Composition using a solvent compound for organic field light-emitting devices, and method for manufacturing organic field light-emitting devices.

Abstract

To provide a solvent compound for organic electroluminescent devices that can improve the flatness of the layers. [Solution] A solvent compound for an organic electroluminescent element represented by the following formula (1). [Formula 1] TIFF2026067894000128.tif46166 (in formula (1), R 1 , R 2 , R 3 , n 1 , m 1 The definition is as stated in the specification.

Description

[Technical Field]

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

[0002] While the common method for manufacturing organic electroluminescent devices involves depositing organic materials into films using vacuum deposition and then stacking them, in recent years, research has been actively pursuing wet deposition methods, which involve depositing dissolved organic materials into films using inkjet technology and other methods, as a manufacturing method with superior material utilization efficiency.

[0003] In the manufacturing of organic electroluminescent devices, particularly organic EL displays, by wet deposition, a method has been investigated in which each pixel is partitioned by a partition called a bank, and an ink, which is an organic electroluminescent device forming composition for forming the organic film constituting the organic electroluminescent device, is ejected by an inkjet method into a minute region within the bank. In this process, a technique has been proposed to obtain a flatter film within the region enclosed by the bank by mixing various surface modifiers with the ink (Patent Documents 1 and 2).

[0004] However, conventional methods did not provide sufficient flatness of the membrane within the region enclosed by the bank. Patent Document 3 discloses a technique for using two or more solvents with different boiling points in order to form a functional layer with a nearly flat cross-sectional shape after drying and solidification. For example, it discloses a technique using 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 [Overview of the project] [Problems that the invention aims to solve]

[0006] The solvents used in organic electroluminescent devices manufactured by wet deposition, particularly by coating with inkjet devices, are required to have properties that dissolve functional materials such as light-emitting materials and hole transport materials, as well as properties that ensure the layer becomes flat when deposited.

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

[0008] However, there is still room for improvement regarding the flatness of the layers. The present invention aims to provide a solvent compound for organic electroluminescent devices that can improve the flatness of layers, a composition using the same, and a method for manufacturing organic electroluminescent devices. [Means for solving the problem]

[0009] In other words, the present invention is as follows: <1> ~ <19> This concerns... <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 It 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 and R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, n 1 and m 1 represent integers from 0 to 5.) <2>A composition for an organic electroluminescent device, comprising a functional material and the solvent compound represented by the formula (1). <3>The composition for an organic electroluminescent device according to <2>, comprising at least an electron-accepting compound as the functional material. <4>The composition for an organic electroluminescent device according to <3>, wherein the electron-accepting compound is a tetraarylborate ion compound. <5>The composition for an organic electroluminescent device according to <4>, wherein the tetraarylborate ion compound is an ionic compound composed of a tetraarylborate ion represented by the following formula (2) and a counter cation.

[0012] [Chemical formula]

[0013] (In formula (2), Ar 1 、Ar 2 、Ar 3 and Ar 4Each of these independently represents a monovalent group consisting of multiple structures selected from optionally substituted aromatic hydrocarbon ring groups, optionally substituted aromatic heterocyclic groups, or optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups. The substituent may also be a crosslinking group. Ar 1 Ar 2 Ar 3 and Ar 4 At least one of them has a fluorine atom or a fluorine-substituted alkyl group as a substituent. <6> Ar in equation (2) above 1 Ar 2 Ar 3 and Ar 4 At least one of them is a group represented by the following formula (3): <5> The organic electroluminescent light-emitting composition described above.

[0014] [ka]

[0015] (In formula (3), R 100 Each of these independently consists of a substituted aromatic hydrocarbon ring group, a substituted aromatic heterocyclic group, a monovalent group formed by linking multiple structures selected from a substituted aromatic hydrocarbon ring group and a substituted aromatic heterocyclic group, a fluorine-substituted alkyl group, or R 100 It is a group that contains a crosslinking group, F4 indicates that four fluorine atoms are substituted. F (5-m) Each of these independently represents that 5-m fluorine atoms are substituted, k represents an integer from 0 to 5, independently. (Each 'm' represents an independent integer between 0 and 5.) <7> The aforementioned crosslinking group is represented by any of the following formulas (X1) to (X18): <6> The organic electroluminescent light-emitting composition described above.

