the present invention, ^Z2 is an alkyl-substituted dibenzothienyl group. In one aspect of the present invention, ^Z2 is an aryl-substituted dibenzothienyl group. In one aspect of the present invention, ^Z2 is a phenyl-substituted dibenzothienyl group.

Specific examples of substituted or unsubstituted dibenzofuryl groups and substituted or unsubstituted dibenzothienyl groups that ^Z2 can take are given below. However, what can be employed in the present invention should not be construed as being limited by the following specific examples. In the following specific examples, * indicates the bonding position. Also, methyl groups are omitted. Therefore, X20 and X40 represent structures substituted with methyl groups.

In addition to the specific examples above, groups in which the methyl groups ( _CH3 ) of X20 and X40 are replaced with deuterated _CD3 are exemplified here as X20(m) and X40(m) _, respectively. Furthermore, groups in which the phenyl groups ( _C6H5 ) of X5 to X19 and X25 to X39 are replaced with _{deuterated C6D5} are exemplified here as X5(p) to X19(p) and X25(p) to X39(p), respectively. Furthermore, groups in which all hydrogen atoms of X1 to X40 are deuterated are exemplified here as X1(D) to X40(D), respectively.

In general formula (1), R ¹ to R ⁶ each independently represent a hydrogen atom, a deuterium atom, an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. The aryl group is preferably an optionally deuterated aryl group or an aryl group optionally substituted with an alkyl group. For details and preferred ranges of the alkyl group and aryl group, please refer to the details and preferred ranges of the alkyl group and aryl group that are substituents of the benzofurocarbazolyl group and the benzothienocarbazolyl group.
In one embodiment of the present invention, R ¹ to R ⁶ are hydrogen atoms or deuterium atoms. In one embodiment of the present invention, R ¹ to R ⁶ are hydrogen atoms. In one embodiment of the present invention, at least one of R ¹ to R ⁶ is a substituted or unsubstituted alkyl group. In one embodiment of the present invention, at least one of R ¹ to R ⁶ is an unsubstituted alkyl group. In one embodiment of the present invention, at least one of R ¹ to R ⁶ is a substituted or unsubstituted aryl group. In one embodiment of the present invention, at least one of R ¹ to R ⁶ is an unsubstituted aryl group. In one embodiment of the present invention, R ¹ is a hydrogen atom or a deuterium atom. In one embodiment of the present invention, R ¹ is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. In one embodiment of the present invention, R ² is a hydrogen atom or a deuterium atom. In one embodiment of the present invention, R ² is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. In one embodiment of the present invention, R ³ is a hydrogen atom or a deuterium atom. In one aspect of the present invention, ^R3 is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. In one aspect of the present invention, ^R4 is a hydrogen atom or a deuterium atom. In one aspect of the present invention, ^R4 is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. In one aspect of the present invention, ^R5 is a hydrogen atom or a deuterium atom. In one aspect of the present invention, ^R5 is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group. In one aspect of the present invention, ^R6 is a hydrogen atom or a deuterium atom. In one aspect of the present invention, ^R6 is an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group.

In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group, and Z ² is a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group. In another embodiment of the present invention, Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group, and Z ² is a substituted or unsubstituted dibenzofuryl group. In another embodiment of the present invention, Z ¹ is a substituted or unsubstituted benzothienocarbazolyl group, and Z ² is a substituted or unsubstituted dibenzothienyl group.
In one embodiment of the present invention, ^Z1 and ^Z2 are each independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, ^Z1 and ^Z2 are different benzofurocarbazolyl groups. In one embodiment of the present invention, ^Z1 and Z2 are the same benzofurocarbazolyl group. In one embodiment of the present invention, ^Z1 and ^Z2 are different ^{benzothienocarbazolyl} groups. In one embodiment of the present invention, ^Z1 and ^Z2 are the same benzothienocarbazolyl group.
In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted carbazolyl group, and Z ² is a substituted or unsubstituted benzofurocarbazolyl group, or a substituted or unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted carbazolyl group, and Z ² is a substituted or unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, Z ¹ is an unsubstituted carbazolyl group, and Z ² is an unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, Z ¹ is an unsubstituted carbazolyl group, and Z ² is a substituted benzofurocarbazolyl group. In one embodiment of the present invention, Z 1 is a substituted carbazolyl group, and Z ² is an unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, Z ¹ is a substituted carbazolyl group, and Z ² is an unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, Z 1 is a substituted carbazolyl group, and Z ² is an unsubstituted benzofurocarbazolyl group. In one embodiment of the present invention, Z ¹ is a substituted or unsubstituted carbazolyl group, and Z ² is a substituted or unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, Z ¹ is an unsubstituted carbazolyl group, and Z ² is an unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, Z ¹ is an unsubstituted carbazolyl group, and Z ² is a substituted benzothienocarbazolyl group. In one embodiment of the present invention, Z 1 is a substituted carbazolyl group, and Z ² is an unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, Z ¹ is a substituted carbazolyl group, and Z 2 is an unsubstituted benzothienocarbazolyl group. In one embodiment of the present invention, Z ¹ is a substituted carbazolyl group, and Z ² is a substituted benzothienocarbazolyl group.

In one embodiment of the present invention, the compound of general formula (1) is represented by the following general formula (2): Here, for the explanation and preferred ranges of R ¹ to R ⁶ , Z ¹ and Z ² , the corresponding descriptions of general formula (1) can be referred to.

In one embodiment of the present invention, the compound of general formula (1) is represented by the following general formula (3): Here, for the explanation and preferred ranges of R ¹ to R ⁶ , Z ¹ and Z ² , the corresponding descriptions of general formula (1) can be referred to.

The compound represented by general formula (1) does not contain any metal elements. In one aspect of the present invention, the compound represented by general formula (1) consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. In one aspect of the present invention, the compound represented by general formula (1) consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms. In one aspect of the present invention, the compound represented by general formula (1) consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, and sulfur atoms.

In the present specification, the term "substituent group A" refers to a deuterium atom, a hydroxyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (for example, having 1 to 40 carbon atoms), an alkoxy group (for example, having 1 to 40 carbon atoms), an alkylthio group (for example, having 1 to 40 carbon atoms), an aryl group (for example, having 6 to 30 carbon atoms), an aryloxy group (for example, having 6 to 30 carbon atoms), an arylthio group (for example, having 6 to 30 carbon atoms), a heteroaryl group (for example, having 5 to 30 atoms constituting the ring skeleton), a heteroaryloxy group (for example, having 5 to 3 atoms constituting the ring skeleton), a substituted or unsubstituted aryl group (for example, having 5 to 30 ... or a group in which two or more groups selected from the group consisting of a heteroarylthio group (for example, having 5 to 30 atoms in the ring skeleton), an acyl group (for example, having 1 to 40 carbon atoms), an alkenyl group (for example, having 1 to 40 carbon atoms), an alkynyl group (for example, having 1 to 40 carbon atoms), an alkoxycarbonyl group (for example, having 1 to 40 carbon atoms), an aryloxycarbonyl group (for example, having 1 to 40 carbon atoms), a heteroaryloxycarbonyl group (for example, having 1 to 40 carbon atoms), a silyl group (for example, a trialkylsilyl group having 1 to 40 carbon atoms), and a nitro group are combined.
As used herein, "substituent group B" means one or a combination of two or more selected from the group consisting of a deuterium atom, an alkyl group (for example, having 1 to 40 carbon atoms), an alkoxy group (for example, having 1 to 40 carbon atoms), an aryl group (for example, having 6 to 30 carbon atoms), an aryloxy group (for example, having 6 to 30 carbon atoms), a heteroaryl group (for example, having 5 to 30 ring skeleton atoms), a heteroaryloxy group (for example, having 5 to 30 ring skeleton atoms), and a diarylaminoamino group (for example, having 0 to 20 carbon atoms).
As used herein, "substituent group C" refers to one or a combination of two or more selected from the group consisting of a deuterium atom, an alkyl group (e.g., having 1 to 20 carbon atoms), an aryl group (e.g., having 6 to 22 carbon atoms), a heteroaryl group (e.g., having 5 to 20 ring skeleton atoms), and a diarylamino group (e.g., having 12 to 20 carbon atoms).
As used herein, the term "substituent group D" refers to one or a combination of two or more selected from the group consisting of a deuterium atom, an alkyl group (e.g., having 1 to 20 carbon atoms), an aryl group (e.g., having 6 to 22 carbon atoms), and a heteroaryl group (e.g., having 5 to 20 ring skeleton atoms).
As used herein, the term "substituent group E" refers to one or a combination of two or more selected from the group consisting of a deuterium atom, an alkyl group (e.g., having 1 to 20 carbon atoms), and an aryl group (e.g., having 6 to 22 carbon atoms).

Specific examples of compounds represented by general formula (1) are listed below, but the compounds that can be used in the present invention are not limited to these specific examples. In the specific examples in Tables 1 to 4, R ¹ to R ⁶ are hydrogen atoms. In Table 1, the structures of Compounds 1 to 736 are specified by defining Z ¹ and Z ² in each structure.

In Table 2, the structures of Compounds 1 to 7360 are specified by defining ^Z1 and ^Z2 in each structure. Each row in Table 2 sequentially specifies 184 compounds in which ^Z2 is fixed and ^Z1 is changed to D1 to D184. Compounds 1 to 736 in Table 2 are specified as the same as Compounds 1 to 736 in Table 1.

In Table 3, the structures of compounds 7361 to 41216 are identified by specifying ^Z1 and ^Z2 in each structure. Each row in Table 3 sequentially identifies 184 compounds in which ^Z1 is fixed and ^Z2 is varied from D1 to D184.

