Composition using solvent compound for organic electroluminescent device, and method for manufacturing organic electroluminescent device

Abstract

The present invention addresses the problem of providing a solvent compound for an organic electroluminescent device capable of improving the flatness of a layer. The present invention relates to a solvent compound for an electroluminescent device represented by formula (1) (In formula (1), the definitions of R1, R2, R3, n1, and m1 are as described in the specification.).

Description

[Technical Field]

[0001] The present invention relates to a solvent compound for organic electroluminescent elements that is suitably used for forming a functional film, which is an organic film made of a functional material, in the production of organic electroluminescent elements, a composition using the same, and a method for producing an organic electroluminescent element. [Background technology]

[0002] A common method for manufacturing organic electroluminescent devices is to form a film of organic material by vacuum deposition and then laminate it. However, in recent years, research has been actively conducted into wet film formation methods in which a solution of organic material is formed into a film by an inkjet method or the like and then laminated, as a manufacturing method with better material utilization efficiency.

[0003] In the manufacture of organic electroluminescent devices, particularly organic EL displays, by wet film formation, a method has been considered in which each pixel is partitioned by a partition wall called a bank, and an ink, which is a composition for forming an organic electroluminescent device for forming an organic film that constitutes the organic electroluminescent device, is ejected by an inkjet method into a minute region within the bank to form a film. In this case, a technique has been proposed in which various surface modifiers are mixed into the ink to obtain a flatter film within the region surrounded by the bank (Patent Documents 1 and 2).

[0004] However, in the conventional method, the flatness of the film within the area surrounded by the bank was not sufficient. Patent Document 3 discloses a technique that uses two or more solvents with different boiling points in order to form a functional layer with a substantially flat cross-sectional shape after drying and solidification. For example, the technique discloses the use of 1,1-bis(3,4-dimethylphenyl)ethane as a high-boiling-point solvent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2010 / 104183 [Patent Document 2] Japanese Patent Application Publication No. 2002-056980 [Patent Document 3] Japanese Patent Publication No. 2015-185640 Summary of the Invention [Problem to be solved by the invention]

[0006] Solvents used in organic electroluminescent devices manufactured by wet film formation, particularly by coating with an inkjet device, are required to have the properties of dissolving functional materials such as light-emitting materials and hole transport materials, and of forming flat layers when the devices are formed into films.

[0007] 1,1-bis(3,4-dimethylphenyl)ethane, as disclosed in Patent Document 3, can dissolve functional materials. In addition, because 1,1-bis(3,4-dimethylphenyl)ethane has a high boiling point, it remains in the layer until the latter half of the drying process, preventing the precipitation of functional materials.

[0008] However, there is still room for improvement in the planarity of the layers. An object of the present invention is to provide a solvent compound for an organic electroluminescent device that can improve the flatness of a layer, a composition using the same, and a method for producing an organic electroluminescent device. [Means for solving the problem]

[0009] That is, the present invention provides the following <1> ~ <19> It is related to. <1> A solvent compound for organic electroluminescent devices represented by the following formula (1):

[0010] [ka]

[0011] (In formula (1), R 1 , R 2 , R 3 , n 1 , m 1 satisfies either (i) or (ii) below. (i) R 1 represents an alkyl group having 1 to 6 carbon atoms, R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, n 1 represents an integer from 1 to 5, R 3 does not exist, i.e., m 1 =0. (ii) R 1 represents an alkyl group having 2 to 6 carbon atoms, R 2 , R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, n 1 , m 1 represents an integer between 0 and 5.) <2> A composition for organic electroluminescent devices, comprising a functional material and a solvent compound represented by the formula (1). <3> The functional material contains at least an electron-accepting compound. <2> The composition for organic electroluminescent elements according to claim 1. <4> the electron-accepting compound is a tetraarylborate ion compound; <3> The composition for organic electroluminescent elements according to claim 1. <5> The tetraarylborate ion compound is an ionic compound consisting of a tetraarylborate ion represented by the following formula (2) and a counter cation: <4> The composition for organic electroluminescent elements according to claim 1.

[0012] [ka]

[0013] (In formula (2), Ar 1 , Ar 2 , Ar 3 and Ar 4each independently represent an optionally substituted aromatic hydrocarbon ring group, an optionally substituted aromatic heterocyclic group, or a monovalent group formed by linking together a plurality of structures selected from optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups; The substituent may be a bridging 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. <6> Ar in the formula (2) 1 , Ar 2 , Ar 3 and Ar 4 At least one of the above is a group represented by the following formula (3): <5> The composition for organic electroluminescent elements according to claim 1.

[0014] [ka]

[0015] (In formula (3), R 100 each independently represents an aromatic hydrocarbon ring group which may have a substituent, an aromatic heterocyclic group which may have a substituent, a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together, a fluorine-substituted alkyl group, or R 100 is a group containing a bridging group, F4 represents four fluorine atoms substituted, F (5-m) each independently represents substitution with 5-m fluorine atoms, Each k independently represents an integer of 0 to 5, Each m independently represents an integer of 0 to 5. <7> The crosslinking group is represented by any one of the following formulas (X1) to (X18): <6> The composition for organic electroluminescent elements according to claim 1.

[0016] [ka]

[0017] 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 (10) 110 represents a hydrogen atom or an alkyl group which may have a substituent. <8> The functional material includes at least a hole transport polymer compound, the hole transport polymer compound is a polymer having a triarylamine structure as a repeating unit; <2> ~ <7> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <9> The triarylamine structure as the repeating unit contains at least a repeating unit selected from a repeating unit represented by the following formula (54), a repeating unit represented by the following formula (55), a repeating unit represented by the following formula (56), and a repeating unit represented by the following formula (57): <8> The composition for organic electroluminescent elements according to claim 1.

[0018] [ka]

[0019] (In formula (54), Ar 51 represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a group in which a plurality of groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent 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 222each 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.

[0020] [ka]

[0021] (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.

[0022] [ka]

[0023] (In formula (56), Ar 51is 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 are each independently an integer of 0 to 4.

[0024] [ka]

[0025] (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.) <10> In the repeating unit represented by the formula (54), the repeating unit represented by the formula (55), the repeating unit represented by the formula (56), and the repeating unit represented by the formula (57), Ar 51is a group selected from a group containing a monovalent or divalent group in which 2 to 5 optionally substituted benzene rings are linked together, a fluorenyl group which may have a substituent, a group represented by the following formula (51), a group represented by the following formula (52), and a group represented by the following formula (53): <9> The composition for organic electroluminescent elements according to claim 1.

[0026] [ka]

[0027] (In formula (51), * represents a bond to a nitrogen atom in the main chain of the formula (54), the formula (55), the formula (56), and the formula (57), 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.

[0028] [ka]

[0029] (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 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. * represents the bonding position to the nitrogen atom of the main chain in the formula (54), the formula (55), the formula (56), and the formula (57).

[0030] [ka]

[0031] (In formula (53), * represents a bond to a nitrogen atom in the main chain of the formula (54), the formula (55), the formula (56), and the formula (57), Ar 71 represents a divalent aromatic hydrocarbon group which may have a substituent, Ar 72 and Ar 73 each independently represent an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups are linked together directly or via a linking group; 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. <11> the weight-average molecular weight of the polymer having a triarylamine structure as a repeating unit is 50,000 or less; <8> ~ <10> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <12> The triarylamine structure of the repeating unit includes a repeating unit represented by formula (54). <9> ~ <11> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <13> Further containing solvent B, The solvent B is a solvate having a boiling point of 200°C or higher, different from the solvate. <2> ~ <12> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <14> the total content of the solvent compound and the solvent B relative to the total amount of solvents contained in the composition is 50% by weight or more; <13> The composition for organic electroluminescent elements according to claim 1. <15> The viscosity of the solvent B at 23°C is 5 mPas or less. <13> or <14> The composition for organic electroluminescent elements according to claim 1. <16> the boiling point a of the solvent compound and the boiling point b of the solvent B satisfy the condition: boiling point b<boiling point a; <13> ~ <15> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <17> The difference between the boiling point a and the boiling point b is 10°C or more. <13> ~ <16> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <18> The boiling point a is in the range of 270°C or higher and 340°C or lower, and the boiling point b is in the range of 250°C or higher and 340°C or lower. <13> ~ <17> 10. The composition for organic electroluminescent devices according to claim 9, wherein the organic electroluminescent device is a polyimide film. <19> <2> ~ <18> 10. A method for producing an organic electroluminescent element, comprising a step of wet film formation using the composition for organic electroluminescent elements according to any one of 1 to 9. [Effects of the Invention]

[0032] According to the present invention, it is possible to provide a solvent compound for an organic electroluminescent device that can improve the flatness of a layer, a composition using the same, and a method for producing an organic electroluminescent device. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the structure of an organic electroluminescent device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] 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 modified forms within the scope of the gist thereof.

[0035] As a result of intensive research conducted by the present inventors to solve the above problems, it was found that the flatness of the layer can be improved by using a solvent compound represented by formula (1), and that this makes it possible to provide an aromatic compound that can adjust wavelengths over a wider range, particularly to the long wavelength side represented by red.

[0036] <Solvent compounds for organic electroluminescent devices> The solvent compound for organic electroluminescent devices of the present invention is a solvent compound for organic electroluminescent devices represented by the following formula (1).

[0037] [ka]

[0038] (In formula (1), R 1 , R 2 , R 3 , n 1 , m 1 satisfies either (i) or (ii) below. (i) R 1 represents an alkyl group having 1 to 6 carbon atoms, R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, n 1 represents an integer from 1 to 5, R 3 does not exist, i.e., m 1 =0. (ii) R 1 represents an alkyl group having 2 to 6 carbon atoms, R 2 , R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, n 1 , m 1 represents an integer between 0 and 5.)

[0039] Generally, functional materials forming organic electroluminescent devices are aromatic compounds. The solvate of the present invention has two phenyl groups bonded to one terminal carbon of an alkyl group. That is, the two phenyl groups are connected by a methylene group. Here, the phenyl groups interact with aromatic solute compounds, allowing the aromatic solute compounds, which are functional materials, to be dissolved at high concentrations. Furthermore, the two benzene rings are connected by a quaternary carbon, which disrupts the planarity of the molecular skeleton and increases its degree of freedom. This facilitates free arrangement to improve affinity with solute compounds, presumably further increasing solubility.

[0040] In the case of (i), it is further considered that the asymmetry is increased by having a substituent on only one of the two phenyl groups in the solvate of the present invention, and asymmetric aggregates are formed, allowing the solute compound to disperse more than in a symmetric solvent, forming a more uniform and flat amorphous organic film.

[0041] In addition, in the case of (ii) and in the case of (i), n 1 Furthermore, when the alkyl group having two phenyl groups bonded to its terminal is an alkyl group having three or more carbon atoms, the solvent compounds of the present invention interact with each other at the sites where the two phenyl groups are not bonded to form a uniform solution. Therefore, it is believed that the solute compound is dispersed more uniformly, forming a uniform, flat, amorphous organic film.

[0042] As a result, it is expected that a light-emitting element with excellent luminous efficiency and / or long life can be obtained.

[0043] In the following description, the solvate for organic electroluminescent devices of the present invention may be simply referred to as a solvent or a solvent. Whether or not something simply referred to as a solvent or a solvent is the solvate for organic electroluminescent devices of the present invention is to be appropriately interpreted in accordance with the context.

[0044] <Case (i)> R 1represents an alkyl group having 1 to 6 carbon atoms, and R 2 each independently represents an alkyl group having 1 to 3 carbon atoms, and n 1 represents an integer from 1 to 5, and R 3 does not exist, i.e., m 1 =0.

[0045] <R 1 > R 1 is an alkyl group having 1 to 6 carbon atoms. The alkyl group may be a straight-chain alkyl group, or a branched-chain alkyl group can also be used. For example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group can be used. Preferred ranges are a methyl group, an ethyl group, a straight-chain or branched-chain propyl group, a straight-chain or branched-chain butyl group, a straight-chain or branched-chain pentyl group, and a straight-chain or branched-chain hexyl group. In terms of film flatness, a methyl group, an ethyl group, or an n-propyl group is particularly preferred, and a methyl group is most preferred.

[0046] <R 2 > R 2 are each independently an alkyl group having 1 to 3 carbon atoms. The alkyl group may be a straight-chain alkyl group, or a branched-chain alkyl group. Preferred ranges are methyl, ethyl, and propyl groups, and from the viewpoint of film flatness, methyl and ethyl groups are particularly preferred.

[0047] <n 1 > n 1 is an integer of 1 to 5, and is preferably an integer of 1 to 2 in terms of the flatness of the film. n 1 R 1 , R 2 The preferred range of R is 1 is a methyl group, an ethyl group, an n-propyl group, or an n-butyl group, and R 2 is preferably a methyl group or an ethyl group, and from the viewpoint of coating property, R 1 is a methyl group or an ethyl group, and R 2 is preferably an ethyl group.

[0048] n 1 If is 2, R 1 is a methyl group, an ethyl group, or a propyl group, and R 2 is preferably a methyl group from the viewpoint of the stability of the coating film, and from the viewpoint of the storage stability of the ink, 1 is a methyl group, R 2 is particularly preferably a methyl group.

[0049] When the solvent compound for organic electroluminescent devices of the present invention is (i), R 2 has an alkyl group as R 3 Since there is no R, it is thought that the two benzene rings are asymmetric, which gives the compound excellent solubility. 1 and R 2 It is believed that the stability of the solvent compound itself is improved by the fact that the methyl group has a small number of carbon atoms, and as a result, it is believed that an ink having high solubility in functional materials used in organic electroluminescent devices containing many aromatic ring groups and excellent storage stability can be obtained.

[0050] <Case (ii)> R 1 represents an alkyl group having 2 to 6 carbon atoms, and R 2 , R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, and n 1 , m 1 represents an integer from 0 to 5.

[0051] <R 1 > R 1 is an alkyl group having 2 to 6 carbon atoms. The alkyl group may be a straight-chain alkyl group, or a branched-chain alkyl group may be used. For example, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group may be used. From the viewpoint of improving flatness, the alkyl group is particularly preferably an ethyl group, a straight-chain or branched-chain propyl group, a straight-chain or branched-chain butyl group, a straight-chain or branched-chain pentyl group, or a straight-chain or branched-chain hexyl group. From the viewpoint of the flatness, stability, and solubility of the film, R 1is preferably an alkyl group having 3 to 5 carbon atoms, more preferably an alkyl group having 4 or 5 carbon atoms. In terms of the flatness and stability of the film, an n-butyl group or an n-pentyl group is more preferred.

[0052] <R 2 , R 3 > R 2 , R 3 Each independently represents an alkyl group having 1 to 3 carbon atoms. The alkyl group may be a linear alkyl group or a branched alkyl group. Preferred alkyl groups are methyl, ethyl, and propyl groups, and from the viewpoint of the flatness of the film, methyl is particularly preferred.

[0053] R 2 and R 3 may be the same or different, but from the viewpoint of improving the solubility of the solute and the uniformity of the film, it is preferable that they are different.

[0054] <n 1 , m 1 > n 1 , m 1 is an integer between 0 and 5. 1 , m 1 is preferably an integer of 0 to 2, and particularly preferably 0 or 1, from the viewpoint of the flatness of the film.

[0055] R 1 , R 2 , n 1 The preferred range of n 1 If is 0, m 1 is 0 and R 1 has preferably 3 or more carbon atoms, and is preferably an n-propyl group, an n-butyl group, or an n-pentyl group. From the viewpoint of coatability, it is particularly preferably 4 or more carbon atoms, and an n-butyl group or an n-pentyl group is preferred from the viewpoint of the stability of the coated film. In this case, the two benzene rings in formula (1) have no substituents and there is little steric hindrance, so it is thought that they easily interact with the aromatic ring group of the functional material used in the organic electroluminescent element, and furthermore, R 1It is believed that the solubility is further improved by the fact that the number of carbon atoms is 3 or more.

[0056] n 1 If is 1, then m 1 is 1 and R 1 is an n-propyl group, an n-butyl group, and R 2 , R 3 is preferably a methyl group or an ethyl group from the viewpoint of the stability of the coating film.

[0057] n 1 If is 2, then m 1 is 1 or 2, and R 1 is an ethyl group or a propyl group, and R 2 , R 3 is preferably a methyl group from the viewpoint of the stability of the coating film.

[0058] <Composition for organic electroluminescent devices> The composition for organic electroluminescent devices of the present invention (hereinafter sometimes referred to as the composition of the present invention) is a composition containing a functional material and a solvent A, where the solvent A is a solvent compound for organic electroluminescent devices having the structure of the above general formula (1). The composition of the present invention also preferably contains a solvent B, where the solvent B is a solvent compound different from the solvent A and has a boiling point of 200°C or higher.

[0059] The content of solvent A is preferably 0.5 to 50% by weight based on the total amount of solvents. The proportion of functional material is approximately 0.5 to 10% by weight, and if solvent A is included at least 0.5% by weight, the ratio of solvent A to the solute will be high just before film formation, and it is thought that solvent A will affect the smoothness of the film.

