Organic electroluminescent element, and display and lighting device having the same

Abstract

To provide an organic electroluminescent element with high luminous efficiency and long driving lifetime.SOLUTION: It is an organic electroluminescent element having an anode, a cathode, a luminescent layer, and a hole injection layer, wherein the luminescent layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the luminescent layer, the luminescent layer contains a compound represented by a specific formula and the hole injection layer contains tetraarylborate ions, or an organic electroluminescent element having an anode, a cathode, a luminescent layer and a hole injection layer, wherein the luminescent layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the luminescent layer, the luminescent layer contains a compound represented by a specific formula, and the hole injection layer contains a crosslinked reaction product having a tetraarylborate ion represented by a specific formula, an arylamine structure represented by a specific formula as a repeating unit, and a crosslinking agent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an organic electroluminescent device, an organic EL display device, an organic EL lighting device, and a method for manufacturing an organic electroluminescent device. [Background technology]

[0002] In recent years, organic electroluminescent devices using organic thin films have been developed instead of those using inorganic materials as thin-film electroluminescent devices. Organic electroluminescent devices (OLEDs) usually have a hole injection layer, hole transport layer, organic light-emitting layer, electron transport layer, etc. between an anode and a cathode, and materials suitable for each of these layers are being developed, and development is also progressing for each of the emitted colors: red, green, and blue.

[0003] Methods for forming the organic layers of organic electroluminescent devices include vacuum deposition and wet film-forming methods (coating methods). Vacuum deposition methods are easy to form layers, and therefore have the advantages of improving charge injection from the anode and / or cathode and facilitating exciton confinement in the light-emitting layer. On the other hand, wet film-forming methods have the advantages of not requiring a vacuum process, being easy to scale up, and being able to easily form layers containing multiple materials with various functions by using a coating solution containing a mixture of multiple materials with various functions. For this reason, in recent years, research and development of organic electroluminescent devices using film-forming methods by coating methods has been actively conducted.

[0004] Patent Document 1 discloses an organic electroluminescent device in which an emitting layer containing a compound having a biscarbazole skeleton as shown below is formed by a vacuum deposition method, and attempts are made to improve the driving voltage and efficiency.

[0005] [ka]

[0006] Patent Document 2 discloses an organic electroluminescent device in which an emitting layer containing a compound having a biscarbazole skeleton as shown below is formed by a wet film-forming method, and attempts are made to provide a composition for forming an emitting layer for an organic electroluminescent device that has excellent solubility in organic solvents.

[0007] [ka]

[0008] Non-Patent Document 1 describes an organic electroluminescent device in which a hole injection layer containing polystyrene sulfonic acid and a light-emitting layer containing a compound having a biscarbazole skeleton are laminated. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japan Special Publication No. 2019-525463 [Patent Document 2] Japanese Patent Application Publication No. 2020-105152 [Non-patent literature]

[0010] [Non-Patent Document 1] J. Mater. Chem. C, 2016, 4, 9509-9515 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the above-mentioned prior art cannot be said to be sufficient in terms of the performance of the organic electroluminescent element for display applications, and there has been a demand for further improvement in the luminous efficiency and driving life of organic electroluminescent elements formed by a wet film-forming method.

[0012] The present invention has been made in view of the above-mentioned conventional circumstances, and an object to be achieved is to provide an organic electroluminescent device having high luminous efficiency and a long driving life. [Means for solving the problem]

[0013] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a hole injection layer containing a stable tetraarylborate ion that satisfies the octet rule and has no vacant p orbital on boron, and a compound having a specific carbazole structure in an emission layer, and have thus completed the present invention. Furthermore, as a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a hole injection layer containing a crosslinked product of an electron-accepting compound having a crosslinking group and a compound having a specific carbazole structure in an emitting layer, and have thus completed the present invention.

[0014] That is, the gist of the present invention is as follows.

[0015] Aspect 1 of the present invention is An organic electroluminescent device having an anode, a cathode, a light-emitting layer, and a hole injection layer, the light-emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the light emitting layer, The light-emitting layer contains a compound represented by the following formula (240) or the following formula (241): The present invention relates to an organic electroluminescent device, wherein the hole injection layer contains tetraarylborate ions.

[0016] [ka]

[0017] (In formula (240), Ar 611 , Ar 612 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 611 , R 612 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R611 and R 612 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 611 represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 611 , n 612 are each independently an integer of 1 to 4.

[0018] [ka]

[0019] (In formula (241), Ar 613 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 613 , R 614 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R 613 and R 614 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 612 , G 613 each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 613 , n 614 are each independently an integer of 1 to 4.

[0020] A second aspect of the present invention is the organic electroluminescent device of the first aspect, Ar in the formula (240) and formula (241) 611 ~Ar 615 and each independently represents a monovalent group in which a plurality of benzene rings, which may have a substituent, are bonded in a linear or branched manner.

[0021] A third aspect of the present invention is the organic electroluminescent device of the first or second aspect, R in the formula (240) and the formula (241) 611 ~R 614 and each independently represent a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent.

[0022] A fourth aspect of the present invention is an organic electroluminescent device according to any one of the first to third aspects, wherein The present invention relates to an organic electroluminescent device, wherein the compound represented by the formula (240) or the formula (241) is a compound represented by the following formula (240-1) or the following formula (241-1).

[0023] [ka]

[0024] (In formula (240-1), Ar 611 , Ar 612 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 611 , R 612 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R 611 and R 612 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.)

[0025] [ka]

[0026] (In formula (241-1), Ar 613 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 613 , R 614each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R 613 and R 614 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.)

[0027] A fifth aspect of the present invention is an organic electroluminescent device according to any one of the first to fourth aspects, wherein The present invention relates to an organic electroluminescent device, wherein the tetraarylborate ion is represented by the following formula (81):

[0028] [ka]

[0029] (In formula (81), Ar 1 , Ar 2 , Ar 3 and Ar 4 each independently represents an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group, an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, or a monovalent group formed by linking together a plurality of structures selected from an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group and an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

[0030] A sixth aspect of the present invention relates to the organic electroluminescent device of any one of the first to fifth aspects, The present invention relates to an organic electroluminescent device, wherein the hole injection layer further contains a polymer having an arylamine structure represented by the following formula (50) as a repeating unit and having a crosslinking group.

[0031] [ka]

[0032] (In formula (50), Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; Ar 52 represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon groups and the divalent aromatic heterocyclic groups is linked together directly or via a linking group. Ar 51 and Ar 52 may form a ring via a single bond or a linking group. Ar 51 , Ar 52 may have a substituent.

[0033] A seventh aspect of the present invention is the organic electroluminescent device of the sixth aspect, The present invention relates to an organic electroluminescent device, wherein the polymer having an arylamine structure represented by the formula (50) as a repeating unit has a crosslinking group selected from the formulae (X1) to (X18) in the following group T of crosslinking groups. <Bridging group T>

[0034] [ka]

[0035] In the formulae (X1) to (X4), the benzene ring and the naphthalene ring may have a substituent. In addition, the substituents may be bonded to each other to form a ring. R in formula (X4), formula (X5), formula (X6) and formula (X10) X each independently represents an alkyl group which may have a substituent. In the formulae (X1) to (X18), * represents a bonding position.

[0036] Aspect 8 of the present invention is the organic electroluminescent device of aspect 7, The present invention relates to an organic electroluminescent device in which the crosslinking group is any one of the formulae (X1) to (X3).

[0037] A ninth aspect of the present invention is an organic electroluminescent device according to any one of the sixth to eighth aspects, wherein The organic electroluminescent device relates to a repeating unit represented by the formula (50) having a repeating unit represented by the following formula (54) to the following formula (57) or the following formula (60).

[0038] [ka]

[0039] (In formula (54), Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; X is -C(R 207 )(R 208 )-, -N(R 209 )- or -C(R 211 )(R 212 )-C(R 213 )(R 214 )- and R 201 , R 202 , R 221 and R 222 each independently represents an alkyl group which may have a substituent, R 207 ~R 209 and R 211 ~R 214 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aromatic hydrocarbon group, a and b each independently represent an integer of 0 to 4, c is an integer from 0 to 3, d is an integer from 0 to 4, i and j are each independently an integer of 0 to 3.

[0040] [ka]

[0041] (In formula (55), Ar 51 is Ar in the formula (54). 51 is the same as R 303 and R 306 each independently represents an alkyl group which may have a substituent, R 304 and R 305 each independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group, l is 0 or 1; m is 1 or 2; n is 0 or 1, p is 0 or 1; q is 0 or 1.

[0042] [ka]

[0043] (In formula (56), Ar 51 is Ar in the formula (54). 51 is the same as Ar 41 represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked together directly or via a linking group; R 441 and R 442 each independently represents an alkyl group which may have a substituent, t is 1 or 2; u is 0 or 1; r and s each independently represent an integer of 0 to 4.

[0044] [ka]

[0045] (In formula (57), Ar 51 is Ar in the formula (54). 51 is the same as R 517 ~R 519 each independently represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; f, g, and h each independently represent an integer of 0 to 4; e represents an integer of 0 to 3; However, if g is 1 or greater, e is 1 or greater.)

[0046] [ka]

[0047] (In formula (60), Ar 51 is Ar in the formula (50). 51 is the same as n 60 represents an integer from 1 to 5.)

[0048] A tenth aspect of the present invention is the organic electroluminescent device of the ninth aspect, Ar in the formula (54) to the formula (57) or the formula (60) 51 , R 201 , R 202 , R 221 , R 222 , R 207 ~R 209 , R 211 ~R 214 is R 303 ~R 306 , R 441 , R 442 , R 517 ~R 519The above relates to an organic electroluminescent device in which none of the above has a substituent.

[0049] An eleventh aspect of the present invention is an organic electroluminescent device according to any one of the sixth to tenth aspects, wherein The present invention relates to an organic electroluminescent device, wherein the repeating unit represented by the formula (50) further has a structure represented by the following formula (50-2) as a linking group:

[0050] [ka]

[0051] (In the formula, R 81 , R 83 R each independently represents a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. 81 , R 83 When there are multiple p, they may be the same or different. 80 represents an integer from 1 to 5.)

[0052] A twelfth aspect of the present invention relates to the organic electroluminescent device of any one of aspects 1 to 11, wherein the light-emitting layer contains at least one compound represented by the following formula (3) as a light-emitting material:

[0053] [ka]

[0054] [In formula (3), Ring A1 represents an aromatic hydrocarbon structure which may have a substituent or an aromatic heterostructure which may have a substituent. Ring A2 represents an aromatic heterostructure which may have a substituent. R 201 , R 202 are each independently a structure represented by formula (b), and "*" indicates the bonding position to ring A1 or ring A2. 201 , R 202 may be the same or different, and R 201 , R 202When there are a plurality of each of the groups, they may be the same or different. Ar 201 , Ar 203 each independently represents an aromatic hydrocarbon structure which may have a substituent, or an aromatic heterostructure which may have a substituent. Ar 202 represents an aromatic hydrocarbon structure which may have a substituent, an aromatic heterostructure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. The substituents bonded to ring A1 may bond to each other, the substituents bonded to ring A2 may bond to each other, or the substituents bonded to ring A1 and the substituents bonded to ring A2 may bond to each other to form a ring. B 201 -L 200 -B 202 represents an anionic bidentate ligand. 201 and B 202 Each of L independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. 200 is a single bond or B 201 and B 202 represents the atomic group that together with B constitutes a bidentate ligand. 201 -L 200 -B 202 When there are multiple groups, they may be the same or different. In addition, in formula (3) and formula (b), i1 and i2 each independently represent an integer of 0 to 12, i3 is Ar 202 represents an integer greater than or equal to 0, with the upper limit being the number that can be replaced by i4 is Ar 201 represents an integer greater than or equal to 0, with the upper limit being the number that can be replaced by k1 and k2 each independently represent an integer of 0 or greater, the upper limit of which is the number of groups that can be substituted on ring A1 and ring A2; z represents an integer of 1 to 3. M represents a metal atom selected from Groups 7 to 11 of the periodic table.

[0055] A thirteenth aspect of the present invention relates to the organic electroluminescent device of the twelfth aspect, The organic electroluminescent device relates to the above-mentioned light-emitting layer, wherein the light-emitting layer further contains at least one compound selected from the group consisting of a compound represented by the following formula (250) and a compound represented by the following formula (260):

[0056] [ka]

[0057] (In formula (250), each W independently represents CH or N, and at least one W is N; Xa 1 , Ya 1 , and Za 1 each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, Xa 2 , Ya 2 and Za 2 each independently represents a hydrogen atom, an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted monovalent aromatic heterocyclic group having 3 to 30 carbon atoms, g11, h11, and j11 each independently represent an integer of 0 to 6; At least one of g11, h11, and j11 is an integer of 1 or greater, If g11 is 2 or more, multiple Xa 1 may be the same or different, If h11 is 2 or more, multiple Ya 1 may be the same or different, If j11 is 2 or more, multiple Za 1 may be the same or different, R 31 represents a hydrogen atom or a substituent, and four R 31 may be the same or different, However, if g11, h11, or j11 is 0, the corresponding Xa 2 , Ya 2 , Za 2 is not a hydrogen atom.)

[0058] [ka]

[0059] (In formula (260), Ar 21 ~Ar 35 each independently represents a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group in which 2 to 10 phenyl groups which may have a substituent are linked in an unbranched or branched manner.

[0060] A fourteenth aspect of the present invention is the organic electroluminescent device of the thirteenth aspect, The organic electroluminescent device relates to the light-emitting layer containing at least the compound represented by the formula (250).

[0061] A fifteenth aspect of the present invention is An organic electroluminescent device having an anode, a cathode, a light-emitting layer, and a hole injection layer, the light-emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the light emitting layer, The light-emitting layer contains a compound represented by the following formula (240) or the following formula (241): The hole injection layer relates to an organic electroluminescent device, which contains a crosslinking reaction product of a tetraarylborate ion represented by the following formula (81) and a polymer having an arylamine structure represented by the following formula (50) as a repeating unit and having a crosslinking group:

[0062] [ka]

[0063] (In formula (240), Ar 611 , Ar 612 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 611 , R 612each independently represents a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R 611 and R 612 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 611 represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 611 , n 612 are each independently an integer of 1 to 4.

[0064] [ka]

[0065] (In formula (241), Ar 613 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 613 , R 614 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R 613 and R 614 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 612 , G 613 each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 613 , n 614 are each independently an integer of 1 to 4.

[0066] [ka]

[0067] (In formula (81), Ar 1 , Ar 2 , Ar 3and Ar 4 each independently represents an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group, an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, or a monovalent group formed by linking together a plurality of structures selected from an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group and an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

[0068] [ka]

[0069] (In formula (50), Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; Ar 52 represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon groups and the divalent aromatic heterocyclic groups is linked together directly or via a linking group. Ar 51 and Ar 52 may form a ring via a single bond or a linking group. Ar 51 , Ar 52 may have a substituent.

[0070] A sixteenth aspect of the present invention is The present invention relates to a display device comprising the organic electroluminescent device according to any one of the first to fifteenth embodiments.

[0071] A seventeenth aspect of the present invention is The present invention relates to a lighting device comprising the organic electroluminescent device according to any one of the first to fifteenth embodiments. [Effects of the Invention]

[0072] According to the present invention, it is possible to provide a composition for producing an organic electroluminescent device having higher luminous efficiency and longer operating life than conventional ones.

[0073] The present invention can provide an organic electroluminescent device having the composition, a composition containing the composition and an organic solvent, a thin film forming method, and a method for producing an organic electroluminescent device. [Brief explanation of the drawings]

[0074] [Figure 1] FIG. 1 is a cross-sectional view showing a structural example of an organic electroluminescent device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0075] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments and can be practiced in various modifications within the scope of the gist. In addition, when the expression "to" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0076] In the present invention, the phrase "optionally having a substituent" means that the group may have one or more substituents.

[0077] In this specification, the terms "(hetero)aralkyl group," "(hetero)aryloxy group," and "(hetero)aryl group" refer to an aralkyl group that may contain a heteroatom, an aryloxy group that may contain a heteroatom, and an aryl group that may contain a heteroatom, respectively. "May contain a heteroatom" means that one or more carbon atoms forming the aryl skeleton in the main skeleton of the aralkyl group, aryloxy group, or aryl group are substituted with heteroatoms. Examples of heteroatoms include nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, and silicon atoms. Among these, nitrogen atoms are preferred from the viewpoint of durability. In addition, in this specification, the term "(hetero)aryl group" is used to mean a monocyclic group, a 2- to 4-fused ring group, and a group in which a plurality of monocyclic and / or 2- to 4-fused ring groups are linked together. The (hetero)aryl group represents an aryl group which may contain a heteroatom, that is, an aryl group or a heteroaryl group, where an aryl group is an aromatic hydrocarbon group and a heteroaryl group is an aromatic heterocyclic group.

[0078] [Organic electroluminescent device] The organic electroluminescent device according to the embodiment of the present invention has an anode, a cathode, an emitting layer, and a hole injection layer, wherein the emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the emitting layer, the emitting layer contains a compound represented by the following formula (240) or the following formula (241), and the hole injection layer contains a tetraarylborate ion. The reasons why the organic electroluminescent device according to the embodiment of the present invention exhibits effects are as follows. The benzene ring in the carbazole skeleton has a high electron density, and the 3- and 6-positions are particularly reactive and likely to react with electron-donating substances. As a result of this reaction, an oxide of the electron-donating substance is formed, which may further degrade the device during operation. The compound represented by formula (240) or formula (241) contained in the emissive layer caps the highly reactive sites of the carbazole skeleton, which is thought to suppress compound degradation. Furthermore, capping the highly reactive sites broadens the highest occupied molecular orbital (HOMO), improving hole transport and improving the efficiency of organic electroluminescent devices. Meanwhile, tetraarylborate ions, which have a stable structure that satisfies the octet rule and lacks an empty p-orbital on boron, have the effect of stabilizing cations formed by the oxidation of electron-donating substances. Therefore, using tetraarylborate ions as a material for the hole-injection layer is thought to suppress degradation during device operation.

[0079] Preferred embodiments of the compound represented by formula (240) or formula (241) and the tetraarylborate ion are as described below.

[0080] <Compound represented by formula (240) or formula (241)>

[0081] [ka]

[0082] (In formula (240), Ar 611 , Ar 612 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 611 , R 612 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R 611 and R 612 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 611 represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 611 , n 612 are each independently an integer of 1 to 4.

[0083] [ka]

[0084] (In formula (241), Ar 613 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 613 , R 614 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R 613 and R 614 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G 612 , G 613each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n 613 , n 614 are each independently an integer of 1 to 4.

[0085] (Ar 611 ~Ar 615 ) Ar 611 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. The aromatic hydrocarbon group typically has 6 to 50 carbon atoms, preferably 6 to 30 carbon atoms, and more preferably 6 to 18 carbon atoms. Specific examples of the aromatic hydrocarbon group include monovalent groups of aromatic hydrocarbon structures, such as benzene rings, naphthalene rings, anthracene rings, tetraphenylene rings, phenanthrene rings, chrysene rings, pyrene rings, benzanthracene rings, and perylene rings, each having a carbon number of typically 6 or more and typically 30 or less, preferably 18 or less, and more preferably 14 or less, or monovalent groups of structures in which multiple structures selected from these structures are bonded in a chain or branched manner. When multiple aromatic hydrocarbon rings are linked, typically, 2 to 8 rings are linked, and preferably, 2 to 5 rings are linked. When multiple aromatic hydrocarbon rings are linked, the linked rings may be the same or different.

[0086] Ar 611 ~Ar 615 are preferably each independently phenyl group, a monovalent group in which multiple benzene rings are bonded in a chain or branched manner, a monovalent group in which one or more benzene rings and at least one naphthalene ring are bonded in a linear or branched manner, a monovalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a linear or branched manner, or a monovalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a linear or branched manner; and more preferably a monovalent group in which a plurality of benzene rings are bonded in a linear or branched manner. In either case, the order of bonding does not matter. Ar 611 ~Ar 615 is particularly preferably each independently a monovalent group in which a plurality of benzene rings, which may have a substituent, are bonded in a chain or branched manner, and is most preferably each independently a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner.

[0087] As described above, the number of linked benzene rings, naphthalene rings, phenanthrene rings, and tetraphenylene rings is usually 2 to 8, and preferably 2 to 5. Among these, preferred are monovalent groups in which 1 to 4 benzene rings are linked together, monovalent groups in which 1 to 4 benzene rings and a naphthalene ring are linked together, monovalent groups in which 1 to 4 benzene rings and a phenanthrene ring are linked together, and monovalent groups in which 1 to 4 benzene rings and a tetraphenylene ring are linked together.

[0088] These aromatic hydrocarbon groups may have a substituent. The substituent that the aromatic hydrocarbon group may have can be selected from the following substituent group Z2. Preferred substituents are the preferred substituents in the following substituent group Z2.

[0089] Ar 611 ~Ar 615 From the viewpoint of the solubility and durability of the compound, it is preferable that at least one of the above has at least one partial structure selected from the following formulae (72-1) to (72-7).

[0090] [ka]

[0091] In each of the above formulas (72-1) to (72-7), * represents a bonding position to an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position to an adjacent structure. In the following description, * has the same definition unless otherwise specified.

[0092] More preferably, Ar 611 , Ar 612 At least one of the above has at least one partial structure selected from the formulae (72-1) to (72-4) and (72-7). More preferably, Ar 611 , Ar 612 Each of these has at least one partial structure selected from the formulae (72-1) to (72-3) and (72-7). Particularly preferably, Ar 611 , Ar 612 Each of these has at least one partial structure selected from the formula (72-1), the formula (72-2), and the formula (72-7).

[0093] Formula (72-2) is preferably the following formula (72-2-2).

[0094] [ka]

[0095] Formula (72-2) is more preferably the following formula (72-2-3).

[0096] [ka]

[0097] In addition, from the viewpoint of the solubility and durability of the compound, Ar 611 , Ar 612 The partial structure that at least one of the above preferably has includes a partial structure represented by formula (72-1) and a partial structure represented by formula (72-2).

