Charge transport material, composition and organic light-emitting device

Abstract

To provide a compound useful as a host material for organic luminescent elements.SOLUTION: A host material comprises a compound represented by D-Ar-Z, where D represents a donating group, Ar represents an arylene group or a biphenylylene group, and Z represents a benzofurodibenzofuryl group, a benzothienodibenzothienyl group, or the like.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a compound useful as a charge transport material, a composition using the compound, and an organic light-emitting device. [Background technology]

[0002] Active research has been conducted into improving the luminous efficiency of light-emitting elements such as organic electroluminescent elements (organic EL elements). In particular, various efforts have been made to improve the luminous efficiency by newly developing and combining electron transport materials, hole transport materials, luminescent materials, host materials, etc. that constitute organic electroluminescent elements. Among these, organic electroluminescent elements that utilize delayed fluorescent materials have been developed and are attracting attention (see Non-Patent Document 1).

[0003] Delayed fluorescent materials are materials that, in an excited state, undergo reverse intersystem crossing from an excited triplet state to an excited singlet state, and then emit fluorescence upon returning from that excited singlet state to the ground state. Fluorescence via this pathway is observed later than fluorescence from the excited singlet state (normal fluorescence) that arises directly from the ground state, hence the term delayed fluorescence. For example, when a light-emitting compound is excited by carrier injection, the probability of occurrence of the excited singlet state and the excited triplet state is statistically 25%:75%, so there is a limit to the improvement in luminous efficiency when relying solely on fluorescence from the directly arisen excited singlet state. On the other hand, delayed fluorescent materials can utilize not only the excited singlet state but also the excited triplet state for fluorescence emission via the above-mentioned reverse intersystem crossing pathway, thereby achieving higher luminous efficiency than conventional fluorescent materials. Delayed fluorescent materials with these characteristics are generally used together with host materials in the emissive layer of organic electroluminescent devices, where they actually contribute to improving luminous efficiency. [Prior art documents] [Patent documents]

[0004] [Non-Patent Document 1] Uoyama et al, Nature, 492, 234-238 (2012) Summary of the Invention [Problem to be solved by the invention]

[0005] A compound having a minimum excited singlet energy greater than that of the delayed fluorescent material is selected as the host material to be combined with the delayed fluorescent material. However, even if a host material that has been used in combination with a conventional fluorescent material that does not emit delayed fluorescence is directly combined with a delayed fluorescent material, sufficient light-emitting performance cannot be achieved. In particular, organic electroluminescent elements using delayed fluorescent materials have room for improvement in device characteristics such as driving voltage. For this reason, the present inventors have conducted research to improve the device characteristics of organic light-emitting elements using delayed fluorescent materials. [Means for solving the problem]

[0006] As a result of extensive investigations, the present inventors have found that compounds having specific structures are useful as charge transport materials such as host materials. The present invention has been proposed based on this finding, and specifically has the following configurations.

[0007] [1] A compound represented by the following general formula (1): General formula (1) D-Ar-Z [In general formula (1), D represents a donor group, Ar represents a substituted or unsubstituted arylene group or a substituted or unsubstituted biphenylylene group (however, the two benzene rings constituting the biphenylylene group may be further linked to each other via a linking group), and Z represents a substituted or unsubstituted benzofurodibenzofuryl group, a substituted or unsubstituted benzofurodibenzothienyl group, a substituted or unsubstituted benzothienodibenzofuryl group, or a substituted or unsubstituted benzothienodibenzothienyl group.] [2] The compound according to [1], wherein Ar has any one of the following skeletons: [ka] [In the above formula, * represents the bonding position to D or Z. Each hydrogen atom in the above skeleton may be independently substituted with a deuterium atom or a substituent, or may be substituted with an adjacent hydrogen atom by a linking group to form a cyclic structure.] [3] The compound according to [1], represented by the following general formula (2): [ka] [In the general formula (2), X 1 and X 2 R each independently represents an oxygen atom or a sulfur atom. 1 ~R 7 each independently represents a deuterium atom or a substituent. n represents 0 or 1, n1, n2, n3, n4, n5, and n7 each independently represents an integer of 0 to 4, and n6 represents an integer of 0 to 2. R 3 and R 4 , two adjacent R 1 , two adjacent R 2 , two adjacent R 3 , two adjacent R 4 , two adjacent R 5 , two adjacent R 6 , two adjacent R 7 may be bonded to each other to form a cyclic structure. [4] The compound according to [1], represented by any one of the following general formulas (3-1) to (3-16): [ka] JPEG0007764013000004.jpg232161 [In the general formulas (3-1) to (3-16), R 1 ~R 7 each independently represents a deuterium atom or a substituent. n represents 0 or 1, n1, n2, n3, n4, n5, and n7 each independently represents an integer of 0 to 4, n3' and n4' each independently represents an integer of 0 to 3, and n6 represents an integer of 0 to 2. R 3 and R 4, two adjacent R 1 , two adjacent R 2 , two adjacent R 3 , two adjacent R 4 , two adjacent R 5 , two adjacent R 6 , two adjacent R 7 may be bonded to each other to form a cyclic structure. [5] Two adjacent R 1 do not bond to each other to form a ring structure, and two adjacent R 2 are not bonded to each other to form a cyclic structure. [6] R 1 and R 2 The compound according to any one of [3] to [5], wherein none of the groups contains a carbazole ring structure. [7] A charge transport material comprising the compound according to any one of [1] to [6]. [8] The charge transport material according to [7], which is a host material. [9] A composition in which a host material comprising the compound according to any one of [1] to [6] is doped with a delayed fluorescent material.

[10] The composition according to [9], which is in the form of a film.

[11] The composition according to [9] or

[10] , wherein the delayed fluorescent material is a compound having a cyanobenzene structure in which one cyano group is substituted on a benzene ring.

[12] The composition according to [9] or

[10] , wherein the delayed fluorescent material is a compound having a dicyanobenzene structure in which two cyano groups are substituted on a benzene ring.

[13] The composition according to any one of [9] to

[12] , wherein the delayed fluorescent material is a compound having an azabenzene structure in which at least one of the carbon atoms constituting the ring skeleton of a benzene ring is substituted with a nitrogen atom.

[14] The composition according to any one of [9] to

[13] , further comprising a fluorescent compound having a minimum excited singlet energy lower than those of the host material and the delayed fluorescent material.

[15] An organic light-emitting device having a layer made of the composition according to any one of [9] to

[14] .

[16] The organic light-emitting device according to

[15] , 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.

[17] The organic light-emitting device according to

[15] , 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.

[18] The organic light-emitting device according to any one of

[15] to

[17] , which is an organic electroluminescence device.

[19] The organic light-emitting device according to any one of

[15] to

[18] , wherein the composition does not contain the fluorescent compound, and the largest component of the light emitted from the device is light emitted from the delayed fluorescent material.

[20] The organic light-emitting device according to any one of

[15] to

[18] , 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. [Effects of the Invention]

[0008] The compound of the present invention is useful as a charge transport material and can be effectively used in organic semiconductor devices. For example, by using the compound of the present invention as a host material in the light-emitting layer of an organic electroluminescence device, the device characteristics can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescence element. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The following description of the constituent elements may be based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In addition, some or all of the hydrogen atoms present in the molecules of the compound used in the present invention may be replaced with deuterium atoms ( 2 In the chemical structural formulas herein, hydrogen atoms are represented by H or are omitted. For example, when the atom bonded to a carbon atom constituting the ring skeleton of a benzene ring is omitted, it is assumed that H is bonded to the carbon atom constituting the ring skeleton at the omitted position. In this specification, the term "substituent" refers to an atom or atomic group other than a hydrogen atom or a deuterium atom. On the other hand, the term "substituted or unsubstituted" means that a hydrogen atom may be substituted with a deuterium atom or a substituent.