In Table 4, the structures of compounds 41217 to 42320 are identified by specifying ^Z1 and ^Z2 in each structure. Each row in Table 4 sequentially identifies 184 compounds in which ^Z1 is fixed and ^Z2 is varied from D1 to D184.

Compounds in which hydrogen atoms in Compounds 1 to 42320 are substituted with deuterium atoms are exemplified here as Compounds 1(D) to 42320(D) in this order.
In one aspect of the present invention, the compound is selected from compounds 1-7360.
In one embodiment of the present invention, a compound is selected from compounds 7361 to 41216. In one embodiment of the present invention, a compound is selected from compounds 7361 to 11040. In one embodiment of the present invention, a compound is selected from compounds 11041 to 14720. In one embodiment of the present invention, a compound is selected from compounds 14721 to 18400. In one embodiment of the present invention, a compound is selected from compounds 18401 to 22080. In one embodiment of the present invention, a compound is selected from compounds 22081 to 25760. In one embodiment of the present invention, a compound is selected from compounds 25761 to 29440. In one embodiment of the present invention, a compound is selected from compounds 29441 to 33120. In one embodiment of the present invention, a compound is selected from compounds 33121 to 36800. In one embodiment of the present invention, a compound is selected from compounds 36801 to 41216.
In one aspect of the present invention, a compound is selected from compounds 41217 to 42320. In one aspect of the present invention, a compound is selected from compounds 41217 to 41400. In one aspect of the present invention, a compound is selected from compounds 41401 to 41584. In one aspect of the present invention, a compound is selected from compounds 41585 to 41768. In one aspect of the present invention, a compound is selected from compounds 41769 to 41952. In one aspect of the present invention, a compound is selected from compounds 41953 to 42136. In one aspect of the present invention, a compound is selected from compounds 42137 to 42320.

An example of a preferred group of compounds represented by general formula (1) is given below. Here, in each structure, a compound in which X is O and a compound in which X is S are individually disclosed. This group can be further divided into a group of compounds in which X is O and a group of compounds in which X is S.

Below, an example of another preferred group of compounds represented by general formula (1) is given. Here, in each structure, a compound in which X is O and a compound in which X is S are individually disclosed. This group can be further divided into a group of compounds in which X is O and a group of compounds in which X is S.

Below, an example of another preferred group of compounds represented by general formula (1) is given. Here, in each structure, a compound in which X is O and a compound in which X is S are individually disclosed. This group can be further divided into a group of compounds in which X is O and a group of compounds in which X is S.

Below, an example of another preferred group of compounds represented by general formula (1) is given. Here, in each structure, a compound in which X is O and a compound in which X is S are individually disclosed. This group can be further divided into a group of compounds in which X is O and a group of compounds in which X is S.

The compound represented by general formula (1) is useful as a host material for doping a light-emitting material. In particular, it is useful as a host material for doping a delayed fluorescent material. The doping material may be one type or multiple types. The doping material is selected from those having a lower minimum excited singlet energy than the compound represented by general formula (1).
The compound represented by formula (1) is also useful as a carrier blocking material, for example, as an electron blocking material, and can be effectively used in a blocking layer (e.g., an electron blocking layer) in an organic light-emitting device such as an organic electroluminescence device.

(Delayed fluorescent material)
The compound represented by the general formula (1) is useful as a host material to be used together with a delayed fluorescent material.
The term "delayed fluorescent material" as used herein refers to an organic compound that undergoes reverse intersystem crossing from an excited triplet state to an excited singlet state in an excited state, and emits delayed fluorescence when returning from the excited singlet state to the ground state. In the present invention, a delayed fluorescent material is one that emits fluorescence with an emission lifetime of 100 ns (nanoseconds) or more when its emission lifetime is measured using a fluorescence lifetime measurement system (such as a streak camera system manufactured by Hamamatsu Photonics K.K.).
When a compound represented by general formula (1) is used in combination with a delayed fluorescent material, the delayed fluorescent material receives energy from the compound represented by general formula (1) in an excited singlet state and transitions to an excited singlet state. Alternatively, the delayed fluorescent material may receive energy from the compound represented by general formula (1) in an excited triplet state and transition to an excited triplet state. Since the delayed fluorescent material has a small difference (ΔE _ST ) between the excited singlet energy and the excited triplet energy, the delayed fluorescent material in the excited triplet state is likely to undergo reverse intersystem crossing to the delayed fluorescent material in the excited singlet state. The delayed fluorescent material in the excited singlet state generated by these pathways contributes to light emission.

The delayed fluorescent material preferably has a difference ΔE _ST between the lowest excited singlet energy and the lowest excited triplet energy at 77 K of 0.3 eV or less, more preferably 0.25 eV or less, more preferably 0.2 eV or less, more preferably 0.15 eV or less, even more preferably 0.1 eV or less, still more preferably 0.07 eV or less, even more preferably 0.05 eV or less, still more preferably 0.03 eV or less, and particularly preferably 0.01 eV or less.
If ΔE _ST is small, reverse intersystem crossing from an excited singlet state to an excited triplet state is easily achieved by absorbing thermal energy, and the material functions as a thermally activated delayed fluorescent material. The thermally activated delayed fluorescent material absorbs heat emitted by a device and relatively easily undergoes reverse intersystem crossing from an excited triplet state to an excited singlet state, and the excited triplet energy can efficiently contribute to light emission.

In the present invention, the lowest excited singlet energy (E _S1 ) and the lowest excited triplet energy (E _T1 ) of the compound are values determined by the following procedure: ΔE _ST is a value determined by calculating E _S1 −E _T1 .
(1) Lowest excited singlet energy (E _S1 )
A thin film or toluene solution (concentration 10 ^-5 mol/L) of the compound to be measured is prepared as a sample. The fluorescence spectrum of this sample is measured at room temperature (300K). The fluorescence spectrum has emission on the vertical axis and wavelength on the horizontal axis. A tangent line is drawn to the rising edge on the short wavelength side of this emission spectrum, and the wavelength value λedge [nm] at the intersection of this tangent line and the horizontal axis is determined. This wavelength value is converted to an energy value using the following conversion formula, and the value is defined as E _S1 .
Conversion formula: E _S1 [eV] = 1239.85/λedge
In the examples described below, emission spectra were measured using an LED light source (M300L4, manufactured by Thorlabs) as an excitation light source and a detector (PMA-12 multichannel spectrometer C10027-01, manufactured by Hamamatsu Photonics KK).
(2) Lowest excited triplet energy (E _T1 )
The same sample used in measuring the lowest excited singlet energy (E _S1 ) is cooled to 77 [K] with liquid nitrogen, and the sample for phosphorescence measurement is irradiated with excitation light (300 nm), and phosphorescence is measured using a detector. The emission from 100 milliseconds after irradiation with excitation light is taken as the phosphorescence spectrum. A tangent line is drawn to the rising edge on the short wavelength side of this phosphorescence spectrum, and the wavelength value λedge [nm] at the intersection of this tangent line and the horizontal axis is determined. This wavelength value is converted to an energy value using the following conversion formula, and the value is taken as _ET1 .
Conversion formula: E _T1 [eV] = 1239.85/λedge
The tangent to the rising edge of the phosphorescence spectrum on the short wavelength side is drawn as follows: When moving along the spectral curve from the short wavelength side of the phosphorescence spectrum to the shortest maximum of the spectral maxima, consider the tangent at each point on the curve toward the long wavelength side. The slope of this tangent increases as the curve rises (i.e., as the vertical axis increases). The tangent drawn at the point where this slope is at its maximum is defined as the tangent to the rising edge of the phosphorescence spectrum on the short wavelength side.
Note that a maximum point having a peak intensity that is 10% or less of the maximum peak intensity of the spectrum is not included in the above-mentioned maximum value on the shortest wavelength side, and a tangent drawn at the point where the slope value is the maximum value that is closest to the maximum value on the shortest wavelength side is defined as the tangent to the rising edge on the short wavelength side of the phosphorescence spectrum.

In one preferred embodiment of the present invention, a compound (cyanobenzene derivative) having a cyanobenzene structure in which one cyano group is substituted on the benzene ring is used as the delayed fluorescent material. In another preferred embodiment of the present invention, a compound (dicyanobenzene derivative) having a dicyanobenzene structure in which two cyano groups are substituted on the benzene ring is used as the delayed fluorescent material. In another preferred embodiment of the present invention, a compound (azabenzene derivative) having an azabenzene structure in which at least one of the carbon atoms constituting the ring skeleton of the benzene ring is substituted with a nitrogen atom is used as the delayed fluorescent material.

In a preferred embodiment of the present invention, a compound represented by the following general formula (4) is used as the delayed fluorescent material.
In general formula (4), one of R ²¹ to R ²³ represents a cyano group or a group represented by the following general formula (5), the remaining two of R ²¹ to R ²³ and at least one of R ²⁴ and R ²⁵ represent a group represented by the following general formula (6), and the remaining R ²¹ to R ²⁵ represent a hydrogen atom or a substituent (however, the substituent here does not represent a cyano group, a group represented by the following general formula (5), or a group represented by the following general formula (6)).
In formula (5), L ¹ represents a single bond or a divalent linking group, R ³¹ and R ³² each independently represent a hydrogen atom or a substituent, and * represents the bonding position.
In formula (6), L ² represents a single bond or a divalent linking group, R ³³ and R ³⁴ each independently represent a hydrogen atom or a substituent, and * represents the bonding position.

In a preferred embodiment of the present invention, R ²² is a cyano group. In a preferred embodiment of the present invention, R ²² is a group represented by general formula (5). In an embodiment of the present invention, R ²¹ is a cyano group or a group represented by general formula (5). In an embodiment of the present invention, R ²³ is a cyano group or a group represented by general formula (5). In an embodiment of the present invention, one of R ²¹ to R ²³ is a cyano group. In an embodiment of the present invention, one of R ²¹ to R ²³ is a group represented by general formula (5).