[0060] Solvent A contained in the composition of the present invention is a compound having a structure represented by formula (1), which has a specific asymmetric structural formula, and has both high solubility for functional materials and appropriate viscosity, making it possible to use it as an ink that can be ejected from a micro-nozzle.

[0061] The composition of the present invention exhibits a moderate viscosity at room temperature, but when the temperature drops due to the heat of vaporization during vacuum drying, the viscosity increases. This slows the liquid flow rate, making it possible to control the film shape and obtain a flat film. This is particularly noticeable in compositions using low-molecular-weight materials that are relatively more crystalline than polymers.

[0062] In this specification, when the composition of the present invention is used as ink to be ejected from a nozzle of an inkjet or the like, it may be simply referred to as ink.

[0063] When the composition of the present invention is used as an ink to be ejected from a nozzle of an inkjet or the like and is ejected from the nozzle and applied within an area surrounded by a bank, the ink within the area surrounded by the bank may be referred to as a liquid or a liquid film, and the ink ejected from the nozzle may be referred to as droplets.

[0064] When the liquid film in the area surrounded by the bank is dried and the solvent volatilizes, the solvent composition ratio of the liquid film changes, and this may also be referred to as a liquid or a liquid film.

[0065] A film containing a functional material obtained by applying the composition of the present invention to form a film and then drying it by volatilizing the organic solvent is called a functional film. Also, a film containing an organic compound that does not contain a solvent or that has been dried by substantially volatilizing the solvent is called an organic film. A functional film is a type of organic film.

[0066] <Type of solvent> From the viewpoints of decreasing the temperature, improving flatness by increasing the viscosity, and ensuring flatness at the panel edge, it is preferable to use at least one type of solvent B in addition to solvent A.

[0067] The solvent B is not particularly limited as long as it has a boiling point of 200°C or higher, but preferred examples include water-insoluble aromatic solvents such as aromatic hydrocarbon solvents, aromatic ester solvents, aromatic ether solvents, and aromatic ketone solvents, or mixtures thereof.

[0068] As the aromatic hydrocarbon solvent, benzene derivatives, naphthalene derivatives, hydrogenated naphthalene derivatives, and biphenyl derivatives are preferred.

[0069] The benzene derivative is preferably a benzene derivative having a total carbon number of 5 to 12 inclusive in the substituents and having a linear, branched, or alicyclic alkyl group as a substituent, and examples thereof include n-octylbenzene, n-nonylbenzene, n-decylbenzene, and dodecylbenzene.

[0070] The naphthalene derivative is not particularly limited, but is preferably a naphthalene derivative substituted with an alkyl group, and examples thereof include 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, 2,6-dimethylnaphthalene, and 1-methoxynaphthalene.

[0071] Examples of hydrogenated naphthalene derivatives include tetralin, 1,2-dihydronaphthalene, and 1,4-dihydronaphthalene, which may be substituted with an alkyl group having 1 to 6 carbon atoms.

[0072] The biphenyl derivative is not particularly limited, but is preferably a biphenyl derivative substituted with an alkyl group having 1 to 6 carbon atoms, such as 3-ethylbiphenyl or 4-isopropylbiphenyl.

[0073] Other preferred aromatic hydrocarbon solvents include diphenylmethane and methyldiphenylmethane.

[0074] Examples of aromatic ester solvents include benzoate ester solvents, phenylacetate ester solvents, and phthalate ester solvents.

[0075] The benzoate ester solvent is a compound having an ester bond with benzoic acid, and a compound in which an optionally substituted benzoic acid is ester-bonded to an alcohol having from 2 to 12 carbon atoms can be used. The optional substituent is preferably a linear or branched alkyl group having from 1 to 6 carbon atoms, or a linear or branched alkoxy group having from 1 to 6 carbon atoms. There may be multiple of these substituents, and when there are multiple substituents, the total number of carbon atoms as the substituents is preferably 6 or less. Examples of the benzoate ester solvent include butyl benzoate, n-pentyl benzoate, isoamyl benzoate, n-hexyl benzoate, 2-ethylhexyl benzoate, benzyl benzoate, and ethyl 4-methoxybenzoate.

[0076] Examples of the phenylacetic acid ester solvent include ethyl phenylacetate. Examples of phthalate ester solvents include dimethyl phthalate, diethyl phthalate, and dibutyl phthalate.

[0077] Other preferred aromatic ester solvents include 2-phenoxyethyl acetate, 2-phenoxyethyl isobutyrate, and the like.

[0078] Aromatic ether solvents are compounds having an aromatic ring and an ether bond, and examples thereof include the following: Examples of diphenyl ether derivatives which may be substituted with a linear or branched alkyl group having from 1 to 6 carbon atoms include diphenyl ether, 2-phenoxytoluene, 3-phenoxytoluene, and 4-phenoxytoluene; Benzene derivatives having two ether bonds with a linear or branched alkyl group having from 1 to 6 carbon atoms, such as 1,4-diethoxybenzene and 1-ethoxy-4-hexyloxybenzene; Benzene derivatives having a linear or branched alkyl group having from 4 to 12 carbon atoms and one ether bond, such as phenylhexyl ether; Benzyl ether solvents, such as dibenzyl ether; Other aromatic ether solvents include 2-phenoxyethanol:

[0079] Aromatic ketone solvents are compounds having an aromatic ring and a ketone structure, and examples thereof include 1-acetylnaphthalene.

[0080] The solvent B used in the present invention may be a water-insoluble non-aromatic solvent, and examples of the water-insoluble non-aromatic solvent include ether solvents and glycol ester solvents.

[0081] <Other solvent components> The composition of the present invention may contain a third component other than solvent A and solvent B. Examples of the third component include solvent components that do not satisfy formula (1) and have a boiling point of less than 200°C. For example, among the solvent components that can be used in solvent B, those having a boiling point of less than 200°C can be mentioned.

[0082] The content of the third component is preferably in the range of 0 to 60% by weight based on the composition of the present invention, and from the viewpoint of the flatness of the film, is preferably in the range of 0 to 30% by weight.

[0083] <boiling point> The boiling point of solvent A is preferably 200°C or higher, more preferably in the range of 260°C to 350°C, and particularly preferably in the range of 270°C to 340°C. Of the solvents contained in the composition of the present invention, solvent B has a boiling point of 200°C or higher, and particularly preferably in the range of 250°C to 340°C.

[0084] By using a solvent with a specific structure (formula (1)) as the solvent with a higher boiling point, it is possible to improve the uniformity of the film thickness when an organic film is wet-formed in the area surrounded by the bank.

[0085] Therefore, it is preferable that the boiling points satisfy the condition b of solvent B < a of solvent A. This is thought to increase the viscosity of solvent A due to the heat of vaporization when solvent B evaporates, resulting in the formation of a flat film.

[0086] It is also preferable that the difference between the boiling point a of solvent A and the boiling point b of solvent B is 10°C or more.

[0087] The boiling points of solvent A and solvent B used in the present invention are both 200°C or higher, and it is preferable from the viewpoint of film formation that the boiling point of solvent A be higher than that of solvent B. During the drying process after application, solvent B, which has a lower boiling point, usually volatilizes before solvent A. As will be described later, when a liquid film is formed using a composition discharged into a bank and the liquid film is dried by vacuum drying or the like, solvent B, which has a lower boiling point, volatilizes first. At this time, the temperature of the liquid film is lowered by the loss of heat of vaporization. At this time, it is believed that the viscosity of solvent A remaining in the liquid film increases, and the asymmetric structure inherent to the solvent can impart a uniform film shape, allowing a flat film to be obtained. In the present invention, the boiling point of the solvent is a value measured under 1 atmosphere.

[0088] Specific examples of the compound represented by formula (1) are listed below, but the present invention is not limited to these.

[0089] [ka]

[0090] [ka]

[0091] <Viscosity> The viscosity of solvent A is preferably 3 mPas or more and 20 mPas or less. Solvent B preferably has a viscosity of 5 mPas or less at 23° C. When the viscosity of solvent B is equal to or less than the above upper limit, it becomes possible to select a solvent A with a higher viscosity or a functional material that can easily increase the viscosity when preparing the composition, thereby widening the range of choices for solvent A and functional materials, and the range of choices for ink concentration.

[0092] The viscosity of solvent B is particularly preferably 4.5 mPas or less. On the other hand, from the viewpoint of making it easier to retain the ink in the inkjet head when filled with solvent B, the viscosity of solvent B is preferably 1.0 mPas or more.

[0093] In the present invention, the viscosity of the solvent can be measured using an E-type viscometer RE85L (manufactured by Toki Sangyo Co., Ltd.) in an environment of 23° C. with a cone plate rotation speed of 20 rpm to 100 rpm.

[0094] <Surface tension> The surface tension of solvent A is preferably 30 mN / m or more and 45 mN / m or less. It is believed that keeping the surface tension of the ink as a whole within this range will maintain an appropriate range, enabling stable ejection from an inkjet device. It is also believed that having the surface tension of solvent A within this range will facilitate flattening of the liquid surface within the bank, which is preferable. When the surface tension of solvent A is above the lower limit, tension of a certain level or more is generated on the liquid surface during drying, which tends to reduce the surface area, making it less likely for wrinkles to form in the film. On the other hand, when the surface tension of solvent A is below the upper limit, it is less likely for surface tension differences to occur during drying, making it less likely for unnecessary Marangoni convection to occur, making it easier to form a flat film, which is preferable.

[0095] In the present invention, the surface tension of a solvent can be measured in an environment of 23.0°C by the plate method using a platinum plate.

[0096] <Solvent combination> The solvent A and the solvent B contained in the composition of the present invention may each be one type or multiple types.

[0097] In particular, the inclusion of two or more types of solvent A is preferable because it makes it possible to adjust the surface tension that tends to generate convection of the solvent in front of the thin film, and solvent A, which has an asymmetric structure, can further suppress heterogeneity, thereby further improving flatness.

[0098] The solvent B contained in the composition of the present invention is preferably a water-insoluble solvent, and more preferably a water-insoluble aromatic solvent.

[0099] In particular, from the viewpoint of dissolving the functional material well and preventing it from easily precipitating during the drying process, it is preferable that solvent B is any one of naphthalene, benzoic acid ester, and aromatic ether, each of which may have a substituent.

[0100] [Content of solvent A and solvent B] The content of solvent A is 0.5 to 50% by weight relative to the total amount of solvents in the composition of the present invention. In order to efficiently lower the temperature of solvent A by volatilizing solvent B, it is necessary to maintain a large amount of volatile components, so the content of solvent A is 50% by weight or less, preferably 40% by weight or less, and more preferably 30% by weight or less. In order to keep the functional material dissolved when solvent B volatilizes, the content of solvent A is 0.5% by weight or more, preferably 5% by weight or more, and more preferably 15% by weight or more.

[0101] The total content of solvent A and solvent B relative to the total amount of solvents contained in the composition is preferably 50% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, particularly preferably 85% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more, with the upper limit being 100% by weight. When the total content of solvent A and solvent B is equal to or more than the above lower limit, the ink can be used as an ink that can be ejected from a micro-nozzle, drying of the solvent can be easily controlled, and the effects of the present invention can be easily achieved.

[0102] [Functional materials] The functional material in the present invention preferably has a molecular weight of 50,000 or less. The functional material in the present invention may be a low-molecular-weight material or a high-molecular-weight material, but a more significant effect can be obtained when the material is a low-molecular-weight material. Here, the low-molecular-weight material preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5,000 or less.

[0103] As the functional material in the present invention, a material for a light-emitting layer, a material for a hole-injection layer, a material for a hole-transport layer, or a material for an electron-transport layer, which will be described later, can be used, and a material for a light-emitting layer, a material for a hole-injection layer, or a material for a hole-transport layer is preferred. A material for a light-emitting layer is more preferably a low-molecular-weight material for a light-emitting layer.

[0104] The functional material of the present invention is preferably an electron-accepting compound. When the composition of the present invention contains an electron-accepting compound, the composition of the present invention is preferably a composition for forming a hole injection layer.

[0105] The functional material in the present invention is preferably a polymer compound. The polymer compound is preferably a hole-transporting polymer compound, and is usually used as a material for a hole injection layer, a hole-transport layer, or a light-emitting layer.

[0106] The composition of the present invention may contain only one type of functional material or may contain two or more types. When the composition of the present invention contains an electron-accepting compound as a functional material, it preferably further contains a hole-transporting polymer compound.

[0107] [Electron-accepting compounds] The composition of the present invention preferably contains a solvent compound represented by the formula (1) and an electron-accepting compound. The electron-accepting compounds preferably used in the composition of the present invention are as follows.

[0108] The electron-accepting compound is preferably a compound having oxidizing power and the ability to accept one electron from the hole-transporting material. Specifically, the electron-accepting compound is preferably a compound having an electron affinity of 4.0 eV or more, more preferably 5.0 eV or more.

[0109] Examples of such electron-accepting compounds include one or more compounds selected from the group consisting of tetraarylboron ion compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. More specifically, examples of the electron-accepting compound include onium salts substituted with organic groups, such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate (WO 2005 / 089024 and WO 2017 / 164268); high-valent inorganic compounds, such as iron(III) chloride (JP 11-251067 A) and ammonium peroxodisulfate; cyano compounds, such as tetracyanoethylene; and aromatic boron compounds, such as tris(pentafluorophenyl)borane (JP 2003-31365 A); fullerene derivatives; iodine; and sulfonate ions, such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphorsulfonate ions.

[0110] [Tetraarylborate ion] A tetraarylborate ion is a monovalent anion in which the boron atom is substituted with four optionally substituted aromatic hydrocarbon rings or optionally substituted aromatic heterocyclic rings.

[0111] The tetraarylborate ion preferably contained in the composition of the present invention has a fluorine atom or a fluorine-substituted alkyl group as a substituent on the aryl group, and therefore is highly stable. Furthermore, the tetraarylborate ion preferably contained in the composition of the present invention is preferably an ionic compound consisting of a tetraarylborate ion represented by the following formula (2) and a counter cation. The presence of the tetraarylborate ion represented by the following formula (2) further increases the stability of the anion and further enhances the effect of stabilizing the cation.

[0112] [ka]

[0113] (In formula (2), Ar 1 , Ar 2 , Ar 3 and Ar 4 each independently represent an optionally substituted aromatic hydrocarbon ring group, an optionally substituted aromatic heterocyclic group, or a monovalent group formed by linking together a plurality of structures selected from optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups; The substituent may be a bridging 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.

[0114] In addition, Ar in the formula (2) 1 , Ar 2 , Ar 3 and Ar 4 At least one of the above is preferably a group represented by the following formula (3).

[0115] [ka]

[0116] (In formula (3), R 100 each independently represents an aromatic hydrocarbon ring group which may have a substituent, an aromatic heterocyclic group which may have a substituent, a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together, a fluorine-substituted alkyl group, or R 100 is a group containing a bridging group, F4 represents four fluorine atoms substituted, F (5-m) each independently represents substitution with 5-m fluorine atoms, Each k independently represents an integer of 0 to 5, Each m independently represents an integer of 0 to 5.

[0117] Ar 1 , Ar 2 , Ar 3 and Ar 4 The aromatic hydrocarbon ring in the aromatic hydrocarbon ring 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.

[0118] Ar 1 , Ar 2 , Ar 3 and Ar 4 The aromatic heterocyclic ring in 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.

[0119] 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.

[0120] The number of monocyclic or 2 to 6 fused ring aromatic hydrocarbon ring 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 optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups are linked together is 2 or more, preferably 8 or less, more preferably 4 or less, and even more preferably 3 or less.

[0121] 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.

[0122] Ar 1 , Ar 2 , Ar 3 and Ar 4 The substituent of is preferably a fluorine atom or a fluorine-substituted alkyl group, since it increases the stability of the anion and improves 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.

[0123] 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 the crosslinked product of the electron-accepting compound having a crosslinking group and the coating film laminated thereon will be stable.

[0124] The tetraarylborate ions contained in the composition of the present invention are Ar 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 the formula (3), 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 the formula (3), and Ar 1 , Ar 2 , Ar 3 and Ar 4 It is most preferred that all of them are each independently a group represented by formula (3).

[0125] 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 more preferably 0.

[0126] m is preferably 0 in view of superior durability, and is preferably 1 or more in view of the possibility of introducing various functions into the tetraarylborate ion, and is more preferably 1 or 2 in view of compatibility with durability.

[0127] In terms of improving the stability of the anion and providing excellent durability, k+m≧1 is preferred, and k+m≧2 is more preferred.

[0128] R 100 The aromatic hydrocarbon ring group or aromatic heterocyclic group may have the following preferred structures and substituents: 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.

[0129] R 100 Examples of the substituent include the groups described in the substituent group W below.

[0130] In formula (3), at least one R 100 is preferably the above-mentioned fluorine-substituted alkyl group, more preferably a perfluoroalkyl group, and more preferably a trifluoromethyl group.

[0131] [Bridging group] In formula (3), at least one R 100 contains a crosslinking group, and the crosslinking group is preferably represented by any one of the following formulae (X1) to (X18) in the following group T of crosslinking groups.