[0011] [Compound represented by general formula (1)] The compound of the present invention is a compound represented by the following general formula (1). General formula (1) D-Ar-Z

[0012] In general formula (1), Z represents a substituted or unsubstituted benzofurodibenzofuryl group, a substituted or unsubstituted benzofurodibenzothienyl group, a substituted or unsubstituted benzothienodibenzofuryl group, or a substituted or unsubstituted benzothienodibenzothienyl group. In one embodiment of the present invention, Z is bonded through a fused ring containing at least one furan structure. In one embodiment of the present invention, Z is bonded through a fused ring containing at least one thiophene structure. In one embodiment of the present invention, Z is bonded through a fused ring containing at least one furan structure and at least one thiophene structure. In one embodiment of the present invention, Z is bonded through a fused ring containing at least one furan structure but no thiophene structure. In one embodiment of the present invention, Z is bonded through a fused ring containing at least one thiophene structure but no furan structure. In one embodiment of the present invention, Z is bonded through a fused ring having five fused rings. In one embodiment of the present invention, Z is an unsubstituted benzofurodibenzofuryl group, an unsubstituted benzofurodibenzothienyl group, an unsubstituted benzothienodibenzofuryl group, or an unsubstituted benzothienodibenzothienyl group. In another embodiment of the present invention, Z is a substituted benzofurodibenzofuryl group, a substituted benzofurodibenzothienyl group, a substituted benzothienodibenzofuryl group, or a substituted benzothienodibenzothienyl group. In one embodiment of the present invention, Z is a substituted or unsubstituted benzofurodibenzofuryl group. In one embodiment of the present invention, Z is a substituted or unsubstituted benzofurodibenzothienyl group. In one embodiment of the present invention, Z is a substituted or unsubstituted benzothienodibenzofuryl group. In one embodiment of the present invention, Z is a substituted or unsubstituted benzothienodibenzothienyl group. In one embodiment of the present invention, Z is bonded to a benzene ring constituting an end of the fused ring structure of a benzofurodibenzofuryl group, a benzofurodibenzothienyl group, a benzothienodibenzofuryl group, or a benzothienodibenzothienyl group. In another embodiment of the present invention, Z is bonded to a benzene ring constituting the center of the fused ring structure of a benzofurodibenzofuryl group, a benzofurodibenzothienyl group, a benzothienodibenzofuryl group, or a benzothienodibenzothienyl group.

[0013] When Z is a substituted or unsubstituted benzofurodibenzofuryl group, Z may have any of the following skeletons 1a to 1f. In one embodiment of the present invention, Z has any of the skeletons 1a to 1c. In one embodiment of the present invention, Z has any of the skeletons 1d to 1f. In one embodiment of the present invention, Z has the skeleton 1a or 1b. In one embodiment of the present invention, Z has the skeleton 1c or 1d. In one embodiment of the present invention, Z has the skeleton 1e or 1f. In one embodiment of the present invention, Z has the skeleton 1c. [ka]

[0014] When Z is a substituted or unsubstituted benzofurodibenzothienyl group, Z may have any of the following skeletons 2a to 2f. In one embodiment of the present invention, Z has any of the skeletons 2a to 2c. In one embodiment of the present invention, Z has any of the skeletons 2d to 2f. In one embodiment of the present invention, Z has the skeleton 2a or 2b. In one embodiment of the present invention, Z has the skeleton 2c or 2d. In one embodiment of the present invention, Z has the skeleton 2e or 2f. In one embodiment of the present invention, Z has the skeleton 2c. [ka]

[0015] When Z is a substituted or unsubstituted benzothienodibenzofuryl group, Z may have any of the following skeletons 3a to 3f. In one embodiment of the present invention, Z has any of the skeletons 3a to 3c. In one embodiment of the present invention, Z has any of the skeletons 3d to 3f. In one embodiment of the present invention, Z has the skeleton 3a or 3b. In one embodiment of the present invention, Z has the skeleton 3c or 3d. In one embodiment of the present invention, Z has the skeleton 3e or 3f. In one embodiment of the present invention, Z has the skeleton 3c. [ka]

[0016] When Z is a substituted or unsubstituted benzothienodibenzothienyl group, Z may have any of the following skeletons 4a to 4f. In one embodiment of the present invention, Z has any of the skeletons 4a to 4c. In one embodiment of the present invention, Z has any of the skeletons 4d to 4f. In one embodiment of the present invention, Z has the skeleton 4a or 4b. In one embodiment of the present invention, Z has the skeleton 4c or 4d. In one embodiment of the present invention, Z has the skeleton 4e or 4f. In one embodiment of the present invention, Z has the skeleton 4c. [ka]

[0017] The hydrogen atoms in the above skeletons 1a to 4f may be substituted with deuterium atoms or substituents. For example, some of the hydrogen atoms bonded to the skeleton may be substituted with deuterium atoms, or all of the hydrogen atoms bonded to the skeleton may be substituted with deuterium atoms. Unsubstituted skeletons are also preferably employed. The substituents may be selected from Substituent Group A, Substituent Group B, Substituent Group C, Substituent Group D, or Substituent Group E.

[0018] In one embodiment of the present invention, Z has any of Skeletons 1a, 2a, 3a, and 4a. In one embodiment of the present invention, Z has any of Skeletons 1b, 2b, 3b, and 4b. In one embodiment of the present invention, Z has any of Skeletons 1c, 2c, 3c, and 4c. In one embodiment of the present invention, Z has any of Skeletons 1d, 2d, 3d, and 4d. In one embodiment of the present invention, Z has any of Skeletons 1e, 2e, 3e, and 4e. In one embodiment of the present invention, Z has any of Skeletons 1f, 2f, 3f, and 4f. In one embodiment of the present invention, no further rings are fused to Skeletons 1a to 4f. In one embodiment of the present invention, further rings are fused to Skeletons 1a to 4f. For example, a benzene ring, a benzofuro structure, or a benzothieno structure may be fused.

[0019] In general formula (1), Ar represents a substituted or unsubstituted arylene group, or a substituted or unsubstituted biphenylylene group. For the description and preferred range of the arylene group, please refer to the description and preferred range of the aryl group described below. Ar is preferably a substituted or unsubstituted phenylene group. The phenylene group may be any of a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group, with a 1,3-phenylene group and a 1,4-phenylene group being preferred. For example, a 1,3-phenylene group or a 1,4-phenylene group may be employed. The biphenylylene group is a linking group in which two phenylene groups are linked together, and may be any of a biphenyl-2,2'-diyl group, a biphenyl-3,3'-diyl group, and a biphenyl-4,4'-diyl group. However, a biphenyl-3,3'-diyl group or a biphenyl-4,4'-diyl group is preferred. For example, a biphenyl-3,3'-diyl group or a biphenyl-4,4'-diyl group may be adopted. The two benzene rings constituting the biphenylylene group may be further linked to each other via a linking group. In one embodiment of the present invention, a substituted or unsubstituted dibenzofurandiyl group is formed by bonding via an oxygen atom (-O-). In another embodiment of the present invention, a dibenzothiophenediyl structure is formed by bonding via a sulfur atom (-S-). In a preferred embodiment of the present invention, Ar has any of the following skeletons: [ka]

[0020] In the above skeletons 5a to 5f, * represents the bonding position to D or Z. Each hydrogen atom in the above skeleton may be independently substituted with a deuterium atom or a substituent, or may be substituted with an adjacent hydrogen atom by a linking group to form a cyclic structure. In one embodiment of the present invention, Ar has a skeleton of 5a or 5b. In one embodiment of the present invention, Ar has a skeleton of any of 5c to 5f. In one embodiment of the present invention, Ar has a skeleton of 5c or 5d. In one embodiment of the present invention, Ar has a skeleton of 5e or 5f. In one embodiment of the present invention, Ar has a skeleton of 5c or 5e. In one embodiment of the present invention, Ar has a skeleton of 5d or 5fd.