In a preferred embodiment of the present invention, L ¹ in general formula (5) is a single bond. In one embodiment of the present invention, L ¹ is a divalent linking group, preferably a substituted or unsubstituted arylene group or a substituted or unsubstituted heteroarylene group, more preferably a substituted or unsubstituted arylene group, and even more preferably a substituted or unsubstituted 1,4-phenylene group (with, for example, an alkyl group having 1 to 3 carbon atoms as the substituent).
In one embodiment of the present invention, R ³¹ and R ³² in general formula (5) are each independently one group or a combination of two or more groups selected from the group consisting of alkyl groups (e.g., 1 to 40 carbon atoms), aryl groups (e.g., 6 to 30 carbon atoms), heteroaryl groups (e.g., 5 to 30 ring skeleton atoms), alkenyl groups (e.g., 1 to 40 carbon atoms), and alkynyl groups (e.g., 1 to 40 carbon atoms) (hereinafter, these groups are referred to as "groups of substituent group A"). In a preferred embodiment of the present invention, R ³¹ and R ³² are each independently a substituted or unsubstituted aryl group (e.g., 6 to 30 carbon atoms), and examples of the substituents on the aryl group include groups of substituent group A. In a preferred embodiment of the present invention, R ³¹ and R ³² are the same.

In a preferred embodiment of the present invention, ^L2 in general formula (6) is a single bond. In one embodiment of the present invention, ^L2 is a divalent linking group, preferably a substituted or unsubstituted arylene group or a substituted or unsubstituted heteroarylene group, more preferably a substituted or unsubstituted arylene group, and even more preferably a substituted or unsubstituted 1,4-phenylene group (with, for example, an alkyl group having 1 to 3 carbon atoms as the substituent).
In one embodiment of the present invention, R ³³ and R ³⁴ in general formula (6) each independently represent a substituted or unsubstituted alkyl group (e.g., having 1 to 40 carbon atoms), a substituted or unsubstituted alkenyl group (e.g., having 1 to 40 carbon atoms), a substituted or unsubstituted aryl group (e.g., having 6 to 30 carbon atoms), or a substituted or unsubstituted heteroaryl group (e.g., having 5 to 30 carbon atoms). Examples of the substituents of the alkyl group, alkenyl group, aryl group, and heteroaryl group referred to here include a hydroxyl group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (e.g., having 1 to 40 carbon atoms), an alkoxy group (e.g., having 1 to 40 carbon atoms), an alkylthio group (e.g., having 1 to 40 carbon atoms), an aryl group (e.g., having 6 to 30 carbon atoms), an aryloxy group (e.g., having 6 to 30 carbon atoms), an arylthio group (e.g., having 6 to 30 carbon atoms), a heteroaryl group (e.g., having 5 to 30 atoms constituting the ring skeleton), a heteroaryloxy group (e.g., having 5 to 30 atoms constituting the ring skeleton), and a heteroarylthi group. Examples include one group or a combination of two or more groups selected from the group consisting of an aryl group (e.g., having 5 to 30 ring skeleton atoms), an acyl group (e.g., having 1 to 40 carbon atoms), an alkenyl group (e.g., having 1 to 40 carbon atoms), an alkynyl group (e.g., having 1 to 40 carbon atoms), an alkoxycarbonyl group (e.g., having 1 to 40 carbon atoms), an aryloxycarbonyl group (e.g., having 1 to 40 carbon atoms), a heteroaryloxycarbonyl group (e.g., having 1 to 40 carbon atoms), a silyl group (e.g., a trialkylsilyl group having 1 to 40 carbon atoms), a nitro group, and a cyano group (hereinafter, these groups are referred to as "groups of substituent group B").
R ³³ and R ³⁴ may be bonded to each other via a single bond or a linking group to form a cyclic structure. In particular, when R ³³ and R ³⁴ are aryl groups, it is preferable that they be bonded to each other via a single bond or a linking group to form a cyclic structure. Examples of the linking group include -O-, -S-, -N(R ³⁵ )-, -C(R ³⁶ )(R ³⁷ )-, and -C(═O)-. Preferred are -O-, -S-, -N(R ³⁵ )-, and -C(R ³⁶ )(R ³⁷ )-, with -O-, -S-, and -N(R ³⁵ )- being more preferred. R ³⁵ to R ³⁷ each independently represent a hydrogen atom or a substituent. The substituent may be a group selected from the above-mentioned Substituent Group A or a group selected from the below-mentioned Substituent Group B, and is preferably one group or a combination of two or more groups selected from the group consisting of alkyl groups having 1 to 10 carbon atoms and aryl groups having 6 to 14 carbon atoms.

The group represented by general formula (6) is preferably a group represented by the following general formula (7).

In formula (7), L ¹¹ represents a single bond or a divalent linking group. For the description and preferred range of L ¹¹ , the description and preferred range of L ² above can be referred to.
In general formula (7), R ⁴¹ to R ⁴⁸ each independently represent a hydrogen atom or a substituent. R ⁴¹ and R ⁴² , R ⁴² and R ⁴³ , R ⁴³ and R ⁴⁴ , R ⁴⁴ and R ⁴⁵ , R ⁴⁵ and R ⁴⁶ , R ⁴⁶ and R ⁴⁷ , and R ⁴⁷ and R ⁴⁸ may be bonded to each other to form a cyclic structure. The cyclic structure formed by bonding to each other may be an aromatic ring or an aliphatic ring, or may contain a heteroatom, and the cyclic structure may be a condensed ring of two or more rings. The heteroatom referred to here is preferably selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of the cyclic structure formed include a benzene ring, a naphthalene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an imidazoline ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a cyclohexadiene ring, a cyclohexene ring, a cyclopentaene ring, a cycloheptatriene ring, a cycloheptadiene ring, a furan ring, a thiophene ring, a naphthyridine ring, a quinoxaline ring, and a quinoline ring. For example, a ring formed by condensing multiple rings, such as a phenanthrene ring or a triphenylene ring, may also be formed. The number of rings contained in the group represented by general formula (7) may be selected from the range of 3 to 5, or may be selected from the range of 5 to 7.
Substituents that R ⁴¹ to R ⁴⁸ can take include groups in the above-mentioned Substituent Group B, and are preferably unsubstituted alkyl groups having 1 to 10 carbon atoms, or aryl groups having 6 to 10 carbon atoms which may be substituted with an unsubstituted alkyl group having 1 to 10 carbon atoms. In a preferred embodiment of the present invention, ^{R 41} to R ⁴⁸ are hydrogen atoms or unsubstituted alkyl groups having 1 to 10 carbon atoms. In a preferred embodiment of the present invention, ^{R 41 to} R ⁴⁸ are all hydrogen atoms.
In formula (7), * represents a bonding position.

In a preferred embodiment of the present invention, an azabenzene derivative is used as the delayed fluorescent material. In a preferred embodiment of the present invention, the azabenzene derivative has an azabenzene structure in which three of the carbon atoms constituting the ring skeleton of the benzene ring are substituted with nitrogen atoms. For example, an azabenzene derivative having a 1,3,5-triazine structure can be preferably selected. In a preferred embodiment of the present invention, the azabenzene derivative has an azabenzene structure in which two of the carbon atoms constituting the ring skeleton of the benzene ring are substituted with nitrogen atoms. Examples include azabenzene derivatives having a pyridazine structure, pyrimidine structure, and pyrazine structure, and an azabenzene derivative having a pyrimidine structure can be preferably selected. In one embodiment of the present invention, the azabenzene derivative has a pyridine structure in which one of the carbon atoms constituting the ring skeleton of the benzene ring is substituted with a nitrogen atom.

In a preferred embodiment of the present invention, a compound represented by the following general formula (8) is used as the delayed fluorescent material.
In general formula (8), at least one of ^Y1 , ^Y2 , and ^Y3 represents a nitrogen atom and the rest represent methine groups. In one embodiment of the present invention, ^Y1 is a nitrogen atom, and ^Y2 and ^Y3 are methine groups. Preferably, ^Y1 and ^Y2 are nitrogen atoms, and ^Y3 is a methine group. More preferably, all of ^Y1 to ^Y3 are nitrogen atoms.
In general formula (8), Z ¹ to Z ³ each independently represent a hydrogen atom or a substituent, with at least one being a donor substituent. A donor substituent refers to a group with a negative Hammett σp value. Preferably, at least one of Z ¹ to Z ³ is a group containing a diarylamino structure (the two aryl groups bonded to the nitrogen atom may be bonded to each other), more preferably a group represented by general formula (6) above, for example, a group represented by general formula (7) above. In one aspect of the present invention, only one of Z ¹ to Z ³ is a group represented by general formula (6) or (7). In one aspect of the present invention, only two of Z ¹ to Z ³ are each independently a group represented by general formula (6) or (7). In one aspect of the present invention, all of Z ¹ to Z ³ are each independently a group represented by general formula (6) or (7). For details and preferred ranges of general formula (6) and general formula (7), please refer to the corresponding descriptions above. The remaining Z ¹ to Z ³ , which are not the groups represented by general formula (6) and general formula (7), are preferably substituted or unsubstituted aryl groups (e.g., having 6 to 40 carbon atoms, preferably 6 to 20 carbon atoms), and examples of the substituent of the aryl group here include one group selected from the group consisting of aryl groups (e.g., having 6 to 20 carbon atoms, preferably 6 to 14 carbon atoms) and alkyl groups (e.g., having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms), or a group in combination of two or more groups. In one embodiment of the present invention, general formula (8) does not contain a cyano group.