[0132] (Bridging group T)

[0133] [ka]

[0134] 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 (10) 110 represents a hydrogen atom or an alkyl group which may have a substituent.

[0135] The groups represented by (X1) to (X4) may have a substituent, and examples of the substituent include R 100 The substituents are the same as those that may be possessed by the group. R 110 When is an alkyl group, it is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

[0136] R 100 is preferably a group represented by formula (X1), a group represented by formula (X2), or a group represented by formula (X4), or a structure in which one or more groups represented by formula (X1), (X2), or (X4) are bonded to an aromatic hydrocarbon group.

[0137] R 100 However, when one or more groups represented by formula (X1), (X2), or (X4) are bonded to an aromatic hydrocarbon group, the aromatic hydrocarbon group is preferably a group containing 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. 100 is a group containing a structure in which a group represented by formula (X1), a group represented by formula (X2), or a group represented by formula (X4) is bonded to a monocyclic benzene ring or a monocyclic naphthalene ring, more preferably a group containing a structure in which a group represented by formula (X1), a group represented by formula (X2), or a group represented by formula (X4) is bonded to a benzene ring, and particularly preferably a group containing a structure in which one or two groups represented by formula (X1), a group represented by formula (X2), or a group represented by formula (X4) are bonded.

[0138] These groups represented by formulae (X1) to (X18) are preferred because they have crosslinking properties and are thought to prevent the tetraarylborate ion and the counter cation from diffusing into other layers.

[0139] (Substituent group W) The substituent group W is a hydrogen atom, a halogen atom, a cyano group, an aromatic ring group consisting of 1 to 5 aromatic rings, a 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.

[0140] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, and fluorine atoms are preferred from the viewpoint of compound stability. Substitution with four or more fluorine atoms is particularly preferred from the viewpoint of compound stability.

[0141] Examples of the aromatic ring group consisting of 1 to 5 aromatic 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, naphthyl group, biphenyl group, terphenyl group, or quaterphenyl group is preferred from the viewpoint of the stability of the compound.

[0142] Examples of the hydrocarbon ring group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0143] 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 i-propyl group, an n-butyl group, an i-butyl 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.

[0144] The alkenyl group has a carbon number of usually 2 or more and usually 24 or less, preferably 12 or less. Specific examples include a vinyl group, a propenyl group, and a butenyl group.

[0145] The alkynyl group generally has 2 or more carbon atoms and generally 24 or less, preferably 12 or less carbon atoms, and specific examples thereof include an acetyl group, a propynyl group, and a butynyl group.

[0146] Examples of the aralkyl group include a benzyl group, a phenylethyl group, and a phenylhexyl group.

[0147] The alkoxy group typically has 1 or more carbon atoms and typically 24 or less, preferably 12 or less, and more preferably 6 or less, and specific examples include a methoxy group, an ethoxy group, a butyloxy group, a hexyloxy group, and an octyloxy group.

[0148] 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.

[0149] 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.

[0150] The arylthio group generally has 4 or more carbon atoms, preferably 5 or more carbon atoms, and generally has 36 or less carbon atoms, preferably 24 or less carbon atoms. Specific examples include a phenylthio group and a naphthylthio group.

[0151] The alkyl ketone group typically has 1 or more carbon atoms and typically 24 or less, preferably 12 or less, and more preferably 6 or less, and specific examples include an acetyl group, an ethylcarbonyl group, a butylcarbonyl group, and an octylcarbonyl group.

[0152] The aryl ketone group generally has 5 or more carbon atoms, preferably 7 or more carbon atoms, and generally has 25 or less carbon atoms, preferably 13 or less carbon atoms. Specific examples include a benzoyl group and a naphthylcarbonyl group.

[0153] Adjacent substituents may be bonded to form a ring. Examples of the ring include a cyclobutene ring and a cyclopentene ring.

[0154] These substituents may further be substituted with a substituent, and examples of the substituent include a halogen atom, an alkyl group, or an aryl group.

[0155] 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.

[0156] [Examples of tetraarylborate ions] Specific examples of the tetraarylborate ion used in the composition of the present invention are listed below, but the present invention is not limited to these.

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167] Among the above specific examples, compounds represented by (A-1) or (A-2) are preferred in terms of electron-accepting property, heat resistance, and solubility. Furthermore, compounds represented by (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 represented by (A-19), (A-21), (A-25), (A-26), and (A-28) are particularly preferred in terms of composition stability.

[0168] [Electron-accepting ionic compounds containing tetraarylborate ions] The tetraarylborate ion is also preferably used as an electron-accepting ionic compound containing the tetraarylborate ion. The electron-accepting ionic 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.

[0169] 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.

[0170] The iodonium cation is preferably a structure represented by the general formula (6) described below, and the same also applies to more preferred structures.

[0171] 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.

[0172] 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.

[0173] Specific examples of the carbocation include trisubstituted carbocations such as triphenyl carbocation, tri(methylphenyl) carbocation, and tri(dimethylphenyl) carbocation.

[0174] 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.

[0175] 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.

[0176] Among these, in terms of film stability of the compound, iodonium cation, carbocation and sulfonium cation are preferred, with iodonium cation being more preferred.

[0177] The iodonium cation serving as the counter cation of the first ionic compound preferably has a structure represented by the following formula (6).

[0178] [ka]

[0179] In formula (6), Ar 5 , Ar 6 Each of Ar is 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 ring group or 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

[0180] The counter cation represented by the formula (6) is preferably represented by the following formula (7).

[0181] [ka]

[0182] In formula (7), Ar 7 and Ar 8 is the Ar in the above formula (6). 5 and Ar 6 The substituents are the same as those that may be possessed by the group.

[0183] The molecular weight of the first ionic compound used in the present invention is usually 900 or more, preferably 1000 or more, more preferably 1200 or more, and usually 10000 or less, preferably 5000 or less, 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.

[0184] [Specific example] Specific examples of ionic compounds with iodonium cations are listed below as the first ionic compound in the present invention, but the first ionic compound is not limited to these.

[0185] [ka]

[0186] [ka]

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] Among the above specific examples, compounds represented by (B-1) or (B-2) are preferred in terms of electron-accepting property, heat resistance, and solubility. Furthermore, compounds represented by (B-18), (B-19), (B-20), (B-21), (B-25), (B-26), and (B-28) are more preferred in terms of high stability as a composition for a charge transport film, and compounds represented by (B-19), (B-21), (B-25), (B-26), and (B-28) are particularly preferred in terms of composition stability.

[0198] Incorporating such an electron-accepting compound is also preferable for achieving a flatter film. Electron-accepting compounds are typically highly electronegative to achieve high electron affinity. This results in a relatively large polarity parameter in terms of the Hansen solubility parameter, making them less soluble in nonpolar solvents. When using a solvent compound represented by general formula (1), the compatibility between the two benzene rings and the electron-accepting compound is very poor, which is thought to lead to the electron-accepting compound tending to accumulate on the outermost surface of the ink. When forming the hole-injection layer, the electron-accepting compound precipitates slightly during the drying process, distributing to the outermost surface of the ink. This reduces flow due to Laplace pressure and suppresses Marangoni convection caused by differences in surface tension, which is thought to be favorable for obtaining a flatter film.

[0199] [Hole-transporting polymer compounds] The composition of the present invention preferably contains a hole transport polymer compound. The hole transport polymer compound is usually used to form a hole injection layer, a hole transport layer, or a light emitting layer, and is contained in a composition for forming a hole injection layer, a composition for forming a hole transport layer, or a composition for forming a light emitting layer, which will be described later. In this case, the composition of the present invention is a composition for forming a hole injection layer, a composition for forming a hole transport layer, or a composition for forming a light emitting layer.

[0200] The hole transport polymer compound is preferably a polymer containing the following triarylamine structure as a repeating unit.

[0201] [Preferred polymer] When the functional material contained in the composition of the present invention includes a hole-transporting polymer, the hole-transporting polymer is preferably a polymer having a triarylamine structure as a repeating unit, the repeating unit of which is represented by the following formula (50):

[0202] [ka]

[0203] (In formula (50), Ar 51 represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a group in which a plurality of groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together; Ar 52 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 groups and the divalent aromatic heterocyclic groups 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. 51 , Ar 52 may have a crosslinking group.

[0204] The bridging group is Ar 51 or Ar 52 It is preferably bonded to directly or via a linking group. The linking group is preferably an aromatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a structure in which a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic hydrocarbon groups which may have a substituent are linked together, and the aromatic hydrocarbon group is preferably a phenyl group. The substituent which the aromatic hydrocarbon group serving as a linking group may have is selected from the following substituent group Z. It is preferable that the aromatic hydrocarbon group serving as a linking group does not have a substituent.

[0205] (crosslinking group) Here, the crosslinking group refers to a group that reacts with another crosslinking 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.

[0206] The crosslinking group is not limited to, but includes a group containing an alkenyl group, a group containing a conjugated diene structure, a group containing an alkynyl group, a group containing an oxirane structure, a group containing an oxetane structure, a group containing an aziridine structure, an azide group, a group containing a maleic anhydride structure, a group containing an alkenyl group bonded to an aromatic ring, a cyclobutene ring fused to an aromatic ring, etc. Specific examples of preferred crosslinking groups include crosslinking groups selected from the group T of crosslinking groups.

[0207] (Ar 52 ) [Main chain] In the repeating unit represented by the above formula (50), Ar 52 represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a group in which a plurality of groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together. Here, the substituents which the aromatic hydrocarbon group and the aromatic heterocyclic group may have are preferably the same groups as those in the substituent group Z described below.

[0208] The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms. Specific examples include divalent groups of 6-membered monocyclic or 2-5 fused rings, such as a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring, or groups formed by linking multiple rings thereof. When multiple rings are linked, divalent groups formed by linking 2 to 10 rings are exemplified, and divalent groups formed by linking 2 to 5 rings are preferred. For example, a "divalent group of a benzene ring" refers to a "benzene ring having two free valences," i.e., a phenylene group. Preferred aromatic hydrocarbon groups include a benzene ring, a biphenyl ring (i.e., a structure in which two benzene rings are linked), a terphenyl ring (i.e., a structure in which three benzene rings are linked), a quaterphenylene ring (i.e., a structure in which four benzene rings are linked), and a divalent group of a fluorene ring.

[0209] The aromatic heterocyclic group preferably has 3 or more and 60 or less carbon atoms, and 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 benzoyl ... Examples of the aromatic heterocyclic group include a divalent group of a 5- or 6-membered monocyclic ring or a 2- to 4-fused ring such as an isoxazole 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 benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring, or a group in which multiple rings are linked together. When multiple rings are linked together, examples include a divalent group in which 2 to 10 rings are linked together, and a divalent group in which 2 to 5 rings are linked together is preferred. The aromatic heterocyclic group is preferably a divalent group of a thiophene ring, a benzothiophene ring, a carbazole ring, or a triazine ring.

[0210] The divalent group in which a plurality of optionally substituted aromatic hydrocarbon groups or optionally substituted aromatic heterocyclic groups are linked directly or via a linking group may be a group in which a plurality of the same groups are linked, or a group in which a plurality of different groups are linked. Examples of the group in which a plurality of groups are linked include divalent groups in which 2 to 10 groups are linked, and a divalent group in which 2 to 5 groups are linked is preferred.

[0211] (Ar 51 ) [Side chain] In the repeating unit represented by the above formula (50), Ar 51 represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a group in which a plurality of groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together. The substituent is preferably the same group as the substituent group Z described below.

[0212] The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms, and specific examples thereof include monovalent groups of 6-membered rings or 2-5 condensed rings, such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring, or groups in which multiple rings are linked together. When multiple rings are linked together, examples include monovalent groups in which 2 to 10 rings are linked together, and monovalent groups in which 2 to 5 rings are linked together are preferred. For example, a "monovalent group of a benzene ring" means a "benzene ring having a single free valence," i.e., a phenyl group.

[0213] The aromatic heterocyclic group preferably has 3 or more and 60 or less carbon atoms, and 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 benzoyl ... Examples of the monovalent group include a 5- or 6-membered monocyclic or 2- to 4-fused ring monovalent group, such as an isoxazole 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 benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring, or a group in which multiple rings are linked together. When multiple rings are linked together, examples include a monovalent group in which 2 to 10 rings are linked together, and a monovalent group in which 2 to 5 rings are linked together is preferred.

[0214] The monovalent group in which a plurality of optionally substituted aromatic hydrocarbon groups or optionally substituted aromatic heterocyclic groups are linked directly or via a linking group may be a group in which a plurality of the same groups are linked, or a group in which a plurality of different groups are linked. Examples of the group in which a plurality of groups are linked include monovalent groups in which 2 to 10 groups are linked, and a monovalent group in which 2 to 5 groups are linked is preferred.

[0215] Ar51 In terms of excellent charge transport properties and durability, Ar preferably contains a monovalent or divalent group in which 2 to 5 aromatic hydrocarbon groups, which may have a substituent, are linked together, and more preferably contains a monovalent or divalent group in which 2 to 5 benzene rings, which may have a substituent, are linked together. 51 When the group contains a divalent group in which 2 to 5 optionally substituted aromatic hydrocarbon groups are linked, the terminal is a monovalent aromatic hydrocarbon group which may have a substituent or a monovalent aromatic heterocyclic group which may have a substituent. As the substituent, a group selected from the group Z of substituents described below or a crosslinking group selected from the group T of crosslinking groups is preferred.

[0216] Ar 51 When has a bridging group as a substituent, Ar 51 is preferably a structure having a crosslinking group selected from the group T of crosslinking groups at the end 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.

[0217] Ar 51 is preferably an aromatic hydrocarbon group which may have a substituent, from the viewpoints of excellent charge transport properties and excellent durability, and among these, a monovalent group of a benzene ring or fluorene ring which may have a substituent, i.e., a phenyl group or fluorenyl group which may have a substituent, is more preferred, a fluorenyl group which may have a substituent is still more preferred, and a 2-fluorenyl group which may have a substituent is particularly preferred.

[0218] Ar 51 The 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.

[0219] Ar 51 In terms of solubility in a coating 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.

[0220] 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.

[0221] Also, Ar 51 is also preferably a spirobifluorenyl group from the viewpoint of solubility in a coating solvent.

[0222] (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 the polymer 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.

[0223] The polymer may be composed solely of repeating units represented by formula (50), but for the purpose of balancing various performances when made into an organic electroluminescent device, it may contain repeating units other than formula (50). In this case, the content of repeating units represented by formula (50) in the polymer is usually 99 mol % or less, preferably 95 mol % or less.

[0224] (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 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.

[0225] 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 i-propyl group, an n-butyl group, an i-butyl 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 generally has 2 or more and 24 or less carbon atoms, and preferably 12 or less carbon atoms; a linear or branched alkynyl group, such as an ethynyl group, having typically 2 to 24 carbon atoms, preferably 12 or less; Examples include aromatic hydrocarbon groups having usually 6 to 36 carbon atoms, preferably 24 or less, such as phenyl and naphthyl groups.

[0226] 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 a plurality of these optional additional substituents, they may be bonded to each other to form a ring.

[0227] From the viewpoint of charge transportability and durability, the terminal group is preferably an alkyl group or an aromatic hydrocarbon group, and more preferably an aromatic hydrocarbon group.

[0228] (Substituent group Z) The substituent group Z is a group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, alkoxycarbonyl groups, dialkylamino groups, diarylamino groups, arylalkylamino groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, silyl groups, siloxy groups, cyano groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups. These substituents may have any of a linear, branched, and cyclic structure.

[0229] More specifically, the substituent group Z includes the following structures. A linear, branched, or cyclic alkyl group having 1 or more carbon atoms, preferably 4 or more, and 24 or less, preferably 12 or less, further preferably 8 or less, and even more preferably 6 or less. Specific examples include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclohexyl group, and a dodecyl group. linear, branched, or cyclic alkenyl groups, such as vinyl groups, which usually have 2 or more carbon atoms and usually have 24 or less, preferably 12 or less, carbon atoms; For example, a linear or branched alkynyl group, such as an ethynyl group, having typically 2 or more carbon atoms and typically 24 or less, preferably 12 or less, carbon atoms; An alkoxy group having a carbon number of 1 or more and 24 or less, preferably 12 or less. Specific examples include a methoxy group and an ethoxy group. An aryloxy group or heteroaryloxy group having 4 or more, preferably 5 or more, carbon atoms and 36 or less, preferably 24 or less. Specific examples include a phenoxy group, a naphthoxy group, and a pyridyloxy group. An alkoxycarbonyl group having 2 or more and 24 or less carbon atoms, preferably 12 or less carbon atoms. Specific examples include a methoxycarbonyl group and an ethoxycarbonyl group. A dialkylamino group having 2 or more and 24 or less carbon atoms, preferably 12 or less. Specific examples include a dimethylamino group and a diethylamino group. A diarylamino group having 10 or more, preferably 12 or more, and 36 or less, preferably 24 or less carbon atoms. Specific examples include a diphenylamino group, a ditolylamino group, and an N-carbazolyl group. An arylalkylamino group having 7 or more and 36 or less carbon atoms, preferably 24 or less, such as a phenylmethylamino group. An acyl group having a carbon number of 2 or more and 24 or less, preferably 12 or less. Specific examples include an acetyl group and a benzoyl group. a halogen atom such as a fluorine atom or a chlorine atom, preferably a fluorine atom; A haloalkyl group having 1 to 12 carbon atoms, preferably 6 or less. Specific examples include a trifluoromethyl group. An alkylthio group having 1 or more carbon atoms and usually 24 or less, preferably 12 or less carbon atoms. Specific examples include a methylthio group and an ethylthio group. An arylthio group having 4 or more, preferably 5 or more, carbon atoms and 36 or less, preferably 24 or less. Specific examples include a phenylthio group, a naphthylthio group, and a pyridylthio group. A silyl group having a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less. Specific examples include a trimethylsilyl group and a triphenylsilyl group. A siloxy group having 2 or more carbon atoms, preferably 3 or more carbon atoms, and usually 36 or less, preferably 24 or less carbon atoms. Specific examples include a trimethylsiloxy group and a triphenylsiloxy group. Cyano group. An aromatic hydrocarbon group having a carbon number of 6 or more and 36 or less, preferably 24 or less. Specific examples include a phenyl group and a naphthyl group. An aromatic heterocyclic group having 3 or more carbon atoms, preferably 4 or more carbon atoms, and 36 or less, preferably 24 or less carbon atoms. Specific examples include a thienyl group and a pyridyl group.