[0021] The hydrogen atoms of the arylene group or biphenylylene group that Ar can take, and the hydrogen atoms in the skeletons 5a to 5f may be substituted with deuterium atoms or substituents. For example, some of the hydrogen atoms may be substituted with deuterium atoms, or all of the hydrogen atoms may be substituted with deuterium atoms. Unsubstituted groups are also preferably employed. The substituent may be selected from Substituent Group A, Substituent Group B, Substituent Group C, Substituent Group D, or Substituent Group E.

[0022] D in general formula (1) represents a donor group. The donor group here is a group with a negative Hammett σp value. Here, the "Hammett σp value" was proposed by L.P. Hammett, and quantifies the influence of a substituent on the reaction rate or equilibrium of a para-substituted benzene derivative. Specifically, the following equation holds between the substituent in a para-substituted benzene derivative and the reaction rate constant or equilibrium constant: log(k / k0) = ρσp or log(K / K0) = ρσp where k is the rate constant for the unsubstituted benzene derivative, k is the rate constant for the substituted benzene derivative, K is the equilibrium constant for the unsubstituted benzene derivative, K is the equilibrium constant for the substituted benzene derivative, and ρ is a reaction constant determined by the type and conditions of the reaction. For an explanation of the "Hammett σp value" and the numerical values ​​of each substituent in this invention, please refer to the description of σp values ​​in Hansch, C. et al., Chem. Rev., 91, 165-195 (1991). Groups with a positive Hammett σp value tend to exhibit electron-withdrawing (acceptor) properties. In one embodiment of the present invention, the compound represented by general formula (1) does not contain a substituent with a σp value of 0.2 or greater.

[0023] The donor group is preferably a group containing a substituted amino group. The substituent bonded to the nitrogen atom of the amino group is preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, more preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and even more preferably a substituted or unsubstituted aryl group. The substituted amino group is particularly preferably a substituted or unsubstituted diarylamino group or a substituted or unsubstituted diheteroarylamino group. The two atomic groups bonded to the nitrogen atom of the substituted amino group may be bonded to each other to form a cyclic structure. The donor group in the present invention may be a group bonded via the nitrogen atom of the substituted amino group, or may be a group bonded via a group to which the substituted amino group is bonded. The group to which the substituted amino group is bonded is preferably a π-conjugated group. More preferred are groups bonded through the nitrogen atom of the substituted amino group, or groups bonded through the benzene ring in which the nitrogen atom of the substituted amino group is bonded, and even more preferred are groups bonded through the nitrogen atom of the substituted amino group. A particularly preferred donor group in the present invention is a substituted or unsubstituted carbazol-9-yl group. A benzene ring or a heterocycle may be further fused to the carbazol-9-yl group. In one embodiment of the present invention, a benzene ring or a heterocycle is not further fused to the carbazol-9-yl group. The substituent of the carbazol-9-yl group may be, for example, a substituent selected from the following Substituent Group A, a substituent selected from the following Substituent Group B, a substituent selected from the following Substituent Group C, a substituent selected from the following Substituent Group D, or a substituent selected from the following Substituent Group E. Preferable examples of the carbazol-9-yl group include an unsubstituted carbazol-9-yl group, a carbazol-9-yl group substituted at at least one of the 3- and 6-positions, and a carbazol-9-yl group substituted at both the 3- and 6-positions.

[0024] In a preferred embodiment of the present invention, a group represented by the following general formula is used as the donor group: Ar 1 and Ar 2 each independently represents a phenyl group, a 2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group, a p-terphenylyl group, or an m-terphenylyl group. p represents 0 or 1. When p is 1, Ar 1 and Ar 2 may be the same or different. * indicates the bonding position. [ka]

[0025] In a preferred embodiment of the present invention, a group represented by the following general formula is used as the donor group: X 3 represents an oxygen atom or a sulfur atom. 3 and Ar 4 Each independently represents a phenyl group, a 2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group, a p-terphenylyl group, or an m-terphenylyl group. Each independently represents 0 or 1, and q+r is 1 or 2. When both q and r are 1, Ar 3and Ar 4 may be the same or different. * indicates the bonding position. [ka]

[0026] The donor group that D can take preferably has 13 or more atoms other than hydrogen atoms and deuterium atoms, and for example, one in the range of 13 to 40 atoms, or one in the range of 13 to 26 atoms, can also be selected. The donor group which D can take may be composed only of atoms selected from, for example, hydrogen atoms, deuterium atoms, carbon atoms, nitrogen atoms, and oxygen atoms; may be composed only of atoms selected from, for example, hydrogen atoms, deuterium atoms, carbon atoms, and nitrogen atoms; may be composed only of atoms selected from, for example, hydrogen atoms, carbon atoms, and nitrogen atoms.

[0027] Specific examples of donor groups that can be used for D are given below, but the donor groups that can be used for D are not limited to these specific examples. * indicates a bonding position. [ka] JPEG0007764013000013.jpg175165

[0028] The compound represented by general formula (1) preferably has a structure represented by the following general formula (2). [ka]

[0029] In general formula (2), X 1 and X 2 Each independently represents an oxygen atom or a sulfur atom. 1 and X 2 In one embodiment of the present invention, at least one of X 1 and X 2In one embodiment of the present invention, at least one of X 1 and X 2 In one embodiment of the present invention, X 1 and X 2 are oxygen atoms. In one embodiment of the present invention, X 1 and X 2 are all sulfur atoms. In general formula (2), X 1 Which of the two benzene rings to which (R 4 ) n4 Preferably, the two benzene rings are bonded to the benzene ring to which X is bonded. 2 is bonded to the benzene ring that is not bonded.

[0030] In general formula (2), n represents 0 or 1. In one embodiment of the present invention, n is 0. In one embodiment of the present invention, n is 1. In general formula (2), n1, n2, n3, n4, n5, and n7 each independently represent an integer of 0 to 4, and n6 represents an integer of 0 to 2. In one embodiment of the present invention, n1 to n6 each independently represent an integer of 0 to 2. In one embodiment of the present invention, n1 to n6 each independently represent 0 or 1. In one embodiment of the present invention, n1 and n2 are 0. In one embodiment of the present invention, n3 and n4 are 0. In one embodiment of the present invention, n5 and n6 are 0.

[0031] In general formula (2), R 1 ~R 7 Each independently represents a deuterium atom or a substituent. 1 ~R 7 is a deuterium atom. Examples of the substituent include a substituent selected from the following substituent group A, a substituent selected from the following substituent group B, a substituent selected from the following substituent group C, a substituent selected from the following substituent group D, and a substituent selected from the following substituent group E. R in general formula (2) 3 and R 4, two adjacent R 1 , two adjacent R 2 , two adjacent R 3 , two adjacent R 4 , two adjacent R 5 , two adjacent R 6 , two adjacent R 7 may be bonded to each other to form a ring structure. In one embodiment of the present invention, two adjacent R 1 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 2 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 3 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 4 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 5 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 6 are not bonded to each other and do not form a ring structure. In one embodiment of the present invention, two adjacent R 7 are not bonded to each other and do not form a ring structure. 3 and R 4 , two adjacent R 1 , two adjacent R 2 , two adjacent R 3 , two adjacent R 4 , two adjacent R 5 , two adjacent R 6 , two adjacent R 7 are not bonded to each other to form a ring structure.