[0016] [ka]

[0017] (In formulas (X1) to (X4), the benzene ring and the naphthalene ring may have substituents. The substituents may also be bonded to each other to form a ring.) R in equations (X4), (X5), (X6), and (10) 110 (This 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> A composition for an organic electroluminescent element as described in any one of the following. <9> The repeating unit, a triarylamine structure, comprises at least a repeating unit selected from the repeating units represented by formula (54), formula (55), formula (56), and formula (57). <8> The organic electroluminescent light-emitting composition described above.

[0018] [ka]

[0019] (In formula (54), Ar 51 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a group formed by linking multiple groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups. 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 222is, independently of each other, an alkyl group which may have a substituent, R 207 ~R 209 and R 211 ~R 214 are, independently of each other, 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, a and b are, independently of each other, integers from 0 to 4, c is an integer from 0 to 3, [[ID=十六]]d is an integer from 0 to 4, i and j are each independently an integer from 0 to 3.)

[0020] )]]

Chemical formula

[0021] (In formula (55), Ar 51 is the same as Ar in the above formula (54), 51 and R 303 and R 306 are, independently of each other, an alkyl group which may have a substituent, R 304 and R 305 are, independently of each other, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aralkyl group which may have a substituent, 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]

Chemical formula

[0023] (In formula (56), Ar 51 It should be noted that there may be some inaccuracies in the above translation due to the lack of clear context for some symbols and expressions. It is recommended to double-check with the original text for a more accurate understanding.This is Ar in equation (54) above. 51 It is similar to, Ar 41 This is a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is directly or via a linking group, R 441 and R 442 Each of these is an alkyl group which may have substituents, t is either 1 or 2. u is either 0 or 1, r and s are independent integers between 0 and 4.

[0024] [ka]

[0025] (In formula (57), Ar 51 This is Ar in equation (54) above. 51 It is similar to, R 517 ~R 519 Each of these independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aralkyl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. f, g, and h each independently represent integers from 0 to 4. e represents an integer from 0 to 3. However, if g is 1 or greater, then e is 1 or greater. <10> In the repeating unit represented by formula (54), the repeating unit represented by formula (55), the repeating unit represented by formula (56), and the repeating unit represented by formula (57), Ar 51However, the group is selected from a group comprising a monovalent or divalent group having 2 to 5 linked benzene rings which may have substituents, a fluorenyl group which may have substituents, 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 organic electroluminescent light-emitting composition described above.

[0026] [ka]

[0027] (In formula (51), * represents the bond with the nitrogen atom of the main chain in formulas (54), (55), (56), and (57). Ar 53 Ar 54 Each of these independently represents a divalent aromatic hydrocarbon group which may have substituents, a heterocyclic aromatic group which may have substituents, or a divalent group in which multiple heterocyclic aromatic hydrocarbon groups which may have substituents are linked directly or via linking groups. Ar 55 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group is directly or via a linking group. Ar 56 (This represents a hydrogen atom or substituent.)

[0028] [ka]

[0029] (In formula (52), Ar 61 and Ar 62 Each of these is independently a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which multiple aromatic hydrocarbon groups or aromatic heterocyclic groups which may have substituents are linked directly or via linking groups. Ar 63 ~Ar 65 Each of these is independently a hydrogen atom or a substituent. * indicates the bond position of the main chain to the nitrogen atom in formulas (54), (55), (56), and (57).

[0030] [ka]