[0230] The above substituents may have any of a straight-chain, branched, or cyclic structure. When the above-mentioned substituents are adjacent to each other, the adjacent substituents may be bonded to each other to form a ring. The ring size is preferably a 4-membered ring, a 5-membered ring, or a 6-membered ring, and specific examples thereof include a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.

[0231] Among the above-mentioned substituent group Z, alkyl groups, alkoxy groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups are preferred.

[0232] Furthermore, each of the substituents in the above-mentioned substituent group Z may further have a substituent. Examples of such a substituent include the same as those in the above-mentioned substituent group Z. Preferably, the further substituent is not present, or is 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. From the viewpoint of charge transport properties, it is more preferable that the further substituent is not present.

[0233] (preferably Ar 51 ) In addition, the polymer may contain Ar in the repeating unit represented by the formula (50). 51 At least one of the above is preferably a group containing a monovalent or divalent group in which 2 to 5 optionally substituted benzene rings are linked, a fluorenyl group which may have a substituent, 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).

[0234] (Formula (51))

[0235] [ka]

[0236] In formula (51), * represents a bond to the nitrogen atom of the main chain of formula (50), Ar 53 , Ar 54each 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.

[0237] Here, the substituents that each aromatic hydrocarbon group and each aromatic heterocyclic group may have, and Ar when they are substituents, 56 may have a crosslinking group. As the crosslinking group, a group selected from the group T of crosslinking groups can be used.

[0238] (Ar 53 , Ar 54 ) In the repeating unit represented by the formula (51), Ar 53 , Ar 54 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 directly or via a linking group. 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 is preferred. The substituents which the aromatic hydrocarbon group and the aromatic heterocyclic group may have may have a crosslinking group, and are preferably the same groups as those in the group Z of substituents. As the crosslinking group, a group selected from the group T of crosslinking groups may be used.

[0239] Ar 53 and Ar 54 The aromatic hydrocarbon group and aromatic heterocyclic group are 52The same aromatic hydrocarbon groups and aromatic heterocyclic groups as those mentioned above can be used.

[0240] The divalent group in which a plurality of optionally substituted aromatic hydrocarbon groups or optionally substituted aromatic heterocyclic groups are linked directly or via a linking group may be a group in which a plurality of the same groups are linked, or a group in which a plurality of different groups are linked.

[0241] When a plurality of the above divalent groups are linked together, examples include divalent groups with 2 to 10 linked groups, and divalent groups with 2 to 5 linked groups are preferred.

[0242] Ar 53 is preferably a group in which 1 to 6 optionally substituted divalent aromatic hydrocarbon groups are linked together, more preferably a group in which 2 to 4 optionally substituted divalent aromatic hydrocarbon groups are linked together, and among these, a group in which 1 to 4 optionally substituted phenylene rings are linked together is more preferred, and biphenylene in which 2 optionally substituted phenylene rings are linked together is particularly preferred.

[0243] When a plurality of such divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are linked, the group is preferably one in which the plurality of linked divalent aromatic hydrocarbon groups are bonded so as not to be conjugated. Specifically, it is preferable that the group contains a 1,3-phenylene group or a group having a substituent and forming a twisted structure due to the steric effect of the substituent.

[0244] Ar 53 The substituents that Ar may have are preferably the same as those in the substituent group Z. 53 has no substituents.

[0245] Ar 54From the viewpoints 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 benzene rings, naphthalene rings, anthracene rings, and fluorene rings, and more preferably benzene rings and fluorene rings. Preferred groups in which multiple groups are linked together are groups in which one to four phenylene rings, which may have a substituent, are linked together, or groups in which a phenylene ring, which may have a substituent, and a fluorene ring, which may have a substituent, are linked together. From the viewpoint of a wider LUMO, biphenylene, in which two phenylene rings, which may have a substituent, are linked together, is particularly preferred.

[0246] Ar 54 The substituent that may be possessed by may be any of the substituents in the above-mentioned group Z, or a combination thereof. The substituent is preferably other than an N-carbazolyl group, an indolocarbazolyl group, or an indenocarbazolyl group, and more preferably a phenyl group, a naphthyl group, or a fluorenyl group. It is also preferable that the group has no substituent.

[0247] (Ar 55 ) Ar 55 is a monovalent group in which a plurality of groups selected from an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group are linked together directly or via a linking group. Preferably, it is a group in which a plurality of optionally substituted monovalent aromatic hydrocarbon groups or optionally substituted monovalent aromatic hydrocarbon groups are linked together.

[0248] The substituents which the aromatic hydrocarbon group and the aromatic heterocyclic group may have may have a crosslinking group, and the crosslinking group is preferably the same as the group of substituents Z. As the crosslinking group, a group selected from the group of crosslinking groups T can be used.

[0249] When a plurality of aromatic hydrocarbons are linked, they are preferably divalent groups of 2 to 10 linked rings, and more preferably monovalent groups of 2 to 5 linked rings. 51 The same aromatic hydrocarbon groups and aromatic heterocyclic groups as those mentioned above can be used.

[0250] Ar 55 It is preferable that the compound has a structure represented by any one of the following schemes 2. Furthermore, from the viewpoint of distributing the LUMO of the molecule, 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 e1 to e4 is preferable. 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, and e1 to e4 is preferable. 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, and e1 to e4 is preferable. Furthermore, from the viewpoint of easy synthesis and excellent stability, d-1 and d-10 are more preferable, and the benzene ring structure of d-1 is particularly preferable. Furthermore, these structures may have a substituent. In the figure, "-*" represents Ar 54 If there are multiple "-*", one of them must be Ar 54 represents the bonding position with

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] <R 31 and R 32 > R in Scheme 2 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.

[0255] R 31 and R 32 may be the same or different, but all R 31 and R 32 are preferably the same groups.

[0256] Ar 55 As the substituent that may be possessed by Ar, any one of the substituents in the above-mentioned group Z or a combination thereof can be used. 54 It is preferable that the substituents are selected from the same substituents that may be possessed by the group.

[0257] (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 which may have a substituent or an aromatic heterocyclic group which may have a substituent. 53 ~Ar 54 It is a monovalent structure similar to the aromatic hydrocarbon structure and aromatic heterocyclic structure mentioned above.

[0258] Ar 56 When is a substituent, it may have a crosslinking group. As the crosslinking group, a group selected from the group T of crosslinking groups can be used.

[0259] Ar 56When Ar is a substituent, it is preferably bonded to the 3-position of carbazole from the viewpoint of improving durability. 56 is 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.

[0260] Ar 56 is preferably a hydrogen atom from the viewpoint of ease of synthesis and charge transport properties.

[0261] Ar 56 When is an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, the substituents are the same as those exemplified in the above-mentioned substituent group Z, the preferred substituents are also the same, and the substituents that these substituents may further have are also the same.

[0262] (Formula (52)) Ar in the repeating unit represented by the above formula (50) 51 At least one of the groups is preferably a group represented by the following formula (52): The reason for this is thought to be that in the two carbazole structures in the following formula (52), the LUMOs are distributed in the aromatic hydrocarbon group or aromatic heterocyclic group between the nitrogen atoms, thereby suppressing the influence on the main chain amine in formula (50) and improving the durability of the main chain amine against electrons and excitons.

[0263] [ka]

[0264] (In formula (52), Ar 61 and Ar 62each 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 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).

[0265] Substituents that each aromatic hydrocarbon group and each aromatic heterocyclic group may have, and Ar when it is a substituent 63 ~Ar 65 may have a crosslinking group. As the crosslinking group, a group selected from the group T of crosslinking groups can be used.

[0266] (Ar 63 ~Ar 65 ) Ar 63 ~Ar 65 are each independently 56 is the same as:

[0267] (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 group in which a plurality of divalent aromatic hydrocarbon groups which may have a substituent or divalent aromatic hydrocarbon groups which may have a substituent are linked together.

[0268] Ar 62 The specific structure of Ar 54 is the same as:

[0269] 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-".

[0270] Ar 62 In these preferred structures, the phenylene group does not have a substituent other than the linking position, which is advantageous in that the steric effect of the substituent 62 In addition, it is preferable that the fluorenylene group has substituents at the 9,9' positions from the viewpoint of improving the solubility and durability of the fluorene structure.

[0271] (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. (Formula (53)) Ar in the repeating unit represented by the formula (50) 51 At least one of the above is preferably a group represented by the following formula (53):

[0272] [ka]

[0273] In formula (53), * represents a bond to the nitrogen atom of the main chain of formula (50), Ar 71 represents a divalent aromatic hydrocarbon group which may have a substituent, Ar 72 and Ar 73each independently represent an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups are linked together directly or via a linking group; 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 the groups is a carbon atom, the carbon atom may have a substituent.

[0274] <Ar 71 > Ar 71 is the Ar 53 is a group similar to Ar 71 As the divalent aromatic hydrocarbon group, one optionally substituted divalent hydrocarbon group or a group in which 2 to 10 optionally substituted divalent aromatic hydrocarbon groups are linked together is preferred, one optionally substituted divalent aromatic hydrocarbon group or a group in which 2 to 8 optionally substituted divalent aromatic hydrocarbon groups are linked together is more preferred, and among these, a group in which two or more optionally substituted divalent aromatic hydrocarbon groups are linked together is preferred.

[0275] 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.

[0276] 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.

[0277] Ar 71In 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.

[0278] For this reason, Ar 71 Preferred structures linking the nitrogen atom in the main chain of the polymer and the ring HA in the formula (53) are as shown in Scheme 2-1 and Scheme 2-2 below. "-*" represents the bonding site 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.

[0279] [ka]

[0280] [ka]

[0281] 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 G is the same as the substituents that may be possessed when G is an aromatic hydrocarbon group.

[0282] <X 2 and Y 2 > X 2 and Y 2 each independently represents a C (carbon) atom or an N (nitrogen) atom. 2 and Y 2 When at least one of them is a C atom, it may have a substituent.

[0283] X is chosen to localize the LUMO more easily around the HA ring. 2 and Y 2 are preferably all N atoms.

[0284] X 2 and Y 2 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.

[0285] <Ar 72 and Ar 73 > Ar 72 and Ar 73 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 two or more groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together directly or via a linking group.

[0286] From the viewpoint of distributing the LUMO of the molecule, Ar 72 and Ar 73 each independently have 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 Scheme 2 above.

[0287] 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-5, d-1 to d-12, and e-1 to e-4 are preferred.

[0288] 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.

[0289] 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.

[0290] These structures may also have a substituent. "-*" indicates the binding site to the cyclic HA. When there are multiple "-*", any one of them represents the binding site to the cyclic HA.

[0291] Ar 72 and Ar 73 As the substituent that may be possessed by the compound, any one of the substituents in the substituent group Z or a combination thereof can be used. From the viewpoint of durability and charge transport properties, the substituent is preferably a group similar to the substituent group Z.

[0292] (Preferred main chain) The repeating unit represented by formula (50) is preferably a repeating unit represented by the following formula (54), a repeating unit represented by the following formula (55), a repeating unit represented by the following formula (56), or a repeating unit represented by the following formula (57). It is also preferable that the polymer having a triarylamine structure as a repeating unit contains a plurality of repeating units having different structures in each of the repeating units represented by these formulas.

[0293] <Repeating unit represented by formula (54)>

[0294] [ka]

[0295] (In formula (54), Ar 51 is Ar in the formula (50). 51 is the same as X is -C(R 207 )(R 208 )-, -N(R 209 )- or -C(R 211 )(R 212 )-C(R 213 )(R 214 )- and R 201 , R202 , 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.

[0296] (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 are each independently an alkyl group which may have a substituent.

[0297] 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.

[0298] 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 groups.

[0299] R 221 If there are multiple R 221 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 groups.

[0300] (R 207 ~R 209 and R 211 ~R 214 ) R 207 ~R 209 and R 211 ~R 214 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.

[0301] 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.

[0302] Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, an n-octyl group, a cyclohexyl group, and a dodecyl group.

[0303] 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.

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] 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 those mentioned above as preferred groups.

[0309] 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.

[0310] (a, b, c and d) In the repeating unit represented by the above formula (54), a and b are each independently an integer of 0 to 4. a+b is preferably 1 or greater, and each of a and b is preferably 2 or less, more preferably both a and b are 1. Here, when b is 1 or greater, d is also 1 or greater. Furthermore, 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.

[0311] 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.

[0312] 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.

[0313] 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.

[0314] 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.

[0315] 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 222 is 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.

[0316] (X) X in the above formula (54) is -C(R 207 )(R 208 )- or -N(R 209 )-, and -C(R 207 )(R 208 )- is more preferred.

[0317] (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).

[0318] [ka]

[0319] [ka]

[0320] 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.

[0321] <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.

[0322] [ka]

[0323] [ka]

[0324] [ka]

[0325] [ka]

[0326] [ka]

[0327] [ka]

[0328] [ka]

[0329] [ka]

[0330] <Repeating unit represented by formula (55)>

[0331] [ka]

[0332] (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.

[0333] (R 303 , R 306 ) R in the repeating unit represented by the above formula (55) 303 and R 306are each independently an alkyl group which may have a substituent.

[0334] The alkyl group is R in the formula (54). 201 and R 202 The substituents that may be present and preferred structures are the same as those of R 201 and R 202 The same can be mentioned.

[0335] 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.

[0336] (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.

[0337] 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.

[0338] Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, an n-octyl group, a cyclohexyl group, and a dodecyl group.

[0339] The alkoxy group is not particularly limited, and may be an alkoxy group (—OR 10 )R 10 The 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.

[0340] 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.

[0341] 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.

[0342] 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.

[0343] (l, m and n) l represents 0 or 1, and n represents 0 or 1.

[0344] l and n are each independent, and l+n is 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 contained in the composition of the present invention tends to be increased, and precipitation from the second composition containing the polymer also tends to be suppressed.

[0345] m represents 1 or 2, and is preferably 1, since the organic electroluminescent device of the present invention can be driven at a low voltage and hole injection ability, transport ability, and durability tend to be improved.

[0346] (p and q) p represents 0 or 1, and q represents 0 or 1. When l is 2 or greater, the multiple p's may be the same or different. When n is 2 or greater, the multiple q's may be the same or different. When l = n = 1, p and q do not simultaneously equal 0. When p and q do not simultaneously equal 0, the solubility of the polymer contained in the composition of the present invention is increased, and precipitation from a second composition containing the polymer tends to be suppressed. Furthermore, for the same reasons as in a and b above, when p + q is 1 or greater, the aromatic rings in the main chain are twisted due to steric hindrance, resulting in excellent solubility of the polymer in solvents, and a coating film formed by a wet film-forming method and heat-treated tends to be excellent insolubility in solvents. Therefore, 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.

[0347] <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.

[0348] [ka]

[0349] [ka]

[0350] [ka]

[0351] [ka]

[0352] [ka]

[0353] [ka]

[0354] [ka]

[0355] [ka]

[0356] <Repeating unit represented by formula (56)> [ka]

[0357] (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 are each independently an integer of 0 to 4.

[0358] (R 441 , R 442 ) R in the repeating unit represented by the above formula (56) 441 , R 442 are each independently an alkyl group which may have a substituent.

[0359] 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.

[0360] R 441 and R 442 When there are a plurality of R 441 and R 442 may be the same or different.

[0361] (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 or greater, multiple r's may be the same or different, and when u is 2 or greater, multiple s'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).

[0362] 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.

[0363] (Ar 41 ) Ar 41is 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 groups and the divalent aromatic heterocyclic groups are linked together directly or via a linking group.

[0364] Ar 41 The aromatic hydrocarbon group in the formula (50) is preferably Ar 52 The aromatic hydrocarbon group and the substituents that the aromatic hydrocarbon group may have are preferably the same as those in the substituent group Z, and the substituents that the aromatic hydrocarbon group may further have are also preferably the same as those in the substituent group Z.