[0032] For the embodiments and preferred ranges of general formula (2), reference can be made to the corresponding explanation of general formula (1).

[0033] The compound represented by general formula (1) preferably has a structure represented by any one of the following general formulas (3-1) to (3-16). [ka] JPEG0007764013000016.jpg232161

[0034] In the general formulas (3-1) to (3-16), R 1 ~R 7 each independently represents a deuterium atom or a substituent. n represents 0 or 1, n1, n2, n3, n4, n5, and n7 each independently represents an integer of 0 to 4, n3' and n4' each independently represents an integer of 0 to 3, and n6 represents an integer of 0 to 2. R 3 and R 4 , two adjacent R 1 , two adjacent R 2 , two adjacent R 3 , two adjacent R 4 , two adjacent R 5 , two adjacent R 6 , two adjacent R 7 may be bonded to each other to form a cyclic structure. In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-1) to (3-4). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-5) to (3-8). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-9) to (3-12). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-13) to (3-16). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-1), (3-5), (3-9), and (3-13). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-2), (3-6), (3-10), and (3-14). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-3), (3-7), (3-11), and (3-15). In one embodiment of the present invention, the compound has a structure represented by any one of general formulas (3-4), (3-8), (3-12), and (3-16). For the embodiments and preferred ranges of general formulas (3-1) to (3-16), reference can be made to the corresponding explanations for general formulas (1) and (2).

[0035] In one embodiment of the present invention, the compound represented by general formula (1) has only one carbazole structure in the molecule. In one embodiment of the present invention, the compound represented by general formula (1) does not have a pyrrole ring that does not constitute a carbazole structure. In one embodiment of the present invention, the compound represented by general formula (1) does not have a furan ring that does not constitute a dibenzofuran structure. In one embodiment of the present invention, the compound represented by general formula (1) does not have a thiophene ring that does not constitute a dibenzothiophene structure. In one embodiment of the present invention, the compound represented by general formula (1) does not have a fused ring in which six or more rings are fused.

[0036] Specific examples of the compound represented by general formula (1) are given below, but the compounds represented by general formula (1) that can be used in the present invention should not be construed as being limited by these specific examples. [ka] JPEG0007764013000018.jpg168170

[0037] In one embodiment of the present invention, a compound having an asymmetric structure is selected as the compound represented by general formula (1). When it is intended to use an organic layer containing the compound represented by general formula (1) formed by vapor deposition, the molecular weight of the compound represented by general formula (1) 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 is the molecular weight of the smallest compound in the group of compounds represented by general formula (1). The compound represented by general formula (1) may be formed into a film by a coating method regardless of its molecular weight. By using the coating method, it is possible to form a film even from a compound with a relatively large molecular weight. The compound represented by general formula (1) has the advantage of being easily soluble in organic solvents. Therefore, the compound represented by general formula (1) is easy to apply the coating method to, and is also easy to purify to increase its purity.

[0038] The compound represented by general formula (1) preferably does not contain a metal atom. For example, the compound represented by general formula (1) may be a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, and sulfur atoms. For example, the compound represented by general formula (1) may be a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and oxygen atoms. For example, the compound represented by general formula (1) may be a compound consisting of atoms selected from the group consisting of carbon, hydrogen, nitrogen, and oxygen atoms. For example, the compound represented by general formula (1) may be a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and sulfur atoms. For example, the compound represented by general formula (1) may be a compound consisting of atoms selected from the group consisting of carbon, hydrogen, nitrogen, and sulfur atoms.

[0039] In this specification, the term "alkyl group" may be linear, branched, or cyclic. It may also contain two or more of the linear, cyclic, and branched moieties. 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. The "alkenyl group" may be linear, branched, or cyclic. It may also contain two or more of the linear, cyclic, and branched moieties. The alkenyl group may have, for example, two or more carbon atoms, or four or more carbon atoms. It may also have 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less carbon atoms. 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, and these may be fused rings. 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 number of atoms constituting the ring skeleton of the aryl group is preferably 6 to 40, more preferably 6 to 20, and may be selected within a range of 6 to 14, or may be selected within a range of 6 to 10. The number of atoms constituting the ring skeleton of the heteroaryl group is preferably 4 to 40, more preferably 5 to 20, and may be selected from the range of 5 to 14, or may be selected from the range of 5 to 10. The terms "arylene group" and "heteroaryl group" can be understood by changing the valence of the aryl group and heteroaryl group from 1 to 2.

[0040] In the present specification, "substituent group A" refers to 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 ring skeleton atoms), a heteroaryloxy group (for example, having 5 to 30 ring skeleton atoms), a heteroaryl group, ... It means one group or a combination of two or more groups selected from the group consisting of heteroarylthio groups (for example, having 5 to 30 atoms constituting the ring skeleton), acyl groups (for example, having 1 to 40 carbon atoms), alkenyl groups (for example, having 1 to 40 carbon atoms), alkynyl groups (for example, having 1 to 40 carbon atoms), alkoxycarbonyl groups (for example, having 1 to 40 carbon atoms), aryloxycarbonyl groups (for example, having 1 to 40 carbon atoms), heteroaryloxycarbonyl groups (for example, having 1 to 40 carbon atoms), silyl groups (for example, trialkylsilyl groups having 1 to 40 carbon atoms), and nitro groups. In this specification, the term "substituent group B" refers to one group or a combination of two or more groups selected from the group consisting of alkyl groups (e.g., having 1 to 40 carbon atoms), alkoxy groups (e.g., having 1 to 40 carbon atoms), aryl groups (e.g., having 6 to 30 carbon atoms), aryloxy groups (e.g., having 6 to 30 carbon atoms), heteroaryl groups (e.g., having 5 to 30 ring skeleton atoms), heteroaryloxy groups (e.g., having 5 to 30 ring skeleton atoms), and diarylaminoamino groups (e.g., having 0 to 20 carbon atoms). In this specification, the term "substituent group C" refers to one group or a combination of two or more groups selected from the group consisting of alkyl groups (e.g., having 1 to 20 carbon atoms), aryl groups (e.g., having 6 to 22 carbon atoms), heteroaryl groups (e.g., having 5 to 20 ring skeleton atoms), and diarylamino groups (e.g., having 12 to 20 carbon atoms). In this specification, the term "substituent group D" refers to one group or a combination of two or more groups selected from the group consisting of alkyl groups (e.g., having 1 to 20 carbon atoms), aryl groups (e.g., having 6 to 22 carbon atoms), and heteroaryl groups (e.g., having 5 to 20 ring skeleton atoms). In this specification, the term "substituent group E" refers to one group or a combination of two or more groups selected from the group consisting of alkyl groups (for example, having 1 to 20 carbon atoms) and aryl groups (for example, having 6 to 22 carbon atoms). In the present specification, when a "substituent" or "substituted or unsubstituted" is used, the substituent may be selected from, for example, Substituent Group A, Substituent Group B, Substituent Group C, Substituent Group D, or Substituent Group E.

[0041] [Synthesis of compound represented by general formula (1)] The compound represented by general formula (1) can be synthesized by appropriately combining known synthesis methods. For example, D-Ar-Z, which is represented by general formula (1), can be synthesized by reacting DH with X-Ar-Z. Here, H is a hydrogen atom, and X is a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom). The reaction conditions can be optimized by methods well known to those skilled in the art.