[0031] (In formula (53), * represents the bond with the nitrogen atom of the main chain in formulas (54), (55), (56), and (57). Ar 71 This represents a divalent aromatic hydrocarbon group which may have substituents, Ar 72 and Ar 73 Each of these independently represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group are linked directly or via linking groups. The HA ring is an aromatic heterocycle containing a nitrogen atom. X 2 , Y 2 Each of these independently represents a carbon atom or a nitrogen atom, and X 2 and Y 2 If at least one of them is a carbon atom, that carbon atom may have substituents. <11> The weight-average molecular weight of the polymer having the aforementioned triarylamine structure as a repeating unit is 50,000 or less. <8> ~ <10> A composition for an organic electroluminescent element as described in any one of the following. <12> The repeating unit, a triarylamine structure, includes the repeating unit represented by formula (54). <9> ~ <11> A composition for an organic electroluminescent element as described in any one of the following. <13> Furthermore, containing solvent B, The solvent B is a solvent compound with a boiling point of 200°C or higher, different from the solvent compound. <2> ~ <12> A composition for an organic electroluminescent element as described in any one of the following. <14> The total content of the solvent compound and solvent B relative to the total amount of solvent contained in the composition is 50% by weight or more. <13> The organic electroluminescent light-emitting composition described above. <15> The viscosity of solvent B at 23°C is 5 mPas or less. <13> or <14> The organic electroluminescent light-emitting composition described above. <16> The boiling point a of the solvent compound and the boiling point b of the solvent B satisfy boiling point b < boiling point a. <13> ~ <15> A composition for an organic electroluminescent element as described in any one of the following. <17> The difference between the boiling point a and the boiling point b is 10°C or more. <13> ~ <16> A composition for an organic electroluminescent element as described in any one of the following. <18> The boiling point a is in the range of 270°C to 340°C, and the boiling point b is in the range of 250°C to 340°C. <13> ~ <17> A composition for an organic electroluminescent element as described in any one of the following. <19> <2> ~ <18> A method for manufacturing an organic electroluminescent element, comprising the step of wet-forming a film using an organic electroluminescent element composition described in any one of the above. [Effects of the Invention]

[0032] The present invention provides a solvent compound for organic electroluminescent devices that can improve the flatness of layers, a composition using the same, and a method for manufacturing organic electroluminescent devices. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the structure of the organic electroluminescent element of the present invention. [Modes for carrying out the invention]

[0034] The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist thereof.

[0035] As a result of intensive studies by the present inventors to solve the above problems, it has been found that the flatness of the layer can be improved by using the solvent compound represented by formula (1). As a result, it has been found that wavelength adjustment can be performed over a wider range, and an aromatic compound adjusted to the long wavelength side represented by red in particular can be provided.

[0036] <Solvent Compound for Organic Electroluminescent Device> The solvent compound for an organic electroluminescent device of the present invention is a solvent compound for an organic electroluminescent device represented by the following formula (1).

[0037] <000​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0039] Generally, the functional materials that form organic electroluminescent devices are aromatic compounds. In the solvent compound of the present invention, two phenyl groups are bonded to one terminal carbon of an alkyl group. That is, the two phenyl groups are linked by a methylene group. Here, the phenyl groups interact with the aromatic solute compound, allowing the aromatic solute compound, which is the functional material, to be dissolved at a high concentration. Furthermore, it is presumed that the linkage of the two benzene rings by a quaternary carbon breaks down the planarity of the molecular skeleton, increasing its degrees of freedom, making it easier to freely arrange itself to improve its affinity with the solute compound, and thus further increasing its solubility.

[0040] In case (i), the solvent compound of the present invention is further thought to have high asymmetry due to the substituent being on only one of the two phenyl groups, forming an asymmetric aggregate, which leads to better dispersion of the solute compound than in a symmetric solvent and the formation of a more uniform and flat amorphous organic film.

[0041] Also, in the case of (ii), and in the case of (i), n 1 If the number of phenyl groups is 2 or more, the alkyl group having two phenyl groups bonded to its terminals is an alkyl group with 3 or more carbon atoms. Therefore, the solvent compounds of the present invention interact with each other at the sites where the two phenyl groups are not bonded, resulting in a homogeneous solution. Consequently, the solute compounds are more uniformly dispersed, forming a uniform and flat amorphous organic film.

[0042] These results are expected to lead to the acquisition of devices with excellent luminous efficiency and / or long-life light-emitting elements.

[0043] Furthermore, the solvent compound for the organic electroluminescent device of the present invention may be referred to simply as "solvent" or "solvent" in the following description. Whether what is referred to simply as "solvent" or "solvent" is the solvent compound for the organic electroluminescent device of the present invention will be appropriately interpreted from the context.

[0044] <(i) case> 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 of 1 to 5, and R 3 is absent, that is, m 1 = 0.

[0045] <R 1 > R 1 is an alkyl group having 1 to 6 carbon atoms. As the alkyl group, a linear alkyl group may be used, or a branched alkyl group may 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. The preferable range is a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group, or a linear or branched hexyl group. From the viewpoint of the flatness of the film, a methyl group, an ethyl group, and an n-propyl group are particularly preferable, and a methyl group is most preferable.

[0046] <R 2 > R 2 each independently is an alkyl group having 1 to 3 carbon atoms. As the alkyl group, a linear alkyl group may be used, or a branched alkyl group may also be used. The preferable range is a methyl group, an ethyl group, and a propyl group, and from the viewpoint of the flatness of the film, a methyl group and an ethyl group are particularly preferable.