[0365] <Specific examples of repeating units represented by formula (56)> The repeating unit represented by formula (56) is not particularly limited, but examples thereof include the following structures.

[0366] [ka]

[0367] <Repeating unit represented by formula (57)>

[0368] [ka]

[0369] (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.)

[0370] (R 517 ~R 519 ) R 517 ~R 519 The aromatic hydrocarbon group and aromatic heterocyclic group in each of the Ar 51 The substituents which these groups may have are preferably the same as those in the above-mentioned group Z of substituents.

[0371] R 517 ~R 519 The alkyl group and aralkyl group in the R 207 The same groups as those listed in R are preferred, and the substituents that may further be contained are also the same as those listed in R 207 Groups similar to the following are preferred.

[0372] R 517 ~R 519 The alkoxy group in the formula (I) is preferably the alkoxy group exemplified in the above-mentioned group Z of substituents, and the substituents that may be further substituted are also the same as those in the above-mentioned group Z of substituents.

[0373] (f, g, h) f, g, and h each independently represent an integer of 0 to 4. 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.

[0374] 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 identical to

[0375] 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.

[0376] 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.

[0377] [ka]

[0378] When the polymer of this embodiment contains a repeating unit represented by formula (57), the ratio of the compound represented by formula (1) to the repeating unit represented by formula (57), (number of moles of repeating units represented by formula (57)) / (number of moles of the compound represented by formula (1)), 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. The ratio is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0379] The repeating unit represented by the formula (57) is preferably a repeating unit represented by the following formula (58).

[0380] Preferred formula (57) = formula (58)

[0381] [ka]

[0382] 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.

[0383] 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.

[0384] Preferred formula (58) = formula (59)

[0385] [ka]

[0386] 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 2nd and 5th 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.

[0387] <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.

[0388] [ka]

[0389] The repeating units represented by formulas (50) to (59) preferably do not have a crosslinking group. When a crosslinking group is not present, it is preferable because polymer chain distortion is less likely to occur when the film is heated and dried or baked (heat-cured) after wet film formation. 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.

[0390] (Preferred repeating units) When the functional material used in the composition 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).

[0391] Among these, A repeating unit represented by the formula (54) containing a partial structure represented by the following formula (61): A repeating unit represented by the formula (55) containing a partial structure represented by the following formula (61): A repeating unit represented by the formula (56) containing a partial structure represented by the following formula (61): Alternatively, it is preferably a repeating unit represented by the formula (57) containing a partial structure represented by the following formula (61).

[0392] [ka]

[0393] (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+, R in formula (57) 517 , R518 or R 519 and -* represents a bond to 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. 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 406 , if it is a partial structure of formula (56), R 441 or R442, if it is a partial structure of formula (57), R 517 , R 518 or R 519 It may have.)

[0394] The partial structure represented by the formula (61) or (61′) is a substantially planar structure of Ring A and Ring B formed by π conjugation, which is represented by R 601 The steric hindrance of the π-conjugated bond distorts the structure of the main chain, resulting in a more twisted structure than that of a normal π-conjugated bond. In other words, the degree of freedom is increased. When the solvate represented by formula (1) is applied to this, the solvate represented by formula (1) has a high degree of freedom and moderate flexibility because the two benzene rings are bonded by a quaternary carbon atom. These two benzene rings with a high degree of freedom are highly compatible with the functional material, allowing it to penetrate more easily and improving solubility. As a result, even if the solvent evaporates and the concentration of the functional material increases in the applied wet film, it is expected that the solute will be more easily dispersed uniformly in the solvent, improving flatness.

[0395] In display panels using organic electroluminescent elements, pixels are divided by banks. To form a film within the microscopic regions divided by the banks, a composition in which a functional material is dissolved in a solvent is applied using an inkjet device, and the solvent is dried to form a functional material film within the bank. When the solvent compound represented by formula (1) is used as the solvent, the solvent compound represented by formula (1) easily penetrates the functional material as described above. Therefore, even if the solvent volatilizes and the functional material concentration increases, the flatness of the film is maintained, and it is thought that a flat functional material film can be formed within the bank.

[0396] (Formula (54-2)) The repeating unit of formula (54) is particularly preferred. The composition of the present invention preferably contains a solvent compound represented by formula (1) and a polymer having this repeating unit, in order to form a more flat thin film. The repeating unit of formula (54) is preferably a repeating unit of formula (62) below.

[0397] [ka]

[0398] (In formula (62), Ar 51 , X, R 201 , R 202 , R 221 , R 222 , a, b, c, d, i, j are Ar in the formula (54). 51 , X, R 201 , R 202 , R 221 , R 222 , a, b, c, d, i, j are the same, a 1 , a 2 , b 1 , 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 and d are 1 or greater, and 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 Here, a in formula (54) being 1 or more means that a 1 , a 2 and 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.)

[0399] As shown below, the formula (62) contains the formula (61) or the formula (61') as a partial structure. a 1 , a2 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, It contains 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 and b is 1 or more, the formula (61) or the formula (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 RingA2 form the partial structure of 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, since the formula (62) contains a structure in which the aromatic ring of the main chain is twisted, it is preferable because a flat film can be easily obtained for the reasons described above.

[0400] [Molecular weight of polymer] The molecular weight of the polymer contained in the composition of the present invention will be described below.

[0401] The weight-average molecular weight (Mw) of the polymer having the above-mentioned triarylamine structure as a repeating unit is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 200,000 or less, particularly preferably 100,000 or less, and most preferably 50,000 or less. The weight-average molecular weight is usually 2,500 or more, preferably 5,000 or more, more preferably 10,000 or more, even more preferably 15,000 or more, and particularly preferably 17,000 or more.

[0402] When the weight-average molecular weight of the polymer having the triarylamine structure as a repeating unit is not more than the upper limit, the polymer tends to have good solubility in solvents and excellent film-forming properties. When the weight-average molecular weight of the polymer is not less than the lower limit, the polymer may have improved heat resistance by suppressing decreases in its glass transition temperature, melting point, and vaporization temperature.

[0403] The number average molecular weight (Mn) of the polymer having the above-mentioned triarylamine structure as a repeating unit is usually 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, and particularly preferably 100,000 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.

[0404] Furthermore, the dispersity (Mw / Mn) of the polymer having the above-mentioned triarylamine 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.

[0405] 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.

[0406] [Specific example] Specific examples of polymers containing the repeating unit represented by formula (54) are shown below, but the polymers used in the present invention are not limited to these. The numbers in the chemical formulas represent the molar ratios of the repeating units, and n represents the number of repeats.

[0407] 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.

[0408] [ka]

[0409] A polymer containing a repeating unit represented by formula (55) and Ar of the repeating unit represented by formula (55) 51 Specific examples of polymers having a structure represented by formula (51) or (52) are shown below, but the polymers used in the present invention are not limited to these. The numbers in the chemical formulas represent the molar ratio of repeating units, and n represents the number of repeats.

[0410] These polymers may be any of random copolymers, alternating copolymers, block copolymers, graft copolymers, etc., and the sequence of the monomers is not limited.

[0411] [ka]

[0412] [ka]

[0413] [ka]

[0414] [ka]

[0415] Specific examples of polymers containing the repeating unit represented by formula (56) are shown below, but the polymers used in the present invention are not limited to these. The numbers in the chemical formula represent the molar ratio of the repeating unit. n represents the number of repeats.

[0416] 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.

[0417] [ka]

[0418] [ka]

[0419] <Method of producing polymer> The method for producing the polymer contained in the composition of the present invention is not particularly limited and may be any method, such as a polymerization method based on the Suzuki reaction, a polymerization method based on the Grignard reaction, a polymerization method based on the Yamamoto reaction, a polymerization method based on the Ullmann reaction, or a polymerization method based on the Buchwald-Hartwig reaction.

[0420] 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).

[0421] [ka]

[0422] (In the above reaction scheme, Ar 51 , R 201 , R 202 , X, and a to d are defined as in the formula (54).

[0423] In the case of a polymerization method using the Ullmann reaction and a polymerization method using the Buchwald-Hartwig reaction, for example, a polymer containing a repeating unit represented by formula (55) is synthesized by reacting an aryl dihalide represented by formula (3a) (Z represents a halogen atom such as I, Br, Cl, or F) with a primary aminoaryl represented by formula (3b).

[0424] [ka]

[0425] (In the above reaction scheme, Ar 51 , R 303 ~R 306 , n, m, l, p, and q are defined as in the formula (55).

[0426] 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, triethylamine, etc. Alternatively, it can be carried out in the presence of a transition metal catalyst such as a copper or palladium complex.

[0427] [Solvent and functional material content] The content of the functional material in the composition of the present invention is not particularly limited, but is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and more preferably 1.0% by weight or more, and is preferably 20% by weight or less, more preferably 15% by weight or less, and more preferably 10% by weight or less.

[0428] Specific examples of the composition of the present invention include a light-emitting layer-forming composition, a hole-injection layer-forming composition, a hole-transport layer-forming composition, and an electron-transport layer-forming composition, which will be described later. The preferred content of the solvent is as described later for each layer-forming composition. The content of the functional material also corresponds to the content of the light-emitting layer material, the hole-injection layer material, the hole-transport layer material, and the electron-transport layer material, which will be described later for each layer-forming composition.

[0429] [Film formation by wet film formation method] The composition of the present invention is suitably used for forming a functional film in the production of an organic electroluminescent device, the configuration of which is as described below.

[0430] The organic electroluminescent device of the present invention generally has minute regions, each of which is partitioned by a partition wall called a bank, on a substrate provided with an electrode, and a functional film is formed by discharging the composition of the present invention into the minute regions partitioned by the bank, drying the composition, and appropriately heating the composition.

[0431] The ejection method is a method in which droplets smaller than the micro-regions partitioned by the banks are ejected from a micro-nozzle, and it is preferable that the micro-regions partitioned by the banks are filled with the composition of the present invention by ejecting a plurality of droplets. The ejection method is preferably an ink-jet method.

[0432] In the wet film-forming method, the minute regions partitioned by the banks are filled with the composition of the present invention, and then the composition is dried in a vacuum, which is a process of volatilizing the solvent by reducing the pressure.

[0433] Although most of both solvents A and B can be evaporated by vacuum drying, to ensure sufficient drying, heat drying is then performed. The heating temperature and time are preferably set so that the functional film does not crystallize or aggregate.

[0434] When the functional material is a low molecular weight material, the heating temperature is usually 50° C. or higher, preferably 80° C. or higher, more preferably 100° C. or higher, and more preferably 120° C. or higher, and usually 200° C. or lower, preferably 180° C. or lower, and more preferably 150° C. or lower. The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and more preferably 5 minutes or longer, and usually 120 minutes or shorter, preferably 90 minutes or shorter, and more preferably 60 minutes or shorter.

[0435] When the functional material is a polymer material, the heating temperature is usually 80° C. or higher, preferably 100° C. or higher, more preferably 150° C. or higher, and more preferably 200° C. or higher, and usually 300° C. or lower, preferably 270° C. or lower, and more preferably 240° C. or lower. The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and more preferably 5 minutes or longer, and usually 120 minutes or shorter, preferably 90 minutes or shorter, and more preferably 60 minutes or shorter.

[0436] The heating method can be carried out using a hot plate, an oven, infrared radiation, or the like. In the case of infrared irradiation, which directly imparts molecular vibrations, a heating time close to the above lower limit is sufficient, while in the case of hot plate heating, in which the substrate is in direct contact with the heat source or is placed very close to the heat source, a longer heating time is required than in the case of infrared irradiation. In the case of oven heating, i.e., heating using the gas in the oven, usually air or an inert gas such as nitrogen or argon, it takes time for the temperature to rise, so a heating time close to the above upper limit is preferred. The heating time is adjusted appropriately depending on the heating method.

[0437] [Functional membrane] The functional material contained in the functional film is usually 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably 95% by weight or more, and most preferably substantially 100% by weight, with the upper limit being 100% by weight. Substantially 100% by weight means that the functional film may contain trace amounts of additives, residual solvents, and impurities. By ensuring that the content of the functional material in the functional film is within this range, the function of the functional material can be more effectively expressed.

[0438] [Layer structure and formation method of organic electroluminescent element] A preferred example of the layer structure of an organic electroluminescent device manufactured using the composition of the present invention (hereinafter, sometimes referred to as "organic electroluminescent device of the present invention") and an embodiment of a method for forming the same will be described with reference to FIG. 1.

[0439] Fig. 1 is a schematic cross-sectional view showing an example of the structure of an organic electroluminescent device 10 of the present invention. 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 a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.

[0440] The organic electroluminescent device of the present invention has an anode, an emitting layer, and a cathode as essential constituent layers, but may have other functional layers between the anode 2 and the emitting layer 5 and between the cathode 9 and the emitting layer 5, as shown in FIG. 1, if necessary.

[0441] [substrate] The substrate 1 serves as a support for the organic electroluminescent element. Examples of substrate 1 that can be used include quartz or glass plates, metal plates or foils, and plastic films or sheets. Glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, and polysulfone are particularly preferred. When using a synthetic resin substrate, it is preferable to pay attention to its gas barrier properties. It is preferable for the gas barrier properties of the substrate to be high, since this makes it difficult for the organic electroluminescent element to be deteriorated by the outside air passing through the substrate. Therefore, one preferred method is to ensure gas barrier properties by providing a dense silicon oxide film or the like on at least one side of the synthetic resin substrate.

[0442] [anode] The anode 2 is an electrode that serves to inject holes into the layer on the light-emitting layer 5 side. 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.

[0443] The anode 2 is usually formed by a method such as sputtering or vacuum deposition. When forming the anode 2 using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, or the like, the anode 2 can also be formed by dispersing these fine particles in an appropriate binder resin solution and applying the solution to the substrate 1.

[0444] In the case of a conductive polymer, a thin film can be formed directly on the substrate 1 by electrolytic polymerization. The anode 2 can also be formed by applying a conductive polymer onto the substrate 1 (Appl. Phys. Lett., Vol. 60, p. 2711, 1992). The anode 2 usually has a single layer structure, but can also have a laminated structure made of multiple materials if desired.

[0445] The thickness of the anode 2 may be appropriately selected depending on the required transparency, etc. When transparency is required, it is preferable that the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, 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. When opaqueness is sufficient, the thickness of the anode 2 is optional. A substrate 1 that also functions as the anode 2 may be used. It is also possible to laminate a different conductive material on the above-mentioned anode 2.

[0446] It is preferable to subject the surface of the anode 2 to ultraviolet (UV) / ozone treatment, oxygen plasma treatment, or argon plasma treatment in order to remove impurities adhering to the anode 2 and adjust the ionization potential to improve hole injection properties.

[0447] [Hole injection layer] The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5. When the hole injection layer 3 is provided, the hole injection layer 3 is usually formed on the anode 2.

[0448] The method for forming the hole injection layer 3 is not particularly limited and may be a vacuum deposition method or a wet film formation method. From the viewpoint of reducing dark spots, the hole injection layer 3 is preferably formed by a wet film formation method.

[0449] The thickness of the hole injection layer 3 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0450] (hole transport material) The composition for forming the hole injection layer usually contains a hole transport material and a solvent as constituent materials of the hole injection layer 3 . The hole transport material is generally used in the hole injection layer 3 of an organic electroluminescent element, and may be a high molecular weight compound such as a polymer or a low molecular weight compound such as a monomer, as long as it has hole transport properties. However, a high molecular weight compound is preferred.

[0451] The hole transport material is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of the charge injection barrier from the anode 2 to the hole injection layer 3. Examples of the hole transport material include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which a tertiary amine is linked via a fluorene group, hydrazone derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, and carbon.

[0452] In the present invention, the derivative, for example, in the case of an aromatic amine derivative, includes the aromatic amine itself and a compound having an aromatic amine as the main skeleton, and may be either a polymer or a monomer.

[0453] The hole transport material used as the material for the hole injection layer 3 may contain any one of these compounds alone or two or more of them. When two or more hole transport materials are contained, they may be combined in any desired manner, but it is preferable to use one or more aromatic tertiary amine polymer compounds in combination with one or more other hole transport materials.

[0454] Among the above-listed hole transport materials, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred, from the viewpoints of amorphousness and visible light transmittance. The aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure and also include compounds having a group derived from an aromatic tertiary amine.

[0455] The type of aromatic tertiary amine compound is not particularly limited, but from the viewpoint of uniform light emission due to the surface smoothing effect, a polymer compound (polymerized compound having a series of repeating units) having a weight average molecular weight of 1,000 or more and 1,000,000 or less is more preferred. Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds having repeating units represented by the following formula (20) or (11):

[0456] [ka]

[0457] (In formula (20), Ar 3 represents an aromatic hydrocarbon group or an aromatic heterocyclic group, each of which may have a substituent; Ar 4 represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group, each of which may have a substituent, or a divalent group in which a plurality of such aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together directly or via a linking group.