[0098] (R 611 ~R 614 ) R 611 ~R 614 are each independently a hydrogen atom, a deuterium atom, a halogen atom such as a fluorine atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R 611 and R612 , R 613 and R 614 At least one of them is a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. Preferably, R 611 ~R 614 are each independently a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms, more preferably 6 to 30 carbon atoms, still more preferably 6 to 18 carbon atoms, and particularly preferably 6 to 10 carbon atoms, which may have a substituent. Specific examples of the monovalent aromatic hydrocarbon group include the above-mentioned Ar 611 The same applies to the preferred aromatic hydrocarbon groups, with a phenyl group being particularly preferred. These aromatic hydrocarbon groups may have a substituent. The substituent that the aromatic hydrocarbon group may have is as described above, and specifically, can be selected from the following substituent group Z2. Preferred substituents are the preferred substituents in the following substituent group Z2.

[0099] (n 611 ~n 614 ) n 611 ~n 614 are each independently an integer of 1 to 4. 611 ~n 614 are each independently preferably an integer of 1 to 2, and more preferably 1.

[0100] (substituent) Ar 611 ~Ar 615 , R 611 ~R 614 When is a monovalent aromatic hydrocarbon group, the substituent that may be possessed is preferably a substituent selected from the following substituent group Z2.

[0101] <Substituent group Z2> The substituent group Z2 is a group consisting of an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an arylalkylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may have any of a linear, branched, and cyclic structure.

[0102] More specifically, the substituent group Z2 includes the following structures. For example, a linear, branched, or cyclic alkyl group having a carbon number of usually 1 or more, preferably 4 or more, and usually 24 or less, preferably 12 or less, more preferably 8 or less, and even more preferably 6 or less, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, or a dodecyl group; For example, alkoxy groups having usually 1 or more and usually 24 or less, preferably 12 or less carbon atoms, such as a methoxy group or an ethoxy group; For example, an aryloxy group or heteroaryloxy group having usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less, carbon atoms, such as a phenoxy group, naphthoxy group, or pyridyloxy group; For example, alkoxycarbonyl groups having usually 2 or more and usually 24 or less, preferably 12 or less carbon atoms, such as a methoxycarbonyl group or an ethoxycarbonyl group; For example, dialkylamino groups having usually 2 or more and usually 24 or less, preferably 12 or less carbon atoms, such as a dimethylamino group or a diethylamino group; For example, diarylamino groups, such as a diphenylamino group and a ditolylamino group, each having usually 10 or more, preferably 12 or more, and usually 36 or less, preferably 24 or less carbon atoms; For example, an arylalkylamino group having typically 7 or more carbon atoms and typically 36 or less, preferably 24 or less, such as a phenylmethylamino group; For example, acyl groups such as an acetyl group and a benzoyl group, each of which usually has 2 or more carbon atoms and usually has 24 or less carbon atoms, and preferably has 12 or less carbon atoms; For example, halogen atoms such as fluorine atoms and chlorine atoms; For example, haloalkyl groups having typically 1 or more carbon atoms and typically 12 or less, preferably 6 or less, such as a trifluoromethyl group; For example, alkylthio groups having usually 1 or more and usually 24 or less, preferably 12 or less carbon atoms, such as a methylthio group or an ethylthio group; For example, an arylthio group having usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less, carbon atoms, such as a phenylthio group, a naphthylthio group, or a pyridylthio group; For example, a silyl group having usually 2 or more, preferably 3 or more, carbon atoms and usually 36 or less, preferably 24 or less, such as a trimethylsilyl group or a triphenylsilyl group; For example, a siloxy group having a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less, such as a trimethylsiloxy group or a triphenylsiloxy group; cyano group; For example, aromatic hydrocarbon groups such as phenyl and naphthyl groups, each having a carbon number of usually 6 or more and usually 36 or less, and preferably 24 or less; For example, aromatic heterocyclic groups having usually 3 or more, preferably 4 or more, carbon atoms and usually 36 or less, preferably 24 or less, such as a thienyl group or a pyridyl group.

[0103] Among the above-mentioned substituent group Z2, alkyl groups, alkoxy groups, diarylamino groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups are preferred. From the viewpoint of charge transportability, aromatic hydrocarbon groups or aromatic heterocyclic groups are preferred as the substituent, more preferably aromatic hydrocarbon groups, and even more preferably no substituent. From the viewpoint of improving solubility, alkyl groups or alkoxy groups are preferred as the substituent.

[0104] Each substituent in the above-mentioned substituent group Z2 may further have a substituent. Examples of such a substituent include the same as those in the above-mentioned substituent group Z2. Each substituent that the above-mentioned substituent group Z2 may have is preferably an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms, or a phenyl group, and from the viewpoint of charge transportability, it is more preferable that each substituent in the above-mentioned substituent group Z2 does not have any further substituent.

[0105] (G 611 ~G 613 ) G 611 ~G 613 each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.

[0106] G 611 ~G 613 The number of carbon atoms in the aromatic hydrocarbon group is usually 6 to 50, preferably 6 to 30, and more preferably 6 to 18. Specific examples of the aromatic hydrocarbon group include divalent groups of aromatic hydrocarbon structures, such as benzene rings, naphthalene rings, anthracene rings, tetraphenylene rings, phenanthrene rings, chrysene rings, pyrene rings, benzanthracene rings, and perylene rings, each having a carbon number of usually 6 or more and usually 30 or less, preferably 18 or less, and more preferably 14 or less, or divalent groups of structures in which a plurality of structures selected from these structures are linked in a chain or branched manner. When a plurality of aromatic hydrocarbon rings are linked, a structure in which 2 to 8 rings are linked is usually used, and a structure in which 2 to 5 rings are linked is preferred. When a plurality of aromatic hydrocarbon rings are linked, the linked rings may be the same structure or different structures.

[0107] G 611 ~G 613 is preferably single bond, a phenylene group, a divalent group in which multiple benzene rings are bonded in a chain or branched manner, a divalent group in which one or more benzene rings and at least one naphthalene ring are bonded in a linear or branched manner, a divalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a linear or branched manner, or a divalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a linear or branched manner, and more preferably a divalent group in which a plurality of benzene rings are bonded in a linear or branched manner. In either case, the order of bonding is not important.

[0108] As described above, the number of linked benzene rings, naphthalene rings, phenanthrene rings, and tetraphenylene rings is usually 2 to 8, and preferably 2 to 5. Among these, more preferred are divalent groups in which 1 to 4 benzene rings are linked together, divalent groups in which 1 to 4 benzene rings and a naphthalene ring are linked together, divalent groups in which 1 to 4 benzene rings and a phenanthrene ring are linked together, and divalent groups in which 1 to 4 benzene rings and a tetraphenylene ring are linked together.

[0109] These aromatic hydrocarbon groups may have a substituent. The substituent that the aromatic hydrocarbon group may have can be selected from the aforementioned substituent group Z2. Preferred substituents are the preferred substituents in the aforementioned substituent group Z2.

[0110] The compound represented by the formula (240) or (241) is preferably a compound represented by the following formula (240-1) or (241-1).

[0111] [ka]

[0112] (In formula (240-1), Ar 611 , Ar 612 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 611 , R 612each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R 611 and R 612 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.)

[0113] [ka]

[0114] (In formula (241-1), Ar 613 ~Ar 615 each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R 613 , R 614 each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R 613 and R 614 At least one of these represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.)

[0115] Ar in the formula (240-1) and the formula (241-1) 611 ~Ar 615 , R 611 ~R 614 A preferred embodiment of the formula (240) is Ar in the formula (241). 611 ~Ar 615 , R 611 ~R 614 is the same as:

[0116] (molecular weight) The compound represented by the formula (240), the formula (241), the formula (240-1), or the formula (241-1) is a low-molecular-weight material, and its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, even more preferably 2,000 or less, particularly preferably 1,500 or less, and is usually 300 or more, preferably 350 or more, more preferably 400 or more.

[0117] (Specific examples of the compounds represented by the formula (240), the formula (241), the formula (240-1) or the formula (241-1)) Preferred specific examples of the compound represented by the formula (240), the formula (241), the formula (240-1) or the formula (241-1) are shown below, but the present invention is not limited to these.

[0118] [ka]

[0119] The light-emitting layer according to the embodiment of the present invention may contain only one type of compound represented by the formula (240), the formula (241), the formula (240-1), or the formula (241-1), or may contain two or more types.

[0120] [Luminescent materials] The light-emitting layer according to the embodiment of the present invention may contain a light-emitting material. The light-emitting material may be any known material that is typically used as a light-emitting material for organic electroluminescent devices, and is not particularly limited as long as it emits light at a desired emission wavelength and has good luminous efficiency. The light-emitting material may be a fluorescent compound or a phosphorescent compound, but is preferably a phosphorescent compound from the viewpoint of internal quantum efficiency. More preferably, the red and green light-emitting materials are phosphorescent compounds, and the blue light-emitting material is a fluorescent compound.

[0121] (Phosphorescent compounds) A phosphorescent compound is a compound that emits light from an excited triplet state. Representative examples include metal complex compounds containing Ir, Pt, Eu, etc., and the material structure preferably includes a metal complex. Among metal complexes, phosphorescent organometallic complexes that emit light via a triplet state include Werner complexes or organometallic complex compounds containing a central metal selected from Groups 7 to 11 of the long-form periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long-form periodic table). Examples of such phosphorescent compounds include the phosphorescent compounds described in WO 2014 / 024889, WO 2015 / 087961, WO 2016 / 194784, and JP 2014-074000 A. Preferably, the compound represented by formula (3) or formula (205) is used, and more preferably, the compound represented by formula (3) is used. That is, in the light-emitting layer according to the embodiment of the present invention, the light-emitting material is preferably a compound represented by formula (3) or formula (205), and more preferably, the compound represented by formula (3). Furthermore, the light-emitting layer according to the embodiment of the present invention preferably contains at least one compound selected from the group consisting of a compound represented by formula (250) and a compound represented by formula (260), which will be described later, in addition to the compound represented by formula (3) below, and more preferably contains at least a compound represented by formula (250).

[0122] [ka]

[0123] [In formula (3), Ring A1 represents an aromatic hydrocarbon structure which may have a substituent or an aromatic heterostructure which may have a substituent. Ring A2 represents an aromatic heterostructure which may have a substituent. R 201 , R 202 are each independently a structure represented by formula (b), and "*" indicates the bonding position to ring A1 or ring A2. 201 , R 202 may be the same or different, and R 201 , R 202When there are a plurality of each of the groups, they may be the same or different.

[0124] Ar 201 , Ar 203 each independently represents an aromatic hydrocarbon structure which may have a substituent, or an aromatic heterostructure which may have a substituent. Ar 202 represents an aromatic hydrocarbon structure which may have a substituent, an aromatic heterostructure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. The substituents bonded to ring A1 may bond to each other, the substituents bonded to ring A2 may bond to each other, or the substituents bonded to ring A1 and the substituents bonded to ring A2 may bond to each other to form a ring.

[0125] B 201 -L 200 -B 202 represents an anionic bidentate ligand. 201 and B 202 Each of L independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. 200 is a single bond or B 201 and B 202 represents the atomic group that together with B constitutes a bidentate ligand. 201 -L 200 -B 202 When there are multiple groups, they may be the same or different.

[0126] In addition, in formula (3) and formula (b), i1 and i2 each independently represent an integer of 0 to 12, i3 is Ar 202 represents an integer greater than or equal to 0, with the upper limit being the number that can be replaced by i4 is Ar 201 represents an integer greater than or equal to 0, with the upper limit being the number that can be replaced by k1 and k2 each independently represent an integer of 0 or greater, the upper limit of which is the number of groups that can be substituted on ring A1 and ring A2; z represents an integer of 1 to 3. M represents a metal atom selected from Groups 7 to 11 of the periodic table.

[0127] In formula (3), specific examples of M include metal atoms selected from Groups 7 to 11 of the periodic table. Among these, preferred are ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold, and particularly preferred are trivalent metals such as iridium.

[0128] Unless otherwise specified, the substituent is preferably a group selected from the following substituent group S. Substituent group S: An alkyl group, preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 to 6 carbon atoms. An alkoxy group, preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and even more preferably an alkoxy group having 1 to 6 carbon atoms. An aryloxy group, preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, even more preferably an aryloxy group having 6 to 12 carbon atoms, and particularly preferably an aryloxy group having 6 carbon atoms. A heteroaryloxy group, preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms. An alkylamino group, preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms.

[0129] An arylamino group, preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms. An aralkyl group, preferably an aralkyl group having 7 to 40 carbon atoms, more preferably an aralkyl group having 7 to 18 carbon atoms, and even more preferably an aralkyl group having 7 to 12 carbon atoms. Heteroaralkyl groups, preferably heteroaralkyl groups having 7 to 40 carbon atoms, more preferably heteroaralkyl groups having 7 to 18 carbon atoms. An alkenyl group, preferably an alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, even more preferably an alkenyl group having 2 to 8 carbon atoms, and particularly preferably an alkenyl group having 2 to 6 carbon atoms. An alkynyl group, preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms.

[0130] An aryl group, preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, even more preferably an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 14 carbon atoms. Heteroaryl groups, preferably heteroaryl groups having 3 to 30 carbon atoms, more preferably heteroaryl groups having 3 to 24 carbon atoms, even more preferably heteroaryl groups having 3 to 18 carbon atoms, and particularly preferably heteroaryl groups having 3 to 14 carbon atoms. An alkylsilyl group, preferably an alkylsilyl group having an alkyl group with 1 to 20 carbon atoms, more preferably an alkylsilyl group having an alkyl group with 1 to 12 carbon atoms. An arylsilyl group, preferably an arylsilyl group having 6 to 20 carbon atoms in the aryl group, more preferably an arylsilyl group having 6 to 14 carbon atoms in the aryl group. An alkylcarbonyl group, preferably an alkylcarbonyl group having 2 to 20 carbon atoms. An arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms. In the above groups, one or more hydrogen atoms may be replaced by fluorine atoms, or one or more hydrogen atoms may be replaced by deuterium atoms. Unless otherwise specified, aryl is an aromatic hydrocarbon ring and heteroaryl is an aromatic heterocyclic ring.

[0131] -Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF5.

[0132] Among the substituent group S, preferred are an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group, and groups in which one or more hydrogen atoms of these groups are replaced by fluorine atoms, a fluorine atom, a cyano group, or -SF5; More preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, and groups in which one or more hydrogen atoms of these groups are replaced with fluorine atoms, fluorine atoms, cyano groups, or -SF5; More preferred are alkyl groups, alkoxy groups, aryloxy groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, alkylsilyl groups, and arylsilyl groups. Particularly preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, and heteroaryl groups. Most preferred are alkyl groups, arylamino groups, aralkyl groups, aryl groups and heteroaryl groups.

[0133] These substituents in the substituent group S may further have a substituent selected from the substituent group S as a substituent. The preferred groups, more preferred groups, even more preferred groups, particularly preferred groups, and most preferred groups of the substituents that may be had are the same as the preferred groups in the substituent group S.

[0134] Ring A1 represents an aromatic hydrocarbon structure which may have a substituent or an aromatic heterostructure which may have a substituent. The aromatic hydrocarbon ring is preferably an aromatic hydrocarbon ring having a carbon number of 6 to 30. Specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring is preferred. The aromatic heterocycle is preferably an aromatic heterocycle having 3 to 30 carbon atoms and containing a nitrogen atom, oxygen atom, or sulfur atom as a heteroatom, more preferably a furan ring, a benzofuran ring, a thiophene ring, or a benzothiophene ring.

[0135] Ring A1 is more preferably a benzene ring, a naphthalene ring, or a fluorene ring, particularly preferably a benzene ring or a fluorene ring, and most preferably a benzene ring.

[0136] Ring A2 represents an aromatic heterostructure which may have a substituent. The aromatic heterocycle is preferably an aromatic heterocycle having 3 to 30 carbon atoms and containing a nitrogen atom, oxygen atom, or sulfur atom as a heteroatom. Specific examples include a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, an oxazole ring, a thiazole ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, and a phenanthridine ring. Preferred are a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, a benzothiazole ring, a benzoxazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, and a quinazoline ring. More preferred are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, and a quinazoline ring. Most preferred are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, a quinoxaline ring, and a quinazoline ring.

[0137] Preferred combinations of ring A1 and ring A2, when expressed as (ring A1-ring A2), include (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring-quinazoline ring), (benzene ring-benzothiazole ring), (benzene ring-imidazole ring), (benzene ring-pyrrole ring), (benzene ring-diazole ring), and (benzene ring-thiophene ring). The substituents that the ring A1 and ring A2 may have can be selected arbitrarily, but are preferably one or more types of substituents selected from the above-mentioned group S of substituents.

[0138] Ar 201 , Ar 203each independently represents an aromatic hydrocarbon structure which may have a substituent, or an aromatic heterostructure which may have a substituent. Ar 202 represents an aromatic hydrocarbon structure which may have a substituent, an aromatic heterostructure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent.

[0139] Ar 201 , Ar 202 , Ar 203 When any one of the above is an aromatic hydrocarbon structure which may have a substituent, the aromatic hydrocarbon structure is preferably an aromatic hydrocarbon ring having a carbon number of 6 to 30. Specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring is preferred, a benzene ring, a naphthalene ring, or a fluorene ring is more preferred, and a benzene ring is most preferred.

[0140] Ar 201 , Ar 202 When any one of the above is a benzene ring which may have a substituent, it is preferable that at least one benzene ring is bonded to an adjacent structure at an ortho-position or a meta-position, and it is more preferable that at least one benzene ring is bonded to an adjacent structure at a meta-position.

[0141] Ar 201 , Ar 202 , Ar 203 When either of the above is a fluorene ring which may have a substituent, the 9- and 9'-positions of the fluorene ring preferably have a substituent or are bonded to an adjacent structure.

[0142] Ar 201 , Ar 202 , Ar 203is an aromatic heterostructure which may have a substituent, the aromatic heterostructure is preferably an aromatic heterocycle having 3 to 30 carbon atoms and containing a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom, and specific examples thereof include a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, an oxazole ring, a thiazole ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, a phenanthridine ring, a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring, and preferably a pyridine ring, a pyrimidine ring, a triazine ring, a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring. Ar 201 , Ar 202 , Ar 203 When either of the above is a carbazole ring which may have a substituent, the N-position of the carbazole ring preferably has a substituent or is bonded to an adjacent structure.

[0143] Ar 202 When is an aliphatic hydrocarbon structure which may have a substituent, it is an aliphatic hydrocarbon structure having a straight chain, branched chain, or cyclic structure, and preferably has 1 or more and 24 or less carbon atoms, more preferably has 1 or more and 12 or less carbon atoms, and still more preferably has 1 or more and 8 or less carbon atoms.

[0144] i1 and i2 each independently represent an integer of 0 to 12, preferably an integer of 1 to 12, more preferably an integer of 1 to 8, and even more preferably an integer of 1 to 6. Within this range, improvements in solubility and charge transport properties are expected. i3 preferably represents an integer of 0 to 5, more preferably an integer of 0 to 2, and even more preferably 0 or 1. i4 preferably represents an integer of 0 to 2, and more preferably 0 or 1. k1 and k2 each independently represent an integer of preferably 0 to 3, more preferably an integer of 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

[0145] Ar 201 , Ar 202 , Ar 203 The substituents that may be possessed by may be arbitrarily selected, but are preferably one or more substituents selected from the above-mentioned substituent group S. The preferred groups are also the same as those in the above-mentioned substituent group S, but are more preferably unsubstituted (hydrogen atom), alkyl groups, or aryl groups, particularly preferably unsubstituted (hydrogen atom) or alkyl groups, and most preferably unsubstituted (hydrogen atom) or tertiary butyl groups, and the tertiary butyl groups are preferably Ar 203 If Ar exists, 203 To, Ar 203 If there is no Ar 202 To, Ar 202 and Ar 203 If there is no Ar 201 It is preferred that the substituent is

[0146] The compound represented by the formula (3) is preferably a compound that satisfies one or more of the following (I) to (IV):

[0147] (I) Phenylene-linked The structure represented by formula (b) is preferably a structure having a group linked to benzene rings, i.e., a benzene ring structure, where i1 is an integer of 1 to 6, and at least one of the benzene rings is bonded to an adjacent structure at the ortho or meta position. Such a structure is expected to improve solubility and charge transport properties.

[0148] (II) (phenylene)-aralkyl(alkyl) A structure having an aromatic hydrocarbon group or aromatic heterocyclic group to which an alkyl group or an aralkyl group is bonded in ring A1 or ring A2, i.e., Ar 201 is an aromatic hydrocarbon structure or an aromatic heterostructure, i1 is an integer of 1 to 6, Ar 202 is an aliphatic hydrocarbon structure, i2 is an integer of 1 to 12, preferably an integer of 3 to 8, Ar 203 is a benzene ring structure, i3 is 0 or 1, preferably Ar 201is the aromatic hydrocarbon structure, more preferably a structure in which 1 to 5 benzene rings are linked together, and even more preferably a structure in which there is one benzene ring. Such a structure is expected to improve solubility and charge transport properties.

[0149] (III) Dendron A structure in which a dendron is bonded to ring A1 or ring A2, for example, Ar 201 , Ar 202 is a benzene ring structure, Ar 203 is a biphenyl or terphenyl structure, i1 and i2 are integers of 1 to 6, i3 is 2, and j is 2. Such a structure is expected to improve solubility and charge transport properties.

[0150] (IV)B 201 -L 200 -B 202 B 201 -L 200 -B 202 The structure represented by the formula (203) is preferably a structure represented by the formula (204) below.

[0151] [ka]

[0152] In formula (203), R 211 , R 212 , R 213 each independently represents a substituent. In formula (204), ring B3 represents an aromatic heterostructure containing a nitrogen atom, which may have a substituent, and ring B3 is preferably a pyridine ring.

[0153] The phosphorescent compound represented by the formula (201) is not particularly limited, but preferred examples include the following.

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] Also preferred is a phosphorescent compound represented by the following formula (205):

[0158] [ka]

[0159] [In formula (205), M 2 represents a metal, and T represents a carbon atom or a nitrogen atom. 92 ~R 95 each independently represents a substituent, provided that when T is a nitrogen atom, R 94 and R 95 There is none.]

[0160] In formula (205), M 2 Specific examples of the metal include metals selected from Groups 7 to 11 of the periodic table. Among these, preferred are ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold, and particularly preferred are divalent metals such as platinum and palladium.