In a preferred embodiment of the present invention, a compound represented by the following general formula (9) is used as the delayed fluorescent material.
In general formula (9), Ar ¹ forms a cyclic structure which may be substituted by A ¹ and D ¹ below, and represents a benzene ring, a naphthalene ring, an anthracene ring, or a phenanthrene ring. Ar ² and Ar ³ may each form a cyclic structure, and if they form a cyclic structure, they represent a benzene ring, a naphthalene ring, a pyridine ring, or a benzene ring substituted with a cyano group. m1 represents an integer of 0 to 2, and m2 represents an integer of 0 to 1. ^{A 1} represents a cyano group, a phenyl group, a pyrimidyl group, a triazyl group, or a benzonitrile group. ^{D 1} represents a substituted or unsubstituted 5H-indolo[3,2,1-de]phenazin-5-yl group, or a substituted or unsubstituted heterocyclic-fused carbazolyl group not containing a naphthalene structure, and when multiple D ^1s are present in general formula (9), they may be the same or different. In addition, the substituents of ^D1 may be bonded to each other to form a cyclic structure.

Preferred compounds that can be used as delayed fluorescent materials are listed below, but the delayed fluorescent materials that can be used in the present invention are not limited to these specific examples.

In the present invention, other known delayed fluorescent materials can be used in appropriate combination with the compound represented by general formula (1). Even unknown delayed fluorescent materials can be used.
Examples of delayed fluorescent materials include those described in paragraphs 0008 to 0048 and 0095 to 0133 of WO2013/154064, paragraphs 0007 to 0047 and 0073 to 0085 of WO2013/011954, paragraphs 0007 to 0033 and 0059 to 0066 of WO2013/011955, and paragraphs 0008 to 007 of WO2013/081088. 1 and 0118 to 0133, paragraphs 0009 to 0046 and 0093 to 0134 of JP 2013-256490 A, paragraphs 0008 to 0020 and 0038 to 0040 of JP 2013-116975 A, paragraphs 0007 to 0032 and 0079 to 0084 of WO 2013/133359 A, paragraphs 0008 to 0032 of WO 2013/161437 A JP-A-2014-9352, paragraphs 0007 to 0041 and 0060 to 0069, JP-A-2014-9224, paragraphs 0008 to 0048 and 0067 to 0076, JP-A-2017-119663, paragraphs 0013 to 0025, JP-A-2017-119664, paragraphs 0013 to 0026, JP-A-2017- JP-A-2017-226838, paragraphs 0010 to 0050, JP-A-2018-100411, paragraphs 0012 to 0043, and WO 2018/047853, paragraphs 0016 to 0044. Compounds encompassed by the general formulas described in paragraphs 0012 to 0025, particularly exemplary compounds, which emit delayed fluorescence can be mentioned. Also, Japanese Patent Application Laid-Open No. 2013-253121, WO2013/133359, WO2014/034535, WO2014/115743, WO2014/122895, WO2014/126200, WO2014/136758, WO2014/133121, WO2014/ 136860, WO2014/196585, WO2014/189122, WO2014/168101, WO2015/00858 0 publication, WO2014/203840 publication, WO2015/002213 publication, WO2015/016200 publication, WO2015/019725 publication, WO2015/072470, WO2015/108049, WO2015/080182, WO2015/072537, WO2015/080183, JP2015-129240A, WO2015/129714, WO2015/129715, WO2015/133 It is also possible to employ luminescent materials that emit delayed fluorescence, such as those described in WO2015/136880, WO2015/137244, WO2015/137202, WO2015/137136, WO2015/146541, and WO2015/159541. The above publications described in this paragraph are incorporated herein by reference.

The delayed fluorescent material used in the present invention preferably does not contain metal atoms. For example, a compound consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms can be selected as the delayed fluorescent material. For example, a compound consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms can be selected as the delayed fluorescent material. For example, a compound consisting of carbon atoms, hydrogen atoms, and nitrogen atoms can be selected as the delayed fluorescent material.

In this specification, alkyl groups, alkenyl groups, aryl groups, heteroaryl groups, etc. represent the following groups unless otherwise specified.
The "alkyl group" may be linear, branched, or cyclic. Two or more of the linear, cyclic, and branched groups may be present. The number of carbon atoms in the alkyl group may be, for example, 1 or more, 2 or more, or 4 or more. The number of carbon atoms may be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, an isohexyl group, a 2-ethylhexyl group, an n-heptyl group, an isoheptyl group, an n-octyl group, an isooctyl group, an n-nonyl group, an isononyl group, an n-decanyl group, an isodecanyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The alkyl group may be further substituted with an aryl group. For the alkyl moieties of "alkoxy groups,""alkylthiogroups,""acylgroups," and "alkoxycarbonyl groups," the explanation of "alkyl groups" herein can be referred to.
The "alkenyl group" may be linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched moieties may be mixed. The number of carbon atoms in the alkenyl group may be, for example, 2 or more or 4 or more. Furthermore, the number of carbon atoms may be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of the alkenyl group include ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, isopentenyl, n-hexenyl, isohexenyl, and 2-ethylhexenyl. The substituted alkenyl group may be further substituted with a substituent.
The "aryl group" and "heteroaryl group" may be a single ring or a fused ring in which two or more rings are fused. In the case of a fused ring, the number of fused rings is preferably 2 to 6, and can be selected from, for example, 2 to 4. Specific examples of the ring include a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a triphenylene ring, a quinoline ring, a pyrazine ring, a quinoxaline ring, and a naphthyridine ring. Specific examples of the aryl group or heteroaryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, a 9-anthracenyl group, a 2-pyridyl group, a 3-pyridyl group, and a 4-pyridyl group. The terms "arylene group" and "heteroaryl group" can be used in the same manner as in the description of the aryl group and heteroaryl group, except that the valence is changed from 1 to 2. The aryl moiety of an "aryloxy group," an "arylthio group," and an "aryloxycarbonyl group" can also be referred to the explanation of the "aryl group" herein. The heteroaryl moiety of a "heteroaryloxy group," an "heteroarylthio group," and an "heteroaryloxycarbonyl group" can also be referred to the explanation of the "heteroaryl group" herein.

(composition)
The composition of the present invention includes a compound represented by general formula (1) and a delayed fluorescent material. In one embodiment of the present invention, the composition is composed solely of one or more compounds represented by general formula (1) and one or more delayed fluorescent materials. In one embodiment of the present invention, the composition is composed solely of one compound represented by general formula (1) and one delayed fluorescent material. In one embodiment of the present invention, the composition includes a third component in addition to the compound represented by general formula (1) and the delayed fluorescent material. The third component here is neither a compound represented by general formula (1) nor a delayed fluorescent material. The third component may include only one type, or may include two or more types. The content of the third component in the composition may be selected within a range of 30% by weight or less, 10% by weight or less, 1% by weight or less, or 0.1% by weight or less. In one embodiment of the present invention, the third component does not emit light. In one embodiment of the present invention, the third component emits fluorescence. In a preferred embodiment of the present invention, the maximum component of light emitted from the composition of the present invention is fluorescence (including delayed fluorescence).
In the composition of the present invention, the compound represented by general formula (1) is contained in a larger amount by weight than the delayed fluorescent material. The content of the compound represented by general formula (1) may be selected within a range of 3 times or more by weight, 10 times or more by weight, 100 times or more by weight, 1000 times or more by weight, or, for example, 10,000 times or less by weight of the delayed fluorescent material.
In the composition of the present invention, it is preferable to select a delayed fluorescent material having a lower excited singlet energy than the excited singlet energy of the compound represented by general formula (1). The difference in excited singlet energy may be 0.1 eV or more, 0.3 eV or more, or 0.5 eV or more, or may be 2 eV or less, 1.5 eV or less, or 1.0 eV or less.
The composition of the present invention preferably does not contain metal elements. In one embodiment of the present invention, the composition of the present invention consists only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, and halogen atoms. In one embodiment of the present invention, the composition of the present invention consists only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms.

In one embodiment of the present invention, the compound represented by general formula (1) is useful as a host material for use together with a delayed fluorescent material and a fluorescent compound. Therefore, in one embodiment of the present invention, the composition of the present invention includes a fluorescent compound in addition to the compound represented by general formula (1) and the delayed fluorescent material.

The fluorescent compound preferably has a lower minimum excited singlet energy (E _S1 ) than the compound represented by general formula (1) and the delayed fluorescent material. The fluorescent compound receives energy from the compound represented by general formula (1) and the delayed fluorescent material in an excited singlet state, and from the delayed fluorescent material that has undergone reverse intersystem crossing from an excited triplet state to an excited singlet state, transitions to a singlet excited state, and then emits fluorescence when returning to the ground state. The fluorescent compound is not particularly limited as long as it can receive energy from the compound represented by general formula (1) and the delayed fluorescent material and emit fluorescence, and the emission may be either fluorescence or delayed fluorescence. In particular, it is preferable that the light emitter used as the fluorescent compound emits fluorescence when returning from the lowest excited singlet energy level to the ground energy level. Two or more fluorescent compounds may be used. For example, by using two or more fluorescent compounds with different emission colors in combination, it is possible to emit a desired color.
Examples of fluorescent compounds that can be used include anthracene derivatives, tetracene derivatives, naphthacene derivatives, pyrene derivatives, perylene derivatives, chrysene derivatives, rubrene derivatives, coumarin derivatives, pyran derivatives, stilbene derivatives, fluorene derivatives, anthryl derivatives, pyrromethene derivatives, terphenyl derivatives, terphenylene derivatives, fluoranthene derivatives, amine derivatives, quinacridone derivatives, oxadiazole derivatives, malononitrile derivatives, pyran derivatives, carbazole derivatives, julolidine derivatives, thiazole derivatives, derivatives containing metals (Al, Zn), and compounds having a boron-containing polycyclic aromatic skeleton such as diazaboranaphthoanthracene, and other compounds that exhibit a multiple resonance effect. These exemplary skeletons may or may not have a substituent. These exemplary skeletons may also be combined with each other.