[0042] (Delayed fluorescent material) The use of the compound represented by general formula (1) is not particularly limited. The compound represented by general formula (1) may be used as a host material for a light-emitting material (dopant), or may be used as a charge transport material or a light-emitting material depending on the mode of use. When used as a host material for a light-emitting material, it may be used as a host material for any of light-emitting materials, such as delayed fluorescent materials, fluorescent materials that do not emit delayed fluorescence (prompt fluorescent materials), and phosphorescent materials. The compound represented by the general formula (1) is particularly excellent as a host material for a light-emitting material. The compound represented by the general formula (1) is particularly useful as a host material for use 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 longer when its emission lifetime is measured using a fluorescence lifetime measurement system (such as a streak camera system manufactured by Hamamatsu Photonics KK). 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. The delayed fluorescent material may also receive energy from the compound represented by general formula (1) in an excited triplet state and transition to an excited triplet state. The delayed fluorescent material has a difference between the excited singlet energy and the excited triplet energy (ΔE ST ) is small, 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.

[0043] The delayed fluorescent material has a difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy at 77K. ST is preferably 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, even more preferably 0.07 eV or less, even more preferably 0.05 eV or less, even more preferably 0.03 eV or less, and particularly preferably 0.01 eV or less. ΔE ST If the δ is small, reverse intersystem crossing from the excited singlet state to the excited triplet state is easily achieved by absorbing thermal energy, and the material functions as a thermally activated delayed fluorescent material. Thermally activated delayed fluorescent materials absorb heat emitted by a device and relatively easily undergo reverse intersystem crossing from the excited triplet state to the excited singlet state, allowing the excited triplet energy to efficiently contribute to light emission.

[0044] In the present invention, the lowest excited singlet energy (E S1 ) and the lowest excited triplet energy (E T1 ) is a value calculated by the following procedure. ST is E S1 -E T1 This is the value obtained by calculating (1) The lowest excited singlet energy (E S1 ) Thin film or toluene solution (concentration 10 -5 A sample is prepared at a concentration of 1000 mol / L. The fluorescence spectrum of this sample is measured at room temperature (300K). The fluorescence spectrum has the emission on the vertical axis and the wavelength on the horizontal axis. A tangent line is drawn to the rising edge of 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 found. This wavelength value is converted to an energy value using the following conversion formula and is called E. S1 Let's say. 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 the excitation light source and a detector (PMA-12 multichannel spectrometer C10027-01, manufactured by Hamamatsu Photonics KK). (2) The lowest excited triplet energy (E T1 ) The lowest excited singlet energy (E S1 The same sample used in the measurement of ) is cooled to 77[K] with liquid nitrogen, and the sample for phosphorescence measurement is irradiated with excitation light (300 nm), and the 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 of 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 found. This wavelength value is converted to an energy value using the following conversion formula, and the value is called E T1 Let's say. 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 considered to be 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 the 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.

[0045] In a preferred embodiment of the present invention, a compound (cyanobenzene derivative) having a cyanobenzene structure in which one cyano group is substituted on a 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 a 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.

[0046] In a preferred embodiment of the present invention, a compound represented by the following general formula (4) is used as the delayed fluorescent material. [ka] In general formula (4), R 21 ~R 23 one of the groups represents a cyano group or a group represented by the following general formula (5), and R 21 ~R 23 The remaining two and R 24 and R 25 At least one of R represents a group represented by the following general formula (6): 21 ~R 25The remainder represents 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)). [ka] In general formula (5), L 1 represents a single bond or a divalent linking group, and R 31 and R 32 each independently represents a hydrogen atom or a substituent, and * represents the bonding position. [ka] In general formula (6), L 2 represents a single bond or a divalent linking group, and R 33 and R 34 each independently represents a hydrogen atom or a substituent, and * represents the bonding position.

[0047] 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 one embodiment of the present invention, R 21 is a cyano group or a group represented by general formula (5). 23 is a cyano group or a group represented by general formula (5). 21 ~R 23 In one embodiment of the present invention, one of R 21 ~R 23 One of these is a group represented by general formula (5).

[0048] In a preferred embodiment of the present invention, L in general formula (5) 1 is a single bond. In one aspect 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 in general formula (5) 31 and R 32 are each independently one group or a combination of two or more groups selected from the group consisting of alkyl groups (e.g., having 1 to 40 carbon atoms), aryl groups (e.g., having 6 to 30 carbon atoms), heteroaryl groups (e.g., having 5 to 30 ring skeleton atoms), alkenyl groups (e.g., having 1 to 40 carbon atoms), and alkynyl groups (e.g., having 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., having 6 to 30 carbon atoms), and examples of the substituent of the aryl group include the groups in Substituent Group A. In a preferred embodiment of the present invention, R 31 and R 32 are identical.

[0049] In a preferred embodiment of the present invention, L in general formula (6) 2 is a single bond. In one aspect of the present invention, L 2 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 in general formula (6) 33 and R 34each independently represents 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 on the alkyl group, alkenyl group, aryl group, and heteroaryl group 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 ring skeleton atoms), a heteroaryloxy group (e.g., having 5 to 30 ring skeleton atoms), and a heteroarylthi group. Examples thereof 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. 33 and R 34 When R is an aryl group, they are preferably bonded to each other via a single bond or a linking group to form a cyclic structure. The linking group here includes -O-, -S-, -N(R 35 )-, -C(R 36 )(R 37 )-, -C(=O)-, -O-, -S-, -N(R 35 )-, -C(R 36 )(R 37 )- is preferred, and -O-, -S-, -N(R 35)- is more preferred. R 35 ~R 37 each independently represents a hydrogen atom or a substituent. The substituent may be selected from the groups in the above-mentioned Substituent Group A or the groups in 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.

[0050] The group represented by general formula (6) is preferably a group represented by the following general formula (7). [ka]

[0051] L in general formula (7) 11 represents a single bond or a divalent linking group. 11 For a description and preferred range of 2 Reference can be made to the description and preferred ranges of R in general formula (7) 41 ~R 48 R each independently represents a hydrogen atom or a substituent. 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 , R 47 and R 48may 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, may contain a heteroatom, and may further be a fused 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 cycloheptaene 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. R 41 ~R 48 Examples of the substituent that R may have include the groups in the above-mentioned substituent group B, and preferably an unsubstituted alkyl group having 1 to 10 carbon atoms or an aryl group 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 ~R 48 is a hydrogen atom or an unsubstituted alkyl group having 1 to 10 carbon atoms. In a preferred embodiment of the present invention, R 41 ~R 48 is a hydrogen atom or an unsubstituted aryl group having 6 to 10 carbon atoms. In a preferred embodiment of the present invention, R 41 ~R 48 are all hydrogen atoms. In the general formula (7), * represents a bonding position.

[0052] 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. For example, azabenzene derivatives having a pyridazine structure, pyrimidine structure, or pyrazine structure can be mentioned, 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.

[0053] In a preferred embodiment of the present invention, a compound represented by the following general formula (8) is used as the delayed fluorescent material. [ka] In the general formula (8), Y 1 , Y 2 and Y 3 At least one of Y represents a nitrogen atom and the rest represent methine groups. 1 is a nitrogen atom, and Y 2 and Y 3 is a methine group. Preferably, Y 1 and Y 2 is a nitrogen atom, and Y 3 is a methine group. More preferably, Y 1 ~Y 3 All of the atoms are nitrogen atoms. In general formula (8), Z 1 ~Z 3 Each of Z independently represents a hydrogen atom or a substituent, and at least one of them is a donor substituent. A donor substituent refers to a group having a negative Hammett σp value. Preferably, Z 1 ~Z 3At least one of Z is a group containing a diarylamino structure (two aryl groups bonded to a nitrogen atom may be bonded to each other), more preferably a group represented by the above general formula (6), for example a group represented by the above general formula (7). 1 ~Z 3 In one embodiment of the present invention, only one of Z is a group represented by general formula (6) or (7). 1 ~Z 3 In one embodiment of the present invention, only two of Z are independently a group represented by general formula (6) or (7). 1 ~Z 3 All of the groups are independently 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 that are not groups represented by general formula (6) or general formula (7) 1 ~Z 3 is preferably a substituted or unsubstituted aryl group (e.g., having 6 to 40 carbon atoms, preferably 6 to 20 carbon atoms), and examples of the substituent of the aryl group herein 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 consisting of a combination of two or more groups. In one embodiment of the present invention, general formula (8) does not contain a cyano group.