[0161] Also, in equation (205), R 92 and R 93 each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxy group, an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

[0162] Furthermore, if T is a carbon atom, R 94 and R 95 are each independently R 92 and R 93 In addition, when T is a nitrogen atom, R 94 or R 95 does not exist. Also, R 92 ~R 95 may further have a substituent. The substituent may be the same as those described above. 92 ~R 95 Any two or more of the groups may be linked to each other to form a ring.

[0163] The molecular weight of the phosphorescent compound is preferably 5,000 or less, more preferably 4,000 or less, and particularly preferably 3,000 or less. The molecular weight of the phosphorescent compound is preferably 1,200 or more, more preferably 1,400 or more, and even more preferably 1,600 or more. It is believed that within this molecular weight range, the phosphorescent compounds do not aggregate with each other and can be uniformly mixed with the charge transport material, thereby making it possible to obtain a light-emitting layer with high luminous efficiency.

[0164] The molecular weight of the phosphorescent compound is preferably large in that it has a high Tg, melting point, decomposition temperature, etc., and the heat resistance of the phosphorescent compound and the formed light-emitting layer is excellent, and it is less likely to cause deterioration in film quality due to gas generation, recrystallization, molecular migration, etc., or an increase in impurity concentration due to thermal decomposition of the material. On the other hand, the molecular weight of the phosphorescent compound is preferably small in that it makes it easier to purify the organic compound.

[0165] <Compound represented by formula (250)>

[0166] [ka]

[0167] (In formula (250), each W independently represents CH or N, and at least one W is N; Xa 1 , Ya 1 , and Za 1 each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, Xa 2 , Ya 2 and Za 2 each independently represents a hydrogen atom, an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted monovalent aromatic heterocyclic group having 3 to 30 carbon atoms, g11, h11, and j11 each independently represent an integer of 0 to 6; At least one of g11, h11, and j11 is an integer of 1 or greater, If g11 is 2 or more, multiple Xa 1 may be the same or different, If h11 is 2 or more, multiple Ya 1 may be the same or different, If j11 is 2 or more, multiple Za 1 may be the same or different, R 31 represents a hydrogen atom or a substituent, and four R 31 may be the same or different, However, if g11, h11, or j11 is 0, the corresponding Xa 2 , Ya 2 , Za 2 is not a hydrogen atom.)

[0168] The compound represented by the above formula (250) is preferably a charge transporting compound, that is, a charge transporting host material.

[0169] (W) In the formula (250), W represents CH or N, and at least one of them is N. From the viewpoint of electron transport properties and electron durability, it is preferable that at least two of them are N, and it is more preferable that all of them are N.

[0170] (Xa 1 , Ya 1 , Za 1 , Xa 2 , Ya 2 , Za 2 ) Xa in the formula (250) 1 , Ya 1 , and Za 1 each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent. 2 , Ya 2 and Za 2 each independently represents a hydrogen atom, an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted monovalent aromatic heterocyclic group having 3 to 30 carbon atoms. If g11 is 2 or more, multiple Xa 1 may be the same or different, and when h11 is 2 or more, multiple Ya 1 may be the same or different, and when j11 is 2 or more, multiple Za 1 may be the same or different, and R 31 represents a hydrogen atom or a substituent, and four R 31 may be the same or different, provided that when g11, h11, or j11 is 0, the corresponding Xa 2 , Ya 2 , Za 2 is not a hydrogen atom.

[0171] In the formula (250), Xa 1 , Ya 1 , Za 1 is a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, and Xa 2 , Ya 2, Za 2 When the aromatic hydrocarbon group having 6 to 30 carbon atoms optionally having a substituent is an aromatic hydrocarbon group having 6 to 30 carbon atoms, the aromatic hydrocarbon ring of the aromatic hydrocarbon group having 6 to 30 carbon atoms is preferably a 6-membered monocyclic ring or 2 to 5 condensed rings. Specific examples include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, a fluoranthene ring, and an indenofluorene ring. Among these, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, or a fluorene ring is preferred, a benzene ring, a naphthalene ring, a phenanthrene ring, or a fluorene ring is more preferred, and a benzene ring, a naphthalene ring, or a fluorene ring is even more preferred. In addition, when g11 is 2 or more, the terminal partial structure, -Xa 1 -Xa 2 , -Ya is a terminal partial structure when h11 is 2 or more. 1 -Ya 2 and a terminal partial structure when j11 is 2 or more, -Za 1 -Za 2 The compound represented by formula (250) may have a spirofluorene structure. 1 -Xa 2 , -Ya is a terminal partial structure when h11 is 2 or more. 1 -Ya 2 and a terminal partial structure when j11 is 2 or more, -Za 1 -Za 2 At least one of these preferably has a spirofluorene structure.

[0172] In the formula (250), Xa 1 , Ya 1 , Za 1 is a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, and Xa 2 , Ya 2 , Za 2When is an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, the aromatic heterocyclic ring of the aromatic heterocyclic group having 3 to 30 carbon atoms is preferably a 5- or 6-membered monocyclic ring or 2 to 5 condensed rings. Specific examples thereof include a furan ring, a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, an indolocarbazole ring, an indenocarbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a perimidine ring, a quinazoline ring, and a quinazolinone ring. Among these, a thiophene ring, a pyrrole ring, an imidazole ring, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, an indolocarbazole ring, a phenanthroline ring, or an indenocarbazole ring is preferred, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, an indolocarbazole ring, an indenocarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring is more preferred, and a carbazole ring, an indolocarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring is even more preferred.

[0173] Xa in the formula (250) 1 , Ya 1 , Za 1 , Xa 2 , Ya 2 , and Za 2 In the above, particularly preferred aromatic hydrocarbon rings are a benzene ring, a naphthalene ring, or a phenanthrene ring, and particularly preferred aromatic heterocycles are a carbazole ring, an indolocarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring.

[0174] Xa in the formula (250)1 , Ya 1 , Za 1 , Xa 2 , Ya 2 and Za 2 In the above formula, the substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms may have and the substituents that the aromatic heterocyclic group having 3 to 30 carbon atoms may have are preferably each independently selected from the substituent group Z2, and it is more preferable that the substituents selected from the substituent group Z2 do not have any further substituents. It is believed that the absence of any further substituents in the substituents selected from the substituent group Z2 makes it possible to maintain high charge transport properties and durability, which is preferable. Among the substituent group Z2, aromatic hydrocarbon groups and aromatic heterocyclic groups are preferred, and aromatic hydrocarbon groups are particularly preferred, from the viewpoint of charge transport properties and durability.

[0175] <g11、h11、j11> g11, h11, and j11 each independently represent an integer of 0 to 6, and at least one of g11, h11, and j11 is an integer of 1 or greater. From the viewpoint of charge transport properties and durability, it is preferred that g11 is 2 or greater, or at least one of h11 and j11 is 3 or greater.

[0176] Furthermore, it is preferable that the compound represented by the formula (250) has a total of 8 to 18 of these rings, including the ring having three central Ws, from the viewpoints of charge transport properties, durability, and solubility in organic solvents.

[0177] ((Xa 1 ) g11 , (Ya 1 ) h11、 (Za 1 ) j11 ) (Xa 1 ) g11 , (Ya 1 ) h11、 and (Za 1 ) j11In view of the solubility and durability of the compound, it is preferable that at least one group selected from each independently has a partial structure selected from a partial structure represented by the following formula (11), a partial structure represented by the following formula (12), and a partial structure represented by the following formula (13), and when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11、 and j11 is 1 or more (Za 1 ) j11 It is more preferable that each independently have a partial structure selected from a partial structure represented by the following formula (11), a partial structure represented by the following formula (12), and a partial structure represented by the following formula (13).

[0178] [ka]

[0179] In each of the above formulas (11) to (13), * indicates the bonding position with the adjacent structure, or Xa in formula (250). 2 , Ya 2 , or Za 2 represents the hydrogen atom when * is a hydrogen atom. At least one of the two * marks represents the bonding position to the adjacent structure. In the following description, * has the same definition unless otherwise specified.

[0180] More preferably, when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11 , and when j11 is 1 or more (Za 1 ) j11 each independently has a partial structure represented by formula (11) or a partial structure represented by formula (12). More preferably, when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11, and when j11 is 1 or more (Za 1 ) j11 each independently has a partial structure represented by formula (11) and a partial structure represented by formula (12).

[0181] The partial structure represented by formula (12) is preferably a partial structure represented by the following formula (12-2).

[0182] [ka]

[0183] The partial structure represented by formula (12) is more preferably a partial structure represented by the following formula (12-3).

[0184] [ka]

[0185] As the partial structure having the partial structure represented by formula (11) and the partial structure represented by formula (12), from the viewpoint of solubility, a partial structure selected from the following formulas (14) to (17), which is a structure containing a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12), is preferred. That is, when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11、 and j11 is 1 or more (Za 1 ) j11 Each of the formulas (11) to (13) preferably has a partial structure selected from the following formulas (14) to (17). In other words, from the viewpoint of solubility, when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11 , and when j11 is 1 or more (Za 1 ) j11each independently preferably has a partial structure selected from formulas (11) to (17).

[0186] [ka]

[0187] A structure containing a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12) means, for example, a partial structure represented by formula (14) that can be considered to have one partial structure represented by formula (11) and two partial structures represented by formula (12), as in the following formula (14a):

[0188] [ka]

[0189] More preferably, (Xa 1 ) g11 , (Ya 1 ) h11、 and (Za 1 ) j11 At least one of the groups has at least a partial structure represented by formula (14) or a partial structure represented by formula (15). More preferably, when g11 is 1 or more, (Xa 1 ) g11 , when h11 is 1 or more (Ya 1 ) h11 , and when j11 is 1 or more (Za 1 ) j11 has a partial structure represented by formula (14) or a partial structure represented by formula (15).

[0190] The partial structure represented by formula (14) is preferably a partial structure represented by the following formula (14-2).

[0191] [ka]

[0192] The partial structure represented by formula (14) is more preferably a partial structure represented by the following formula (14-3).

[0193] [ka]

[0194] The partial structure represented by formula (15) is preferably a partial structure represented by the following formula (15-2).

[0195] [ka]

[0196] The partial structure represented by formula (15) is more preferably a partial structure represented by the following formula (15-3).

[0197] [ka]

[0198] The partial structure represented by formula (17) is preferably a partial structure represented by the following formula (17-2).

[0199] [ka]

[0200] (Xa 1 ) g11 , (Ya 1 ) h11、 and (Za 1 ) j11 It is more preferable that at least one of the above has a partial structure represented by the following formula (19) or a partial structure represented by the following formula (20) as a partial structure containing a partial structure represented by formula (13).

[0201] [ka]

[0202] In each of the above formulas (14) to (20), * indicates the bonding position with the adjacent structure, or Xa 2 , Ya 2 , or Za 2 represents the hydrogen atom. At least one of the two * marks represents the bonding position to the adjacent structure.

[0203] Among the partial structures represented by formulas (14) to (20), the partial structure represented by formula (14-3) and the partial structure represented by formula (15-3) are preferred, with formula (14-3) being more preferred.

[0204] -(Xa 1 ) g11 -(Xa 2 ), -(Ya 1 ) h11 -(Ya 2 ), and -(Za 1 ) j11 -(Za 2 ) each independently preferably has a partial structure represented by formula (11), a partial structure represented by formula (12-3), a partial structure represented by formula (14-3), or a partial structure represented by formula (15-3).

[0205] Also, -(Xa 1 ) g11 -(Xa 2 ), -(Ya 1 ) h11 -(Ya 2 ), and -(Za 1 ) j11 -(Za 2 ) preferably has any one of partial structures or terminal structures represented by the following formulae (250-1) to (250-10).

[0206] [ka]

[0207] In formulas (250-1) to (250-10), * represents a bonding position. 250represents an aromatic hydrocarbon group having 6 to 20 carbon atoms. 32 represents a substituent, and the structures represented by formulae (250-1) to (250-10) may further have a substituent.]

[0208] The substituents that these structures may have are R 32 is the same as:

[0209] Ar 250 is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group or a biphenyl group, and even more preferably a phenyl group.

[0210] R 32 In a structure having two R 32 may be the same or different. R 32 is preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, or a heteroaryl group having 3 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, or an aryl group having 6 to 14 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms.

[0211] <R 31 > R when it is a substituent 31is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent. From the viewpoint of improving durability and charge transportability, an aromatic hydrocarbon group which may have a substituent is more preferred. When R is a substituent, 31 When there are a plurality of groups, they may be different from each other.

[0212] The substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms may have, the substituents that the aromatic heterocyclic group having 3 to 30 carbon atoms may have, and the substituent R 31 The substituent that may be possessed by can be selected from the above-mentioned substituent group Z2.

[0213] From the viewpoint of charge transport properties, R 31 is preferably a hydrogen atom.

[0214] In addition, from the viewpoint of solubility, -(Ya 1 ) h11 -(Ya 2 ), and -(Za 1 ) j11 -(Za 2 ) is preferably not also an unsubstituted phenyl group.

[0215] <Molecular weight> The compound represented by the formula (250) is a low molecular weight material, and its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, particularly preferably 2,000 or less, and most preferably 1,500 or less. The lower limit of the molecular weight of the compound is usually 400 or more, preferably 500 or more, and more preferably 600 or more.

[0216] <Specific examples of the compound represented by formula (250)> The compound represented by formula (250) is not particularly limited, but examples thereof include the following compounds.

[0217] [ka]

[0218] [ka]

[0219] [ka]

[0220] [ka]

[0221] [ka]

[0222] [ka]

[0223] The light-emitting layer according to the embodiment of the present invention may contain only one type of compound represented by the formula (250), or may contain two or more types.

[0224] <Compound represented by formula (260)>

[0225] [ka]

[0226] (In formula (260), Ar 21 ~Ar 35 each independently represents a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group in which 2 to 10 phenyl groups which may have a substituent are linked in an unbranched or branched manner.

[0227] In formula (260), Ar 21 ~Ar 35is a phenyl group which may have a substituent, or in the case where 2 to 10 phenyl groups which may have a substituent are linked in an unbranched or branched manner, the substituent which the phenyl group may have is preferably an alkyl group.

[0228] (Alkyl group as a substituent) The alkyl group as a substituent is a linear, branched, or cyclic alkyl group having a carbon number of usually 1 or more and 12 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, and a 2-ethylhexyl group.

[0229] In the formula (260), Ar 21 , Ar 25 , Ar 26 , Ar 30 , Ar 31 and Ar 35 is preferably a hydrogen atom. 22 ~Ar 24 At least one of the groups is a phenyl group which may have a substituent or a monovalent group in which 2 to 10 phenyl groups which may have a substituent are linked in an unbranched or branched manner, and / or Ar 22 ~Ar 24 At least one of, and Ar 27 ~Ar 29 At least one of the groups is preferably a phenyl group which may have the above-mentioned substituent or a monovalent group in which 2 to 10 phenyl groups which may have the above-mentioned substituent are linked in an unbranched or branched manner. 22 ~Ar 24 , Ar 27 ~Ar 29 , and Ar 32 ~Ar 34 is a hydrogen atom, a phenyl group, or a structure selected from the following formulas (261-1) to (261-9). Particularly preferably, in the formula (260), Ar 21 , Ar25 , Ar 26 , Ar 30 , Ar 31 and Ar 35 is a hydrogen atom, and Ar 22 ~Ar 24 , Ar 27 ~Ar 29 , and Ar 32 ~Ar 34 are each independently a hydrogen atom, a phenyl group which may have a substituent, or a structure selected from the following formulas (261-1) to (261-9), each of which may have a substituent. These structures may have the substituent, for example, may be substituted with an alkyl group as the substituent. From the viewpoint of improving solubility, it is preferable that they be substituted with an alkyl group. From the viewpoint of charge transport properties and durability during device operation, it is preferable that they have no substituent.

[0230] [ka]

[0231] In the formulae (261-1) to (261-9), * represents the bonding position to the benzene ring in the formula (260).

[0232] It is believed that the inclusion of such a structure in the compound represented by formula (260) allows the charge transport property in the light-emitting layer to be appropriately adjusted, thereby increasing the light-emitting efficiency. It is also believed that the inclusion of such a structure provides excellent solubility and durability during device operation.

[0233] (molecular weight) The compound represented by the formula (260) is a low molecular weight material, and its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, even more preferably 2,000 or less, particularly preferably 1,500 or less, and is usually 300 or more, preferably 350 or more, more preferably 400 or more.

[0234] (Specific examples of compounds represented by formula (260)) The compound represented by formula (260) is not particularly limited, but examples thereof include the following compounds.

[0235] [ka]

[0236] [ka]

[0237] The light-emitting layer according to the embodiment of the present invention may contain only one type of compound represented by the formula (260), or may contain two or more types.

[0238] [Hole injection layer] The organic electroluminescent device according to the embodiment of the present invention has a hole injection layer between the anode and the light emitting layer. The hole injection layer is usually formed on and in contact with the anode. The hole injection layer must have the function of transporting holes, and therefore contains a hole transport material. The organic electroluminescent device according to the embodiment of the present invention contains a tetraarylborate ion in the hole injection layer. The organic electroluminescent device according to the embodiment of the present invention preferably contains an electron-accepting compound containing a tetraarylborate ion in the hole injection layer. The tetraarylborate ion, which has a stable structure that satisfies the octet rule and has no empty p orbital on boron, has the effect of stabilizing cations formed by oxidizing an electron-donating substance. Therefore, using a tetraarylborate ion as a material for the hole injection layer tends to suppress degradation reactions during device operation.

[0239] In order to improve hole injection from the anode to the hole injection layer and improve hole transport within the hole injection layer, it is preferable that the hole transport material contained in the hole injection layer contains a cation radical moiety. To convert the hole transport material into a cation radical, an electron-accepting compound is used when forming the hole injection layer. As the backbone of the electron-accepting compound, an ionic compound consisting of a tetraarylborate ion, which is an anion with an ionic valence of 1 (described later), and a counter cation is preferred because of its high stability.

[0240] The hole transport material is converted into a cation radical as follows: When a compound having a triarylamine structure is used as the hole transport material, for example, and a tetraarylborate salt having diaryliodonium as a counter cation is used as the electron accepting compound, the counter cation can change from diaryliodonium to triarylaminium as shown in the following formula during the formation of the hole injection layer.

[0241] [ka]

[0242] (e.g., Ar, Ar 1 ~Ar 4 are each independently an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together.

[0243] The triarylaminium produced in the above reaction has a half-occupied molecular orbital (SOMO) that can accept electrons, so the tetraarylborate salt with the triarylaminium as the counter cation is an electron-accepting compound.

[0244] In the embodiment of the present invention, the compound consisting of the cation of the hole transport material and the anion, tetraarylborate ion, is referred to as a charge transporting ionic compound, as will be described in detail later.

[0245] [Electron-accepting compounds] The electron-accepting compound has, as a mother skeleton, an ionic compound comprising a tetraarylborate ion and a counter cation, as described above, or an ionic compound comprising a tetraarylborate ion and a counter cation as a mother skeleton. The tetraarylborate ion in the embodiment of the present invention preferably has the following crosslinking group:

[0246] (crosslinking group) In an embodiment of the present invention, the crosslinking group refers to a group that reacts with another group located in the vicinity of the crosslinking group upon exposure to heat and / or active energy rays to form a new chemical bond. In this case, the reactive group may be the same as or different from the crosslinking group.

[0247] When the tetraarylborate ion contains a crosslinking group, a crosslinking reaction proceeds during the formation of the hole injection layer, allowing the electron-accepting compound containing the tetraarylborate ion to be fixed to the hole injection layer, and it is thought that the electron-accepting compound will not diffuse into the layer above the hole injection layer when the layer above the hole injection layer is formed by a wet film formation method. Therefore, it is presumed that the use of a tetraarylborate ion having a crosslinking group can suppress deterioration reactions during operation.

[0248] The crosslinking group is preferably a crosslinking group represented by any one of formulas (X1) to (X18) which belong to the following group T of crosslinking groups.

[0249] [ka]

[0250] In the formulae (X1) to (X4), the benzene ring and the naphthalene ring may have a substituent. In addition, the substituents may be bonded to each other to form a ring. R in formula (X4), formula (X5), formula (X6) and formula (X10) X each independently represents an alkyl group which may have a substituent. In the formulae (X1) to (X18), * represents a bonding position.

[0251] R X The alkyl group represented by the formula (I) has a linear, branched or cyclic structure and has 1 or more carbon atoms, preferably 24 or less, more preferably 12 or less, and even more preferably 8 or less.

[0252] Benzene rings and naphthalene rings of formulas (X1) to (X4), R of formulas (X4) to (X6) and (X10) X The substituent that may be possessed by the group is preferably an alkyl group, an aromatic hydrocarbon group, an alkyloxy group, or an aralkyl group.

[0253] The alkyl group as a substituent has a linear, branched or cyclic structure and preferably has 24 or less carbon atoms, more preferably 12 or less, even more preferably 8 or less, and preferably 1 or more carbon atoms.

[0254] The number of carbon atoms in the aromatic hydrocarbon group as a substituent is preferably 24 or less, more preferably 18 or less, even more preferably 12 or less, and is preferably 6 or more. The aromatic hydrocarbon group may further have the above-mentioned alkyl group as a substituent.

[0255] The alkyloxy group as a substituent preferably has 24 or less carbon atoms, more preferably 12 or less carbon atoms, even more preferably 8 or less carbon atoms, and preferably 1 or more carbon atoms.

[0256] The number of carbon atoms in the aralkyl group as a substituent is preferably 30 or less, more preferably 24 or less, even more preferably 14 or less, and is preferably 7 or more. The alkylene group contained in the aralkyl group preferably has a linear or branched structure. The aryl group contained in the aralkyl group may further have the above-mentioned alkyl group as a substituent.

[0257] As the crosslinking group, a crosslinking group represented by any one of formulas (X1) to (X4) is preferred because it has low polarity and little effect on charge transport, and further, a crosslinking group represented by any one of formulas (X1) to (X3) is more preferred because the crosslinking reaction proceeds only with heat.

[0258] In the crosslinking group represented by formula (X1), the cyclobutene ring is opened by heat, and the ring-opened groups bond to each other to form a crosslinked structure, as shown in the following formula.

[0259] [ka]

[0260] In the crosslinking group represented by formula (X2), the cyclobutene ring is opened by heat, and the open ring groups bond to each other to form a crosslinked structure, as shown in the following formula.