Specific examples of fluorescent compounds include the compounds listed as specific examples of delayed fluorescent materials. In this case, the composition of the present invention contains two or more delayed fluorescent materials. The delayed fluorescent material with a higher lowest excited singlet energy functions as an assist dopant, while the delayed fluorescent material with a lower lowest excited singlet energy functions as the primary emitting fluorescent compound. The compound used as the fluorescent compound preferably exhibits a PL quantum yield of 60% or more, more preferably 80% or more. The compound used as the fluorescent compound preferably exhibits an instantaneous fluorescence lifetime of 50 ns or less, more preferably 20 ns or less. The instantaneous fluorescence lifetime here refers to the emission lifetime of the component that decays most rapidly among multiple exponential decay components observed when measuring the emission lifetime of a compound exhibiting thermally activated delayed fluorescence. Furthermore, the compound used as the third compound preferably has a fluorescence emission rate from the lowest excited singlet (S1) to the ground state that is greater than the intersystem crossing rate from S1 to the lowest excited triplet (T1). For methods for calculating the rate constant of a compound, reference can be made to known literature on thermally activated delayed fluorescent materials (e.g., H. Uoyama, et al., Nature 492, 234 (2012) and K. Masui, et al., Org. Electron. 14, 2721, (2013)).

Preferred compounds that can be used as fluorescent compounds together with delayed fluorescent materials are listed below, but the fluorescent compounds that can be used in the present invention should not be construed as being limited to these specific examples.

The compounds described in paragraphs 0220 to 0239 of WO 2015/022974 are also particularly suitable for use as the fluorescent compound of the present invention.

In one embodiment of the present invention, the compound represented by general formula (1) can be used together with other host materials to form an emitting layer (composition) containing multiple host materials. That is, in one embodiment of the present invention, the composition of the present invention contains multiple host materials including the compound represented by general formula (1). The composition of the present invention may contain multiple types of compounds represented by general formula (1), or may use a compound represented by general formula (1) in combination with a host material not represented by general formula (1).
Preferred compounds that can be used as the second host material together with the compound represented by general formula (1) are listed below, but the second host material that can be used in the present invention should not be construed as being limited by these specific examples.

The form of the composition of the present invention is not particularly limited. In a particularly preferred embodiment of the present invention, the composition of the present invention is in the form of a film. The film made of the composition of the present invention may be formed by a wet process or a dry process.
In a wet process, a solution containing the composition of the present invention is applied to a surface, and after removing the solvent, a light-emitting layer is formed. Wet processes include, but are not limited to, spin coating, slit coating, inkjet printing (spraying), gravure printing, offset printing, and flexographic printing. In a wet process, an appropriate organic solvent capable of dissolving the composition of the present invention is selected and used. In some embodiments, a substituent (e.g., an alkyl group) that increases the solubility in organic solvents can be introduced into the compound contained in the composition of the present invention.
A vacuum deposition method can be preferably used as the dry process. When using a vacuum deposition method, the compounds constituting the composition of the present invention may be co-deposited from separate deposition sources, or from a single deposition source containing a mixture of all compounds. When a single deposition source is used, a mixed powder containing all the compounds may be used, or a compressed compact obtained by compressing the mixed powder may be used, or a mixture obtained by heating, melting, mixing, and then cooling may be used. In some embodiments, co-deposition is performed under conditions where the deposition rates (weight loss rates) of the multiple compounds contained in a single deposition source are the same or nearly the same, thereby forming a film having a composition ratio corresponding to the composition ratio of the multiple compounds contained in the deposition source. By mixing multiple compounds in the same composition ratio as the composition ratio of the film to be formed and using the resulting deposition source as a deposition source, a film having a desired composition ratio can be easily formed. In some embodiments, the temperature at which the weight loss rate of each of the co-deposited compounds is the same can be identified, and that temperature can be used as the temperature during co-deposition. When the film is formed by a vapor deposition method, the molecular weight of each compound constituting the composition is preferably 1500 or less, more preferably 1200 or less, even more preferably 1000 or less, and even more preferably 900 or less. The lower limit of the molecular weight may be, for example, 450, 500, or 600.

(Organic Light-Emitting Element)
By forming a light-emitting layer made of the composition of the present invention, it is possible to provide an excellent organic light-emitting device such as an organic photoluminescence device (organic PL device) or an organic electroluminescence device (organic EL device). The organic light-emitting device of the present invention is a fluorescent light-emitting device, and the largest component of light emitted from the device is fluorescence (fluorescence here includes delayed fluorescence).
The thickness of the light-emitting layer can be, for example, 1 to 15 nm, 2 to 10 nm, or 3 to 7 nm.
An organic photoluminescence element has a structure in which at least a light-emitting layer is formed on a substrate. An organic electroluminescence element has a structure in which at least an anode, a cathode, and an organic layer are formed between the anode and the cathode. The organic layer includes at least a light-emitting layer, and may consist of only the light-emitting layer, or may have one or more organic layers in addition to the light-emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer may be a hole injection transport layer having a hole injection function, and the electron transport layer may be an electron injection transport layer having an electron injection function.
When the organic light-emitting element of the present invention is a multi-wavelength light-emitting organic light-emitting element, the emission with the shortest wavelength may include delayed fluorescence. Alternatively, the emission with the shortest wavelength may not include delayed fluorescence.
Organic light-emitting devices using the compositions of the present invention, when excited by thermal or electronic means, can emit light in the ultraviolet region, the blue, green, yellow, orange, or red region of the visible spectrum (e.g., 420-500 nm, 500-600 nm, or 600-700 nm), or the near-infrared region. For example, the organic light-emitting devices can emit light in the red or orange region (e.g., 620-780 nm). For example, the organic light-emitting devices can emit light in the orange or yellow region (e.g., 570-620 nm). For example, the organic light-emitting devices can emit light in the green region (e.g., 490-575 nm). For example, the organic light-emitting devices can emit light in the blue region (e.g., 400-490 nm). For example, the organic light-emitting devices can emit light in the ultraviolet region of the spectrum (e.g., 280-400 nm). For example, the organic light-emitting devices can emit light in the infrared region of the spectrum (e.g., 780 nm to 2 μm).
The largest component of the light emitted from the organic light-emitting device using the composition of the present invention is preferably the light emitted from the delayed fluorescent material contained in the composition of the present invention. The light emitted from the compound represented by general formula (1) is preferably less than 10% of the light emitted from the organic light-emitting device, for example, less than 1%, less than 0.1%, less than 0.01%, or even below the detection limit. The light emitted from the delayed fluorescent material may be, for example, more than 50%, more than 90%, or more than 99% of the light emitted from the organic light-emitting device. When the layer (light-emitting layer) containing the composition of the present invention contains a fluorescent material as a third component, the largest component of the light emitted from the organic light-emitting device may be the light emitted from the fluorescent material. In this case, the light emitted from the light-emitting material may be, for example, more than 50%, more than 90%, or more than 99% of the light emitted from the organic light-emitting device.

The following describes each component of the organic electroluminescent element and each layer other than the light-emitting layer.

Base material:
In some embodiments, the organic electroluminescent device of the present invention is supported by a substrate, and the substrate is not particularly limited and may be any material commonly used in organic electroluminescent devices, such as glass, transparent plastic, quartz, and silicon.

anode:
In some embodiments, the anode of the organic electroluminescent device is made of a metal, an alloy, a conductive compound, or a combination thereof. In some embodiments, the metal, alloy, or conductive compound has a high work function (4 eV or greater). In some embodiments, the metal is Au. In some embodiments, the conductive transparent material is selected from CuI, indium tin oxide (ITO), _SnO2 , and ZnO. In some embodiments, an amorphous material capable of forming a transparent conductive film, such as IDIXO ( _In2O3 - _ZnO ), is used. In some embodiments, the anode is a thin film. In some embodiments, the thin film is formed by evaporation or sputtering. In some embodiments, the film is patterned by a photolithography method. In some embodiments, if the pattern does not need to be highly accurate (e.g., greater than about 100 μm), the pattern may be formed using a mask with a shape suitable for evaporation or sputtering of the electrode material. In some embodiments, when a coating material, such as an organic conductive compound, can be applied, a wet film formation method, such as a printing method or a coating method, is used. In some embodiments, the anode has a transmittance of greater than 10% when emitted light passes through it, and the anode has a sheet resistance of several hundred ohms per unit area or less. In some embodiments, the anode has a thickness of 10 to 1,000 nm. In some embodiments, the anode has a thickness of 10 to 200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

cathode:
In some embodiments, the cathode is made of an electrode material such as a metal with a low work function (4 eV or less) (referred to as an electron-injecting metal), an alloy, a conductive compound, or a combination thereof. In some embodiments, the electrode material is selected from sodium, sodium-potassium alloy, magnesium, lithium, a magnesium-copper mixture, a magnesium-silver mixture, a magnesium-aluminum mixture, a magnesium-indium mixture, an aluminum-aluminum oxide (Al ₂ O ₃ ) mixture, indium, a lithium-aluminum mixture, and a rare earth element. In some embodiments, a mixture of an electron-injecting metal and a second metal, which is a stable metal having a higher work function than the electron-injecting metal, is used. In some embodiments, the mixture is selected from a magnesium-silver mixture, a magnesium-aluminum mixture, a magnesium-indium mixture, an aluminum-aluminum oxide (Al ₂ O ₃ ) mixture, a lithium-aluminum mixture, and aluminum. In some embodiments, the mixture improves electron-injecting properties and oxidation resistance. In some embodiments, the cathode is fabricated by forming the electrode material as a thin film by evaporation or sputtering. In some embodiments, the cathode has a sheet resistance of several hundred ohms per unit area or less. In some embodiments, the cathode has a thickness of 10 nm to 5 μm. In some embodiments, the cathode has a thickness of 50 to 200 nm. In some embodiments, either the anode or the cathode of the organic electroluminescent device is transparent or semi-transparent to allow emitted light to pass through. In some embodiments, a transparent or semi-transparent electroluminescent device improves light radiance.
In some embodiments, the cathode is formed from a conductive, transparent material as described above for the anode, thereby forming a transparent or semi-transparent cathode. In some embodiments, a device includes an anode and a cathode, both of which are transparent or semi-transparent.