[0054] In a preferred embodiment of the present invention, a compound represented by the following general formula (9) is used as the delayed fluorescent material. [ka] In the general formula (9), Ar 1 is the following A 1 and D 1 and represents a benzene ring, a naphthalene ring, an anthracene ring, or a phenanthrene ring. 2 , Ar 3may each form a cyclic structure, and when a cyclic structure is formed, it represents 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 there are multiple D 1 When present, they may be the same or different. 1 The substituents may be bonded to each other to form a ring structure.

[0055] 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. [ka] JPEG0007764013000026.jpg240170JPEG0007764013000027.jpg224170JPEG0007764013000028.jpg23116 7JPEG0007764013000029.jpg235169JPEG0007764013000030.jpg233170JPEG0007764013000031.jpg94168

[0056] In the present invention, other known delayed fluorescent materials can be used in appropriate combination with the compound represented by general formula (1), and unknown delayed fluorescent materials can also be used. As delayed fluorescent materials, 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, 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 WO2013 / 133359 A, paragraphs 0008 to 0032 of WO2013 / 161437 A 0054 and 0101 to 0121, paragraphs 0007 to 0041 and 0060 to 0069 of JP 2014-9352 A, paragraphs 0008 to 0048 and 0067 to 0076 of JP 2014-9224 A, paragraphs 0013 to 0025 of JP 2017-119663 A, paragraphs 0013 to 0026 of JP 2017-119664 A, Examples include compounds encompassed by the general formulas described in paragraphs 0012 to 0025 of JP 222623 A, paragraphs 0010 to 0050 of JP 2017-226838 A, paragraphs 0012 to 0043 of JP 2018-100411 A, and paragraphs 0016 to 0044 of WO 2018 / 047853 A, particularly exemplary compounds that emit delayed fluorescence.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.

[0057] The delayed fluorescent material used in the present invention preferably does not contain metal atoms.For example, as the delayed fluorescent material, 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.For example, as the delayed fluorescent material, a compound consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms and oxygen atoms can be selected.For example, as the delayed fluorescent material, a compound consisting of carbon atoms, hydrogen atoms and nitrogen atoms can be selected.

[0058] (composition) The composition of the present invention contains 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 contains 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 contain only one type, or may contain two or more types. The content of the third component in the composition may be selected from 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 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.

[0059] In one embodiment of the present invention, the compound represented by 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 formula (1) and the delayed fluorescent material.

[0060] The fluorescent compound has a lowest excited singlet energy (E S1 ) is preferably small. The fluorescent compound receives energy from the compound represented by general formula (1) and the delayed fluorescent material in the excited singlet state, and from the delayed fluorescent material that has undergone reverse intersystem crossing from the excited triplet state to the excited singlet state, transitions to the 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 light of 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.

[0061] 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, with the one with a higher lowest excited singlet energy functioning as an assist dopant and the one with a lower lowest excited singlet energy functioning as the primary emitting fluorescent compound. The compound used as the fluorescent compound preferably exhibits a PL emission quantum yield of 60% or more, more preferably 80% or more. Furthermore, 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 faster than the intersystem crossing rate from S1 to the lowest excited triplet (T1). For a method for calculating the rate constant of a compound, reference can be made to known literature on thermally activated delayed fluorescent materials (H. Uoyama, et al., Nature 492, 234 (2012), K. Masui, et al., Org. Electron. 14, 2721, (2013), etc.).

[0062] Preferred compounds that can be used as the fluorescent compound together with the delayed fluorescent material 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.

[0063] [ka] JPEG0007764013000033.jpg229170JPEG0007764013000034.jpg156170

[0064] Furthermore, the compounds described in paragraphs 0220 to 0239 of WO2015 / 022974 can also be particularly preferably used as the fluorescent compound of the present invention.

[0065] 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 is not limited to these specific examples.

[0066] [ka] JPEG0007764013000036.jpg220161

[0067] 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. Examples of 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 multiple compounds contained in a single deposition source are identical or nearly identical, thereby forming a film having a composition ratio corresponding to the composition ratio of 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 deposition source as a deposition source, a film having a desired composition ratio can be easily formed. In some embodiments, the temperature at which each compound to be co-deposited has the same weight loss rate 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.

[0068] (organic light-emitting element) By forming a light-emitting layer made of the composition of the present invention, it is possible to provide excellent organic light-emitting devices such as organic photoluminescence devices (organic PL devices) and organic electroluminescence devices (organic EL devices). 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 photoluminescent device has a structure in which at least an emitting layer is formed on a substrate. An organic electroluminescent device 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 an emitting layer, and may consist of only the emitting layer, or may have one or more organic layers in addition to the 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 with hole injection function, and the electron transport layer may be an electron injection transport layer with electron injection function. A specific example of the structure of an organic electroluminescent device is shown in Figure 1. In Figure 1, 1 represents the substrate, 2 represents the anode, 3 represents the hole injection layer, 4 represents the hole transport layer, 5 represents the emitting layer, 6 represents the electron transport layer, and 7 represents the cathode. 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. When excited by thermal or electronic means, organic light-emitting devices using the compositions of the present invention 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, organic light-emitting devices can emit light in the red or orange region (e.g., 620-780 nm). For example, organic light-emitting devices can emit light in the orange or yellow region (e.g., 570-620 nm). For example, organic light-emitting devices can emit light in the green region (e.g., 490-575 nm). For example, organic light-emitting devices can emit light in the blue region (e.g., 400-490 nm). For example, organic light-emitting devices can emit light in the ultraviolet spectral region (e.g., 280-400 nm). For example, organic light-emitting devices can emit light in the infrared spectral region (e.g., 780 nm-2 μm). The largest component of the light emitted from an 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, and may be, 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 containing the composition of the present invention (light-emitting layer) 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.

[0069] Each component of the organic electroluminescence element and each layer other than the light-emitting layer will be described below.

[0070] 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.

[0071] 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), SnO, and ZnO. In some embodiments, an amorphous material capable of forming a transparent conductive film, such as 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 precise (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.

[0072] 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), alloy, conductive compound, or a combination thereof. In some embodiments, the electrode material is selected from sodium, sodium-potassium alloy, magnesium, lithium, magnesium-copper mixture, magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al2O3) mixture, indium, lithium-aluminum mixture, and rare earth elements. 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 magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al2O3) mixture, 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, one of the anode and cathode of the organic electroluminescent device is transparent or semitransparent to transmit emitted light. In some embodiments, a transparent or semitransparent 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.

[0073] 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 the hole injection material are listed below.

[0074] [ka]

[0075] Next, examples of preferred compounds that can be used as the electron injection material will be given. [ka]

[0076] 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.

[0077] 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.

[0078] [ka]

[0079] 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.

[0080] [ka]

[0081] 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.

[0082] 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.

[0083] [ka] JPEG0007764013000042.jpg40170

[0084] 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.

[0085] [ka]

[0086] Furthermore, examples of compounds that can be added to each organic layer are given below, which may be added as a stabilizing material, for example.