[0261] [ka]

[0262] In the crosslinking group represented by formula (X3), the cyclobutene ring is opened by heat, and the ring-opened groups bond to each other to form a crosslinked structure, as shown in the following formula.

[0263] [ka]

[0264] In the crosslinking group represented by any one of formulas (X1) to (X3), the cyclobutene ring is opened by heat, and if a double bond is present nearby, the opened group reacts with the double bond to form a crosslinked structure. Below is an example in which a crosslinked structure is formed by a group formed by opening the ring of the crosslinking group represented by formula (X1) and a crosslinking group represented by formula (X4) having a double bond moiety. (However, if R in formula (X4) X is not shown.)

[0265] [ka]

[0266] Examples of groups containing a double bond that can react with a crosslinking group represented by any one of formulae (X1) to (X3) include the crosslinking group represented by formula (X4) and the crosslinking groups represented by any one of formulae (X5), (X6), (X12), (X15), (X16), (X17), and (X18). When using these double bond-containing groups as crosslinking groups in an electron-accepting compound, it is preferable to incorporate a crosslinking group represented by any one of formulae (X1) to (X3) into other components that form the hole-injection layer, such as a hole-transporting compound, because this increases the possibility of forming a crosslinked structure.

[0267] As the crosslinking group, a radically polymerizable crosslinking group represented by any one of formulas (X4), (X5) and (X6) is preferred because it has low polarity and is unlikely to interfere with charge transport.

[0268] As the crosslinking group, a crosslinking group represented by formula (X7) is preferred in terms of enhancing electron-accepting property. When a crosslinking group represented by formula (X7) is used, the following crosslinking reaction proceeds.

[0269] [ka]

[0270] The crosslinking group represented by either formula (X8) or (X9) is preferred because of its high reactivity. When the crosslinking group represented by formula (X8) or (X9) is used, the following crosslinking reaction proceeds.

[0271] [ka]

[0272] As the crosslinking group, a cationic polymerizable crosslinking group represented by any one of formulas (X10), (X11) and (X12) is preferred in terms of high reactivity.

[0273] (Crosslinked electron-accepting compound) As described later, the hole injection layer of the organic electroluminescent element according to the embodiment of the present invention is preferably obtained by wet film formation of a composition for forming a hole injection layer, and the composition for forming a hole injection layer is preferably a composition obtained by a step of dissolving or dispersing a first ionic compound having a tetraarylborate ion structure described later and a hole transport material described later in an organic solvent. The hole injection layer of the organic electroluminescent element according to the embodiment of the present invention preferably contains a charge transporting ionic compound having a tetraarylborate ion structure described later in an embodiment of the present invention as an anion and a cation of the hole transport material as a counter cation.

[0274] Here, the term "tetraarylborate ion in an embodiment of the present invention" includes a case where the tetraarylborate ion exists as an electron-accepting compound, which is an ionic compound comprising a tetraarylborate ion and a counter cation, as described below, and a case where the tetraarylborate ion exists as a charge-transporting ionic compound comprising a tetraarylborate ion and a cation of a hole-transporting material, as described below. In an embodiment of the present invention, the crosslinked product of the tetraarylborate ion having a crosslinking group may be the following crosslinked product. A compound in which an electron-accepting compound and a tetraarylborate ion according to an embodiment of the present invention are crosslinked. A compound in which tetraarylborate ions are crosslinked with each other according to an embodiment of the present invention. A compound in which a tetraarylborate ion and a hole transport material are crosslinked in an embodiment of the present invention.

[0275] The two crosslinking groups that undergo a crosslinking reaction may be the same or different, as long as they are capable of crosslinking.

[0276] [Tetraarylborate ion] A tetraarylborate ion is a monovalent anion in which the boron atom is substituted with four aromatic hydrocarbon rings or aromatic heterocycles, each of which may have a substituent and / or a bridging group.

[0277] The tetraarylborate ion used in the organic electroluminescent device according to this embodiment of the present invention preferably has a fluorine atom or a fluorine-substituted alkyl group as a substituent on the aryl group, in terms of further improving stability. That is, the tetraarylborate ion is preferably represented by the following formula (81):

[0278] [ka]

[0279] (In formula (81), Ar 1 , Ar 2 , Ar 3 and Ar 4 each independently represents an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group, an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, or a monovalent group formed by linking together a plurality of structures selected from an aromatic hydrocarbon group optionally having a substituent and / or a crosslinking group and an aromatic heterocyclic group optionally having a substituent and / or a crosslinking group, Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

[0280] Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of them preferably has a crosslinking group.

[0281] Ar 1 , Ar 2 , Ar 3 and Ar 4The aromatic hydrocarbon group used in is preferably a single ring or 2 to 6 condensed rings, and specific examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring, a biphenyl structure, a terphenyl structure, and a quaterphenyl structure.

[0282] Ar 1 , Ar 2 , Ar 3 and Ar 4 The aromatic heterocyclic group used in is preferably a single ring or 2 to 6 condensed rings. Specific examples thereof include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring.

[0283] Among these, a monovalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring, or a biphenyl group is more preferred because of its excellent stability and heat resistance. A monovalent group derived from a benzene ring, i.e., a phenyl group or a biphenyl group, is particularly preferred.

[0284] The total number of monocyclic or 2 to 6 fused ring aromatic hydrocarbon groups and monocyclic or 2 to 6 fused ring aromatic heterocyclic groups contained in a monovalent group in which a plurality of structures selected from aromatic hydrocarbon groups which may have a substituent and / or a crosslinking group and aromatic heterocyclic groups which may have a substituent and / or a crosslinking group are linked together is 2 or more, and preferably 8 or less, more preferably 4 or less, and even more preferably 3 or less.

[0285] Ar 1 , Ar 2 , Ar 3 and Ar 4 Examples of the substituent that may be possessed by include the groups described in the substituent group W below.

[0286] Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of the groups has a fluorine atom or a fluorine-substituted alkyl group as a substituent, in order to increase the stability of the anion and improve the effect of stabilizing the cation. 1 , Ar 2 , Ar 3 and Ar 4 Among these, it is preferable that two or more of the groups are substituted, more preferable that three or more of the groups are substituted, and most preferable that four of the groups are substituted.

[0287] Ar 1 , Ar 2 , Ar 3 and Ar 4 The fluorine-substituted alkyl group as the substituent is preferably a linear or branched alkyl group having 1 to 12 carbon atoms substituted with a fluorine atom, more preferably a perfluoroalkyl group, still more preferably a linear or branched perfluoroalkyl group having 1 to 5 carbon atoms, particularly preferably a linear or branched perfluoroalkyl group having 1 to 3 carbon atoms, and most preferably a perfluoromethyl group. The reason for this is that the hole injection layer containing a tetraarylborate ion or a crosslinked product of an electron-accepting compound having a crosslinking group, and the coating film laminated thereon, become stable.

[0288] Ar 1 , Ar 2 , Ar 3 and Ar 4 Examples of the crosslinking group that may be contained in the electron-accepting compound include the crosslinking groups of the electron-accepting compound described above, and the same applies to preferred crosslinking groups.

[0289] The tetraarylborate ion used in the organic electroluminescent device according to the embodiment of the present invention is a tetraarylborate ion represented by Ar 1 , Ar 2 , Ar 3 and Ar 4 At least one of Ar is preferably a group represented by formula (113), 1 , Ar 2 , Ar 3 and Ar 4 It is more preferable that at least two of the groups are each independently a group represented by formula (113), and Ar 1 , Ar 2 , Ar 3 and Ar 4 It is more preferable that at least three of the groups are each independently a group represented by formula (113), and Ar 1 , Ar 2 , Ar 3 and Ar 4 are most preferably each independently a group represented by formula (113).

[0290] [ka]

[0291] (In formula (113), R A each independently represents a monovalent group formed by linking together a plurality of structures selected from an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group, an aromatic heterocyclic group which may have a substituent and / or a crosslinking group, an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group, and an aromatic heterocyclic group which may have a substituent and / or a crosslinking group, a fluorine-substituted alkyl group, a substituent, or a crosslinking group, F4 represents four fluorine atoms substituted, F (5-m) each independently represents substitution with 5-m fluorine atoms, k's each independently represent an integer of 0 to 5; Each m independently represents an integer of 0 to 5. * indicates the bond position.)

[0292] In terms of further improving the stability of the anion, k is preferably 1 or more, and more preferably 2 or more. In terms of facilitating uniform dispersion, k is preferably 0 or 1, and 0 is preferred.

[0293] m is preferably 0 in view of superior durability, and is preferably 1 or more and preferably 3 or less in view of enabling various functions to be introduced into the tetraarylborate ion, and is more preferably 1 or 2 in view of compatibility with durability. It is preferable that k+m≧1, since this improves the stability of the anion and provides excellent durability.

[0294] R 1 As the aromatic hydrocarbon group or aromatic heterocyclic group, preferred structures and optional substituents are Ar 1 , Ar 2 , Ar 3 and Ar 4 The structure and the substituents that may be possessed by the group are the same as those of the group shown above.

[0295] R A As the aromatic hydrocarbon group or aromatic heterocyclic group, preferred structures and optional substituents are Ar 1 , Ar 2 , Ar 3 and Ar 4 The structure and the substituents that may be possessed by the group are the same as those of the group shown above.

[0296] R A The substituents and R A When is a substituent, examples of the substituent include the groups described in the substituent group W below.

[0297] In formula (113), at least one R A is preferably the above-mentioned fluorine-substituted alkyl group, more preferably a perfluoroalkyl group, and more preferably a trifluoromethyl group.

[0298] R A The bridging group and R A When is a crosslinking group, examples of the crosslinking group include the crosslinking groups of the electron-accepting compound described above, and the same applies to preferred crosslinking groups.

[0299] In formula (113), at least one R A It is preferable that R contains the crosslinking group in order to achieve both crosslinking and electron accepting properties. A The crosslinking group is preferably one of the above crosslinking groups or a structure in which one or more of the above crosslinking groups are bonded to the aromatic hydrocarbon group.

[0300] In another embodiment of the present invention, in formula (113), at least one R A is preferably the above-mentioned fluorine-substituted alkyl group, more preferably a perfluoroalkyl group, and more preferably a trifluoromethyl group.

[0301] Ar of the formula (81) 1 , Ar 2 , Ar 3 and Ar 4 At least one group is selected from at least one R A is a crosslinking group, the structure represented by the formula (113) is preferred in terms of achieving both crosslinkability and electron-accepting property. A The crosslinking group is preferably one of the above crosslinking groups or a structure in which one or more of the above crosslinking groups are bonded to the aromatic hydrocarbon group.

[0302] Furthermore, R A is also preferably a group containing a group represented by the following formula (114) or a group represented by the following formula (115).

[0303] [ka]

[0304] The group represented by formula (114) and the group represented by formula (115) may have a substituent, and examples of the substituent include R A The substituents are the same as those that may be possessed by the group.

[0305] R A is preferably a group represented by formula (114) or a group represented by formula (115), or a structure in which one or more groups represented by formula (114) or formula (115) are bonded to an aromatic hydrocarbon group.

[0306] R A However, when one or more of the crosslinking groups are bonded to the aromatic hydrocarbon group, the aromatic hydrocarbon group preferably has a structure in which two or more rings selected from a benzene ring, a naphthalene ring, or a benzene ring and a naphthalene ring are linked together, and the number of rings linked together is preferably 4 or less. A is a structure in which the crosslinking group is bonded to a monocyclic benzene ring or a monocyclic naphthalene ring, more preferably a structure in which the crosslinking group is bonded to a benzene ring, and particularly preferably a structure in which one or two crosslinking groups are bonded.

[0307] R A is a group containing a group represented by formula (114) or a group represented by the following formula (115), more preferable R A is a structure in which a group represented by formula (114) or a group represented by formula (115) is bonded to a monocyclic benzene ring or a monocyclic naphthalene ring, more preferably a structure in which a group represented by formula (114) or a group represented by formula (115) is bonded to a benzene ring, and particularly preferably a structure in which one or two groups represented by formula (114) or groups represented by formula (115) are bonded.

[0308] The groups represented by the formula (114) and the formula (115) are preferred because they have crosslinking properties and are thought to prevent the tetraarylborate ions and counter cations from diffusing into other layers.

[0309] (Substituent group W) The substituent group W is a hydrogen atom, a halogen atom, a cyano group, an aromatic hydrocarbon group consisting of 1 to 5 aromatic hydrocarbon rings, an aliphatic hydrocarbon ring group, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylketone group, or an arylketone group.

[0310] Examples of halogen atoms include fluorine, chlorine, bromine and iodine atoms, with fluorine atoms being preferred in terms of the stability of the compound.

[0311] Examples of the aromatic hydrocarbon group consisting of 1 to 5 aromatic hydrocarbon rings include a phenyl group, a biphenyl group, a terphenyl group, a quaterphenyl group, a naphthyl group, a phenanthrenyl group, a triphenylene group, and a naphthylphenyl group, and the phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, or a quaterphenyl group is preferred from the viewpoint of the stability of the compound.

[0312] Examples of the aliphatic hydrocarbon ring group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0313] The alkyl group has a carbon number of usually 1 or more, preferably 4 or more, and usually 24 or less, preferably 12 or less, further preferably 8 or less, and more preferably 6 or less. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, an octyl group, a 2-ethylhexyl group, and a dodecyl group.

[0314] The alkenyl group generally has 2 or more carbon atoms and generally has 24 or less carbon atoms, preferably 12 or less carbon atoms. Specific examples include a vinyl group, a propenyl group, and a butenyl group.

[0315] The alkynyl group generally has 2 or more carbon atoms and generally 24 or less, preferably 12 or less, and specific examples thereof include an acetyl group, a propynyl group, and a butynyl group.

[0316] Examples of the aralkyl group include a benzyl group, a phenylethyl group, and a phenylhexyl group.

[0317] The alkoxy group typically has 1 or more carbon atoms and typically has 24 or less carbon atoms, preferably 12 or less carbon atoms, and more preferably 6 or less carbon atoms. Specific examples include a methoxy group, an ethoxy group, a butyloxy group, a hexyloxy group, and an octyloxy group.

[0318] The aryloxy group has usually 4 or more carbon atoms, preferably 5 or more carbon atoms, and more preferably 6 or more carbon atoms, and usually 36 or less carbon atoms, preferably 24 or less carbon atoms, and more preferably 12 or less carbon atoms. Specific examples include a phenoxy group and a naphthyloxy group.

[0319] The alkylthio group generally has 1 or more carbon atoms and generally 24 or less, preferably 12 or less, and specific examples include a methylthio group, an ethylthio group, a butylthio group, and a hexylthio group.

[0320] The arylthio group usually has 4 or more carbon atoms, preferably 5 or more carbon atoms, and usually has 36 or less carbon atoms, preferably 24 or less carbon atoms. Specific examples include a phenylthio group and a naphthylthio group.

[0321] The alkyl ketone group typically has 1 or more carbon atoms and typically has 24 or less carbon atoms, preferably 12 or less carbon atoms, and more preferably 6 or less carbon atoms. Specific examples include an acetyl group, an ethylcarbonyl group, a butylcarbonyl group, and an octylcarbonyl group.

[0322] The aryl ketone group usually has 5 or more carbon atoms, preferably 7 or more carbon atoms, and usually has 25 or less carbon atoms, preferably 13 or less carbon atoms. Specific examples include a benzoyl group and a naphthylcarbonyl group.

[0323] Adjacent substituents may be bonded to form a ring. Examples of the ring include a cyclobutene ring and a cyclopentene ring.

[0324] These substituents may further be substituted with a substituent, and examples of the substituent include a halogen atom, an alkyl group, an aryl group, or the above-mentioned crosslinking group.

[0325] Among these substituents, a halogen atom or an aryl group is preferred in terms of the stability of the compound, and a halogen atom is most preferred, with a fluorine atom being particularly preferred among halogen atoms.

[0326] [Examples of tetraarylborate ions] Specific examples of the tetraarylborate ions used in the organic electroluminescent device according to the embodiment of the present invention are listed below, but the present invention is not limited to these.

[0327] [ka]

[0328] [ka]

[0329] [ka]

[0330] [ka]

[0331] [ka]

[0332] [ka]

[0333] [ka]

[0334] [ka]

[0335] [ka]

[0336] [ka]

[0337] Among the above specific examples, compounds (A-1) and (A-2) are preferred in terms of electron-accepting property, heat resistance, and solubility. Furthermore, compounds (A-18), (A-19), (A-20), (A-21), (A-25), (A-26), and (A-28) are more preferred in terms of high stability as a composition for a charge transport film, and compounds (A-19), (A-21), (A-25), (A-26), and (A-28) are particularly preferred in terms of stability of an organic electroluminescent device.

[0338] The tetraarylborate ions (A-18), (A-19), (A-20), (A-21), (A-25), (A-26), (A-28), and (A-29) have crosslinking groups and can therefore form "crosslinked products of electron-accepting compounds."

[0339] [Electron-accepting compounds containing tetraarylborate ions] The tetraarylborate ion is also preferably used as an electron-accepting compound containing the tetraarylborate ion. The electron-accepting compound containing the tetraarylborate ion is referred to as a first ionic compound. The first ionic compound comprises the tetraarylborate ion, which is an anion, and a counter cation. The first ionic compound is used as an electron-accepting compound.

[0340] The counter cation is preferably an iodonium cation, a sulfonium cation, a carbocation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation, or a ferrocenium cation having a transition metal, more preferably an iodonium cation, a sulfonium cation, a carbocation, or an ammonium cation, and particularly preferably an iodonium cation.

[0341] The iodonium cation is preferably a structure represented by the general formula (116) described below, and the same also applies to more preferred structures.

[0342] Specific preferred examples of the iodonium cation include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, 4-tert-butoxyphenylphenyliodonium cation, 4-methoxyphenylphenyliodonium cation, and 4-isopropylphenyl-4-methylphenyliodonium cation.

[0343] Specific preferred examples of the sulfonium cation include triphenylsulfonium cation, 4-hydroxyphenyldiphenylsulfonium cation, 4-cyclohexylphenyldiphenylsulfonium cation, 4-methanesulfonylphenyldiphenylsulfonium cation, (4-tert-butoxyphenyl)diphenylsulfonium cation, bis(4-tert-butoxyphenyl)phenylsulfonium cation, and 4-cyclohexylsulfonylphenyldiphenylsulfonium cation.

[0344] Specific examples of the carbocation include trisubstituted carbocations such as triphenyl carbocation, tri(methylphenyl) carbocation, and tri(dimethylphenyl) carbocation.

[0345] Specific examples of the ammonium cation include trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation, and tri(n-butyl)ammonium cation; N,N-dialkylanilinium cations such as N,N-diethylanilinium cation and N,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations such as di(isopropyl)ammonium cation and dicyclohexylammonium cation.

[0346] Specific preferred phosphonium cations include tetraarylphosphonium cations such as tetraphenylphosphonium cation, tetrakis(methylphenyl)phosphonium cation, and tetrakis(dimethylphenyl)phosphonium cation; and tetraalkylphosphonium cations such as tetrabutylphosphonium cation and tetrapropylphosphonium cation.

[0347] Among these, in terms of film stability of the compound, iodonium cation, carbocation and sulfonium cation are preferred, with iodonium cation being more preferred.

[0348] The iodonium cation serving as the counter cation of the first ionic compound preferably has a structure represented by the following formula (116).

[0349] [ka]

[0350] In formula (116), Ar 5 , Ar 6are each independently an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. 5 , Ar 6 The aromatic hydrocarbon group and aromatic heterocyclic group as Ar 1 , Ar 2 , Ar 3 and Ar 4 The same structures as in the case of Ar can be selected, and the preferred structure is also Ar 1 , Ar 2 , Ar 3 and Ar 4 The same structures can be selected as in the case of Ar 5 , Ar 6 Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group may have include the substituents described in the above-mentioned substituent group W.

[0351] The counter cation represented by the formula (116) is preferably represented by the following formula (117):

[0352] [ka]

[0353] In the above formula (117), Ar 7 and Ar 8 is the Ar in the above formula (116) 5 and Ar 6 The substituents are the same as those that may be possessed by the group.

[0354] The molecular weight of the first ionic compound used in the embodiment of the present invention is usually 900 or more, preferably 1000 or more, and more preferably 1200 or more, and is usually 10000 or less, preferably 5000 or less, and more preferably 3000 or less. If the molecular weight is too small, the delocalization of positive and negative charges will be insufficient, which may result in a decrease in electron-accepting ability, and if the molecular weight is too large, it may hinder charge transport.

[0355] [Specific example] Specific examples of ionic compounds with iodonium cations are listed below as the first ionic compound in the embodiment of the present invention, but the first ionic compound is not limited to these.

[0356] [ka]

[0357] [ka]

[0358] [ka]

[0359] [ka]

[0360] [ka]

[0361] [ka]

[0362] [ka]

[0363] [ka]

[0364] [ka]

[0365] [ka]

[0366] [ka]

[0367] [ka]

[0368] [ka]

[0369] Among the above specific examples, compounds (B-1) and (B-2) are preferred in terms of electron-accepting property, heat resistance, and solubility. Furthermore, compounds (B-18), (B-19), (B-20), (B-21), (B-25), (B-26), (B-28), and (B-29) are more preferred in terms of high stability as a composition for a charge transport film, and compounds (B-19), (B-21), (B-25), (B-26), (B-28), and (B-29) are particularly preferred in terms of stability of an organic electroluminescent device.

[0370] [Polymers containing arylamine structures as repeating units] The hole injection layer in the embodiment of the present invention preferably contains a polymer having an arylamine structure represented by the following formula (50) as a repeating unit and having a crosslinking group.

[0371] [ka]

[0372] (In formula (50), Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; Ar 52represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon groups and the divalent aromatic heterocyclic groups is linked together directly or via a linking group. Ar 51 and Ar 52 may form a ring via a single bond or a linking group. Ar 51 , Ar 52 may have a substituent.

[0373] Ar 51 , Ar 52 The substituent which may be possessed by is preferably a substituent or a bridging group selected from the above-mentioned substituent group Z.

[0374] The polymer having the arylamine structure represented by the formula (50) as a repeating unit preferably has a crosslinking group selected from the formulae (X1) to (X18) in the group of crosslinking groups T, more preferably any one of the formulae (X1) to (X3). 51 , Ar 52 has the crosslinking group.