Injection layer:
An injection layer is a layer between an electrode and an organic layer. In some embodiments, the injection layer reduces driving voltage and enhances light radiance. In some embodiments, the injection layer comprises a hole injection layer and an electron injection layer. The injection layer can be disposed between the anode and the emissive layer or the hole transport layer, and between the cathode and the emissive layer or the electron transport layer. In some embodiments, an injection layer is present. In some embodiments, an injection layer is not present.
Preferred examples of compounds that can be used as hole injection materials are listed below.

Next, examples of preferred compounds that can be used as the electron injection material will be given.

Barrier layer:
A blocking layer is a layer that can prevent charges (electrons or holes) and/or excitons present in the light-emitting layer from diffusing outside the light-emitting layer. In some embodiments, an electron blocking layer is present between the light-emitting layer and the hole transport layer and prevents electrons from passing through the light-emitting layer to the hole transport layer. In some embodiments, a hole blocking layer is present between the light-emitting layer and the electron transport layer and prevents holes from passing through the light-emitting layer to the electron transport layer. In some embodiments, a blocking layer prevents excitons from diffusing outside the light-emitting layer. In some embodiments, the electron blocking layer and the hole blocking layer constitute an exciton blocking layer. As used herein, the terms "electron blocking layer" or "exciton blocking layer" include layers that have both the functionality of an electron blocking layer and an exciton blocking layer.

Hole blocking layer:
The hole blocking layer functions as an electron transport layer. In some embodiments, the hole blocking layer prevents holes from reaching the electron transport layer during electron transport. In some embodiments, the hole blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The materials used for the hole blocking layer can be the same materials as those described above for the electron transport layer.
Preferred examples of compounds that can be used in the hole blocking layer are listed below.

Electron barrier layer:
The electron blocking layer transports holes. In some embodiments, during hole transport, the electron blocking layer prevents electrons from reaching the hole transport layer. In some embodiments, the electron blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The materials used for the electron blocking layer can be the same materials as those described above for the hole transport layer.
Specific examples of preferred compounds that can be used as electron blocking materials are listed below.

Exciton blocking layer:
The exciton blocking layer prevents excitons generated through the recombination of holes and electrons in the emissive layer from diffusing to the charge transport layer. In some embodiments, the exciton blocking layer enables effective confinement of excitons in the emissive layer. In some embodiments, the light emission efficiency of the device is improved. In some embodiments, the exciton blocking layer is adjacent to the emissive layer on either the anode side or the cathode side, and on both sides. In some embodiments, when the exciton blocking layer is present on the anode side, it may be present between the hole transport layer and the emissive layer and adjacent to the emissive layer. In some embodiments, when the exciton blocking layer is present on the cathode side, it may be present between the emissive layer and the cathode and adjacent to the emissive layer. In some embodiments, a hole injection layer, an electron blocking layer, or a similar layer is present between the anode and the exciton blocking layer adjacent to the emissive layer on the anode side. In some embodiments, a hole injection layer, an electron blocking layer, a hole blocking layer, or a similar layer is present between the cathode and the exciton blocking layer adjacent to the emissive layer on the cathode side. In some embodiments, the exciton blocking layer comprises an excited singlet energy and an excited triplet energy, at least one of which is higher than the excited singlet energy and excited triplet energy, respectively, of the light-emitting material.

Hole transport layer:
The hole transport layer comprises a hole transport material. In some embodiments, the hole transport layer is a single layer. In some embodiments, the hole transport layer has multiple layers.
In some embodiments, the hole transport material has one of hole injection or transport properties and electron blocking properties. In some embodiments, the hole transport material is an organic material. In some embodiments, the hole transport material is an inorganic material. Examples of known hole transport materials that can be used in the present invention include, but are not limited to, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, allylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers (especially thiophene oligomers), or combinations thereof. In some embodiments, the hole transport material is selected from porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds. In some embodiments, the hole transport material is an aromatic tertiary amine compound. Specific examples of preferred compounds that can be used as hole transport materials are listed below.

Electron transport layer:
The electron transport layer comprises an electron transport material. In some embodiments, the electron transport layer is a single layer. In some embodiments, the electron transport layer has multiple layers.
In some embodiments, the electron transport material only needs to transport electrons injected from the cathode to the light-emitting layer. In some embodiments, the electron transport material also functions as a hole-blocking material. Examples of electron transport layers that can be used in the present invention include, but are not limited to, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethanes, anthrone derivatives, oxadiazole derivatives, azole derivatives, azine derivatives, or combinations thereof, or polymers thereof. In some embodiments, the electron transport material is a thiadiazole derivative or a quinoxaline derivative. In some embodiments, the electron transport material is a polymer material. Specific examples of preferred compounds that can be used as electron transport materials are listed below.

Furthermore, examples of preferred compounds that can be added to each organic layer are listed below. For example, they can be added as stabilizing materials.

Although specific examples of preferred materials that can be used in organic electroluminescence devices have been given, the materials that can be used in the present invention should not be construed as being limited to the exemplified compounds below. Furthermore, even compounds exemplified as materials with specific functions can be diverted to be used as materials with other functions.

device:
In some embodiments, the light-emitting layer is incorporated into a device, including, but not limited to, an OLED bulb, an OLED lamp, a television display, a computer monitor, a mobile phone, and a tablet.
In some embodiments, the electronic device comprises an OLED having an anode, a cathode, and at least one organic layer comprising an emissive layer between the anode and the cathode.
In some embodiments, the compositions described herein can be incorporated into various photosensitive or photoactivated devices, such as OLEDs or optoelectronic devices. In some embodiments, the compositions can be useful for facilitating charge or energy transfer within devices and/or as hole transport materials, such as organic light-emitting diodes (OLEDs), organic integrated circuits (OICs), organic field-effect transistors (O-FETs), organic thin film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting fuel cells (LECs), or organic laser diodes (O-lasers).

Bulb or lamp:
In some embodiments, the electronic device comprises an OLED comprising an anode, a cathode, and at least one organic layer comprising an emissive layer between the anode and the cathode.
In some embodiments, the device includes OLEDs of different colors. In some embodiments, the device includes an array including a combination of OLEDs. In some embodiments, the combination of OLEDs is a three-color combination (e.g., RGB). In some embodiments, the combination of OLEDs is a combination of colors that are not red, green, or blue (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a two-color, four-color, or more-color combination.
In some embodiments, the device comprises:
a circuit board having a first side with a mounting surface and an opposite second side, the circuit board defining at least one opening;
at least one OLED on the mounting surface, the at least one OLED having a light-emitting configuration including an anode, a cathode, and at least one organic layer including a light-emitting layer between the anode and the cathode;
a housing for the circuit board;
and at least one connector disposed on an end of the housing, the housing and the connector defining a package suitable for attachment to a lighting fixture.
In some embodiments, the OLED light comprises multiple OLEDs mounted on a circuit board such that the OLEDs emit light in multiple directions. In some embodiments, some of the light emitted in a first direction is polarized and emitted in a second direction. In some embodiments, a reflector is used to polarize the light emitted in the first direction.

Display or Screen:
In some embodiments, the light-emitting layer of the present invention can be used in a screen or display. In some embodiments, the compounds of the present invention are deposited onto a substrate using processes such as, but not limited to, vacuum evaporation, deposition, vapor deposition, or chemical vapor deposition (CVD). In some embodiments, the substrate is a photoplate structure useful for two-sided etching to provide pixels with unique aspect ratios. The screen (also called a mask) is used in the manufacturing process of an OLED display. The corresponding artwork pattern design allows for the placement of very steep, narrow tie bars between pixels in the vertical direction and large, wide, beveled openings in the horizontal direction. This allows for the fine patterning of pixels required for high-resolution displays while optimizing chemical vapor deposition onto the TFT backplane.
Internal pixel patterning allows for the construction of three-dimensional pixel openings with various aspect ratios in the horizontal and vertical directions. Furthermore, the use of imaged "stripes" or halftone circles within the pixel area protects etching in specific regions until these specific patterns are undercut and removed from the substrate. At that point, all pixel areas are subjected to similar etch rates, but the depth varies depending on the halftone pattern. Varying the size and spacing of the halftone patterns allows for etching with varying degrees of protection within the pixel, enabling the deep, localized etching required to create steep vertical bevels.
The preferred material for the deposition mask is Invar, a metal alloy that is cold-rolled into long, thin sheets at steel mills. Invar cannot be electrodeposited onto the spin mandrel as a nickel mask. A suitable, low-cost method for forming open areas in the deposition mask is by wet chemical etching.
In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is fabricated using lithography (e.g., photolithography and e-beam lithography). In some embodiments, the screen or display pattern is fabricated using wet chemical etching. In further embodiments, the screen or display pattern is fabricated using plasma etching.