[0047] <n 1 > n 1 is an integer of 1 to 5, and from the viewpoint of the flatness of the film, it is preferably an integer of 1 to 2. n 1 For R 1 , R 2 the preferable range is that when n is 1, R 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, particularly R 1 is a methyl group or an ethyl group, and R 2 is preferably an ethyl group.

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

[0049] When the solvent compound for the organic electroluminescent element of the present invention is (i), R 2 It has an alkyl group as R 3 Since it does not contain R, the two benzene rings are asymmetric, which is thought to give it particularly excellent solubility. 1 and R 2 The presence of a methyl group with a small number of carbon atoms is thought to improve the stability of the solvent compound itself. As a result, it is thought that an ink can be obtained that has high solubility in functional materials used in organic electroluminescent devices containing many aromatic ring groups, and also has excellent storage stability.

[0050] <(ii) case> R 1 R represents an alkyl group with 2 to 6 carbon atoms. 2 , R 3 Each of these independently represents an alkyl group having 1 to 3 carbon atoms, and n 1 , m 1 This represents an integer between 0 and 5.

[0051] <R 1 > R 1 R is an alkyl group having 2 to 6 carbon atoms. The alkyl group may be a linear group or a branched group. For example, ethyl, propyl, butyl, pentyl, and hexyl groups can be used. From the viewpoint of improving flatness, particularly preferred alkyl groups are ethyl, linear or branched propyl, linear or branched butyl, linear or branched pentyl, and linear or branched hexyl. From the viewpoint of film flatness, stability, and solubility, R 1The alkyl group is preferably a C3-C5 alkyl group, and more preferably a C4 or C5 alkyl group. From the viewpoint of film flatness and stability, n-butyl groups and n-pentyl groups are more preferred.

[0052] <R 2 , R 3 > R 2 , R 3 Each of these independently represents 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. The preferred range of alkyl groups is methyl, ethyl, and propyl, with methyl being particularly preferred from the viewpoint of film flatness.

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

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

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

[0056] n 1 If it is 1, m 1 R is 1, 1 R is an n-propyl group, an n-butyl group, 2 , R 3 It is preferable that the group is a methyl group or an ethyl group from the standpoint of the stability of the coated film.

[0057] n 1 If it is 2, then m 1 is 1 or 2, R 1 R is an ethyl group, a propyl group, 2 , R 3 It is preferable that the group is a methyl group from the standpoint of the stability of the coated film.

[0058] <Composition for Organic Electroluminescent Light-Emitting Devices> The present invention's composition for organic electroluminescent devices (hereinafter sometimes referred to as "the composition of the present invention") is a composition comprising a functional material and solvent A, wherein solvent A is an organic electroluminescent device solvent compound having the structure of the general formula (1) described above. Furthermore, the composition of the present invention preferably contains solvent B, wherein solvent B is a solvent compound different from solvent A with a boiling point of 200°C or higher.

[0059] The content of solvent A is preferably 0.5 to 50% by weight relative to the total amount of solvent. The proportion of functional materials is approximately 0.5% to 10% by weight. If solvent A is present at least 0.5% by weight, then in the state just before film formation, the ratio of solvent A to solute becomes large, and the planarity of solvent A is likely to have an effect.

[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 asymmetrical structural formula, possesses high solubility in functional materials and moderate viscosity, and can be used as an ink that can be dispensed from a micro nozzle.

[0061] The composition of the present invention exhibits a moderate viscosity at room temperature, but its viscosity increases as the temperature drops due to the heat of vaporization during the vacuum drying process. This slows down the flow rate of the liquid, allowing for control of the film shape and enabling the creation of a flat film. This effect is particularly pronounced in compositions using low-molecular-weight materials that have relatively higher crystallinity than polymers.

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

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

[0064] When a liquid film within a region enclosed by a bank is dried, and the solvent composition ratio of the liquid film changes due to the evaporation of the solvent, it may also be referred to as a liquid or liquid film.

[0065] A film containing a functional material, obtained by coating the composition of the present invention and drying it after volatilizing the organic solvent, is called a functional film. Furthermore, a film containing an organic compound that does not contain a solvent or is dried after substantially volatilizing the solvent is called an organic film. A functional film is a type of organic film.