[0458] In the formula (20), when a plurality of aromatic hydrocarbon groups and aromatic heterocyclic groups are linked via a linking group, the linking group is a divalent linking group, and examples thereof include a group formed by linking 1 to 30, preferably 1 to 5, and more preferably 1 to 3 groups selected from an -O- group, a -C(=O)- group, and a (optionally substituted) -CH2- group in any order.

[0459] Among the linking groups, Ar in formula (20) is preferred because it is excellent in injecting holes into the light-emitting layer. 4 is preferably an aromatic hydrocarbon group or aromatic heterocyclic group, a plurality of which are linked via a linking group represented by the following formula (30).

[0460] [ka]

[0461] (In formula (30), d represents an integer from 1 to 10; R 8 and R 9 each independently represents a hydrogen atom or an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group, each of which may have a substituent. R 8 , R 9 When there are multiple occurrences of, they may be the same or different.)

[0462] [ka]

[0463] In the above formula (11), j, k, l, m, n, and p each independently represent an integer of 0 or more, provided that l+m≧1. 11 , Ar 12 , Ar 14 each independently represents a divalent aromatic ring group having 30 or less carbon atoms which may have a substituent. 13 represents a divalent aromatic ring group having 30 or less carbon atoms which may have a substituent or a divalent group represented by the following formula (12), and Q 11 , Q 12 each independently represents an oxygen atom, a sulfur atom, or a hydrocarbon chain having 6 or less carbon atoms which may have a substituent; S 1 ~S 4 are each independently represented by a group represented by the following formula (13):

[0464] The aromatic ring group referred to here refers to an aromatic hydrocarbon ring group and an aromatic heterocyclic group. Ar 11 , Ar 12 , Ar 14Examples of the aromatic ring group include a monocyclic ring, a group having 2 to 6 condensed rings, or a group in which two or more of these aromatic rings are linked together. Specific examples of the aromatic ring group having a monocyclic ring or a group having 2 to 6 condensed rings 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 group, a terphenyl group, a quaterphenyl group, 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 pyrrolyl imidazoline ring, a pyrrolidinyl ... Examples of suitable divalent groups include a divalent group derived from a benzene 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 benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. Among these, a divalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring, or a biphenyl group, is preferred because they efficiently delocalize negative charges and are excellent in stability and heat resistance. Ar 13 Examples of aromatic ring groups include Ar 11 , Ar 12 , Ar 14 This is the same as in the case of

[0465] [ka]

[0466] In the above formula (12), R 11 R represents an alkyl group, an aromatic ring group, or a trivalent group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group, which may have a substituent. 12 represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group, which may have a substituent. 31represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have a substituent. q represents 1 to 4. When q is 2 or more, multiple R 12 may be the same or different, and multiple Ar 31 may be the same or different. An asterisk (*) indicates a bond to the nitrogen atom in formula (11).

[0467] R 11 The aromatic ring group is preferably one aromatic ring group which is a monocyclic or fused ring having from 3 to 30 carbon atoms, or a group in which 2 to 6 of these are linked together, and specific examples include a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a trivalent group derived from a group in which 2 to 6 of these are linked together. R 11 The alkyl group is preferably a linear, branched, or cyclic alkyl group having from 1 to 12 carbon atoms, and specific examples include groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, and octane.

[0468] R 11 The group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group is preferably a group in which a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms is linked to one or two to six linked aromatic ring groups which are monocyclic or fused rings having 3 to 30 carbon atoms.

[0469] R 12 Specific examples of the aromatic ring group include a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a divalent group derived from a linked ring having 30 or less carbon atoms formed by linking these rings.

[0470] R 12 Specific examples of the alkyl group include divalent groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, and octane.

[0471] Ar 31Specific examples of the aromatic ring group include a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a monovalent group derived from a linked ring having 30 or less carbon atoms formed by linking these rings.

[0472] Preferred examples of the structure of formula (12) include the following structures, where R 11 The benzene ring or fluorene ring in the main chain of the following structure, which is a partial structure of the above, may further have a substituent.

[0473] [ka]

[0474] Ar 31 Examples of the crosslinking group include groups derived from a benzocyclobutene ring, a naphthocyclobutene ring or an oxetane ring, a vinyl group, an acrylic group, etc. In view of the stability of the compound, groups derived from a benzocyclobutene ring or a naphthocyclobutene ring are preferred.

[0475] [ka]

[0476] In the above formula (13), x and y represent integers of 0 or more. 21 , Ar 23 each independently represents a divalent aromatic ring group, and these groups may have a substituent. 22 represents a monovalent aromatic ring group which may have a substituent, R 13 represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group and an aromatic ring group, which may have a substituent.

[0477] Ar 32 represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have a substituent. 32 is a monovalent bridging group, the bridging group may be the same as Ar 31The asterisk (*) indicates the bond to the nitrogen atom in formula (11).

[0478] Ar 21 , Ar 23 Examples of aromatic ring groups include Ar 11 , Ar 12 , Ar 14 This is the same as in the case of Ar 22 , Ar 32 Examples of the aromatic ring group include a single ring, 2 to 6 condensed rings, and groups in which two or more of these aromatic rings are linked together. Specific examples 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 group, a terphenyl group, a quaterphenyl group, 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 pyrrolopyrene ... Examples of the monovalent group include a pyrazole 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 benzimidazole ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. 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 preferred because of its efficient delocalization of negative charges, excellent stability, and heat resistance.

[0479] R 13 Examples of alkyl groups or aromatic ring groups include R 12 is the same as: Ar 32The crosslinking group is not particularly limited, but preferred examples include groups derived from a benzocyclobutene ring, a naphthocyclobutene ring or an oxetane ring, a vinyl group, an acrylic group, and the like.

[0480] The above Ar 11 ~Ar 14 , R 11 ~R 13 , Ar 21 ~Ar 23 , Ar 31 ~Ar 32 , Q 11 , Q 12 Each of the above may further have a substituent, provided that it does not contradict the spirit of the present invention. The molecular weight of the substituent is preferably 400 or less, and more preferably 250 or less. The type of substituent is not particularly limited, and examples include one or more types selected from the following substituent group W.

[0481] [Substituent group W] alkyl groups having 1 or more, preferably 10 or less, and more preferably 8 or less carbon atoms, such as a methyl group or an ethyl group; alkenyl groups having 2 or more, preferably 11 or less, and more preferably 5 or less carbon atoms, such as a vinyl group; alkynyl groups having 2 or more, preferably 11 or less, and more preferably 5 or less carbon atoms, such as an ethynyl group; alkoxy groups having 1 or more, preferably 10 or less, and more preferably 6 or less carbon atoms, such as a methoxy group or an ethoxy group; and phenoxy groups, naphthoxy groups, pyridyloxy groups, and the like, having 4 or more, preferably 5 or more, preferably 25 or less, and more preferably 4 or more carbon atoms. alkoxycarbonyl groups having 2 or more, preferably 11 or less, and more preferably 7 or less carbon atoms, such as a methoxycarbonyl group or an ethoxycarbonyl group; dialkylamino groups having 2 or more, preferably 20 or less, and more preferably 12 or less carbon atoms, such as a dimethylamino group or a diethylamino group; diarylamino groups having 10 or more, preferably 12 or more, preferably 30 or less, and more preferably 22 or less carbon atoms, such as a diphenylamino group, a ditolylamino group or an N-carbazolyl group; and phenylmethylamino groups having 6 or more carbon atoms. arylalkylamino groups, more preferably 7 or more and preferably 25 or less, and more preferably 17 or less; acyl groups, such as an acetyl group or a benzoyl group, having 2 or more carbon atoms, preferably 10 or less, and more preferably 7 or less; halogen atoms, such as a fluorine atom or a chlorine atom; haloalkyl groups, such as a trifluoromethyl group, having 1 or more carbon atoms, preferably 8 or less, and more preferably 4 or less; alkylthio groups, such as a methylthio group or an ethylthio group, having 1 or more carbon atoms, preferably 10 or less, and more preferably 6 or less; phenylthio group, naphthylthio group, pyridylthio group, and the like. arylthio groups having 4 or more carbon atoms, preferably 5 or more and 25 or less, and more preferably 14 or less; silyl groups having 2 or more carbon atoms, preferably 3 or more and 33 or less, and more preferably 26 or less, such as a trimethylsilyl group or a triphenylsilyl group; siloxy groups having 2 or more carbon atoms, preferably 3 or more and 33 or less, and more preferably 26 or less, such as a trimethylsiloxy group or a triphenylsiloxy group; cyano groups; aromatic hydrocarbon groups having 6 or more carbon atoms, preferably 30 or less, and more preferably 18 or less, such as a phenyl group or a naphthyl group;Aromatic heterocyclic groups having 3 or more, preferably 4 or more, and preferably 28 or less, and more preferably 17 or less carbon atoms, such as a thienyl group or a pyridyl group;

[0482] Of the above substituent group W, alkyl groups or alkoxy groups are preferred from the viewpoint of improving solubility, and aromatic hydrocarbon groups or aromatic heterocyclic groups are preferred from the viewpoint of charge transportability and stability. In particular, among polymer compounds having a repeating unit represented by formula (11), a polymer compound having a repeating unit represented by the following formula (14) is preferred because it has extremely high hole injection and transport properties.

[0483] [ka]

[0484] In the above formula (14), R 21 ~R 25 R each independently represents an arbitrary substituent. 21 ~R 25 Specific examples of the substituent are the same as those described in the above [Substituent Group W]. s and t each independently represent an integer of 0 or more and 5 or less. u, v, and w each independently represent an integer of 0 or more and 4 or less.

[0485] Preferred examples of the aromatic tertiary amine polymeric compound include polymeric compounds containing repeating units represented by the following formula (15) and / or formula (16).

[0486] [ka]

[0487] In the above formulas (15) and (16), Ar 45 , Ar 47 and Ar 48 each independently represents a monovalent aromatic hydrocarbon group which may have a substituent or a monovalent aromatic heterocyclic group which may have a substituent. 44 and Ar46 each independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent.

[0488] R 41 ~R 43 Each independently represents a hydrogen atom or an arbitrary substituent.

[0489] Ar 45 , Ar 47 and Ar 48 Specific examples, preferred examples, examples of the substituents which may be possessed, and preferred examples of the substituents are Ar 22 is similar to Ar 44 and Ar 46 Specific examples, preferred examples, examples of the substituents which may be possessed, and preferred examples of the substituents are Ar 11 , Ar 12 and Ar 14 Similar to R 41 ~R 43 is preferably a hydrogen atom or a substituent described in the above-mentioned [Substituent group W], and more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

[0490] Preferred specific examples of the repeating units represented by formula (15) and formula (16) that can be used in the present invention are listed below, but the present invention is not limited to these.

[0491] [ka]

[0492] The hole transport material preferably further contains a repeating unit of the following formula (a-1) in its structure in order to form a stable film.

[0493] [ka]

[0494] (In formula (a-1), Ar 1 each independently represents an aromatic hydrocarbon ring group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a divalent group in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together; Ar 4 represents an aromatic hydrocarbon ring 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 ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together; R each independently represents a monovalent group formed by linking together a plurality of structures selected from an optionally substituted alkyl group, an optionally substituted alkyloxy group, an optionally substituted alkylthio group, a fluorine atom, an optionally substituted aromatic hydrocarbon ring group, an optionally substituted aromatic heterocyclic group, an optionally substituted aromatic hydrocarbon ring group, and an optionally substituted aromatic heterocyclic group; The subscript n represents an integer between 2 and 5, each subscript m independently represents an integer from 0 to 4; The sum of the multiple independent m's is 1 or greater.)

[0495] In the formula (a-1), the repeating unit of the following formula (54) is particularly preferred in order to form a flatter thin film.

[0496] [ka]

[0497] The structure of (54) is a planar structure formed by π conjugation, R 201 and R 202The side chains of the π-conjugated bond distort the structure, giving it a higher degree of freedom than a normal π-conjugated bond. When the solvent represented by general formula (1) is used, the two free benzene rings of the solvent can easily penetrate each other freely, increasing solubility and making it easier for the solute to disperse more uniformly in the solvent, which is presumed to improve planarity.

[0498] (Electron-accepting compound for hole-injection layer) The composition for forming a hole injection layer preferably contains an electron accepting compound for a hole injection layer as a constituent material of the hole injection layer 3 .

[0499] The electron-accepting compound for the hole injection layer is preferably a compound having oxidizing power and the ability to accept one electron from the hole transport material. Specifically, the electron-accepting compound for the hole injection layer is preferably a compound having an electron affinity of 4.0 eV or more, more preferably a compound having an electron affinity of 5.0 eV or more.

[0500] Examples of such electron-accepting compounds for the hole injection layer include one or more compounds selected from the group consisting of tetraarylboron ion compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. More specifically, examples of the electron-accepting compound for the hole injection layer include onium salts substituted with organic groups, such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and triphenylsulfonium tetrafluoroborate (WO 2005 / 089024 and WO 2017 / 164268); high-valent inorganic compounds, such as iron(III) chloride (JP 11-251067 A) and ammonium peroxodisulfate; cyano compounds, such as tetracyanoethylene; and aromatic boron compounds, such as tris(pentafluorophenyl)borane (JP 2003-31365 A); fullerene derivatives; iodine; and sulfonate ions, such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphorsulfonate ions.

[0501] As the electron-accepting compound for the hole-injection layer, it is preferable to use the compounds described above as the electron-accepting compound.

[0502] The electron-accepting compound can oxidize the hole-transporting material, thereby improving the conductivity of the hole-injection layer 3. In addition, it is preferable to mix such an electron-accepting compound in order to obtain a flatter film.

[0503] (Other constituent materials) The material of the hole injection layer 3 may contain other components in addition to the hole transport material and electron accepting compound described above, as long as the effects of the present invention are not significantly impaired.

[0504] (solvent) At least one of the solvents of the composition for forming a hole injection layer used in the wet film-forming method is preferably a compound capable of dissolving the above-mentioned constituent materials of the hole injection layer 3 .

[0505] When the composition for forming a hole injection layer is the composition of the present invention, the solvents are the solvent A and solvent B of the present invention. Since solvent A has the property of hardly dissolving the electron-accepting compound, in order to ensure the overall solubility of the ink, solvent B is preferably a solvent that relatively easily dissolves the electron-accepting compound. Solvent B is more preferably an aromatic ester solvent, an aromatic ether solvent, or an aromatic ketone solvent.

[0506] Examples of the solvent include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

[0507] Examples of ether 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.

[0508] Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

[0509] Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene.

[0510] Examples of the amide solvent include N,N-dimethylformamide and N,N-dimethylacetamide. Other than this, dimethyl sulfoxide and the like can also be used.

[0511] Among these, aromatic esters and aromatic ethers are preferred. These solvents may be used alone or in any combination of two or more in any ratio.

[0512] The concentration of the hole transport material in the composition for forming a hole injection layer may be any concentration as long as it does not significantly impair the effects of the present invention. From the viewpoint of film thickness uniformity, the concentration of the hole transport material in the composition for forming a hole injection layer is preferably 0.01 wt % or more, more preferably 0.1 wt % or more, and even more preferably 0.5 wt % or more. The concentration of the hole transport material in the composition for forming a hole injection layer is preferably 70 wt % or less, more preferably 60 wt % or less, and even more preferably 50 wt % or less. A low concentration is preferable in terms of preventing film thickness unevenness. A high concentration is also preferable in terms of preventing defects from occurring in the formed hole injection layer.

[0513] (Formation of hole injection layer by wet film formation method) When the hole injection layer 3 is formed by a wet film formation method, typically, the materials constituting the hole injection layer 3 are mixed with an appropriate solvent (hole injection layer solvent) to prepare a film-forming composition (hole injection layer-forming composition), and this hole injection layer-forming composition is applied to a layer corresponding to the lower layer of the hole injection layer (usually the anode 2) by an appropriate method to form a film, and then dried to form the hole injection layer 3.

[0514] (Formation of Hole Injection Layer 3 by Vacuum Vapor Deposition) When the hole injection layer 3 is formed by vacuum deposition, the hole transport layer 3 can be formed, for example, as follows: One or more of the constituent materials of the hole injection layer 3 (the hole transport material, the electron accepting compound, etc.) are placed in a crucible installed in a vacuum chamber (when two or more materials are used, each is placed in a crucible), and the vacuum chamber is evacuated to 100°C using an appropriate vacuum pump. -4 The chamber is evacuated to about Pa. Thereafter, the crucible is heated (if two or more materials are used, each crucible is heated) and the evaporation amount is controlled (if two or more materials are used, each material is evaporated while its evaporation amount is controlled independently), forming a hole injection layer 3 on the anode 2 of the substrate 1 placed opposite the crucible. When two or more materials are used, a mixture of the materials can also be placed in a crucible and heated to evaporate the materials to form the hole injection layer 3.

[0515] 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 more, 9.0×10 -6 Torr (12.0 × -4 The deposition rate is not limited as long as it does not significantly impair the effects of the present invention. The deposition rate is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film formation temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention. The film formation temperature during deposition is preferably 10°C or more and 50°C or less.