[0375] (terminal group) In this specification, the term "terminal group" refers to the structure at the terminal of a polymer formed by an endcapping agent used at the end of polymerization of the polymer. In the composition according to the embodiment of the present invention, the terminal group of the polymer containing the repeating unit represented by formula (50) is preferably a hydrocarbon group. From the viewpoint of charge transportability, the hydrocarbon group is preferably a hydrocarbon group having 1 to 60 carbon atoms, more preferably a hydrocarbon group having 1 to 40 carbon atoms, and even more preferably a hydrocarbon group having 1 to 30 carbon atoms.

[0376] Examples of the hydrocarbon group include: a linear, branched, or cyclic alkyl group having usually 1 or more, preferably 4 or more, and usually 24 or less, preferably 12 or less, carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, or a dodecyl group; a linear, branched, or cyclic alkenyl group, such as a vinyl group, which usually has 2 or more and 24 or less, preferably 12 or less, carbon atoms; a linear or branched alkynyl group, such as an ethynyl group, having typically 2 or more and 24 or less, preferably 12 or less, carbon atoms; aromatic hydrocarbon groups, such as phenyl and naphthyl groups, having a carbon number of usually 6 or more and 36 or less, and preferably 24 or less; Among the group of crosslinking groups T, crosslinking groups that are hydrocarbon groups are preferred, and crosslinking groups represented by the formulae (X1) to (X3) are preferred.

[0377] These hydrocarbon groups may further have a substituent, and the optional substituent is preferably an alkyl group or an aromatic hydrocarbon group. When there are multiple optional substituents, they may be bonded to each other to form a ring. When these hydrocarbon groups are groups other than crosslinking groups, the substituents may further have a crosslinking group selected from the group T of crosslinking groups.

[0378] From the viewpoint of charge transport properties and durability, the terminal group is preferably an alkyl group, an aromatic hydrocarbon group, or a crosslinking group which is a hydrocarbon group selected from the group T of crosslinking groups, more preferably an aromatic hydrocarbon group. When the terminal group is not a crosslinking group, it is also preferable that the terminal group further has a crosslinking group selected from the group T of crosslinking groups.

[0379] (Ar 52 ) Ar 52represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon groups and the divalent aromatic heterocyclic groups is linked together directly or via a linking group, and the aromatic hydrocarbon group and the aromatic heterocyclic group may have a substituent. The substituent that may be possessed is preferably a substituent or a bridging group selected from the above-mentioned substituent group Z. 52 When has a crosslinking group, the crosslinking group is preferably a crosslinking group selected from the group T of crosslinking groups.

[0380] (Twisted structure) The repeating unit represented by the formula (50) may have a partial structure represented by the following formula (63): 52 It is preferable that the main chain has a twisted structure and inhibits conjugation.

[0381] [ka]

[0382] (In equation (63), R 601 represents an alkyl group which may have a substituent, Ar 621 represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent, the ring Ar represents an aromatic hydrocarbon structure which may have a substituent, or a divalent aromatic heterostructure which may have a substituent; -* indicates the bond position with the adjacent atom.) In addition, the repeating unit Ar of the arylamine structure represented by the formula (50) 52 In this case, it does not matter whether it is on the left or right side of the formula (63). That is, the following formula (63') also has the same meaning as the formula (63).

[0383] [ka]

[0384] (Ar 51 ) Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together, and the aromatic hydrocarbon group and the aromatic heterocyclic group may have a substituent. The substituent that may be possessed is preferably a substituent or a crosslinking group selected from the above-mentioned group Z of substituents, and when a crosslinking group is possessed, the crosslinking group is preferably a crosslinking group selected from the above-mentioned group T of crosslinking groups. Ar 51 and Ar 52 may form a ring via a single bond or a linking group.

[0385] (Ar having a bridging group) 51 (preferred structure of Ar 51 When has a bridging group, Ar 51 is preferably a structure having a crosslinking group selected from the group T of crosslinking groups at the terminal of a monovalent group in which 2 to 5 optionally substituted benzene rings are linked together. 51 More preferably, the structure has a crosslinking group selected from the group T of crosslinking groups at the end of a monovalent group in which 2 to 5 unsubstituted benzene rings are linked together.

[0386] <Preferred Ar 51 > Ar 51 In terms of excellent charge transport properties and durability, aromatic hydrocarbon groups are preferred, and among these, a benzene ring (phenyl group), a group in which 2 to 5 benzene rings are linked, or a monovalent group of a fluorene ring (fluorenyl group) is more preferred, with a fluorenyl group being even more preferred, and a 2-fluorenyl group being particularly preferred. These may have a substituent. As the substituent, a group selected from the aforementioned substituent group Z or a crosslinking group is preferred. When a crosslinking group is present, the crosslinking group is preferably a crosslinking group selected from the aforementioned crosslinking group group T.

[0387] Ar 51The substituents that the aromatic hydrocarbon group and aromatic heterocyclic group may have are not particularly limited as long as they do not significantly impair the properties of the present polymer. Preferred examples of the substituents include groups selected from the below-described substituent group Z, with alkyl groups, alkoxy groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups being more preferred, and alkyl groups being even more preferred.

[0388] Ar 51 In terms of solubility in a solvent, a fluorenyl group substituted with an alkyl group having 1 to 24 carbon atoms is preferred, and a 2-fluorenyl group substituted with an alkyl group having 4 to 12 carbon atoms is particularly preferred. Furthermore, a 9-alkyl-2-fluorenyl group in which the 9-position of the 2-fluorenyl group is substituted with an alkyl group is preferred, and a 9,9'-dialkyl-2-fluorenyl group substituted with two alkyl groups is particularly preferred.

[0389] The fluorenyl group substituted with an alkyl group at at least one of the 9- and 9'-positions tends to improve the solubility in solvents and the durability of the fluorene ring. Furthermore, the fluorenyl group substituted with an alkyl group at both the 9- and 9'-positions tends to further improve the solubility in solvents and the durability of the fluorene ring.

[0390] Also, Ar 51 is also preferably a spirobifluorenyl group from the viewpoint of solubility in a solvent.

[0391] In addition, the polymer containing the repeating unit represented by the formula (50) may be a polymer containing the repeating unit represented by the formula (50) in which Ar 51 preferably contains a repeating unit which is a group represented by the following formula (51), a group represented by the following formula (52), or a group represented by the following formula (53).

[0392] <Group represented by formula (51)>

[0393] [ka]

[0394] (In formula (51), * represents the bonding position with the nitrogen atom of the main chain of formula (50), Ar 53 , Ar 54 each independently represent a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a divalent group in which a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic heterocyclic groups which may have a substituent are linked together directly or via a linking group; Ar 55 represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which a plurality of optionally substituted aromatic hydrocarbon groups or aromatic heterocyclic groups are linked together directly or via a linking group; Ar 56 represents a hydrogen atom or a substituent.

[0395] Here, each aromatic hydrocarbon group and each aromatic heterocyclic group may have a substituent. The optional substituent is preferably a group selected from the above-mentioned substituent group Z or a crosslinking group, and when a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned crosslinking group group T.

[0396] (Ar 53 ) Ar 53 is preferably a group in which 1 to 6 divalent aromatic hydrocarbon groups are linked together, more preferably a group in which 2 to 4 divalent aromatic hydrocarbon groups are linked together, and among these, a group in which 1 to 4 phenylene rings are linked together is more preferred, and a biphenylene group in which 2 phenylene rings are linked together is particularly preferred.

[0397] These groups may have a substituent. The substituent that may be had is preferably a group selected from the above-mentioned group Z of substituents or a crosslinking group. When a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned group T of crosslinking groups. Preferably, Ar 53 has no substituents or bridging groups.

[0398] When a plurality of these divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are linked together, the plurality of linked divalent aromatic hydrocarbon groups are preferably bonded together so as not to be conjugated. Specifically, it preferably contains a 1,3-phenylene group or a group that has a substituent and forms a twisted structure due to the steric effect of the substituent, and more preferably contains a 1,3-phenylene group that has no substituent and no crosslinking group, or a group in which multiple 1,3-phenylene groups that have no substituent and no crosslinking group are linked together.

[0399] (Ar 54 ) Ar 54 In terms of excellent charge transport properties and durability, the divalent aromatic hydrocarbon group is preferably a group in which one or more divalent aromatic hydrocarbon groups, which may be the same or different, are linked together, and the divalent aromatic hydrocarbon group may have a substituent. When multiple groups are linked together, the number of linked groups is preferably 2 to 10, more preferably 6 or less, and particularly preferably 3 or less from the viewpoint of film stability. Preferred aromatic hydrocarbon structures are a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring, and more preferably a benzene ring and a fluorene ring. As a group in which multiple groups are linked together, a group in which 1 to 4 phenylene rings are linked together, or a group in which a phenylene ring and a fluorene ring are linked together is preferred. In terms of a wider LUMO, a biphenylene group in which two phenylene rings are linked together is particularly preferred.

[0400] These groups may have a substituent. The substituent that may be had is preferably a group selected from the above-mentioned group Z of substituents or a crosslinking group. When a crosslinking group is had, the crosslinking group is preferably a group selected from the above-mentioned group T of crosslinking groups. More preferred substituents are a phenyl group, a naphthyl group, and a fluorenyl group. It is also preferred that the group has no substituent.

[0401] (Ar 55 ) Ar 55is an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a monovalent group in which a plurality of aromatic hydrocarbon groups or aromatic heterocyclic groups which may have a substituent are linked directly or via a linking group. Preferably, it is a monovalent aromatic hydrocarbon group or a group in which a plurality of monovalent aromatic hydrocarbon groups are linked.

[0402] These groups may have a substituent. The optional substituent is preferably a group selected from the above-mentioned group Z of substituents or a crosslinking group. When a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned group T of crosslinking groups.

[0403] When a plurality of these groups are linked together, it is preferably a divalent group of 2 to 10 linked groups, and more preferably a monovalent group of 2 to 5 linked groups. 51 The same aromatic hydrocarbon groups and aromatic heterocyclic groups as those mentioned above can be used.

[0404] Ar 55 It is preferable that the compound has a structure represented by any one of the following schemes 2A, 2B, and 2C.

[0405] [ka]

[0406] [ka]

[0407] [ka]

[0408] In the above Schemes 2A to 2C, "-*" represents Ar 54 If there are multiple "-*", one of them must be Ar 54 represents the bonding position with These structures may have a substituent. The substituent that these structures may have is preferably a group selected from the above-mentioned substituent group Z or a crosslinking group. When a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned crosslinking group group T.

[0409] (R 31 and R 32 ) R in Schemes 2A and 2B 31 and R 32 are each independently preferably a linear, branched, or cyclic alkyl group which may have a substituent. The number of carbon atoms in the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 to 6, more preferably 3 or less, and further preferably a methyl group or an ethyl group.

[0410] R 31 and R 32 may be the same or different, but all R 31 and R 32 are preferably the same group.

[0411] (Ar d18 ) Ar in Scheme 2B d18 are each independently an aromatic hydrocarbon group or an aromatic heterocyclic group. d18 is preferably an aromatic hydrocarbon group from the viewpoint of stability, more preferably a phenyl group. These groups may further have a substituent or a crosslinking group. The substituent that may be had is preferably a group selected from the above-mentioned group Z of substituents or a crosslinking group. When a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned group T of crosslinking groups.

[0412] From the viewpoint of distributing the LUMO of the molecule, Ar 55As the structure, a structure selected from the above a-1 to a-4, b-1 to b-9, c-1 to c-4, d-1 to d-18, and e-1 to e-4 is preferred. Furthermore, from the viewpoint of promoting the broadening of the LUMO of the molecule by having an electron-withdrawing group, a structure selected from a-1 to a-4, b-1 to b-9, d-1 to d-12, d-17, d-18, and e-1 to e-4 is preferred. Furthermore, from the viewpoint of a high triplet level and the effect of confining excitons formed in the light-emitting layer, a structure selected from a-1 to a-4, d-1 to d-12, d-17, d-18, and e-1 to e-4 is preferred. Furthermore, from the viewpoint of easy synthesis and excellent stability, d-1, d-10, d-17, d-18, and e-1 are more preferred, and the benzene ring structure of d-1, the fluorene structure of d-6, and the carbazole structure of d-17 are particularly preferred.

[0413] Ar 55 In the case of a fluorene structure represented by d-6, a 2-fluorenyl group is preferred. Furthermore, the 9- and 9'-positions may have substituents, and the substituents that may be had are preferably a group selected from the aforementioned group of substituents Z or a crosslinking group. In the case of a crosslinking group, the crosslinking group is preferably a group selected from the aforementioned group of crosslinking groups T. Among these, an alkyl group is preferred as the substituent.

[0414] (Ar 56 ) Ar 56 represents a hydrogen atom or a substituent. 56 When Ar is a substituent, it is not particularly limited, but is preferably an aromatic hydrocarbon group, an aromatic heterocyclic group, or a bridging group, and in the case of an aromatic hydrocarbon group or an aromatic heterocyclic group, it may further have a substituent selected from the substituent group Z or a bridging group. 56 When is a crosslinking group, it is preferably a crosslinking group selected from the group T of crosslinking groups.

[0415] Ar 56 is a substituent, in formula (51), Ar 56 From the viewpoint of improving durability, it is preferable that Ar be bonded to the 3-position of the carbazole structure to which Ar is bonded. 56is preferably a hydrogen atom from the viewpoint of ease of synthesis and charge transport properties. 56 From the viewpoint of improving durability and charge transportability, is preferably an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and more preferably an aromatic hydrocarbon group which may have a substituent.

[0416] Ar 56 is preferably a hydrogen atom from the viewpoint of ease of synthesis and charge transport properties.

[0417] (Specific examples of the group represented by formula (51)) Specific examples of the group represented by formula (51) are listed below, but the group represented by formula (51) is not limited to these.

[0418] [ka]

[0419] <Group represented by formula (52)>

[0420] [ka]

[0421] (In formula (52), Ar 61 and Ar 62 each independently represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic heterocyclic groups which may have a substituent are linked together directly or via a linking group, Ar 63 ~Ar 65 are each independently a hydrogen atom or a substituent. * indicates the bonding position to the nitrogen atom of the main chain in formula (50).

[0422] Substituents which each aromatic hydrocarbon group may have, substituents which each aromatic heterocyclic group may have, and Ar when it is a substituent 63 ~Ar 65 is preferably a group selected from the above-mentioned substituent group Z or a crosslinking group. The bridging group that each aromatic hydrocarbon group may have, the bridging group that each aromatic heterocyclic group may have, and Ar when it is a bridging group 63 ~Ar 65 is preferably a group selected from the group T of crosslinking groups.

[0423] (Ar 63 ~Ar 65 ) Ar 63 ~Ar 65 are each independently the Ar 56 is the same as: Ar 63 ~Ar 65 is preferably a hydrogen atom.

[0424] (Ar 62 ) Ar 62 is a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic heterocyclic groups which may have a substituent are linked together directly or via a linking group. Preferably, it is a divalent aromatic hydrocarbon group which may have a substituent or a group in which a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked together. Here, the substituent which the aromatic hydrocarbon group may have and the substituent which the aromatic heterocyclic group may have are preferably the same groups or crosslinking groups as those in the above-mentioned group Z of substituents. As the crosslinking group which is preferred, a group selected from the above-mentioned group T of crosslinking groups is preferred.

[0425] Ar 62 The specific structure of Ar 54 is the same as:

[0426] Ar 62Specific preferred groups are divalent groups of a benzene ring, a naphthalene ring, an anthracene ring, or a fluorene ring, or a group in which multiple such groups are linked together, more preferably a divalent group of a benzene ring or a group in which multiple such groups are linked together, particularly preferably a 1,4-phenylene group in which benzene rings are linked together at the 1- and 4-positions, a 2,7-fluorenylene group in which fluorene rings are linked together at the 2- and 7-positions, or a group in which multiple such groups are linked together, and most preferably a group containing "1,4-phenylene group-2,7-fluorenylene group-1,4-phenylene group-".

[0427] Ar 62 In these preferred structures, the phenylene group does not have a substituent or a bridging group other than at the linking position, which is advantageous in that the steric effect of the substituents on Ar 62 This is preferred because it does not cause twisting. Furthermore, it is preferred that the fluorenylene group has substituents at the 9,9'-positions from the viewpoint of improving solubility and durability of the fluorene structure. The substituents are preferably substituents or crosslinking groups selected from the above-mentioned substituent group Z, and among these, alkyl groups are more preferred. These substituents may be further substituted with a crosslinking group. The crosslinking group is preferably a crosslinking group selected from the above-mentioned crosslinking group group T. Preferably, it is a substituent selected from the substituent group Z.

[0428] (Ar 61 ) Ar 61 is the Ar 53 The groups are the same as those shown above, and the preferred structures are also the same.

[0429] (Specific examples of the group represented by formula (52)) Specific examples of the group represented by formula (52) are listed below, but the group represented by formula (52) is not limited to these.

[0430] [ka]

[0431] <Group represented by formula (53)>

[0432] [ka]

[0433] (In formula (53), * represents the bonding position with the nitrogen atom of the main chain of formula (50), Ar 71 represents a divalent aromatic hydrocarbon group, Ar 72 and Ar 73 each independently represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a monovalent group in which two or more groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together directly or via a linking group, and these groups may have a substituent; Ring HA is an aromatic heterocycle containing a nitrogen atom, X 2 , Y 2 each independently represents a carbon atom or a nitrogen atom; X 2 and Y 2 When at least one of is a carbon atom, the carbon atom may have a substituent.

[0434] The above-mentioned optional substituent is preferably a group or a crosslinking group selected from the above-mentioned group Z of substituents. When a crosslinking group is present, the crosslinking group is preferably a group selected from the above-mentioned group T of crosslinking groups.

[0435] <Ar 71 > Ar 71 is the Ar 53 is a group similar to

[0436] Ar 71 As the alkyl group, a group in which 2 to 6 benzene rings which may have a substituent are linked is particularly preferred, and a quaterphenylene group in which 4 benzene rings which may have a substituent are linked is most preferred.

[0437] Also, Ar 71 preferably contains at least one benzene ring linked at the 1,3-position, which is a non-conjugated moiety, and more preferably contains two or more.

[0438] Ar 71 In the case where a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked together, it is preferred that all of them are linked together by direct bonding from the viewpoint of charge transport properties or durability.

[0439] For this reason, Ar 71 As such, preferred structures connecting the nitrogen atom in the main chain of the polymer and the ring HA in the formula (53) are as shown in the following schemes 2-1 and 2-2. "-*" represents the bonding position with the nitrogen atom in the main chain of the polymer or the ring HA in the formula (53). Either of the two "-*"s may be bonded to the nitrogen atom in the main chain of the polymer or to the ring HA.

[0440] [ka]

[0441] Ar 71 The substituents that Ar may have include any one of the substituents in the above-mentioned group Z or a combination thereof. 71 The preferred range of the substituents that may be possessed by Ar 53 is the same as the substituent that may be possessed when it is an aromatic hydrocarbon group.

[0442] <X 2 and Y 2 > X 2 and Y 2 Each of X independently represents a carbon (C) atom or a nitrogen (N) atom. 2 and Y 2 When at least one of them is a C atom, it may have a substituent.

[0443] X is chosen to localize the LUMO more easily around the HA ring. 2 and Y 2 are preferably all N atoms.

[0444] X 2 and Y2 When at least one of X is a C atom, the substituent that may be present may be any one of the substituents in the above-mentioned group Z or a combination thereof. 2 and Y 2 More preferably, has no substituent.

[0445] <Ar 72 and Ar 73 > Ar 72 and Ar 73 are each independently an aromatic hydrocarbon group, an aromatic heterocyclic group, or a monovalent group in which two or more groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together directly or via a linking group. These groups may have a substituent, and the optional substituent is preferably a group selected from the aforementioned group Z of substituents or a crosslinking group. When a crosslinking group is present, the crosslinking group is preferably a group selected from the aforementioned group T of crosslinking groups.

[0446] From the viewpoint of distributing the LUMO of the molecule, Ar 72 and Ar 73 each independently has a structure selected from a-1 to a-4, b-1 to b-9, c-1 to c-4, d-1 to d-16, and e-1 to e-4 shown in Schemes 2A to 2C. Furthermore, from the viewpoint of promoting the broadening of the LUMO of the molecule by having an electron-withdrawing group, structures selected from a-1 to a-4, b-1 to b-9, c-1 to c-4, d-1 to d-12, and e-1 to e-4 are preferred. Furthermore, from the viewpoint of a high triplet level and the effect of confining excitons formed in the light-emitting layer, structures selected from a-1 to a-4, d-1 to d-12, and e-1 to e-4 are preferred. In order to prevent aggregation of molecules, structures selected from d-1 to d-12 and e-1 to e-4 are more preferred. 72 =Ar 73 = d-1 or d-10 is preferred, and the benzene ring structure of d-1 is particularly preferred. These structures may also have a substituent.

[0447] (Specific examples of the group represented by formula (53)) Specific examples of the group represented by formula (53) are listed below, but the group represented by formula (53) is not limited to these.

[0448] [ka]

[0449] (Preferred repeating unit represented by formula (50)) The repeating unit represented by the formula (50) preferably has a repeating unit represented by any one of the following formulas (54) to (57) or (60). It is more preferable that the repeating unit represented by the formula (50) is a repeating unit represented by the following formula (54).

[0450] <Repeating unit represented by formula (54)>

[0451] [ka]

[0452] (In formula (54), Ar 51 represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; X is -C(R 207 )(R 208 )-, -N(R 209 )- or -C(R 211 )(R 212 )-C(R 213 )(R 214 )- and R 201 , R 202 , R 221 and R 222 each independently represents an alkyl group which may have a substituent, R 207 ~R 209 and R 211 ~R214 each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aromatic hydrocarbon group, a and b each independently represent an integer of 0 to 4, c is an integer from 0 to 3, d is an integer from 0 to 4, i and j are each independently an integer of 0 to 3.

[0453] (R 201 , R 202 , R 221 , R 222 ) R in the repeating unit represented by the above formula (54) 201 , R 202 , R 221 and R 222 R is an alkyl group which may have a substituent. 201 , R 202 , R 221 and R 222 It is preferred that the group has no substituent.

[0454] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, it is preferably 1 or more, and is preferably 8 or less, more preferably 6 or less, and even more preferably 3 or less. The alkyl group is more preferably a methyl group or an ethyl group.