[0087] [ka]

[0088] 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 following exemplary compounds. Furthermore, even compounds exemplified as materials having specific functions can be diverted to be used as materials having other functions.

[0089] 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).

[0090] 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 light is emitted 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.

[0091] 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 OLED displays. 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.

[0092] 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, an emissive 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, an emissive layer, a counter electrode, and an encapsulation layer, and then cutting the mother panel.

[0093] 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.

[0094] 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 formed 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.

[0095] 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 a source / drain electrode 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.

[0096] 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.

[0097] 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, so that the groove does not penetrate the base substrate. In some embodiments, the TFT layer of each cell panel is formed, and a passivation layer (an inorganic film) and a planarization film (an organic film) are disposed on and cover the TFT layer. At the same time as the planarization film (e.g., polyimide or acrylic) is formed, the grooves at the interface are covered with an organic film (e.g., polyimide or acrylic). This prevents cracks from occurring when each cell panel is cut along the grooves at the interface by allowing the organic film to absorb any impacts that may occur. That is, if all barrier layers were completely exposed without the organic film, the impacts would be transmitted to the barrier layers when each cell panel was cut along the grooves 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 any 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 the planarizing film covering the groove of the interface portion are spaced apart from each other. For example, if the organic film and the planarizing film are connected to each other as one layer, external moisture may penetrate into the display unit through the planarizing film and the remaining portion of the organic film, so the organic film and the planarizing film are spaced apart from each other so that the organic film is spaced apart from the display unit.

[0098] 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 embodiment 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. [Example]

[0099] The features of the present invention will be explained in more detail below with reference to synthesis examples, test 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 (Newport: 1930C), an optical spectrometer (Ocean Optics: USB2000), a spectroradiometer (Topcon: SR-3), a streak camera (Hamamatsu Photonics K.K.: C4334 model), and an extended absolute quantum yield measurement system (Hamamatsu Photonics K.K.: Quantaurus-QY Plus C13534-01).

[0100] (Synthesis Example 1) Synthesis of Compound 1 [ka]

[0101] 2-Bromobenzo[1,2-b:5,4-b']bisbenzofuran (1.09 g, 3.23 mmol), 3-(9H-carbazol-9-yl)phenylboronic acid (1.02 g, 3.55 mmol), tetrakistriphenylphosphinepalladium(0) (0.18 g, 0.16 mmol), and potassium carbonate (1.34 g, 9.69 mmol) were dissolved in a tetrahydrofuran (THF) / water (20 / 10 mL) mixture and stirred at 75 °C for 12 h. The reaction solution was cooled to room temperature, chloroform was added, and the organic layer was washed twice with water, dried over magnesium sulfate, and the solvent was removed. The resulting solid was purified by silica gel column chromatography (eluent: hexane:toluene = 8:2). Further recrystallization (toluene / methanol) afforded compound 1 (1.22 g, 76%) as a white solid. 1HNMR (400MHz, CDCl3, δ): 8.5 (S, 1H), 8.29 (d, J = 2 Hz, 1H), 8.19 (d, J = 8 Hz, 2H), 8.03 (d, J= 8 Hz, 1H), 7.93 (m, 1H), 7.81 (d, J = 8 Hz, 1H), 7.77-7.73 (m, 3H), 7.67 (d, J = 8 Hz, 1H), 7.60 (d, J = 8 Hz, 2H), 7.53 (d, J = 8 Hz, 2H), 7.49 -7.43 (m, 3H), 7.39 (t, J = 7 Hz, 1H), 7.33 (t, J = 7 Hz, 2H). MS (ASAP): 500.22 (M+H + ). Calcd. for C 36 H 21 NO2: 499.16.

[0102] (Synthesis Example 2) Synthesis of Compound 2

change

[0103] Under a nitrogen atmosphere, 2-bromobenzo[1,2-b:5,4-b']bisbenzofuran (1.5 g, 4.45 mmol), bispinacolatodiboron (1.19 g, 4.67 mmol), [1,1-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.33 g, 0.45 mmol), potassium acetate (1.09 g, 11.1 mmol), and dioxane (15 mL) were added and refluxed for 15 hours. After cooling to room temperature, 1-bromo-3-iodobenzene (1.89 g, 6.68 mmol), tetrakistriphenylphosphinepalladium(0) (0.25 g, 0.22 mmol), potassium carbonate (1.23 g, 8.9 mmol), tetrahydrofuran (30 mL), and water (15 mL) were added to the reaction solution and refluxed for 12 hours. The reaction solution was cooled to room temperature, the solvent was removed, chloroform was added, and the organic layer was washed twice with water, dried over magnesium sulfate, and the solvent was removed. The resulting solid was purified by silica gel column chromatography (eluent: hexane:chloroform = 7:3) to give intermediate a (1.58 g, 86%) as a white solid. 1 H NMR (400MHz, CDCl3, δ): 8.51 (s, 1H), 8.20 (s, 1H), 8.04 (d, J = 8 Hz, 1H), 7.86 (m, 1H), 7.75 (s, 1H), 7.69-7.59 (m, 3H), 7.52-7.32 (m, 4H). MS (ASAP): 413.93 (M+H + ). Calcd. for C 24 H 13 BrO2: 412.01.

[0104] Under a nitrogen atmosphere, 2-(3-bromophenyl)benzo[1,2-b:5,4-b']bisbenzofuran (intermediate a; 1.57 g, 3.8 mmol), 3,6-diphenylcarbazole (1.21 g, 3.8 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.35 g, 0.38 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.22 g, 0.76 mmol), and sodium tert-butoxide (0.73 g, 7.6 mmol) were added to toluene (45 mL) and refluxed for 24 hours. The reaction solution was cooled to room temperature, and the toluene was removed. The resulting solid was washed with water and methanol and dried. The resulting solid was purified by silica gel column chromatography (eluent: toluene / n-hexane = 1:1 to 1:4). Further recrystallization (toluene / methanol) gave Compound 2 as a white solid (1.58 g, 64%). 1 H NMR (400MHz, CDCl3, δ): 8.5 (s, 1H), 8.44 (s, 2H), 8.31 (s, 1H), 8.02 (d, J = 8 Hz, 1H), 7.97 (s, 1H), 7.84 (S, 1H), 7.79-7.57 (m, 14H), 7.53-7.43 (m, 5H), 7.39-7.34 (m, 3H). MS (ASAP): 651.77 (M+H + ). Calcd for C 48 H 29 NO2: 651.22.

[0105] Example 1 Each thin film was deposited by vacuum deposition on a glass substrate with an anode made of indium tin oxide (ITO) with a thickness of 50 nm, at a vacuum of 5.0 × 10 -5The layers were laminated by Pa. First, HAT-CN was formed to a thickness of 10 nm on ITO, and NPD was formed on top of that to a thickness of 30 nm. Next, Tris-PCz was formed to a thickness of 10 nm. Next, a delayed fluorescent material (TADF10), a fluorescent material (E35), and Compound 1 were co-deposited from different evaporation sources to form a 40 nm thick layer, which served as the emitting layer. The concentrations of the delayed fluorescent material, fluorescent material, and Compound 1 in the emitting layer were 40 mass%, 0.5 mass%, and 59.5 mass%, respectively. Next, SF3-TRZ was formed to a thickness of 10 nm, and then Liq and SF3-TRZ were co-deposited from different evaporation sources to form a 30 nm thick layer. The concentrations of Liq and SF3-TRZ in this layer were 30 mass% and 70 mass%, respectively. Liq was further formed to a thickness of 2 nm, and then aluminum (Al) was evaporated to a thickness of 100 nm to form a cathode, completing the organic electroluminescence device (EL device 1).