Device manufacturing method:
OLED displays are generally manufactured by forming a large mother panel and then cutting the mother panel into cell panels. Typically, each cell panel on the mother panel is formed by forming a thin film transistor (TFT) having an active layer and source/drain electrodes on a base substrate, applying a planarizing film to the TFT, sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and an encapsulation layer, and then cutting the mother panel.
OLED displays are generally manufactured by forming a large mother panel and then cutting the mother panel into cell panels. Typically, each cell panel on the mother panel is formed by forming a thin film transistor (TFT) having an active layer and source/drain electrodes on a base substrate, applying a planarizing film to the TFT, sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and an encapsulation layer, and then cutting the mother panel.

In another aspect of the present invention, there is provided a method for manufacturing an organic light emitting diode (OLED) display, the method comprising:
forming a barrier layer on a base substrate of the mother panel;
forming a plurality of display units on the barrier layer in cell panel units;
forming an encapsulation layer over each of the display units of the cell panel;
and applying an organic film to the interface between the cell panels.
In some embodiments, the barrier layer is an inorganic film, for example, made of SiNx, and the edges of the barrier layer are covered with an organic film made of polyimide or acrylic. In some embodiments, the organic film helps the mother panel to be softly cut into individual cell panels.
In some embodiments, the thin film transistor (TFT) layer includes a light-emitting layer, a gate electrode, and source/drain electrodes. Each of the plurality of display units may include a thin film transistor (TFT) layer, a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, and the organic film applied to the interface is formed of the same material as the planarization film and is formed simultaneously with the planarization film. In some embodiments, the light-emitting unit is connected to the TFT layer by a passivation layer, the planarization film therebetween, and an encapsulation layer that covers and protects the light-emitting unit. In some embodiments of the manufacturing method, the organic film is not connected to either the display unit or the encapsulation layer.

Each of the organic film and the planarization film may comprise one of polyimide and acrylic. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the base substrate may be formed of polyimide. The method may further include attaching a carrier substrate formed of a glass material to one surface of the base substrate formed of polyimide before forming the barrier layer on the other surface of the base substrate, and separating the carrier substrate from the base substrate before cutting along the interface. In some embodiments, the OLED display is a flexible display.
In some embodiments, the passivation layer is an organic film disposed on the TFT layer to cover the TFT layer. In some embodiments, the planarization film is an organic film formed on the passivation layer. In some embodiments, the planarization film is made of polyimide or acrylic, as is the organic film formed on the edge of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously during the manufacture of an OLED display. In some embodiments, the organic film may be formed on the edge of the barrier layer, such that a portion of the organic film directly contacts the base substrate and a remaining portion of the organic film contacts the barrier layer while surrounding the edge of the barrier layer.

In some embodiments, the light-emitting layer comprises a pixel electrode, a counter electrode, and an organic light-emitting layer disposed between the pixel electrode and the counter electrode, hi some embodiments, the pixel electrode is coupled to source/drain electrodes of the TFT layer.
In some embodiments, when a voltage is applied to the pixel electrode through the TFT layer, a suitable voltage is formed between the pixel electrode and the counter electrode, which causes the organic light-emitting layer to emit light, thereby forming an image. Hereinafter, an image-forming unit having a TFT layer and a light-emitting unit is referred to as a display unit.
In some embodiments, the encapsulation layer that covers the display units and prevents penetration of external moisture may be formed into a thin-film encapsulation structure in which organic films and inorganic films are alternately stacked. In some embodiments, the encapsulation layer has a thin-film encapsulation structure in which multiple thin films are stacked. In some embodiments, the organic film applied to the interface portion is disposed at an interval with each of the multiple display units. In some embodiments, the organic film is formed in such a manner that a portion of the organic film directly contacts the base substrate and the remaining portion of the organic film contacts the barrier layer while surrounding the edge of the barrier layer.

In one embodiment, the OLED display is flexible and uses a flexible base substrate formed of polyimide, hi some embodiments, the base substrate is formed on a carrier substrate formed of a glass material, and the carrier substrate is then separated.
In some embodiments, a barrier layer is formed on the surface of the base substrate opposite the carrier substrate. In one embodiment, the barrier layer is patterned according to the size of each cell panel. For example, while the base substrate is formed on all surfaces of the mother panel, the barrier layer is formed according to the size of each cell panel, thereby forming grooves at the interfaces between the barrier layers of the cell panels. Each cell panel can be cut along the grooves.

In some embodiments, the manufacturing method further includes a step of cutting along the interface, in which a groove is formed in the barrier layer and at least a portion of the organic film is formed in the groove, such that the groove does not penetrate the base substrate. In some embodiments, a TFT layer for each cell panel is formed, and a passivation layer, which is an inorganic film, and a planarization film, which is an organic film, are disposed on and cover the TFT layer. At the same time that the planarization film, made of, for example, polyimide or acrylic, is formed, the groove in the interface is covered with an organic film, made of, for example, polyimide or acrylic. This prevents cracks from occurring when each cell panel is cut along the groove at the interface by allowing the organic film to absorb any impact that occurs. In other words, if all of the barrier layers were completely exposed without the organic film, the impact would be transmitted to the barrier layer when each cell panel was cut along the groove at the interface, thereby increasing the risk of cracks. However, in one embodiment, the grooves at the interface between the barrier layers are covered with an organic film to absorb impacts that would otherwise be transmitted to the barrier layers, allowing each cell panel to be cut softly and preventing cracks from occurring in the barrier layers. In one embodiment, the organic film and planarization film covering the grooves at the interface are spaced apart from each other. For example, if the organic film and planarization film were connected to each other as a single layer, external moisture could enter the display unit through the planarization film and the remaining portion of the organic film. Therefore, the organic film and planarization film are spaced apart from each other so that the organic film is spaced apart from the display unit.

In some embodiments, the display unit is formed by forming a light-emitting unit, and an encapsulation layer is disposed on the display unit to cover the display unit. Thus, after the mother panel is completely manufactured, the carrier substrate carrying the base substrate is separated from the base substrate. In some embodiments, when a laser beam is irradiated onto the carrier substrate, the carrier substrate is separated from the base substrate due to the difference in thermal expansion coefficient between the carrier substrate and the base substrate.
In some embodiments, the mother panel is cut into individual cell panels. In some embodiments, the mother panel is cut along the interface between the cell panels using a cutter. In some embodiments, the grooves at the interface along which the mother panel is cut are covered with an organic film, which absorbs shock during cutting. In some embodiments, this can prevent cracks from occurring in the barrier layer during cutting.
In some embodiments, the method reduces product rejection rates and stabilizes product quality.
Another aspect is an OLED display having a barrier layer formed on a base substrate, a display unit formed on the barrier layer, an encapsulation layer formed on the display unit, and an organic film applied to the edges of the barrier layer.

The features of the present invention will be explained in more detail below with reference to synthesis examples and working examples. The materials, processing details, processing procedures, etc. shown below can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. The emission characteristics were evaluated using a source meter (Keithley: 2400 series), a semiconductor parameter analyzer (Agilent Technologies: E5273A), an optical power meter measuring device (Newport: 1930C), an optical spectrometer (Ocean Optics: USB2000), a spectroradiometer (Topcon: SR-3), and a streak camera (Hamamatsu Photonics K.K.: C4334 model). The HOMO and LUMO energies were measured by atmospheric photoelectron spectroscopy (Riken Keiki AC-3, etc.).
In the following synthesis examples, compounds within the general formula (1) were synthesized.

(Synthesis Example 1) Synthesis of Compound 369

Under a nitrogen atmosphere, 2-bromo-6-iododibenzofuran (1.67 g, 4.48 mmol), 12H-benzofuro[2,3-a]carbazole (0.89 g, 3.45 mmol), copper iodide (0.66 g, 3.45 mmol), trans-1,2-cyclohexanediamine (0.39 g, 3.45 mmol), and potassium phosphate (2.2 g, 10.4 mmol) were added to 50 ml of toluene and refluxed for 12 hours. The reaction solution was cooled to room temperature, and insoluble matter was removed by filtration through Celite. Chloroform was added, and the organic layer was washed twice with water and dried over magnesium sulfate, followed by removal of the solvent. The resulting solid was purified by silica gel column chromatography (developing solvent: chloroform/n-hexane = 1:9) to obtain intermediate a (0.56 g, 32%) as a white solid.
MS (ASAP): 502.83 (M+H ⁺ ). Calcd for C ₃₀ H ₁₆ BrNO ₂ : 501.04.

12-(8-bromodibenzo[b,d]furan-4-yl)-12H-benzofuro[2,3-a]carbazole (intermediate a, 0.83 g, 1.65 mmol), dibenzo[b,d]furan-2-ylboronic acid (0.42 g, 1.98 mmol), tetrakistriphenylphosphinepalladium(0) (0.095 g, 0.083 mmol), and potassium carbonate (0.684 g, 4.96 mmol) were dissolved in a mixture of tetrahydrofuran and water (20/10 ml) and stirred at 75°C for 12 hours. The reaction solution was cooled to room temperature, chloroform was added, and the organic layer was washed twice with water and dried over magnesium sulfate to remove the solvent. The resulting solid was purified by silica gel column chromatography (developing solvent: chloroform/n-hexane = 1:9) to obtain compound 369 (0.322 g, 33%) as a white solid.
¹ H NMR (400MHz, CDCl ₃ , δ): 8.35 (s, 1H), 8.28 -8.22 (m, 3H), 8.19 (d, J= 8 Hz, 1H), 8.04 (d, J = 8 Hz, 1H), 8.02-7.99 (m, 1H), 7.91 (d, J = 8 Hz, 1H), 7.80-7.76 (m, 2H), 7.72 -7.61 (m, 4H), 7.54-7.37 (m, 5H), 7.34-7.24 (m, 4H).
MS (ASAP): 589.93 (M+H ⁺ ). Calcd. for C ₄₂ H ₂₃ NO ₃ : 589.17.