[0455] R 201 If there are multiple R 201 may be the same or different, and R 202 If there are multiple R 202 may be the same or different. Since the charge can be uniformly distributed around the nitrogen atom and synthesis is easy, all R 201 and R 202 are preferably the same group.

[0456] R 221 If there are multiple R221 may be the same or different, and R 222 If there are multiple R 222 may be the same or different. For ease of synthesis, all R 221 and R 222 are preferably the same group.

[0457] (R 207 ~R 209 and R 211 ~R 214 ) R 207 ~R 209 and R 211 ~R 214 R are each independently a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aromatic hydrocarbon group which may have a substituent. 207 ~R 209 and R 211 ~R 214 It is preferred that the group has no substituent.

[0458] The alkyl group is not particularly limited, but since this tends to improve the solubility of the polymer, the number of carbon atoms is preferably 1 or more, and is preferably 24 or less, more preferably 8 or less, and even more preferably 6 or less. The alkyl group may have a linear, branched, or cyclic structure.

[0459] 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 sec-butyl group, a tert-butyl group, an n-hexyl group, an n-octyl group, a cyclohexyl group, and a dodecyl group.

[0460] The aralkyl group is not particularly limited, but preferably has 5 or more carbon atoms, and preferably 60 or less, more preferably 40 or less, since this tends to improve the solubility of the polymer.

[0461] Specific examples of the aralkyl group include a 1,1-dimethyl-1-phenylmethyl group, a 1,1-di(n-butyl)-1-phenylmethyl group, a 1,1-di(n-hexyl)-1-phenylmethyl group, a 1,1-di(n-octyl)-1-phenylmethyl group, a phenylmethyl group, a phenylethyl group, a 3-phenyl-1-propyl group, a 4-phenyl-1-n-butyl group, a 1-methyl-1-phenylethyl group, a 5-phenyl-1-n-propyl group, a 6-phenyl-1-n-hexyl group, a 6-naphthyl-1-n-hexyl group, a 7-phenyl-1-n-heptyl group, an 8-phenyl-1-n-octyl group, and a 4-phenylcyclohexyl group.

[0462] The aromatic hydrocarbon group is not particularly limited, but preferably has 6 or more carbon atoms, and preferably 60 or less, more preferably 30 or less, since this tends to improve the solubility of the polymer.

[0463] Specific examples of the aromatic hydrocarbon group include monovalent groups of 6-membered monocyclic rings or 2 to 5 condensed rings, such as a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring, or groups in which multiple of these are linked together.

[0464] From the viewpoint of improving charge transport properties and durability, R 207 and R 208 is preferably a methyl group or an aromatic hydrocarbon group, and R 207 and R 208 is more preferably a methyl group, and R 209 is more preferably a phenyl group.

[0465] R 201 , R 202 , R 221 , R 222 alkyl group, R 207 ~R 209 and R 211 ~R 214The alkyl group, aralkyl group and aromatic hydrocarbon group may have a substituent. 207 ~R 209 and R 211 ~R 214 Examples of the alkyl group, aralkyl group and aromatic hydrocarbon group include the groups or crosslinking groups mentioned above as preferred groups. Examples of the crosslinking group include crosslinking groups selected from the group T of crosslinking groups.

[0466] R 201 , R 202 , R 221 , R 222 alkyl group, R 207 ~R 209 and R 211 ~R 214 From the viewpoint of reducing the voltage, it is most preferable that the alkyl group, aralkyl group and aromatic hydrocarbon group have no substituent.

[0467] When a crosslinking group is bonded to the main chain structure of the repeating unit represented by formula (54), the crosslinking group is an alkyl group, an aralkyl group, or an aromatic hydrocarbon group, and R 207 ~R 209 , R 211 ~R 213 , or R 214 It is preferred that the hydroxyl group is bonded to the hydroxyl group.

[0468] (a, b, c and d) In the repeating unit represented by the above formula (54), a and b each independently represent an integer of 0 to 4. a+b is preferably 1 or greater, and each of a and b is preferably 2 or less, with both a and b being more preferably 1. When b is 1 or greater, d is also 1 or greater. When c is 2 or greater, multiple a's may be the same or different, and when d is 2 or greater, multiple b's may be the same or different.

[0469] When a+b is 1 or more, the aromatic rings in the main chain are twisted due to steric hindrance, the polymer has excellent solubility in solvents, and the coating film formed by a wet film-forming method and heat-treated tends to have excellent insolubility in solvents. Therefore, when a+b is 1 or more, when another organic layer (e.g., a light-emitting layer) is formed on this coating film by a wet film-forming method, the polymer is prevented from eluting into a composition for forming the other organic layer, which contains an organic solvent.

[0470] In the repeating unit represented by the above formula (54), c is an integer of 0 to 3, and d is an integer of 0 to 4. It is preferable that c and d are each 2 or less, more preferably c and d are equal, and particularly preferably that both c and d are 1 or both c and d are 2.

[0471] In the repeating unit represented by the above formula (54), when both c and d are 1 or both c and d are 2, and both a and b are 2 or 1, R 201 and R 202 are most preferably bonded at positions symmetrical to each other.

[0472] where R 201 and R 202 and are bonded at positions symmetric to each other means that R 201 and R 202 In this case, a 180-degree rotation around the main chain is considered to be the same structure.

[0473] R 221 and R 222 When present, each of R is preferably independently located at the 1st, 3rd, 6th, or 8th position relative to the carbon atom of the benzene ring to which X is bonded. 221 and / or R 222 The existence of R 221 and / or R 222is bonded to a fused ring and the adjacent benzene ring on the main chain are twisted due to steric hindrance, and the polymer has excellent solubility in solvents, and a coating film formed by a wet film-forming method and heat-treated tends to have excellent insolubility in solvents, which is preferable.

[0474] (i, j) In the repeating unit represented by the above formula (54), i and j are each independently an integer of 0 to 3. i and j are each independently preferably an integer of 0 to 2, more preferably 0 or 1. i and j are preferably the same integer. i and j are preferably 1 or 2 in order to twist the main chain of the polymer, and R 221 and / or R 222 is preferably bonded to the 1st and / or 3rd positions of the benzene ring. From the viewpoint of ease of synthesis, it is preferable that i and j are 0. The bonding position of the benzene ring is the carbon atom adjacent to the carbon atom to which X is bonded, and R 221 or R 222 The carbon atom to which the molecule can be bonded is the first position, and the carbon atom that is bonded to the adjacent structure as the main chain is the second position.

[0475] (X) X in the above formula (54) is -C(R 207 )(R 208 )-, -N(R 209 )- or -C(R 211 )(R 212 )-C(R 213 )(R 214 )-. X is -C(R 207 )(R 208 )- or -N(R 209 )-, and -C(R 207 )(R 208 )- is more preferred.

[0476] (Preferred repeating unit) The repeating unit represented by the above formula (54) is particularly preferably a repeating unit represented by any one of the following formulae (54-1) to (54-8).

[0477] [ka]

[0478] [ka]

[0479] In the above formula, R 201 and R 202 are identical and R 201 and R 202 are bonded at symmetric positions to each other.

[0480] <Preferable examples of the main chain of the repeating unit represented by formula (54)> The main chain structure excluding the nitrogen atom in the above formula (54) is not particularly limited, but for example, the following structure is preferred.

[0481] [ka]

[0482] [ka]

[0483] [ka]

[0484] [ka]

[0485] [ka]

[0486] [ka]

[0487] [ka]

[0488] [ka]

[0489] <Repeating unit represented by formula (55)>

[0490] [ka]

[0491] (In formula (55), Ar 51 is Ar in the formula (54). 51 is the same as R 303 and R 306 each independently represents an alkyl group which may have a substituent, R 304 and R 305 each independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group, l is 0 or 1; m is 1 or 2; n is 0 or 1, p is 0 or 1; q is 0 or 1.

[0492] (R 303 , R 306 ) R in the repeating unit represented by the above formula (55) 303 and R 306 are each independently an alkyl group which may have a substituent.

[0493] The alkyl group is R in the formula (54). 201 and R 202The substituents that may be present and preferred structures are the same as those of R 201 and R 202 The same can be mentioned.

[0494] R 303 If there are multiple R 303 may be the same or different, and R 306 If there are multiple R 306 may be the same or different.

[0495] (R 304 , R 305 ) R in the repeating unit represented by the above formula (55) 304 and R 305 are each independently an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group, preferably an optionally substituted alkyl group. R 304 and R 304 are preferably the same.

[0496] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 or more, and is preferably 24 or less, more preferably 8 or less, and even more preferably 6 or less, since this tends to improve the solubility of the polymer.

[0497] 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 sec-butyl group, a tert-butyl group, an n-hexyl group, an n-octyl group, a cyclohexyl group, and a dodecyl group.

[0498] The alkoxy group is not particularly limited, and may be an alkoxy group (—OR 10 )R 10The alkyl group represented by the formula (I) may have any of a linear, branched, or cyclic structure, and since this tends to improve the solubility of the polymer, the number of carbon atoms is preferably 1 or more, and is preferably 24 or less, and more preferably 12 or less.

[0499] Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a hexyloxy group, a 1-methylpentyloxy group, and a cyclohexyloxy group.

[0500] The aralkyl group is not particularly limited, but preferably has 5 or more carbon atoms, and preferably has 60 or less carbon atoms, and more preferably has 40 or less carbon atoms, since this tends to improve the solubility of the polymer.

[0501] Specific examples of the aralkyl group include a 1,1-dimethyl-1-phenylmethyl group, a 1,1-di(n-butyl)-1-phenylmethyl group, a 1,1-di(n-hexyl)-1-phenylmethyl group, a 1,1-di(n-octyl)-1-phenylmethyl group, a phenylmethyl group, a phenylethyl group, a 3-phenyl-1-propyl group, a 4-phenyl-1-n-butyl group, a 1-methyl-1-phenylethyl group, a 5-phenyl-1-n-propyl group, a 6-phenyl-1-n-hexyl group, a 6-naphthyl-1-n-hexyl group, a 7-phenyl-1-n-heptyl group, an 8-phenyl-1-n-octyl group, and a 4-phenylcyclohexyl group.

[0502] R 304 , R 305 The substituents that the alkyl group, alkoxy group, and aralkyl group may have are as defined above in R 207 ~R 209 and R 211 ~R 214 Examples of the crosslinking group include those groups exemplified as preferred groups of the alkyl group, aralkyl group and aromatic hydrocarbon group in the above formula (1) or a crosslinking group. Examples of the crosslinking group include those selected from the group T of crosslinking groups.

[0503] R 304 , R 305From the viewpoint of reducing voltage, it is most preferable that the alkyl group, alkoxy group and aralkyl group have no substituent.

[0504] When a crosslinking group is bonded to the main chain structure of the repeating unit represented by formula (55), the crosslinking group is R 304 and R 305 It is preferred that the hydroxyl group is bonded to the hydroxyl group.

[0505] (l, m and n) l represents 0 or 1; n represents 0 or 1;

[0506] Each of l and n is independently preferably 1 or more, more preferably 1 or 2, and even more preferably 2. When l+n is within the above range, the solubility of the polymer is increased, and precipitation from the composition according to the embodiment of the present invention containing the polymer tends to be suppressed.

[0507] m represents 1 or 2, and is preferably 1 because the organic electroluminescent device produced using the composition according to the embodiment of the present invention can be driven at a low voltage and tends to have improved hole injection ability, transport ability, and durability.

[0508] (p and q) p represents 0 or 1, and q represents 0 or 1. When l = n = 1, p and q cannot be 0 at the same time. When p and q are not 0 at the same time, the solubility of the polymer is increased, and precipitation from the composition according to the embodiment of the present invention containing the polymer tends to be suppressed. Furthermore, for the same reasons as in a and b above, when p + q is 1 or more, the aromatic rings of the main chain are twisted due to steric hindrance, and the polymer has excellent solubility in solvents, and a coating film formed by a wet film-forming method and heat-treated tends to have excellent insolubility in solvents. Therefore, when p + q is 1 or more, when another organic layer (e.g., a light-emitting layer) is formed on this coating film by a wet film-forming method, elution of the polymer into the composition for forming the other organic layer, which contains an organic solvent, is suppressed.

[0509] <Specific examples of the main chain of the repeating unit represented by formula (55)> The main chain structure excluding the nitrogen atom in formula (55) is not particularly limited, but examples thereof include the following structures.

[0510] [ka]

[0511] [ka]

[0512] [ka]

[0513] [ka]

[0514] [ka]

[0515] [ka]

[0516] [ka]

[0517] [ka]

[0518] <Repeating unit represented by formula (56)>

[0519] [ka]

[0520] (In formula (56), Ar 51 is Ar in the formula (54). 51 is the same as Ar 41 represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked together directly or via a linking group; R 441 and R 442 each independently represents an alkyl group which may have a substituent, t is 1 or 2; u is 0 or 1; r and s each independently represent an integer of 0 to 4.

[0521] (R 441 , R 442 ) R in the repeating unit represented by the above formula (56) 441 and R 442 are each independently an alkyl group which may have a substituent.

[0522] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 or more, and is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The alkyl group is more preferably a methyl group or a hexyl group.

[0523] R 441 and R 442 When there are a plurality of R 441 and R 442 may be the same or different.

[0524] (r, s, t and u) In the repeating unit represented by formula (56), r and s each independently represent an integer of 0 to 4. When t is 2, the multiple r's may be the same or different. r+s is preferably 1 or greater, and each of r and s is preferably 2 or less. When r+s is 1 or greater, the operating life of the organic electroluminescent device is thought to be further extended for the same reasons as for a and b in formula (54).

[0525] In the repeating unit represented by the above formula (56), t is 1 or 2, and u is 0 or 1. t is preferably 1, and u is preferably 1.

[0526] (Ar 41 ) Ar 41 is a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked together directly or via a linking group.

[0527] Ar 41 The aromatic hydrocarbon group in the formula (50) is preferably Ar 52 The aromatic hydrocarbon group and the substituents which the aromatic hydrocarbon group may have are preferably groups selected from the aforementioned substituent group Z, and the substituents which the aromatic hydrocarbon group may further have are also preferably the same as those in the aforementioned substituent group Z.

[0528] <Repeating unit represented by formula (57)>

[0529] [ka]

[0530] (In formula (57), Ar 51 is Ar in the formula (54). 51 is the same as R 517 ~R 519each independently represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; f, g, and h each independently represent an integer of 0 to 4; e represents an integer of 0 to 3; However, if g is 1 or greater, e is 1 or greater.)

[0531] (R 517 ~R 519 ) R 517 ~R 519 R each independently represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. 517 ~R 519 The aromatic hydrocarbon group and aromatic heterocyclic group in each of the Ar 51 The substituents that these groups may have are preferably the substituent group Z or crosslinking groups, and the crosslinking groups are preferably crosslinking groups selected from the crosslinking group T.

[0532] R 517 ~R 519 The alkyl group and aralkyl group in the R 207 The substituents which may further be contained are the same as those listed in R 207 Groups similar to the following are preferred.

[0533] R 517 ~R 519 The alkoxy group in the formula (I) is preferably the alkoxy group exemplified in the above-mentioned substituent group Z, and the substituent that may further be possessed is preferably the alkoxy group exemplified in the above-mentioned substituent group Z.

[0534] (e, f, g, h) f, g, and h each independently represent an integer of 0 to 4, and e represents an integer of 0 to 3, provided that when g is 1 or greater, e is 1 or greater. When e is 2 or more, multiple g's may be the same or different. It is preferable that f+g+h is 1 or more. f+h is preferably 1 or greater, It is more preferable that f+h is 1 or more, and f, g, and h are 2 or less. It is more preferable that f+h is 1 or more, and f and h are 1 or less, Most preferably, f and h are both 1.

[0535] When f and h are both 1, R 517 and R 519 are preferably bonded at positions symmetrical to each other. Also, R 517 and R 519 are preferably the same as

[0536] More preferably, g is 2. If g is 2, then two R 518 are most preferably linked to each other in the para position, If g is 2, then two R 518 are most preferably the same.

[0537] where R 517 and R 519 are bonded at positions symmetrical to each other, the bond positions shown below are used. However, for the purposes of notation, a 180-degree rotation around the main chain axis is considered to be the same structure.

[0538] [ka]

[0539] When the polymer according to the embodiment of the present invention contains repeating units represented by formula (54) and repeating units represented by formula (57), the ratio of repeating units represented by formula (54) to repeating units represented by formula (57), i.e., (number of moles of repeating units represented by formula (57)) / (number of moles of repeating units represented by formula (54)), is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, even more preferably 0.9 or more, and particularly preferably 1.0 or more. Furthermore, this ratio is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0540] The repeating unit represented by the formula (57) is preferably a repeating unit represented by the following formula (58).

[0541] [ka]

[0542] (In formula (58), Ar 51 is Ar in the formula (54). 51 is similar to R 517 ~R 519 , f, g, h, and e are R in the formula (57) 517 ~R 519 , f, g, h, e.)

[0543] In the case of the repeating unit represented by the formula (58), it is preferable that g=0 or 2. When g=2, the bonding positions are the 2nd and 5th positions. When g=0, that is, R 518 When there is no steric hindrance due to the presence of two R 518 When the bond is diagonal to the benzene ring, R 517 and R 519 and can be bonded at positions symmetrical to each other.

[0544] Furthermore, the repeating unit represented by the formula (58) is more preferably a repeating unit represented by the following formula (59) in which e=3.

[0545] [ka]

[0546] (In formula (59), Ar 51 is Ar in the formula (54). 51 is similar to R 517 ~R 519 , f, g, and h are R in the formula (57) 517 ~R 519 , f, g, h.)

[0547] In the case of the repeating unit represented by the formula (59), g is preferably 0 or 2. When g is 2, the bonding positions are the 2- and 5-positions. When g is 0, that is, R 518 When there is no steric hindrance due to g = 2 and the bonding positions are 2 and 5, that is, when there is no steric hindrance due to two R 518 When the bond is diagonal to the benzene ring, R 517 and R 519 and can be bonded at positions symmetrical to each other.

[0548] <Specific examples of the main chain of the repeating unit represented by formula (57)> The main chain structure of the repeating unit represented by formula (57) is not particularly limited, but examples thereof include the following structures.

[0549] [ka]

[0550] The repeating units represented by the above formulas (50) to (59) preferably do not have a crosslinking group. When a crosslinking group is not present, polymer chain distortion is less likely to occur upon heat drying or baking (heat baking) after wet film formation, which is preferable. This is because a volume change may occur when the crosslinking group reacts, resulting in polymer chain distortion. Furthermore, polymer chain distortion may occur even when no volume change occurs.

[0551] <Repeating unit represented by formula (60)>

[0552] [ka]

[0553] (In formula (60), Ar 51 is Ar in the formula (50). 51 is the same as n 60 represents an integer from 1 to 5.)

[0554] (n 60 ) n 60 represents an integer of 1 to 5, preferably an integer of 1 to 4, and more preferably an integer of 1 to 3.

[0555] (Twisted structure that inhibits conjugation) When the functional material used in the composition according to an embodiment of the present invention is a polymer having a repeating unit represented by formula (50), the repeating unit represented by formula (50) is more preferably a repeating unit represented by formula (54), a repeating unit represented by formula (55), a repeating unit represented by formula (56), or a repeating unit represented by formula (57), and particularly preferably a repeating unit represented by formula (54). Furthermore, the partial structure represented by formula (63) is preferably a partial structure represented by the following formula (61) or (61'): Therefore, the repeating unit represented by formula (50) is more preferably a repeating unit represented by formula (54) containing a partial structure represented by formula (61) or formula (61′) below as a main chain structure, a repeating unit represented by formula (55) containing a partial structure represented by formula (61) or formula (61′) below as a main chain structure, a repeating unit represented by formula (56) containing a partial structure represented by formula (61) or formula (61′) below as a main chain structure, or a repeating unit represented by formula (57) containing a partial structure represented by formula (61) or formula (61′) below as a main chain structure, and particularly preferably a repeating unit represented by formula (54) containing a partial structure represented by formula (61) or formula (61′) below as a main chain structure.

[0556] [ka]

[0557] (In formula (61) and formula (61'), R 601 is R in equation (54) 201 or R 202 , R in Eq. (55) 303 , R 304 , R 305 , or R 406 , R in Eq. (56) 441 or R 442 , R in Eq. (57) 517 , R 518 or R 519 and -* indicates the bond position with the adjacent atom. When formula (61) is a partial structure of formula (54) or a partial structure of formula (56), Ring B may be part of a fused ring. When formula (61') is a partial structure of formula (54) or a partial structure of formula (56), Ring B may be part of a fused ring. The partial structures represented by formula (61) and formula (61') are R 601 In addition, when Ring A and Ring B are a partial structure of formula (54), R 201 or R 202 , if it is a partial structure of formula (55), R 303 , R 304 , R 305 , or R 306 , if it is a partial structure of formula (56), R 441 or R 442 , if it is a partial structure of formula (57), R 517 , R 518 or R 519 It may have.)

[0558] (Formula (62)) Particularly preferred as the repeating unit represented by formula (50) is a polymer containing a repeating unit represented by formula (62) below, which is a repeating unit represented by formula (54) containing a partial structure represented by formula (61) or formula (61') as a main chain structure.

[0559] [ka]

[0560] (In formula (62), Ar 51 , X, R 201 , R 202 , R 221 , R 222 , a, b, c, and d are Ar in the formula (54). 51 , X, R 201 , R 202 , R 221 , R 222 , a, b, c, d are the same, a 1 , a 2 , b1 , b 2 , i 1 , i 2 , j 1 , j 2 are each independently 0 or 1. However, either of the following conditions (1) or (2) must be met. (1)a 1 , a 2 and at least one of a is 1 or greater; b 1 , b 2 and at least one of b is 1 or greater; c is 1 or greater and d is 1 or greater; If c is 1, then a 1 or a 2 At least one of is 1, If d is 1, then b 1 or b 2 At least one of them is 1. (2)i 1 , i 2 , j 1 and j 2 At least one of is 1. Ring A1 is R 201 and Ring A2 is R 201 a divalent group in which c-1 benzene rings are linked, which may have the formula: Ring A3 refers to a divalent fused ring in which a biphenyl structure is further bonded via X. Ring A4 is R 202 wherein d-1 benzene rings are linked together, and when d=1, the group is a monocyclic divalent benzene ring; Ring A5 is R 202 It refers to a divalent benzene ring which may have

[0561] Here, a in formula (54) being 1 or more means that a 1 , a 2and a are equal to or greater than 1, and b being equal to or greater than 1 in formula (54) means that b 1 , b 2 and at least one of b is equal to or greater than 1.)