[0516] [Hole transport layer] The hole transport layer 4 is a layer that transports holes from the anode 2 to the light-emitting layer 5. The hole transport layer 4 is not an essential layer for the organic electroluminescent device of the present invention. However, when the hole transport layer 4 is provided, the hole transport layer 4 is usually formed on the hole injection layer 3 when the hole injection layer 3 is present, or on the anode 2 when the hole injection layer 3 is not present.

[0517] The method for forming the hole transport layer 4 is not particularly limited and may be a vacuum deposition method or a wet film formation method. From the viewpoint of reducing dark spots, the hole transport layer 4 is preferably formed by a wet film formation method.

[0518] The material forming the hole transport layer 4 is preferably a material that has high hole transport properties and can efficiently transport injected holes. To this end, the material forming the hole transport layer 4 preferably has a low ionization potential, high transparency to visible light, high hole mobility, excellent stability, and is unlikely to generate impurities that act as traps during production or use. In many cases, the hole transport layer 4 is in contact with the light-emitting layer 5, and therefore it is preferable that the hole transport layer 4 does not quench the light emission from the light-emitting layer 5 or form exciplexes with the light-emitting layer 5, thereby reducing efficiency.

[0519] The material of the hole transport layer 4 may be any material that has been conventionally used as a constituent material of the hole transport layer 4. Examples of the material of the hole transport layer 4 include arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatic derivatives, and metal complexes.

[0520] Examples of materials for the hole transport layer 4 include polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophene derivatives, and poly(p-phenylene vinylene) derivatives. These may be alternating copolymers, random polymers, block polymers, or graft copolymers. Furthermore, the material may be a polymer having a branched main chain with three or more terminals, or a so-called dendrimer.

[0521] Among these, polyarylamine derivatives and polyarylene derivatives are preferable as the material for the hole transport layer 4. Specific examples of polyarylamine derivatives and polyarylene derivatives include those described in JP-A-2008-98619. As the polyarylamine derivative, it is preferable to use the aromatic tertiary amine polymer compound.

[0522] When the hole transport layer 4 is formed by a wet film formation method, a composition for forming the hole transport layer is prepared in the same manner as in the formation of the hole injection layer 3, and then the composition is wet-formed and dried. The composition for forming a hole transport layer contains the above-mentioned hole transport material and a solvent. The solvent used is the same as that used in the composition for forming a hole injection layer. The film formation conditions, drying conditions, etc. are also the same as those for forming the hole injection layer 3.

[0523] When the composition for forming a hole transport layer is the composition of the present invention, the solvent is the solvent A and the solvent B of the present invention. When the hole transport layer 4 is formed by vacuum deposition, the film formation conditions are the same as those for forming the hole injection layer 3 described above. The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 200 nm or less, taking into consideration factors such as penetration of the low molecular weight material in the light emitting layer and swelling of the hole transport material.

[0524] [Emitting layer] The light-emitting layer 5 is a layer that serves as a main light source when excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between the electrodes to which an electric field is applied. The light-emitting layer 5 is usually formed on the hole-transporting layer 4 when the hole-transporting layer 4 is present, on the hole-injecting layer 3 when the hole-transporting layer 4 is not present but the hole-injecting layer 3 is present, or on the anode 2 when neither the hole-transporting layer 4 nor the hole-injecting layer 3 is present.

[0525] <Light-emitting layer materials> The materials for the light-emitting layer usually include a light-emitting material and a charge-transporting material that acts as a host.

[0526] <Light-emitting materials> The light-emitting material may be any known material that is usually 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 material or a phosphorescent material, but is preferably a phosphorescent material from the viewpoint of internal quantum efficiency. More preferably, the red and green light-emitting materials are phosphorescent materials, and the blue light-emitting material is a fluorescent material.

[0527] When the composition of the present invention is a composition for forming a light-emitting layer, it is preferable to use the following phosphorescent material, fluorescent material, and charge transport material.

[0528] <Phosphorescent materials> Phosphorescent materials are materials that emit light from an excited triplet state. Representative examples include metal complex compounds containing Ir, Pt, Eu, etc., and materials with a metal complex structure are preferred.

[0529] Among metal complexes, phosphorescent organometallic complexes that emit light via a triplet state include Werner complexes or organometallic complex compounds containing, as a central metal, a metal selected from Groups 7 to 11 of the long periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long periodic table). Examples of such phosphorescent materials include the phosphorescent materials described in WO 2014 / 024889, WO 2015-087961, WO 2016 / 194784, and JP 2014-074000 A. Preferably, the compound represented by the following formula (201) or the compound represented by the following formula (205) is used, and more preferably, the compound represented by the following formula (201).

[0530] [ka]

[0531] In the formula (201), ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent. Ring A2 represents an aromatic heterocyclic structure which may have a substituent. R 201 , R 202 are each independently a structure represented by formula (202), and "*" represents the bonding position to 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.

[0532] Ar 201 , Ar 203each independently represents an aromatic hydrocarbon ring structure which may have a substituent, or an aromatic heterocyclic structure which may have a substituent. Ar 202 represents an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure 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.

[0533] B 201 -L 200 -B 202 represents an anionic bidentate ligand. 201 and B 202 each 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.

[0534] In addition, in formulas (201) and (202), 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.

[0535] (substituent) Unless otherwise specified, the substituent is preferably a group selected from the following substituent group S.

[0536] <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.

[0537] 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.

[0538] 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. An arylamino group, preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms.

[0539] 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. a heteroaralkyl group, preferably a heteroaralkyl group having 7 to 40 carbon atoms, more preferably a heteroaralkyl group 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.

[0540] An alkynyl group, preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms. 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.

[0541] 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.

[0542] 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. Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF 5。

[0543] 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.

[0544] 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.

[0545] (Ring A1) Ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.

[0546] 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.

[0547] 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.

[0548] 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.

[0549] (ring A2) Ring A2 represents an aromatic heterocyclic structure 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.

[0550] (Combination of Ring A1 and Ring A2) 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).

[0551] (Substituents of Ring A1 and Ring A2) 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.

[0552] (Ar 201 , Ar 202 , Ar 203 ) Ar 201 , Ar 203 each independently represents an aromatic hydrocarbon ring structure which may have a substituent, or an aromatic heterocyclic structure which may have a substituent.

[0553] Ar 202 represents an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent.

[0554] Ar 201 , Ar 202 , Ar 203 When any one of the above is an aromatic hydrocarbon ring structure which may have a substituent, the aromatic hydrocarbon ring 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.

[0555] 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.

[0556] 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.

[0557] Ar 201 , Ar 202 , Ar 203is an aromatic heterocyclic structure which may have a substituent, the aromatic heterocyclic structure is preferably an aromatic heterocyclic ring 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.

[0558] 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.

[0559] Ar 202 When is an aliphatic hydrocarbon structure which may have a substituent, it is an aliphatic hydrocarbon structure having a linear, branched, 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 even more preferably has 1 or more and 8 or less carbon atoms.

[0560] (i1, i2, i3, i4, k1, k2) i1 and i2 each independently represent an integer of 0 to 12, preferably 1 to 12, further preferably 1 to 8, and even more preferably 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 0 to 2, and even more preferably 0 or 1.

[0561] 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 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

[0562] (Ar 201 , Ar 202 , Ar 203 Preferred substituents for 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

[0563] (Preferred embodiment of the compound represented by formula (201)) The compound represented by the formula (201) is preferably a compound that satisfies one or more of the following (I) to (IV):

[0564] (I) Phenylene-linked The structure represented by formula (202) is preferably a structure having a group linked to benzene rings, i.e., a benzene ring structure, i1 being 1 to 6, and at least one of the benzene rings being bonded to an adjacent structure at the ortho or meta position. Such a structure is expected to improve solubility and charge transport properties.

[0565] (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 heterocyclic structure, i1 is 1 to 6, Ar 202 is an aliphatic hydrocarbon structure, i2 is 1 to 12, preferably 3 to 8, Ar 203 is a benzene ring structure, i3 is 0 or 1, preferably Ar 201 is 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.

[0566] (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 1 to 6, i3 is 2, and j is 2. Such a structure is expected to improve solubility and charge transport properties.

[0567] (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.

[0568] [ka]

[0569] In formula (203), R 211 , R 212 , R 213 each independently represents a substituent. In formula (204), ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom, which may have a substituent, and ring B3 is preferably a pyridine ring.

[0570] (Preferred Phosphorescent Materials) The phosphorescent material represented by the formula (201) is not particularly limited, but preferred examples include the following.

[0571] [ka]

[0572] [ka]

[0573] Also preferred is a phosphorescent material represented by the following formula (205):

[0574] [ka]

[0575] [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.]

[0576] 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.

[0577] Also, in equation (205), R 92 and R 93each 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 carboxyl 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.

[0578] Furthermore, when 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.

[0579] (molecular weight) The molecular weight of the phosphorescent material is preferably 5000 or less, more preferably 4000 or less, and particularly preferably 3000 or less. The molecular weight of the phosphorescent material is preferably 800 or more, more preferably 1000 or more, and even more preferably 1200 or more. It is believed that by keeping the molecular weight within this range, the phosphorescent material does not aggregate and can be uniformly mixed with the charge transport material, thereby enabling the production of an emitting layer with high luminous efficiency.

[0580] The molecular weight of the phosphorescent material is preferably large in terms of high Tg, melting point, decomposition temperature, etc., resulting in excellent heat resistance of the phosphorescent material and the formed light-emitting layer, and in terms of preventing deterioration of film quality due to gas generation, recrystallization, molecular migration, etc., and an increase in impurity concentration due to thermal decomposition of the material. On the other hand, the molecular weight of the phosphorescent material is preferably small in terms of facilitating purification of the organic compound.

[0581] <Charge transport material> The charge transport material used in the light-emitting layer is a material having a skeleton with excellent charge transport properties, and is preferably selected from electron transport materials, hole transport materials, and bipolar materials capable of transporting both electrons and holes. Specific examples of skeletons having excellent charge transport properties include an aromatic structure, an aromatic amine structure, a triarylamine structure, a dibenzofuran structure, a naphthalene structure, a phenanthrene structure, a phthalocyanine structure, a porphyrin structure, a thiophene structure, a benzylphenyl structure, a fluorene structure, a quinacridone structure, a triphenylene structure, a carbazole structure, a pyrene structure, an anthracene structure, a phenanthroline structure, a quinoline structure, a pyridine structure, a pyrimidine structure, a triazine structure, an oxadiazole structure, and an imidazole structure.

[0582] As the electron transporting material, from the viewpoint of a material having excellent electron transporting properties and a relatively stable structure, a compound having a pyridine structure, a pyrimidine structure, or a triazine structure is more preferable, and a compound having a pyrimidine structure or a triazine structure is even more preferable.

[0583] The hole transport material is a compound having a structure with excellent hole transport properties. Among the central skeletons with excellent charge transport properties, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure is preferred as a structure with excellent hole transport properties, and a carbazole structure, a dibenzofuran structure, or a triarylamine structure is more preferred.

[0584] The charge transport material used in the light-emitting layer preferably has a fused ring structure of three or more rings, and more preferably is a compound having two or more fused ring structures of three or more rings or a compound having at least one fused ring of five or more rings. These compounds increase the rigidity of the molecules, making it easier to achieve the effect of suppressing the degree of molecular motion in response to heat. Furthermore, the fused rings of three or more rings and the fused rings of five or more rings preferably have an aromatic hydrocarbon ring or an aromatic heterocyclic ring in terms of charge transport properties and material durability.

[0585] Specific examples of fused ring structures having three or more rings include an anthracene structure, a phenanthrene structure, a pyrene structure, a chrysene structure, a naphthacene structure, a triphenylene structure, a fluorene structure, a benzofluorene structure, an indenofluorene structure, an indolofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, a dibenzothiophene structure, etc. From the viewpoint of charge transportability and solubility, at least one selected from the group consisting of a phenanthrene structure, a fluorene structure, an indenofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure is preferred, and from the viewpoint of durability against charges, a carbazole structure or an indolocarbazole structure is more preferred.

[0586] In the present invention, from the viewpoint of durability of the organic electroluminescent device against charges, it is preferable that at least one of the charge transport materials in the light-emitting layer is a material having a pyrimidine skeleton or a triazine skeleton.

[0587] The charge transport material of the light-emitting layer is preferably a polymer material from the viewpoint of excellent flexibility. The light-emitting layer formed using a material with excellent flexibility is preferable as the light-emitting layer of an organic electroluminescent element formed on a flexible substrate. When the charge transport material contained in the light-emitting layer is a polymer material, the molecular weight is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and even more preferably 10,000 to 100,000.

[0588] Furthermore, the charge transport material of the light-emitting layer is preferably a low-molecular-weight material from the viewpoints of ease of synthesis and purification, ease of designing electron transport performance and hole transport performance, and ease of adjusting viscosity when dissolved in a solvent. When the charge transport material contained in the light-emitting layer is a low-molecular-weight material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less, and is preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more.

[0589] <Fluorescent materials> The fluorescent material is not particularly limited, but a compound represented by the following formula (211) is preferred.

[0590] [ka]

[0591] In the above formula (211), Ar 241 represents an aromatic hydrocarbon condensed ring structure which may have a substituent, and Ar 242 , Ar 243 each independently represents an alkyl group, an aromatic hydrocarbon group, an aromatic hetero group, or a group formed by combining these groups, which may have a substituent;

[0592] Ar 241 represents an aromatic hydrocarbon condensed ring structure preferably having 10 to 30 carbon atoms, and specific ring structures include naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, tetracene, chrysene, and perylene.

[0593] Ar 241 is more preferably an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms, and specific ring structures include acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, tetracene, chrysene, and perylene.

[0594] Ar 241is more preferably an aromatic hydrocarbon condensed ring structure having 16 to 18 carbon atoms, and specific examples of the ring structure include fluoranthene, pyrene, and chrysene.

[0595] n41 is 1 to 4, preferably 1 to 3, more preferably 1 or 2, and most preferably 2. Ar 242 , Ar 243 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms.

[0596] Ar 242 , Ar 243 The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms, and most preferably a phenyl group or a naphthyl group.

[0597] Ar 242 , Ar 243 The aromatic hetero group is preferably an aromatic hetero group having 3 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 5 to 24 carbon atoms, specifically preferably a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group, more preferably a dibenzofuranyl group.

[0598] Ar 241 , Ar 242 , Ar 243 The substituent that may be possessed by is preferably a group selected from the above-mentioned substituent group S, more preferably a hydrocarbon group included in the substituent group S, and even more preferably a hydrocarbon group among the groups preferred as the substituent group S.

[0599] The charge transport material used together with the fluorescent material is not particularly limited, but is preferably one represented by the following formula (212).

[0600] [ka]

[0601] In the above formula (212), R 251 , R 252 are each independently a structure represented by formula (213), and R 253 represents a substituent, and R 253 When there are a plurality of n43, they may be the same or different, and n43 is an integer of 0 to 8.

[0602] [ka]

[0603] In the above formula (213), * represents a bond to the anthracene ring of formula (212), and Ar 254 , Ar 255 each independently represents an aromatic hydrocarbon structure which may have a substituent, or a heteroaromatic ring structure which may have a substituent; Ar 254 , Ar 255 When there are a plurality of each, they may be the same or different; n44 is an integer of 1 to 5; and n45 is an integer of 0 to 5.

[0604] Ar 254 is preferably an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 30 carbon atoms and which may have a substituent, and more preferably an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 12 carbon atoms and which may have a substituent.

[0605] Ar 255 is preferably an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 30 carbon atoms, which may have a substituent, or an aromatic heterocyclic structure which is a fused ring having 6 to 30 carbon atoms, which may have a substituent. 255 is more preferably an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 12 carbon atoms, which may have a substituent, or an aromatic heterocyclic structure which is a fused ring having 12 carbon atoms, which may have a substituent.

[0606] n44 is preferably an integer of 1 to 3, and more preferably 1 or 2. n45 is preferably an integer of 0 to 3, and more preferably 0 to 2.

[0607] The substituent R 253 , Ar 254 and Ar 255 The substituent that may be possessed by is preferably a group selected from the above-mentioned substituent group S. More preferably, it is a hydrocarbon group included in the substituent group S, and even more preferably, it is a hydrocarbon group among the groups preferred as the substituent group S.

[0608] The molecular weight of the fluorescent material and the charge transport material is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less, and is preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more.

[0609] [Hole blocking layer] A hole-blocking layer 6 may be provided between the light-emitting layer 5 and the electron-injecting layer 8 described below. The hole-blocking layer 6 is a layer of the electron-transporting layer that also plays a role in blocking holes migrating from the anode 2 from reaching the cathode 9. The hole-blocking layer 6 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 9 side.

[0610] The hole blocking layer 6 has the role of preventing holes migrating from the anode 2 from reaching the cathode 9 and the role of efficiently transporting electrons injected from the cathode 9 toward the light-emitting layer 5 .

[0611] The properties required for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet energy level (T1). Examples of materials for the hole-blocking layer 6 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 6.

[0612] There is no limitation on the method for forming the hole blocking layer 6. The hole blocking layer 6 can be formed by a wet film forming method, a vapor deposition method, or other methods.