[0106] (Comparative Example 1) An organic electroluminescence device (comparative EL device 1) was produced by carrying out the same steps as in Example 1, except that comparative compound 1 was used instead of compound 1. [ka]

[0107] (test) EL element 1 and comparative EL element 1 were 50.0 mA / cm 2 The time (LT95) until the luminous intensity reached 95% of the initial luminous intensity was measured. As a result, the relative value of EL element 1 was 1.25, where that of comparative EL element 1 was set to 1.00, and it was confirmed that the use of the compound represented by general formula (1) extended the element life by 25%.

[0108] Example 2 An organic electroluminescence element (EL element 2) was produced by carrying out the same steps as in Example 1, except that compound 2 was used instead of compound 1. It was confirmed that EL element 2 had a lower driving voltage than comparative EL element 1.

[0109] Example 3 An organic electroluminescence device (EL device 3) was fabricated by the same steps as those of comparative EL device 1, except that Tris-PCz was replaced with compound 2. It was confirmed that EL element 3 also had a longer element life than comparative EL element 1.

[0110] [ka] [Industrial Applicability]

[0111] The compound of the present invention is useful as various materials (particularly charge transport materials) used in light-emitting devices, and can be used, for example, as a host material to be doped with a delayed fluorescent material. The use of the compound of the present invention can improve the properties of organic light-emitting devices such as organic electroluminescence devices. Therefore, the present invention has high industrial applicability. [Explanation of symbols]

[0112] 1 Base material 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6 Electron transport layer 7 Cathode

Claims

1. A compound represented by the following general formula (1): General formula (1) D-Ar-Z [In general formula (1), D represents a donor group; Ar represents a substituted or unsubstituted 1,2-phenylene group, a 1,3-phenylene group which may be substituted with a deuterium atom, a substituted or unsubstituted 1,4-phenylene group, or a substituted or unsubstituted biphenylylene group (provided that the two benzene rings constituting the biphenylylene group may be further linked to each other via an oxygen atom or a sulfur atom); Z represents a substituted or unsubstituted benzofurodibenzofuryl group, a substituted or unsubstituted benzofurodibenzofuryl group, or a substituted or unsubstituted benzofurodibenzofuryl group; a dibenzothienyl group, a substituted or unsubstituted benzothienodibenzofuryl group, or a substituted or unsubstituted benzothienodibenzothienyl group, and when the 1,2-phenylene group in Ar and the benzofurodibenzofuryl group, benzofurodibenzothienyl group, benzothienodibenzofuryl group, and benzothienodibenzothienyl group in Z are substituted with a substituent, the substituent is one group selected from the group consisting of alkyl groups and aryl groups, or a group in which two or more groups are combined.]

2. The compound according to claim 1, which is represented by the following general formula (2): 【Chemistry 1】 [In the general formula (2), X １ and X ２ R each independently represents an oxygen atom or a sulfur atom. １ ~R ７ each independently represents a deuterium atom or a substituent. However, the substituents that R 5 to R 7 can have are each independently one group selected from the group consisting of alkyl groups and aryl groups, or a group consisting of a combination of two or more groups. n represents 0 or 1, n1, n2, n3, n4, n5, and n7 each independently represent an integer of 0 to 4, and n6 represents an integer of 0 to 2. When two adjacent R １ Two adjacent R 2 s may be bonded to each other to form a cyclic structure. However, when n is 0 and the phenylene group to which R 4 is bonded is a 1,2-phenylene group, the substituent that R 4 can have is one group selected from the group consisting of alkyl groups and aryl groups, or a group in which two or more groups are combined. When n is 0 and the phenylene group to which R 4 is bonded is a 1,3-phenylene group, R 4 is a deuterium atom.]

3. The compound according to claim 1, represented by any one of the following general formulas (3-1) to (3-16): 【Chemistry 2】 【change】 [In the general formulas (3-1) to (3-16), R １ ~R ７ each independently represents a deuterium atom or a substituent. However, the substituent that R 5 to R 7 can take represents one group selected from the group consisting of alkyl groups and aryl groups, or a group combining two or more groups. n represents 0 or 1, n1, n2, n3, n4, n5, and n7 each independently represent an integer of 0 to 4, n3' and n4' each independently represent an integer of 0 to 3, and n6 represents an integer of 0 to 2. When two adjacent R １ Two adjacent R 2 s may be bonded to each other to form a cyclic structure. However, in general formulas (3-1), (3-5), (3-9) and (3-13), when the phenylene group to which R 4 is bonded is a 1,2-phenylene group, the substituent that R 4 can have is one group or a combination of two or more groups selected from the group consisting of alkyl groups and aryl groups. In general formulas (3-1), (3-5), (3-9) and (3-13), when the phenylene group to which R 4 is bonded is a 1,3-phenylene group, R 4 is a deuterium atom.]

4. Two adjacent R １ do not bond to each other to form a ring structure, and two adjacent R ２ The compound according to claim 2 or 3, wherein are not bonded to each other to form a cyclic structure.

5. R １ and R ２ The compound according to any one of claims 2 to 4, wherein none of the following contains a carbazole ring structure.

6. A charge transport material comprising the compound according to any one of claims 1 to 5.

7. The charge transport material of claim 6 which is a host material.

8. A composition in which a delayed fluorescent material is doped into a host material consisting of a compound represented by the following general formula (1): General formula (1) D-Ar-Z [In general formula (1), D represents a donor group; Ar represents a substituted or unsubstituted arylene group, or a substituted or unsubstituted biphenylylene group (provided that the two benzene rings constituting the biphenylylene group may be further linked to each other via a linking group); Z represents a substituted or unsubstituted benzofurodibenzofuryl group, a substituted or unsubstituted benzofurodibenzothienyl group, a substituted or unsubstituted benzothienodibenzofuryl group, or a substituted or unsubstituted benzothienodibenzothienyl group; and when the 1,2-phenylene group represented by Ar, and the benzofurodibenzofuryl group, benzofurodibenzothienyl group, benzothienodibenzofuryl group, and benzothienodibenzothienyl group represented by Z, are substituted with a substituent, the substituent is one group selected from the group consisting of alkyl groups and aryl groups, or a group consisting of a combination of two or more groups.]

9. The composition of claim 8 in the form of a film.

10. The composition according to claim 8 or 9, wherein the delayed fluorescent material is a compound having a cyanobenzene structure in which one cyano group is substituted on a benzene ring.

11. The composition according to claim 8 or 9, wherein the delayed fluorescent material is a compound having a dicyanobenzene structure in which two cyano groups are substituted on a benzene ring.

12. The delayed fluorescent material is a compound having an azabenzene structure in which at least one of the ring skeleton carbon atoms of a benzene ring is substituted with a nitrogen atom. The composition according to any one of claims 8 to 11.

13. The composition according to any one of claims 8 to 12, further comprising a fluorescent compound having a lowest excited singlet energy lower than those of the host material and the delayed fluorescent material.

14. An organic light-emitting device comprising a layer made of the composition according to any one of claims 8 to 13.

15. 15. The organic light-emitting device according to claim 14, 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.

16. The organic light-emitting device according to claim 14, wherein the layer consists solely of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, and sulfur atoms.

17. The organic light-emitting device according to any one of claims 14 to 16, which is an organic electroluminescence device.

18. The composition does not contain a fluorescent compound having a lower minimum excited singlet energy than the host material and 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 14 to 17.

19. The composition comprises a fluorescent compound having a lowest excited singlet energy lower than that of the host material and the delayed fluorescent material, and the largest component of light emitted from the device is light emitted from the fluorescent compound. The organic light-emitting element according to any one of claims 14 to 17.

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