[0562] As shown below, the formula (62) contains the formula (61) or the formula (61') as a partial structure. a 1 , a 2 and at least one of a is 1 or greater, a 1 or a 2 When at least one of the above is 1, if c is 2 or more, Ring A1 and Ring A2 are connected, and when c is 1, Ring A1 and Ring A3 are connected. When a is 1, Ring A2 and Ring A1, or Ring A2 and Ring A3, contain the formula (61) or the formula (61') as a partial structure. Similarly, b 1 , b 2 It can be seen that when at least one of a and b is 1 or more, the formula (61) or (61') is included as a partial structure. Also, i 1 , i 2 , j 1 and j 2 If at least one of is 1, i 1 and i 2 If one or both of these are 1, then R of Ring A3 221 The ring to which is bonded and the benzene ring of Ring A2 form a partial structure represented by formula (61'), j 1 and j 2 If one or both of these are 1, then R of Ring A3 222 It can be seen that the ring to which is bonded and the benzene ring of Ring A4 form the partial structure of formula (61). That is, it can be seen that Ring A3 and Ring A2, or Ring A3 and Ring A4, have a twisted structure. Therefore, formula (62) is preferable because the aromatic ring of the main chain has a twisted structure that inhibits conjugation.

[0563] <Substituents of repeating units> From the viewpoint of hole transporting property, Ar in the formula (54) to the formula (57) or the formula (60) 51 , R 201 , R 202 , R 221 , R 222 , R 207 ~R 209 , R 211 ~R 214 is R 303 ~R 306 , R 441 , R 442 , R 517 ~R 519 It is preferable that none of the groups has a substituent.

[0564] [Molecular weight of polymer] The molecular weight of the polymer contained in the composition according to the embodiment of the present invention will be described below.

[0565] The weight-average molecular weight (Mw) of the polymer having the above-mentioned arylamine structure as a repeating unit is usually 1,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, even more preferably 70,000 or less, and particularly preferably 50,000 or less. The weight-average molecular weight is usually 5,000 or more, preferably 10,000 or more, even more preferably 12,000 or more, and particularly preferably 15,000 or more.

[0566] When the weight-average molecular weight of the polymer having the above-mentioned arylamine structure as a repeating unit is not more than the upper limit, the polymer tends to be soluble in solvents and have excellent film-forming properties.Furthermore, when the weight-average molecular weight of the polymer is not less than the lower limit, the polymer's glass transition temperature, melting point, and vaporization temperature are prevented from decreasing, and heat resistance may be improved.In addition, the coating film after the crosslinking reaction may have sufficient insolubility in organic solvents.

[0567] The number average molecular weight (Mn) of the polymer having the above-mentioned arylamine structure as a repeating unit is usually 750,000 or less, preferably 250,000 or less, more preferably 100,000 or less, and particularly preferably 50,000 or less, and is usually 2,000 or more, preferably 4,000 or more, more preferably 6,000 or more, and even more preferably 8,000 or more.

[0568] Furthermore, the dispersity (Mw / Mn) of the polymer having the above-mentioned arylamine structure as a repeating unit is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. Since the smaller the dispersity value, the better, the lower limit is ideally 1. When the dispersity of the polymer is the above-mentioned upper limit or less, purification is easy and the solubility in solvents and charge transport ability are good.

[0569] The weight-average molecular weight and number-average molecular weight of a polymer are usually determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the higher the molecular weight component, the shorter the elution time, and the lower the molecular weight component, the longer the elution time. The weight-average molecular weight and number-average molecular weight are calculated by converting the elution time of the sample into molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) with known molecular weight.

[0570] (Content of repeating unit represented by formula (50)) In the polymer, the content of the repeating unit represented by formula (50) is not particularly limited, but the repeating unit represented by formula (50) is usually contained in an amount of 10 mol % or more, preferably 30 mol % or more, more preferably 40 mol % or more, and even more preferably 50 mol % or more, based on 100 mol % of all repeating units in the polymer.

[0571] The polymer may be composed solely of the repeating unit represented by formula (50), but for the purpose of balancing various performances when made into an organic electroluminescent device, the polymer may contain a repeating unit other than the repeating unit represented by formula (50). In this case, the content of the repeating unit represented by formula (50) in the polymer is usually 99 mol % or less, preferably 95 mol % or less.

[0572] <Repeating unit represented by formula (50-2)> In an embodiment of the present invention, the polymer having an arylamine structure represented by formula (50) as a repeating unit may further contain a structure represented by the following formula (50-2) as a linking group.

[0573] [ka]

[0574] (In the formula, R 81 , R 83 R each independently represents a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. 81 , R 83 When there are multiple p, they may be the same or different. 80 represents an integer from 1 to 5.)

[0575] R 81 , R 83 When is an alkyl group, the alkyl group may be a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, it is preferably 1 or more, and is preferably 8 or less, more preferably 6 or less, and even more preferably 3 or less. The alkyl group is more preferably a methyl group or an ethyl group.

[0576] R 81 , R 83 When is an aromatic hydrocarbon group or an aromatic heterocyclic group, the structures described above in the "Definition" section are preferred.

[0577] R81 , R 83 may have a substituent. The substituent is preferably a substituent or a crosslinking group selected from the above-mentioned group Z of substituents. In the case of a crosslinking group, it is preferably a crosslinking group selected from the above-mentioned group T of crosslinking groups.

[0578] From the viewpoint of polymer durability and charge transport property, 80 is preferably 3 or less, more preferably 2 or less, and most preferably 1.

[0579] By including the structure represented by formula (50-2), the conjugation of the main chain of the polymer is broken, and the S1 energy level and the T1 energy level of the polymer are increased. When a composition containing this polymer is used in a hole transport layer of an organic electroluminescent device, it is thought that excitons in the light-emitting layer are less likely to be deactivated, and the light-emitting efficiency is increased, which is preferable.

[0580] (Preferable repeating unit structure of polymer) Here, the specific structure of the repeating unit represented by each formula is referred to as the "repeating unit structure." The specific structure is a structure obtained by substituting specific structures or numerical values ​​for all symbols in the general formula. That is, a polymer having an arylamine structure as a repeating unit may contain only one repeating unit structure among the repeating unit structures represented by formula (54), the repeating unit structure represented by formula (55), the repeating unit structure represented by formula (56), the repeating unit structure represented by formula (57), and the repeating unit structure represented by formula (60), or may contain two or more repeating unit structures. When two or more repeating unit structures are contained, these two or more repeating units may be repeating unit structures represented by the same general formula or repeating unit structures represented by different general formulas. From the viewpoint of charge transport properties and durability, it is more preferable that the polymer having an arylamine structure as a repeating unit is a polymer that contains one or two of the specific repeating unit structures represented by each of these formulas and does not contain any other repeating unit structures.

[0581] [Specific example] Specific examples of the polymer are shown below, but the polymer is not limited to these. The numbers in the chemical formulas represent the molar ratio of the repeating units. These polymers may be any of random copolymers, alternating copolymers, block copolymers, graft copolymers, etc., and there are no limitations on the sequence of the monomers.

[0582] [ka]

[0583] [ka]

[0584] [ka]

[0585] <Method of producing polymer> The method for producing the polymer contained in the composition according to the embodiment of the present invention is not particularly limited and can be any method. For example, a polymerization method using the Suzuki reaction, a polymerization method using the Grignard reaction, a polymerization method using the Yamamoto reaction, a polymerization method using the Ullmann reaction, a polymerization method using the Buchwald-Hartwig reaction, etc. can be mentioned. In addition, it can be produced by a production method similar to the production method for the polymer described in WO 2019 / 177175, WO 2020 / 171190, and WO 2021 / 125011.

[0586] In the polymerization method using the Ullmann reaction and the polymerization method using the Buchwald-Hartwig reaction, for example, a polymer containing a repeating unit represented by the formula (54) is synthesized by reacting an aryl dihalide represented by the following formula (2a) (Z represents a halogen atom such as I, Br, Cl, or F) with a primary amino aryl represented by the following formula (2b).

[0587] [ka]

[0588] (In the above reaction scheme, Ar 51 , R 201 , R 202 , X, and a to d are defined as in the formula (54).

[0589] In the case of the polymerization method using the Ullmann reaction and the polymerization method using the Buchwald-Hartwig reaction, for example, a polymer containing a repeating unit represented by the formula (55) is synthesized by reacting an aryl dihalide represented by the following formula (3a) (Z represents a halogen atom such as I, Br, Cl, or F) with a primary aminoaryl represented by the following formula (3b).

[0590] [ka]

[0591] (In the above reaction scheme, Ar 51 , R 303 ~R 306 , n, m, l, p, and q are defined as in the formula (55).

[0592] In the above polymerization method, the reaction for forming the N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, sodium tert-butoxide, or triethylamine. It can also be carried out in the presence of a transition metal catalyst such as a copper or palladium complex.

[0593] [Charge-transporting ionic compounds] The hole injection layer of the organic electroluminescent device according to the embodiment of the present invention preferably contains a charge transporting ionic compound in which the tetraarylborate ion and the cation radical of the hole transport material are ionically bonded. Alternatively, the hole injection layer of the organic electroluminescent element according to the embodiment of the present invention preferably contains a crosslinked product of an electron-accepting compound having a crosslinking group, and the electron-accepting compound preferably contains a charge-transporting ionic compound in which the tetraarylborate ion and a cation radical of a hole-transporting material are ionically bonded. For example, the hole injection layer of the organic electroluminescent device according to the embodiment of the present invention may contain the tetraarylborate ion having a crosslinking group and / or a crosslinked product of the tetraarylborate ion having a crosslinking group.

[0594] It is particularly preferable that the hole injection layer of the organic electroluminescent element according to this embodiment of the present invention contains a charge-transporting ionic compound in which the tetraarylborate ion and a cation radical of a polymer having an arylamine structure represented by formula (50) as a repeating unit are ionically bonded as a hole-transporting material.

[0595] This charge transporting ionic compound can be obtained by any of the following methods. i) The first ionic compound and the hole transport material are dissolved or dispersed in an organic solvent and mixed. ii) The first ionic compound and the hole transport material are dissolved or dispersed in an organic solvent, mixed, and then heated. iii) The composition obtained in i) or ii) above is wet-formed into a film, and the film is heated.

[0596] Since the first ionic compound is an electron-accepting compound, the hole transport material is oxidized by the first ionic compound to form a cation radical by any of the above methods, resulting in the generation of a charge-transporting ionic compound, which is an ionic compound having the tetraarylborate ion as a counter anion and the cation radical of the hole transport material as a counter cation.

[0597] The hole injection layer of the organic electroluminescent element according to this embodiment of the present invention preferably contains a first ionic compound containing the tetraarylborate ion as a counter anion and a hole transport material, and more preferably contains a charge transporting ionic compound having the tetraarylborate ion as a counter anion and a cation radical of the hole transport material as a counter cation, from the viewpoint of charge transportability.

[0598] [Hole injection layer forming composition] The hole injection layer of the organic electroluminescent device according to the embodiment of the present invention is preferably obtained by wet film formation of a composition for forming a hole injection layer.

[0599] The composition for forming a hole injection layer is preferably a composition obtained through a step of dissolving or dispersing the first ionic compound having a tetraarylborate ion structure and the hole transport material in an organic solvent. Alternatively, the composition for forming the hole injection layer preferably contains an electron-accepting compound having a crosslinking group and an organic solvent, and more preferably is a composition obtained through a process of dissolving or dispersing the first ionic compound having a tetraarylborate ion structure and the hole transport material in an organic solvent.

[0600] From the viewpoint of obtaining a uniform hole injection layer film, the composition for forming a hole injection layer is preferably a solution in which the first ionic compound and the hole transport material are dissolved in an organic solvent.

[0601] Even if the composition for forming a hole injection layer obtained by the method i) does not contain the charge-transporting ionic compound, it is sufficient that the charge-transporting ionic compound can be obtained by the method ii) or iii). Even if the composition for forming a hole injection layer obtained by the method ii) does not contain the charge-transporting ionic compound, it is sufficient that the charge-transporting ionic compound can be obtained by the method iii).

[0602] The compounding ratio of the first ionic compound to the hole transport material to obtain a composition for forming a hole injection layer is such that the amount of the first ionic compound is typically 0.1 parts by mass or more, preferably 1 part by mass or more, and typically 100 parts by mass or less, preferably 40 parts by mass or less, per 100 parts by mass of the hole transport material. When the content of the first ionic compound is above the lower limit, free carriers (cation radicals of the hole transport material) can be generated sufficiently, improving hole transportability, and when the content is below the upper limit, sufficient charge transport ability can be ensured, which is preferred. When two or more types of the first ionic compound are used in combination, the total content of these compounds is set to fall within the above range. The same applies to the hole transport material.

[0603] (organic solvent) The concentration of the organic solvent in the composition for forming a hole injection layer is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more, and is usually 99.999% by mass or less, preferably 99.99% by mass or less, and even more preferably 99.9% by mass or less. When two or more organic solvents are used in combination, the total amount of these organic solvents should satisfy this range.

[0604] Preferred organic solvents include, for example, ether-based solvents and ester-based solvents. Specific examples of ether-based solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole. Examples of ester-based solvents include aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; and aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate. These may be used alone or in any combination and ratio of two or more.

[0605] Examples of solvents that can be used other than the above-mentioned ether-based solvents and ester-based solvents include aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene, amide-based solvents such as N,N-dimethylformamide and N,N-dimethylacetamide, and dimethyl sulfoxide. These may be used alone or in any combination and ratio of two or more. Furthermore, one or more of these solvents may be used in combination with one or more of the above-mentioned ether-based solvents and ester-based solvents. In particular, aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene have a low ability to dissolve electron-accepting compounds and free carriers (cation radicals), so they are preferably used in combination with ether-based solvents and ester-based solvents.

[0606] Among these organic solvents, solvents having an aromatic hydrocarbon structure are more preferred.

[0607] (Film forming method) The hole injection layer can be formed by wet film formation using a composition for forming a hole injection layer. The wet film formation method is similar to the method for wet film formation of a composition for forming an emitting layer, but it is preferable to heat the film after coating and drying. The heating temperature is preferably 120°C or higher, more preferably 150°C or higher, and even more preferably 180°C or higher, and is preferably 300°C or lower, and more preferably 260°C or lower.

[0608] The hole injection layer can be crosslinked by heating the film after coating and drying. At this time, the crosslinking reaction can occur in the following combinations:

[0609] Between cross-linking groups of hole transport materials Crosslinking groups of hole transport materials and electron-accepting compounds Between the cross-linking groups of electron-accepting compounds The crosslinking group of the hole transport material and the crosslinking group of the tetraarylborate ion in an embodiment of the present invention In an embodiment of the present invention, the bridging groups of the tetraarylborate ions The bridging group of the electron-accepting compound and the bridging group of the tetraarylborate ion in an embodiment of the present invention This step forms a crosslinked product of the electron-accepting compound in the hole-injection layer.

[0610] Furthermore, heating is preferred because it promotes the formation of a charge-transporting ionic compound, which is an ionic compound of the tetraarylborate ion, which is the counter anion of the first ionic compound, and the cation radical of the hole-transporting material.

[0611] <Structure of organic electroluminescent device> As an example of the structure of an organic electroluminescent device according to an embodiment of the present invention, Fig. 1 shows a schematic diagram (cross section) of an example of the structure of an organic electroluminescent device 8. In Fig. 1, 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light-emitting layer, 6 represents an electron transport layer, and 7 represents a cathode.

[0612] [substrate] The substrate 1 serves as a support for the organic electroluminescent element, and is typically made of a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like. Of these, a glass plate or a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferred. The substrate is preferably made of a material with high gas barrier properties, as this makes it less likely for the organic electroluminescent element to deteriorate due to exposure to the outside air. Therefore, when using a material with low gas barrier properties, such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one side of the substrate to improve the gas barrier properties.

[0613] [anode] The anode 2 has the function of injecting holes into the layer on the light-emitting layer 5 side.

[0614] The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, or platinum; a metal oxide such as indium and / or tin oxide; a metal halide such as copper iodide; carbon black, or a conductive polymer such as poly(3-methylthiophene), polypyrrole, or polyaniline.

[0615] The anode 2 is usually formed by a dry method such as sputtering or vacuum deposition. When forming the anode using metal particles such as silver, copper iodide, carbon black, conductive metal oxide particles, or conductive polymer fine powder, the anode can be formed by dispersing the particles in an appropriate binder resin solution and applying it to the substrate. In the case of a conductive polymer, a thin film can be formed directly on the substrate by electrolytic polymerization, or the anode can be formed by applying the conductive polymer to the substrate (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0616] The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, a different conductive material may be laminated on the first layer of the anode.

[0617] The thickness of the anode 2 may be determined depending on the required transparency, material, etc. When particularly high transparency is required, a thickness that provides a visible light transmittance of 60% or more is preferred, and a thickness that provides a visible light transmittance of 80% or more is even more preferred. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is not required, the thickness of the anode 2 may be arbitrarily determined depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate.

[0618] When another layer is formed on the surface of the anode 2, it is preferable to perform a treatment with ultraviolet light / ozone, oxygen plasma, argon plasma, or the like before the film formation to remove impurities on the anode 2 and adjust its ionization potential to improve hole injection properties.

[0619] [Hole injection layer] The hole injection layer in the organic electroluminescent device according to the embodiment of the present invention is as described above. Although the wet film formation method has been described above as a method for forming the hole injection layer, a vacuum deposition method may also be used.

[0620] [Formation of hole injection layer by vacuum deposition method] When the hole injection layer of the organic electroluminescent device according to the embodiment of the present invention is formed by vacuum deposition, the first ionic compound is used as the material containing tetraarylborate ions, and a vapor-depositable low-molecular-weight hole transport material can be used as the hole transport material. The vapor-depositable low-molecular-weight hole transport material is preferably a hole transport material having a molecular weight of 1,500 or less, more preferably a hole transport material having a molecular weight of 1,000 or less, more preferably a hole transport material having a molecular weight of 400 or more, and even more preferably a hole transport material having a molecular weight of 600 or more. The low-molecular-weight hole transport material is preferably an aromatic amine compound, more preferably an aromatic tertiary amine compound.

[0621] When forming the hole injection layer 3 by vacuum deposition, one or more types of materials constituting the hole injection layer 3 are usually placed in a crucible installed in a vacuum chamber (when two or more types of materials are used, each is usually placed in a separate crucible), and the inside of the vacuum chamber is vacuumed by a vacuum pump for 10 -4 The chamber is evacuated to approximately 100 Pa. The crucible is then heated (when two or more materials are used, each crucible is usually heated) and the materials in the crucible are evaporated while controlling their evaporation rates (when two or more materials are used, each material is usually evaporated while controlling its evaporation rate independently), forming a hole injection layer on the anode on the substrate placed opposite the crucible. When two or more materials are used, a mixture of the materials can also be placed in the crucible and heated to evaporate to form the hole injection layer.

[0622] The degree of vacuum during deposition is not limited as long as it does not significantly impair the effects of the present invention. -6 Torr (0.13 × 10 -4 Pa) or above, 9.0×10 -6 Torr (12.0 × 10 -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The deposition temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0623] [Hole transport layer] The hole transport layer 4 is a layer that transports holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent device according to the embodiment of the present invention, but it is preferable to form this layer in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5. When the hole transport layer 4 is formed, it is usually formed between the anode 2 and the light-emitting layer 5. Furthermore, when the above-mentioned hole injection layer 3 is present, it is formed between the hole injection layer 3 and the light-emitting layer 5.

[0624] The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and on the other hand, is usually 300 nm or less, preferably 100 nm or less.

[0625] The hole transport layer 4 may be formed by vacuum deposition or wet film formation, but is preferably formed by wet film formation in terms of excellent film formability.

[0626] The hole transport layer 4 usually contains a hole transport compound.

[0627] Examples of hole-transporting compounds include aromatic diamines containing two or more tertiary amines and having two or more condensed aromatic rings substituted with nitrogen atoms, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (Japanese Patent Application Laid-Open No. 5-234681), and aromatic amine compounds having a starburst structure, such as 4,4',4''-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, 999). Preferred examples include aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., p. 2175, 1996), spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), and carbazole derivatives such as 4,4'-N,N'-dicarbazolebiphenyl. Other examples include polyvinylcarbazole, polyvinyltriphenylamine (JP-A-7-53953), and polyarylene ether sulfones containing tetraphenylbenzidine (Polym. Adv. Tech., vol. 7, p. 33, 1996).

[0628] Furthermore, as the hole transporting compound, a polymer having an arylamine structure represented by the above formula (50) as a repeating unit can also be mentioned as a preferred example. The repeating unit represented by formula (50) preferably has repeating units represented by formulas (54) to (57). Preferred embodiments of the repeating units represented by formulas (54) to (57) are as described above.

[0629] [Formation of hole transport layer by wet film formation method] When the hole transport layer is formed by a wet film formation method, it is usually formed using a composition for forming a hole transport layer instead of the composition for forming a hole injection layer, in the same manner as when the hole injection layer described above is formed by a wet film formation method.

[0630] When the hole transport layer is formed by a wet film formation method, the composition for forming the hole transport layer usually further contains a solvent. The solvent used in the composition for forming the hole transport layer can be the same as the solvent used in the composition for forming the hole injection layer described above.

[0631] The concentration of the hole transporting compound in the composition for forming a hole transport layer can be set to the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer.

[0632] [Formation of hole transport layer by vacuum deposition method] When forming the hole transport layer by vacuum deposition, it can be formed in the same manner as when forming the hole injection layer by vacuum deposition, except that the hole transport layer-forming composition is used instead of the hole injection layer-forming composition. The film formation conditions, such as the degree of vacuum, deposition rate, and temperature during deposition, can be the same as those for the vacuum deposition of the hole injection layer.

[0633] [Emitting layer] The light-emitting layer 5 is a layer that emits light when excited by the recombination of holes injected from the anode 2 and electrons injected from the cathode 7 when an electric field is applied between the pair of electrodes. The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 7, and when a hole-injection layer is present on the anode, the light-emitting layer is formed between the hole-injection layer and the cathode, and when a hole-transport layer is present on the anode, the light-emitting layer is formed between the hole-transport layer and the cathode.