[0613] The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effects of the present invention. The thickness of the hole blocking layer 6 is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0614] [Electron transport layer] The electron transport layer 7 is a layer provided between the light emitting layer 5 and the cathode 9 for transporting electrons. As the electron transport material of the electron transport layer 7, a compound is usually used that has a high efficiency of injecting electrons from the cathode 9 or an adjacent layer on the cathode 9 side, and that has high electron mobility and can efficiently transport the injected electrons. Compounds that satisfy these conditions include, for example, metal complexes such as aluminum complexes and lithium 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-t-butyl-9,10-N,N'-dicyanoanthraquinone diimine, triazine compound derivatives, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

[0615] The electron transport material used in the electron transport layer 7 is preferably an electron transporting organic compound, such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline, doped 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), which can achieve both electron injection and transport properties and excellent film quality. It is also effective to dope the above-mentioned electron transporting organic compound with an inorganic salt such as lithium fluoride or cesium carbonate.

[0616] There is no limitation on the method for forming the electron transport layer 7. The electron transport layer 7 can be formed by a wet film formation method, a vapor deposition method, or other methods.

[0617] The thickness of the electron transport layer 7 is arbitrary as long as it does not significantly impair the effects of the present invention. The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0618] [Electron injection layer] In order to efficiently inject electrons injected from the cathode 9 into the light-emitting layer 5, an electron injection layer 8 may be provided between the electron transport layer 7 and the cathode 9 described below. The electron injection layer 8 is made of an inorganic salt or the like.

[0619] Examples of materials for the electron injection layer 8 include lithium fluoride (LiF), magnesium fluoride (MgF), lithium oxide (LiO), and cesium (II) carbonate (CsCO) (see Applied Physics Letters, 1997, Vol. 70, p. 152; Japanese Patent Application Laid-Open No. 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, p. 1245; SID 04 Digest, p. 154, etc.).

[0620] The electron injection layer 8 often does not have charge transport properties, so in order to efficiently inject electrons, it is preferably used as an extremely thin film, and its thickness is usually 0.1 nm or more, preferably 5 nm or less.

[0621] [cathode] The cathode 9 is an electrode that serves to inject electrons into the layer on the light-emitting layer 5 side. Examples of materials for the cathode 9 include metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and / or tin oxide; metal halides such as copper iodide; carbon black; and conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. Among these, metals with a low work function are preferred for efficient electron injection, and suitable metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys thereof, are used. Specific examples include low-work-function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

[0622] The cathode 9 may be made of one material alone or two or more materials in any combination and ratio. The thickness of the cathode 9 varies depending on the required transparency. When transparency is required, it is preferable that the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the cathode 9 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. When opaqueness is sufficient, the thickness of the cathode 9 is arbitrary, and the cathode may be the same thickness as the substrate.

[0623] It is also possible to layer a different conductive material on top of the cathode 9 . For example, in order to protect a cathode made of a metal with a low work function, such as an alkali metal such as sodium or cesium, or an alkaline earth metal such as barium or calcium, it is preferable to further laminate a metal layer having a high work function and being stable against the atmosphere on the cathode, since this increases the stability of the element. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum, etc. These materials may be used alone or in any combination and ratio of two or more.

[0624] [Other layers] The organic electroluminescent device of the present invention may have other configurations within the scope of its spirit. For example, as long as the performance is not impaired, any layer other than the layers described above may be present between the anode 2 and the cathode 9, and any layer not required among the layers described above may be omitted.

[0625] In the layer structure described above, the components other than the substrate may be stacked in the reverse order. For example, in the layer structure shown in Fig. 1, the other components may be provided on the substrate 1 in the following order: cathode 9, electron injection layer 8, electron transport layer 7, hole blocking layer 6, light-emitting layer 5, hole transport layer 4, hole injection layer 3, and anode 2.

[0626] The organic electroluminescent device of the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array, or may be applied to a configuration in which anodes and cathodes are arranged in an XY matrix.

[0627] Each of the above-mentioned layers may contain components other than those described as materials, as long as the effects of the present invention are not significantly impaired.

[0628] <Organic electroluminescent device> Two or more organic electroluminescent elements that emit light of different colors can be provided to form an organic electroluminescent device such as an organic EL display device, an organic EL lighting device, etc. In this organic electroluminescent device, by using the organic electroluminescent element of the present invention as at least one, and preferably all, of the organic electroluminescent elements, a high-quality organic electroluminescent device can be provided.

[0629] <Organic EL display device> There are no particular limitations on the type or structure of the organic EL display device using the organic electroluminescent device of the present invention, and it can be assembled in accordance with a conventional method using the organic electroluminescent device of the present invention. For example, an organic EL display device 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).

[0630] <Organic EL lighting> There are no particular limitations on the type or structure of the organic EL lighting using the organic electroluminescent device of the present invention, and it can be assembled in accordance with a conventional method using the organic electroluminescent device of the present invention. [Example]

[0631] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0632] <Preparing the substrate> A 0.5 mm thick glass substrate was prepared by sputtering an Ag alloy film, followed by a sputtering indium tin oxide (ITO) film on the Ag film, followed by patterning using standard photolithography. A liquid-repellent acrylic resin was applied to the substrate to a thickness of 1.1 μm, and an opening was fabricated using standard photolithography. The opening had a major axis of approximately 180 μm, a minor axis of approximately 60 μm, and a corner radius of 30 μm.

[0633] The prepared substrate was subjected to ultrasonic cleaning in ultrapure water for 15 minutes, after which the remaining water on the substrate was blown off with air and dried for 10 minutes in a clean oven set to 130° C. In all of the following examples and comparative examples, the dried substrate was baked for 10 minutes on a hot plate at 230° C. immediately before applying ink, before use.

[0634] Example 1 <Ink preparation> A hole transport material P-1 and an electron acceptor compound D-1, each having an average molecular weight of 15 kJ, were mixed at a weight ratio of 100:12.5. Separately, butyl benzoate and 1,1-diphenylpentane were mixed at a weight ratio of 75:25 to prepare solvent 1. The content of the mixture relative to solvent 1 was adjusted to 2.0 wt %, and the mixture was heated at 110°C for 3 hours while stirring at 420 rpm using a stirrer, to produce composition 1.

[0635] [Chemical]

[0636] [Chemical]

[0637] <Coating and Drying Process> Composition 1 was filled into a cartridge (DMCLCP-11610) for an inkjet printer, and using an inkjet printer (DMP-2831 manufactured by Fujifilm Corporation), Composition 1 was applied to the openings of the substrate. The application amount was adjusted by setting the ejection voltage of the printer so that the ejection speed of the droplets was 10 m / s, and 5 droplets were dropped onto each opening. It was applied in a pattern such that 21 portions of the openings in the long axis direction and 65 portions of the openings in the short axis direction were applied, and for every 5 portions applied in the short axis direction, 1 portion was not applied, to form Pixel Group 1. As a result, Pixel Group 1 has a periodic structure in which the applied and non-applied openings are repeated with a period of 6 portions of the openings in the short axis direction. The substrate coated with Composition 1 was dried in vacuo, and the obtained organic film was baked on a hot plate at 230 °C for 30 minutes to obtain an organic film.

[0638] <Evaluation of Coating Film> Using a stylus type step profiler (ET-200 manufactured by Kosaka Laboratory), seven portions in the short axis direction of the obtained organic film were measured, and one with less noise was selected from the three measurement results excluding the organic film next to the non-applied opening to obtain the shape profile of the organic film.

[0639] <Quantification of Flatness> Among the obtained organic film profiles, when the thinnest film thickness was defined as Tm, the region where the film thickness T of the organic film was Tm + 15 nm or less was considered as the flat region. That is, the length of the organic film satisfying the condition Tm < T < Tm + 15 nm of the film thickness T of the organic film was defined as Lf, and the length of the opening was defined as Lо, and the flatness F was derived from the following formula (1).

[0640] [[ID=3 четыре]]Flatness F = Lf / Lо % Formula (1)

[0641] Example 2 An organic film was produced using the same process as in Example 1, except that hole transport material P-2 having an average molecular weight of 40 kJ was used instead of hole transport material P-1 used in Example 1, and the flatness was quantified.

[0642] [ka]

[0643] Example 3 An organic film was produced using the same process as in Example 1, except that hole transport material P-3 having an average molecular weight of 15kJ was used instead of hole transport material P-1 used in Example 1, and the flatness was quantified.

[0644] [ka]

[0645] Example 4 An organic film was produced using the same process as in Example 1, except that hole transport material P-4 having an average molecular weight of 40 kJ was used instead of hole transport material P-1 used in Example 1, and the flatness was quantified.

[0646] [ka]

[0647] Example 5 An organic film was produced using the same process as in Example 1, except that the weight ratio of the hole transport material P-1 to the electron accepting compound D-1 used in Example 1 was 100:0, and the flatness was quantified.

[0648] Example 6 An organic film was produced using the same steps as in Example 1, except that electron-accepting compound D-2 was used instead of electron-accepting compound D-1 used in Example 1, and the flatness was quantified.

[0649] [ka]

[0650] Example 7 An organic film was produced using the same steps as in Example 1, except that in the mixed solvent used in Example 1, 1,1-diphenylpentane was changed to mixed solvent 1 having the composition shown below, and the flatness was quantified.

[0651] Composition of mixed solvent 1 1,2-Dimethyl-4-(1-phenylethyl)benzene 1,4-Dimethyl-2-(1-phenylethyl)benzene 2,4-Dimethyl-1-(1-phenylethyl)benzene Ethyl(phenylethyl)benzene

[0652] Example 8 An organic film was produced using the same steps as in Example 1, except that butyl benzoate in Solvent 1 used in Example 1 was changed to diphenyl ether, and the flatness was quantified.

[0653] Example 9 An organic film was produced using the same steps as in Example 1, except that in Solvent 1 used in Example 1, the ratio of 1,1 diphenylpentane and butyl benzoate was changed to 50:50, and the flatness was quantified.

[0654] Example 10 An organic film was produced using the same steps as in Example 1, except that in Solvent 1 used in Example 1, the ratio of 1,1 diphenylpentane to butyl benzoate was changed to 5:95, and the flatness was quantified.

[0655] Example 11 An organic film was produced using the same process as in Example 1, except that the hole transport material used in Example 1 was changed to P-5 and the ratio of the hole transport material P-5 to the electron accepting compound D-1 was changed to 100:0 by weight, and the flatness was quantified.

[0656] [ka]

[0657] (Comparative Example 1) An organic film was produced using the same steps as in Example 1, except that in Solvent 1 used in Example 1, 1,1-diphenylpentane was changed to 4-butylbiphenyl, and the flatness was quantified.

[0658] (Comparative Example 2) An organic film was produced using the same process as in Example 1, except that the ratio of the hole transport material P-1 to the electron acceptor compound D-1 used in Example 1 was changed to 100:0 by weight, and the mixed solvent used in Example 1 was changed from 1,1-diphenylpentane to 4-butylbiphenyl, and the flatness was quantified.

[0659] (result) The profile and flatness of the organic film are summarized in the table below.

[0660] [Table 1]

[0661] [Table 2]

[0662] [Table 3]

[0663] [Table 4]

[0664] As can be seen from the table above, the organic film formed using the solvent represented by formula (1) has a higher degree of flatness than the organic film formed using other solvents.

[0665] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent applications filed on September 30, 2020 (Patent Application No. 2020-165309) and September 30, 2020 (Patent Application No. 2020-165310), the contents of which are incorporated herein by reference. [Explanation of symbols]

[0666] 1 board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6. Hole-blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent device

Claims

1. A solvent compound for an organic electroluminescent device, comprising a functional material and the solvent compound represented by the following formula (1): The functional material contains at least an electron-accepting compound, The composition for organic electroluminescent devices, wherein the electron-accepting compound is a tetraarylborate ion compound. 【Chemistry 1】 (In formula (1), R １ , R ２ , R ３ , n １ , m １ satisfies either (i) or (ii) below. (i) R １ represents an alkyl group having 1 to 6 carbon atoms, R ２ each independently represents an alkyl group having 1 to 3 carbon atoms, n １ represents an integer from 1 to 5, R ３ does not exist, that is, m １ =0. (ii) R １ represents an alkyl group having 2 to 6 carbon atoms, R ２ , R ３ each independently represents an alkyl group having 1 to 3 carbon atoms, n １ , m １ represents an integer from 0 to 5.)

2. 2. The composition for organic electroluminescent elements according to claim 1, wherein the tetraarylborate ion compound is an ionic compound comprising a tetraarylborate ion represented by the following formula (2) and a counter cation: 【Chemistry 2】 (In formula (2), Ar １ , Ar ２ , Ar ３ and Ar ４ each independently represent an optionally substituted aromatic hydrocarbon ring group, an optionally substituted aromatic heterocyclic group, or a monovalent group formed by linking together a plurality of structures selected from optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups; The substituent may be a bridging 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.

3. Ar in the formula (2) １ , Ar ２ , Ar ３ and Ar ４ The composition for organic electroluminescent elements according to claim 2 , wherein at least one of the above is a group represented by the following formula (3): 【Transformation 3】 (In formula (3), R １００ each independently represents an aromatic hydrocarbon ring group which may have a substituent, an aromatic heterocyclic group which may have a substituent, a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked together, a fluorine-substituted alkyl group, or R １００ is a group containing a bridging group, F ４ represents a group having four fluorine atoms substituted thereon, F （５－ｍ） each independently represent substitution with 5-m fluorine atoms, Each k independently represents an integer of 0 to 5, Each m independently represents an integer of 0 to 5.

4. 4. The composition for organic electroluminescent elements according to claim 3, wherein the crosslinking group is represented by any one of the following formulas (X1) to (X18): 【Chemistry 4】 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 (10) １１０ represents a hydrogen atom or an alkyl group which may have a substituent.

5. The functional material includes at least a hole transport polymer compound, 5. The composition for organic electroluminescent devices according to claim 1, wherein the hole transporting polymer compound is a polymer having a triarylamine structure as a repeating unit.

6. 6. The composition for organic electroluminescent elements according to claim 5, wherein the triarylamine structure as the repeating unit contains at least a repeating unit selected from a repeating unit represented by the following formula (54), a repeating unit represented by the following formula (55), a repeating unit represented by the following formula (56), and a repeating unit represented by the following formula (57): 【Transformation 5】 (In formula (54), Ar ５１ represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a group in which a plurality of groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent 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 are each independently 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 are each independently an integer of 0 to 3. 【Transformation 6】 (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. 【Transformation 7】 (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 are each independently an integer of 0 to 4. 【Transformation 8】 (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.)

7. Ar in the repeating unit represented by the formula (54), the repeating unit represented by the formula (55), the repeating unit represented by the formula (56), and the repeating unit represented by the formula (57) ５１ is a group selected from a group containing a monovalent or divalent group in which 2 to 5 optionally substituted benzene rings are linked together, a fluorenyl group which may have a substituent, a group represented by the following formula (51), a group represented by the following formula (52), and a group represented by the following formula (53): 【Chemistry 9】 (In formula (51), * represents a bond to a nitrogen atom of the main chain of the formula (54), the formula (55), the formula (56), and the formula (57), 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. 【Chemistry 10】 (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 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. * represents the bonding position to the nitrogen atom of the main chain in the formula (54), the formula (55), the formula (56), and the formula (57). 【Chemistry 11】 (In formula (53), * represents a bond to a nitrogen atom of the main chain of the formula (54), the formula (55), the formula (56), and the formula (57), Ar ７１ represents a divalent aromatic hydrocarbon group which may have a substituent, Ar ７２ and Ar ７３ each independently represent an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups are linked together directly or via a linking group; 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.)

8. 8. The composition for organic electroluminescent devices according to claim 5, wherein the polymer having a triarylamine structure as a repeating unit has a weight average molecular weight of 50,000 or less.

9. 9. The composition for organic electroluminescent elements according to claim 6, wherein the triarylamine structure as the repeating unit includes a repeating unit represented by formula (54).

10. Further containing a solvent B, 10. The composition for organic electroluminescent elements according to claim 1, wherein the solvent B is a solvent compound having a boiling point of 200° C. or higher, different from the solvent compound.

11. The composition for organic electroluminescent elements according to claim 10 , wherein the total content of the solvent compound and the solvent B relative to the total amount of solvents contained in the composition is 50% by weight or more.

12. 12. The composition for organic electroluminescent elements according to claim 10, wherein the viscosity of the solvent B at 23°C is 5 mPas or less.

13. 13. The composition for organic electroluminescent elements according to claim 10, wherein the boiling point a of the solvent compound and the boiling point b of the solvent B satisfy the relationship: boiling point b<boiling point a.

14. The composition for organic electroluminescent elements according to claim 13, wherein the difference between the boiling point a and the boiling point b is 10°C or more.

15. 15. The composition for organic electroluminescent elements according to claim 13, wherein the boiling point a is in the range of 270°C or higher and 340°C or lower, and the boiling point b is in the range of 250°C or higher and 340°C or lower.

16. A method for producing an organic electroluminescent device, comprising a wet film-forming step using a composition for organic electroluminescent devices according to any one of claims 1 to 15.

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