(Synthesis Example 2) Synthesis of Compound 7546

Under a nitrogen atmosphere, 6-bromo-2-iododibenzofuran (2.22 g, 5.94 mmol), 12H-benzofuro[3,2-a]carbazole (3.36 g, 13.1 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.543 g, 0.594 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.344 g, 1.19 mmol), and sodium tert-butoxide (2.85 g, 29.7 mmol) were added to 20 ml of toluene and refluxed for 24 hours. The reaction solution was cooled to room temperature, and chloroform was added. The resulting organic layer was washed twice with water and dried over magnesium sulfate to remove the solvent. The resulting solid was purified by silica gel column chromatography (developing solvent: chloroform/n-hexane = 3:7). Further recrystallization (chloroform/hexane) afforded compound 7546 (1.43 g, 35%) as a white solid.
MS (ASAP): 679.38 (M+H ⁺ ). Calcd for C ₄₈ H ₂₆ N ₂ O ₃ : 678.19.

(Synthesis Example 3) Synthesis of Compound 41218

Under a nitrogen atmosphere, 6-bromo-2-iododibenzofuran (2.5 g, 6.70 mmol), 12H-benzofuro[3,2-a]carbazole (1.44 g, 5.58 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.255 g, 0.297 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.161 g, 0.558 mmol), and sodium tert-butoxide (1.61 g, 16.7 mmol) were added to 20 mL of toluene and refluxed for 24 hours. The reaction solution was cooled to room temperature, and chloroform was added. The resulting organic layer was washed twice with water and dried over magnesium sulfate to remove the solvent. The resulting solid was purified by silica gel column chromatography (developing solvent: chloroform/n-hexane = 1:9). Further washing with methanol yielded intermediate b (1.67 g, 60%) as a white solid.
MS (ASAP): 503.00 (M+H ⁺ ). Calcd for C ₃₀ H ₁₆ BrNO ₂ : 501.04.

Under a nitrogen atmosphere, 12-(6-bromodibenzo[b,d]furan-2-yl)-12H-benzofuro[3,2-a]carbazole (intermediate b, 1.03 g, 2.05 mmol), carbazole (0.52 g, 3.08 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.188 g, 0.205 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.119 g, 0.411 mmol), and sodium tert-butoxide (0.592 g, 6.16 mmol) were added to 10 ml of toluene and refluxed for 24 hours. The reaction solution was cooled to room temperature, and chloroform was added. The resulting organic layer was washed twice with water, dried over magnesium sulfate, and the solvent was removed. The obtained solid was purified by silica gel column chromatography (developing solvent: chloroform/n-hexane=3:7) to obtain compound 41218 (0.477 g, 40%) as a white solid.
^1H NMR (400MHz, CDCl ₃ , δ): 8.26-8.18 (m, 5H), 8.03 (d, J = 8 Hz, 1H), 7.78 (d, J = 8 Hz, 1H), 7.74-7.68 (m, 2H), 7.62-7.35 (m, 10H), 7.31-7.19 (m, 3H), 6.73 (t, J = 8 Hz, 1H), 5.67 (d, J = 8 Hz, 1H).
MS (ASAP): 589.30 (M+H ⁺ ). Calcd for C ₄₂ H ₂₄ N ₂ O ₂ : 588.18.

(Example 1) Preparation of Organic Electroluminescent Device Each thin film was laminated by vacuum deposition at a vacuum of 1 x ^10-5 Pa on a glass substrate with an anode made of indium tin oxide (ITO) having a thickness of 100 nm. First, HATCN was formed to a thickness of 10 nm on the ITO, and NPD was formed thereon to a thickness of 30 nm. Next, TrisPCz was formed thereon to a thickness of 10 nm. Next, Compound 369, TADF2 (4CzTPN), and E35 were co-deposited from different deposition sources at 64.5 wt%, 35.0 wt%, and 0.5 wt%, respectively, to form a 40 nm thick light-emitting layer. SF3TRZ was formed thereon to a thickness of 10 nm, and SF3TRZ and Liq were co-deposited from different deposition sources at 30 wt% and 70 wt%, respectively, to form a 30 nm thick light-emitting layer. Furthermore, Liq was formed to a thickness of 2 nm, and then aluminum (Al) was vapor-deposited to a thickness of 100 nm to form a cathode. By the above procedures, the organic electroluminescence element of Example 1 was produced.
(Comparative Example 1) Preparation of Comparative Organic Electroluminescence Device An organic electroluminescence device of Comparative Example 1 was prepared in the same manner as in Example 1, except that Comparative Compound 1 was used instead of Compound 369 used in Example 1.
(evaluation)
The driving voltage was measured when a current of 15.4 mA/ ^cm2 was applied to each of the organic electroluminescence elements of Example 1 and Comparative Example 1. As a result, the driving voltage of the organic electroluminescence element of Example 1 was 0.2 eV lower than that of Comparative Example 1.

Example 2 Preparation of Organic Electroluminescence Device An organic electroluminescence device of Example 2 was prepared by the same procedure as in Example 1, except that Compound 7546, TADF2, and E35 were co-deposited from different evaporation sources at concentrations of 69.5 mass%, 30.0 mass%, and 0.5 mass%, respectively, to form an emitting layer having a thickness of 40 nm.
(Comparative Example 2)
An organic electroluminescence device of Comparative Example 2 was produced in the same manner as in Example 2, except that Comparative Compound 2 was used instead of Compound 7546 used in Example 2.
(evaluation)
The driving voltage was measured when a current of 6.3 mA/ ^cm2 was applied to each of the organic electroluminescence elements of Example 2 and Comparative Example 2. As a result, the driving voltage of the organic electroluminescence element of Example 2 was 0.2 eV lower than that of Comparative Example 2.

Example 3 Preparation of Organic Electroluminescence Device An organic electroluminescence device of Comparative Example 3 was prepared in the same manner as in Example 2, except that compound 41218 was used instead of compound 7546 used in Example 2.

The compound represented by general formula (1) is useful, for example, as a host material. Organic light-emitting devices using the compound represented by general formula (1) have excellent properties. Therefore, the present invention has high industrial applicability.

Claims (23)

A compound represented by the following general formula (1):
[In general formula (1),
X represents O or S;
R ¹ to R ⁶ each independently represent a hydrogen atom, a deuterium atom, an optionally deuterated alkyl group, or a substituted or unsubstituted aryl group;
At least one of Z ¹ and Z ² is each independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
Z ¹ may be a substituted or unsubstituted carbazolyl group;
^Z2 may be a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group.
The carbazolyl group, the benzofurocarbazolyl group, and the benzothienocarbazolyl group are each a group bonded via a nitrogen atom constituting a carbazole ring.
However, the general formula (1) satisfies any one of the following conditions (A) to (C).
(A) ^Z1 is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group, and ^Z2 is a substituted or unsubstituted dibenzofuryl group or a substituted or unsubstituted dibenzothienyl group ( excluding the following compounds) :
(B) Z ¹ and Z ² are each independently a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group.
(C) Z ¹ is a substituted or unsubstituted carbazolyl group, and Z ² is a substituted or unsubstituted benzofurocarbazolyl group or a substituted or unsubstituted benzothienocarbazolyl group. The compound according to claim 1 , wherein Z ¹ is a substituted or unsubstituted benzofurocarbazolyl group. The compound according to claim 1 , wherein Z ¹ is a substituted or unsubstituted carbazolyl group. The compound according to any one of claims 1 to 3, wherein ^Z2 is a substituted or unsubstituted dibenzofuryl group. The compound according to claim 4, wherein ^Z2 is a substituted or unsubstituted dibenzofuran-2-yl group. The compound according to any one of claims 1 to 3, wherein ^Z2 is a substituted or unsubstituted benzofurocarbazolyl group. The compound according to claim 1 (excluding the following compounds) which satisfies the above (A).
The compound described in claim 1, which satisfies (B). The compound described in claim 1, which satisfies (C). The compound according to any one of claims 1 to 9, wherein R ¹ to R ⁶ are hydrogen atoms. A host material comprising the compound described in any one of claims 1 to 10. The host material according to claim 11 for use together with a delayed fluorescent material. A composition comprising the compound according to any one of claims 1 to 10 doped with a delayed fluorescent material. The composition described in claim 13, which is in the form of a film. The composition according to claim 13 or 14, wherein the delayed fluorescent material is a compound having a cyanobenzene structure in which one cyano group is substituted on the benzene ring. The composition according to claim 15, wherein the delayed fluorescent material has two or more types of substituted or unsubstituted carbazolyl groups bonded to the benzene ring in addition to the cyano group. The composition described in any one of claims 13 to 16, further comprising a fluorescent compound having a lowest excited singlet energy lower than that of the compound and the delayed fluorescent material. An organic light-emitting device having a layer made of the composition described in any one of claims 13 to 17. The organic light-emitting element according to claim 18, wherein the layer consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, and halogen atoms. The organic light-emitting device according to claim 19, wherein the layer consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. The organic light-emitting device according to any one of claims 18 to 20, which is an organic electroluminescence device. The layer is a layer made of the composition according to any one of claims 13 to 16,
The composition does not contain a fluorescent compound having a lower minimum excited singlet energy than the delayed fluorescent material, and the largest component of light emitted from the element is light emitted from the delayed fluorescent material. The organic light-emitting element according to any one of claims 18 to 21. The organic light-emitting device described in any one of claims 18 to 21, wherein the composition contains a fluorescent compound having a lower minimum excited singlet energy than the delayed fluorescent material, and the largest component of the light emitted from the device is light emitted from the fluorescent compound.