[0634] As described above, the light-emitting layer of the organic electroluminescent device according to the embodiment of the present invention contains the compound represented by formula (240) or formula (241), and preferably further contains the light-emitting material and the host material.

[0635] The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention, but a thicker layer is preferable in terms of preventing defects from occurring in the film, and a thinner layer is preferable in terms of facilitating a low driving voltage. For this reason, the thickness is preferably 3 nm or more, more preferably 5 nm or more, and usually preferably 200 nm or less, more preferably 100 nm or less.

[0636] The light-emitting layer 5 contains at least a material having light-emitting properties (light-emitting material), and preferably contains one or more host materials.

[0637] [Hole blocking layer] A hole-blocking layer may be provided between the light-emitting layer 5 and the electron-injecting layer described below. The hole-blocking layer is a layer laminated on the light-emitting layer 5 so as to be in contact with the interface of the light-emitting layer 5 on the cathode 7 side.

[0638] This hole-blocking layer has the roles of preventing holes migrating from the anode 2 from reaching the cathode 7 and efficiently transporting electrons injected from the cathode 7 toward the light-emitting layer 5. Required physical properties of the material constituting the hole-blocking layer include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1).

[0639] Examples of materials for hole-blocking layers that satisfy these conditions include mixed ligand complexes such as bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolato)aluminum; metal complexes such as bis(2-methyl-8-quinolinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum binuclear metal complex; styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-242996); triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Laid-Open No. 7-41759); and phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2-, 4-, and 6-positions, as described in WO 2005 / 022962, are also preferred as materials for the hole-blocking layer.

[0640] There is no limitation on the method for forming the hole blocking layer, and it can be formed by a wet film forming method, a vapor deposition method, or other methods.

[0641] The thickness of the hole blocking layer is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0642] [Electron transport layer] The electron transport layer 6 is provided between the light-emitting layer 5 and the cathode 7 for the purpose of further improving the current efficiency (cd / A) of the device.

[0643] The electron transport layer 6 is formed from a compound capable of efficiently transporting electrons injected from the cathode 7 between electrodes to which an electric field is applied, toward the light-emitting layer 5. The electron transporting compound used in the electron transport layer 6 is required to have a high efficiency of electron injection from the cathode 7, a high electron mobility, and the ability to efficiently transport the injected electrons.

[0644] Specific examples of the electron transporting compound used in the electron transport layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open Publication No. 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (U.S. Pat. No. 5,645,948), quinoxaline compounds (Japanese Patent Laid-Open Publication No. 6-207169), phenanthroline derivatives (Japanese Patent Laid-Open Publication No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

[0645] The thickness of the electron transport layer 6 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0646] The electron transport layer 6 is formed on the hole blocking layer by the wet film forming method or the vacuum deposition method as described above. Usually, the vacuum deposition method is used.

[0647] [Electron injection layer] The electron injection layer may be provided to efficiently inject electrons injected from the cathode 7 into the electron transport layer 6 or the light-emitting layer 5.

[0648] To efficiently inject electrons, the material forming the electron injection layer is preferably a metal with a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The thickness of the electron injection layer is usually preferably 0.1 nm or more and 5 nm or less.

[0649] Furthermore, it is also preferable to dope an organic electron transport material, typified by a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline, with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium (as described in JP-A Nos. 10-270171, 2002-100478, and 2002-100482, for example), since this improves both the electron injection and transport properties and enables excellent film quality to be achieved.

[0650] The thickness of the electron injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

[0651] The electron injection layer is formed by laminating it on the light-emitting layer 5 or the hole blocking layer or electron transport layer 6 thereon by a wet film-forming method or a vacuum deposition method. The details of the wet film formation method are the same as those of the light-emitting layer described above.

[0652] In some cases, the hole blocking layer, electron transporting layer, and electron injecting layer are formed into one layer by co-doping the electron transporting material with a lithium complex.

[0653] [cathode] The cathode 7 serves to inject electrons into the layer on the light-emitting layer 5 side (such as the electron injection layer or the light-emitting layer).

[0654] The cathode 7 can be made of any of the materials used for the anode 2, but for efficient electron injection, it is preferable to use a metal with a low work function, such as tin, magnesium, indium, calcium, aluminum, silver, or an alloy thereof. Specific examples include low-work-function alloy electrodes such as a magnesium-silver alloy, a magnesium-indium alloy, or an aluminum-lithium alloy.

[0655] In terms of the stability of the organic electroluminescent device, it is preferable to protect the cathode made of a metal having a low work function by laminating a metal layer having a high work function and stability against the atmosphere on the cathode. Examples of the metal to be laminated include aluminum, silver, copper, nickel, chromium, gold, and platinum.

[0656] The thickness of the cathode is usually the same as that of the anode.

[0657] [Other layers] The organic electroluminescent device according to the embodiment of the present invention may further include other layers as long as the effects of the present invention are not significantly impaired. That is, the organic electroluminescent device according to the embodiment of the present invention may include any of the above-described layers between the anode and the cathode.

[0658] [Other element configurations] The organic electroluminescent device according to the embodiment of the present invention may have a structure opposite to that described above, i.e., for example, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light-emitting layer, a hole transport layer, a hole injection layer, and an anode stacked on a substrate in this order.

[0659] When the organic electroluminescent element according to the embodiment of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent element, or may be used in a configuration in which a plurality of organic electroluminescent elements are arranged in an array, or may be used in a configuration in which anodes and cathodes are arranged in an XY matrix.

[0660] Each of the above-described layers may contain components other than those described as materials.

[0661] <Preferred Examples of Organic Electroluminescent Devices> An organic electroluminescent device according to an embodiment of the present invention is an organic electroluminescent device having an anode, a cathode, an emitting layer, and a hole injection layer, wherein the emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the emitting layer, the emitting layer contains a compound represented by formula (240) above or formula (241) below, and the hole injection layer preferably contains a crosslinking reaction product of a tetraarylborate ion represented by formula (81) above and a polymer having an arylamine structure represented by formula (50) above as a repeating unit and having a crosslinking group. Such organic electroluminescent devices are preferred because they tend to have high luminous efficiency and long operating life.

[0662] [Method of manufacturing organic electroluminescent device] The method for manufacturing the organic electroluminescent device according to the embodiment of the present invention is not particularly limited as long as the above-described composition is used. For example, the method for manufacturing the organic electroluminescent device according to the embodiment of the present invention may include a manufacturing method including a step of forming a light-emitting layer by a wet film-forming method using the above-described composition.

[0663] [Display and lighting devices] The display device and lighting device according to the embodiment of the present invention include the organic electroluminescent device described above. The type and structure of the display device and lighting device are not particularly limited, and they can be assembled according to a conventional method using the organic electroluminescent device according to the embodiment of the present invention. For example, the display device and lighting device according to the embodiment of the present invention can be formed by a method such as that described in "Organic EL Display" (Ohmsha, published on August 20, 2004, by Tokito Shizuo, Adachi Chinaya, and Murata Hideyuki). [Example]

[0664] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The values ​​of various conditions and evaluation results in the following examples are meant as preferred upper or lower limit values ​​in the embodiments of the present invention, and a preferred range may be defined by a combination of the above-mentioned upper or lower limit value and the value in the following examples or values ​​between examples.

[0665] [Fabrication and Performance Evaluation of Organic Electroluminescent Devices] [Example I-1] An organic electroluminescent device was fabricated in the following manner. A 50-nm-thick indium tin oxide (ITO) transparent conductive film (Geomatec, sputter-deposited) was deposited on a glass substrate and patterned into 2-mm-wide stripes using standard photolithography and hydrochloric acid etching to form the anode. The substrate with the ITO pattern formed was then ultrasonically cleaned with a surfactant solution, rinsed with ultrapure water, ultrasonically cleaned with ultrapure water, and rinsed with ultrapure water again, followed by drying with compressed air and finally cleaning with ultraviolet ozone.

[0666] A composition for forming a hole injection layer was prepared by dissolving 3.0 mass% of a hole transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6 mass% of an electron accepting compound (HI-1) in ethyl benzoate.

[0667] [ka]

[0668] This composition for forming a hole injection layer was spin-coated onto the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.

[0669] Next, a charge transporting polymer compound having a repeating structure of the following formula (HT-1) was dissolved in 1,3,5-trimethylbenzene to prepare a 2.0 mass % solution. This solution was spin-coated in a nitrogen glove box onto the substrate on which the hole injection layer had been formed, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of 40 nm, which served as a hole transport layer.

[0670] [ka]

[0671] Subsequently, as materials for the light-emitting layer, 2.5 mass % of compound 1, 1.25 mass % of the following compound (H-1), 1.25 mass % of the following compound (H-2), and 1 mass % of the following compound (D-1) were dissolved in cyclohexylbenzene to prepare a composition for forming the light-emitting layer.

[0672] [ka]

[0673] [ka]

[0674] [ka]

[0675] [ka]

[0676] The composition for forming the light-emitting layer was spin-coated onto the substrate on which the hole transport layer had been formed in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of 60 nm, which was used as the light-emitting layer.

[0677] The substrate on which the light-emitting layer had been formed was placed in a vacuum deposition device, and the inside of the device was heated to 2 × 10 -4 The pressure was evacuated until it reached a pressure of 0.1 Pa or less. Next, the following compound (ET-1) and 8-hydroxyquinolinolatolithium were co-deposited on the light-emitting layer in a thickness ratio of 2:3 by vacuum deposition to form an electron transport layer with a thickness of 30 nm.

[0678] [ka]

[0679] Next, a 2 mm wide striped shadow mask was attached to the substrate as a mask for cathode deposition so that it was perpendicular to the ITO stripes of the anode, and aluminum was heated using a molybdenum boat to form an 80 nm thick aluminum layer, forming the cathode.

[0680] In this manner, an organic electroluminescent device having a light-emitting area measuring 2 mm×2 mm was obtained.

[0681] [Comparative example I-1] An organic electroluminescent device was produced in the same manner as in Example I-1, except that the electron-accepting compound (HI-2) was used instead of the electron-accepting compound (HI-1) as the material for the hole-injection layer.

[0682] [ka]

[0683] [Element evaluation] The organic electroluminescent devices obtained in Example I-1 and Comparative Example I-1 were tested at a luminance of 1,000 cd / m 2 The current efficiency (cd / A) was measured when the device was lit at 15 mA / cm. 2 The time (LT95) until the luminance decreased to 95% of the initial luminance when the element was continuously energized at a current density of 1000 kJ / s was measured. The results of these measurements are shown in Table 1. In Table 1, the values ​​for Example I-1 are relative values, with the value for Comparative Example I-1 being set at 1. The results in Table 1 show that the organic electroluminescent devices according to the embodiments of the present invention have high luminous efficiency and long operating life.

[0684] [Table 1] [Industrial Applicability]

[0685] The organic electroluminescent device according to the embodiment of the present invention has high luminous efficiency and a long driving life, and can be used in, for example, a display device or a lighting device. [Explanation of symbols]

[0686] 1 board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6 Electron transport layer 7 Cathode 8. Organic electroluminescent device

Claims

1. An organic electroluminescent device having an anode, a cathode, a light-emitting layer, and a hole injection layer, the light-emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the light emitting layer, The light-emitting layer contains a compound represented by the following formula (240) or (241): The organic electroluminescent device, wherein the hole injection layer contains tetraarylborate ions. 【Chemical 1】 (In formula (240), Ar ６１１ , Ar ６１２ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１１ , R ６１２ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R ６１１ and R ６１２ At least one of the groups represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G ６１１ represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n ６１１ , n ６１２ are each independently an integer of 1 to 4. 【Chemistry 2】 (In formula (241), Ar ６１３ ~Ar ６１５ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１３ , R ６１４ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R ６１３ and R ６１４ At least one of the groups represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G ６１２ , G ６１３ each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n ６１３ , n ６１４ are each independently an integer of 1 to 4.

2. Ar in the formula (240) and the formula (241) ６１１ ~Ar ６１５ 2. The organic electroluminescent device according to claim 1, wherein each of the groups independently represents a monovalent group in which a plurality of benzene rings, which may have a substituent, are bonded in a linear or branched manner.

3. R in the formula (240) and the formula (241) ６１１ ~R ６１４ 2. The organic electroluminescent device according to claim 1, wherein each of the groups independently represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent.

4. 2. The organic electroluminescent device according to claim 1, wherein the compound represented by the formula (240) or the formula (241) is a compound represented by the following formula (240-1) or the following formula (241-1): 【Chemistry 3】 (In formula (240-1), Ar ６１１ , Ar ６１２ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１１ , R ６１２ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R ６１１ and R ６１２ At least one of represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. 【Chemistry 4】 (In formula (241-1), Ar ６１３ ~Ar ６１５ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１３ , R ６１４ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent, provided that R ６１３ and R ６１４ At least one of represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.

5. The organic electroluminescent device according to claim 1 , wherein the tetraarylborate ion is represented by the following formula (81): 【Chemistry 5】 (In formula (81), Ar １ , Ar ２ , Ar ３ and Ar ４ each independently represents an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group, an aromatic heterocyclic group which may have a substituent and / or a crosslinking group, or a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group and an aromatic heterocyclic group which may have a substituent and / or a crosslinking group are linked together; Ar １ , Ar ２ , Ar ３ and Ar ４ At least one of has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

6. 2. The organic electroluminescent device according to claim 1, wherein the hole injection layer further contains a polymer having an arylamine structure represented by the following formula (50) as a repeating unit and having a crosslinking group: 【Chemistry 6】 (In formula (50), Ar ５１ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; Ar ５２ represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which a plurality of at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group are linked together directly or via a linking group. Ar ５１ and Ar ５２ may form a ring via a single bond or a linking group. Ar ５１ , Ar ５２ may have a substituent.)

7. 7. The organic electroluminescent device according to claim 6, wherein the polymer having the arylamine structure represented by formula (50) as a repeating unit has a crosslinking group selected from the formulae (X1) to (X18) in the following crosslinking group group T: <Bridging group group T> 【Chemistry 7】 In formulas (X1) to (X4), the benzene ring and the naphthalene ring may have a substituent. In addition, the substituents may be bonded to each other to form a ring. R in formula (X4), formula (X5), formula (X6) and formula (X10) Ｘ each independently represents an alkyl group which may have a substituent. * in formulas (X1) to (X18) represents a bonding position.

8. 8. The organic electroluminescent device according to claim 7, wherein the crosslinking group is any one of the formulae (X1) to (X3).

9. 7. The organic electroluminescent device according to claim 6, wherein the repeating unit represented by formula (50) has a repeating unit represented by formula (54) to formula (57) or formula (60): 【Chemistry 8】 (In formula (54), Ar ５１ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; X is -C(R ２０７ ) (R ２０８ ) -, -N(R ２０９ ) - or -C(R ２１１ ) (R ２１２ )-C(R ２１３ ) (R ２１４ ) - and R ２０１ , R ２０２ , R ２２１ and R ２２２ each independently represents an alkyl group which may have a substituent, R ２０７ ~R ２０９ and R ２１１ ~R ２１４ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aromatic hydrocarbon group, a and b each independently represent an integer from 0 to 4; c is an integer from 0 to 3; d is an integer from 0 to 4, i and j each independently represent an integer from 0 to 3. 【Chemistry 9】 (In formula (55), Ar ５１ is Ar in the formula (54). ５１ is the same as R ３０３ and R ３０６ each independently represents an alkyl group which may have a substituent, R ３０４ and R ３０５ each independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group, l is 0 or 1; m is 1 or 2; n is 0 or 1; p is 0 or 1; q is 0 or 1. 【Chemistry 10】 (In formula (56), Ar ５１ is Ar in the formula (54). ５１ is the same as Ar ４１ represents a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a divalent group in which a plurality of at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked together directly or via a linking group, R ４４１ and R ４４２ each independently represents an alkyl group which may have a substituent, t is 1 or 2; u is 0 or 1; r and s each independently represent an integer of 0 to 4. 【Chemistry 11】 (In formula (57), Ar ５１ is Ar in the formula (54). ５１ is the same as R ５１７ ~R ５１９ each independently represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent; f, g, and h each independently represent an integer of 0 to 4; e represents an integer of 0 to 3; However, when g is 1 or more, e is 1 or more.) 【Chemistry 12】 (In formula (60), Ar ５１ is Ar in the formula (50). ５１ is the same as n ６０ represents an integer of 1 to 5.)

10. Ar in the formula (54) to the formula (57) or the formula (60) ５１ , R ２０１ , R ２０２ , R ２２１ , R ２２２ , R ２０７ ~R ２０９ , R ２１１ ~R ２１４ is R ３０３ ~R ３０６ , R ４４１ , R ４４２ , R ５１７ ~R ５１９ The organic electroluminescent device according to claim 9 , wherein none of

11. 7. The organic electroluminescent device according to claim 6, wherein the repeating unit represented by the formula (50) further has a structure represented by the following formula (50-2) as a linking group: 【Chemistry 13】 (In the formula, R ８１ , R ８３ R each independently represents a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. ８１ , R ８３ When there are a plurality of p, they may be the same or different. ８０ represents an integer of 1 to 5.)

12. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer contains at least one compound represented by the following formula (3) as a light-emitting material: 【Chemistry 14】 [In formula (3), Ring A1 represents an aromatic hydrocarbon structure which may have a substituent or an aromatic heterostructure which may have a substituent. Ring A2 represents an aromatic heterostructure which may have a substituent. R ２０１ , R ２０２ are each independently a structure represented by formula (b), and "*" represents the bonding position with ring A1 or ring A2. ２０１ , R ２０２ may be the same or different, and R ２０１ , R ２０２ When there are a plurality of each of the groups, they may be the same or different. Ar ２０１ , Ar ２０３ each independently represents an aromatic hydrocarbon structure which may have a substituent, or an aromatic heterostructure which may have a substituent. Ar ２０２ represents an aromatic hydrocarbon structure which may have a substituent, an aromatic heterostructure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. The substituents bonded to ring A1 may be bonded to each other, the substituents bonded to ring A2 may be bonded to each other, or the substituents bonded to ring A1 and the substituents bonded to ring A2 may be bonded to each other to form a ring. B ２０１ -L ２００ -B ２０２ represents an anionic bidentate ligand. ２０１ and B ２０２ Each of L independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. ２００ is a single bond, or B ２０１ and B ２０２ represents an atomic group that together with B constitutes a bidentate ligand. ２０１ -L ２００ -B ２０２ When there are multiple groups, they may be the same or different. In the formula (3) and the formula (b), i1 and i2 each independently represent an integer of 0 to 12, i3 is Ar ２０２ represents an integer of 0 or more, with the upper limit being the number that can be replaced by i4 is Ar ２０１ represents an integer of 0 or more, with the upper limit being the number that can be replaced by k1 and k2 each independently represent an integer of 0 or greater, the upper limit of which is the number of groups that can be substituted on ring A1 and ring A2; z represents an integer of 1 to 3; M represents a metal atom selected from Groups 7 to 11 of the periodic table.

13. The organic electroluminescent device according to claim 12, wherein the light-emitting layer further comprises at least one compound selected from the group consisting of a compound represented by the following formula (250) and a compound represented by the following formula (260): 【Chemistry 15】 (In formula (250), Each W independently represents CH or N, and at least one W is N; Xa １ , Ya １ , and Za １ each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, Xa ２ , Ya ２ and Za ２ each independently represents a hydrogen atom, an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted monovalent aromatic heterocyclic group having 3 to 30 carbon atoms, g11, h11, and j11 each independently represent an integer of 0 to 6; At least one of g11, h11, and j11 is an integer of 1 or more, When g11 is 2 or more, a plurality of Xa １ may be the same or different, When h11 is 2 or more, multiple Ya １ may be the same or different, If j11 is 2 or more, multiple Za １ may be the same or different, R ３１ represents a hydrogen atom or a substituent, and four R ３１ may be the same or different, However, when g11, h11, or j11 is 0, the corresponding Xa ２ , Ya ２ , Za ２ is not a hydrogen atom.) 【Chemistry 16】 (In formula (260), Ar ２１ ~Ar ３５ each independently represents a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group in which 2 to 10 phenyl groups which may have a substituent are linked in an unbranched or branched manner.

14. The organic electroluminescent device according to claim 13, wherein the light-emitting layer contains at least the compound represented by formula (250).

15. An organic electroluminescent device having an anode, a cathode, a light-emitting layer, and a hole injection layer, the light-emitting layer is provided between the anode and the cathode, the hole injection layer is provided between the anode and the light emitting layer, The light-emitting layer contains a compound represented by the following formula (240) or (241): The hole injection layer comprises a crosslinking reaction product of a tetraarylborate ion represented by the following formula (81) and a polymer having an arylamine structure represented by the following formula (50) as a repeating unit and having a crosslinking group. 【Chemistry 17】 (In formula (240), Ar ６１１ , Ar ６１２ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１１ , R ６１２ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R ６１１ and R ６１２ At least one of the groups represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G ６１１ represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n ６１１ , n ６１２ are each independently an integer of 1 to 4. 【Chemistry 18】 (In formula (241), Ar ６１３ ~Ar ６１５ each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. R ６１３ , R ６１４ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent; R ６１３ and R ６１４ At least one of the groups represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms. G ６１２ , G ６１３ each independently represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent. n ６１３ , n ６１４ are each independently an integer of 1 to 4. 【Chemistry 19】 (In formula (81), Ar １ , Ar ２ , Ar ３ and Ar ４ each independently represents an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group, an aromatic heterocyclic group which may have a substituent and / or a crosslinking group, or a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon group which may have a substituent and / or a crosslinking group and an aromatic heterocyclic group which may have a substituent and / or a crosslinking group are linked together; Ar １ , Ar ２ , Ar ３ and Ar ４ At least one of has a fluorine atom or a fluorine-substituted alkyl group as a substituent. 【Chemistry 20】 (In formula (50), Ar ５１ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together; Ar ５２ represents a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or a divalent group in which a plurality of at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group are linked together directly or via a linking group. Ar ５１ and Ar ５２ may form a ring via a single bond or a linking group. Ar ５１ , Ar ５２ may have a substituent.)

16. A display device comprising the organic electroluminescent device according to any one of claims 1 to 15.

17. A lighting device comprising the organic electroluminescent device according to any one of claims 1 to 15.

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