[0066] <Type of solvent> From the viewpoint of improving flatness due to temperature reduction and viscosity increase, and ensuring flatness at the panel edges, it is preferable to use at least one solvent B in addition to solvent A.

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

[0068] Preferred aromatic hydrocarbon solvents include benzene derivatives, naphthalene derivatives, hydrogenated naphthalene derivatives, and biphenyl derivatives.

[0069] Preferred benzene derivatives are those having a total number of carbon atoms of 5 to 12 as substituents, and having linear, branched, or alicyclic alkyl groups as substitutions. Examples include n-octylbenzyl, n-nonylbenzene, n-decylbenzene, and dodecylbenzene.

[0070] While there are no particular limitations on naphthalene derivatives, alkyl-substituted naphthalene derivatives are preferred, including 1-methylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, 2,6-dimethylnaphthalene, and 1-methoxynaphthalene.

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

[0072] While there are no particular limitations on the biphenyl derivative, biphenyl derivatives substituted with alkyl groups having 1 to 6 carbon atoms are preferred, such as 3-ethylbiphenyl and 4-isopropylbiphenyl.

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

[0074] Examples of aromatic ester solvents include benzoic acid ester solvents, phenylacetic acid ester solvents, and phthalic acid ester solvents.

[0075] The benzoic acid ester solvent is a compound having an ester bond with benzoic acid, and a compound formed by ester bonding of benzoic acid (which may have substituents) with an alcohol having 2 to 12 carbon atoms can be used. Preferred substituents are linear or branched alkyl groups having 1 to 6 carbon atoms, and linear or branched alkoxy groups having 1 to 6 carbon atoms. There may be multiple substituents, and if there are multiple substituents, the total number of carbon atoms as substituents is preferably 6 or less. Examples of benzoic acid ester solvents include butyl benzoate, n-pentyl benzoate, isoamyl benzoate, n-hexyl benzoate, 2-ethylhexyl benzoate, benzyl benzoate, and ethyl 4-methoxybenzoate.

[0076] Examples of phenylacetic acid ester solvents include ethyl phenylethyl acetate. Examples of phthalate ester solvents include dimethyl phthalate, diethyl phthalate, and dibutyl phthalate.

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

[0078] Aromatic ether solvents are compounds that have an aromatic ring and an ether bond, and include the following: Examples of diphenyl ether derivatives that may be substituted with linear or branched alkyl groups having 1 to 6 carbon atoms include diphenyl ether, 2-phenoxytoluene, 3-phenoxytoluene, and 4-phenoxytoluene; Examples of benzene derivatives having two ether bonds with linear or branched alkyl groups having 1 to 6 carbon atoms include 1,4-diethoxybenzene and 1-ethoxy-4-hexyloxybenzene; Examples of benzene derivatives having one linear or branched alkyl group with 4 to 12 carbon atoms and one ether bond include phenylhexyl ether; Examples of benzyl ether solvents include dibenzyl ether; Other aromatic ether solvents include 2-phenoxyethanol:

[0079] Aromatic ketone solvents are compounds having both an aromatic ring and a ketone structure, such as 1-acetylnaphthalene.

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

[0081] <Other solvent components> The composition of the present invention may have 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, examples include solvent components that can be used in solvent B and have a boiling point of less than 200°C.

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

[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. Among the solvents contained in the composition of the present invention, solvent B has a boiling point of 200°C or higher, and is 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 the higher boiling point, it is possible to achieve good uniformity of film thickness when wet-forming an organic film within a region surrounded by a bank.

[0085] Therefore, it is preferable that the boiling point of solvent B (b) < the boiling point of solvent A (a). This is thought to increase the viscosity of solvent A due to the heat of vaporization when solvent B evaporates, thus forming a flat film.

[0086] Furthermore, it is 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 solvents A and B used in this invention are both 200°C or higher, and it is preferable for the boiling point of solvent A to be higher than that of solvent B for film formation purposes. During the drying process after coating, solvent B, which has a lower boiling point, usually evaporates before solvent A. As described later, when a liquid film is formed by the composition discharged into the bank and the liquid film is dried by vacuum drying or the like, solvent B, which has a lower boiling point, evaporates first. At this time, the temperature of the liquid film decreases as the heat of vaporization is removed. At this time, it is thought that the viscosity of solvent A remaining in the liquid film increases, and a uniform film shape can be given due to the solvent's inherent asymmetric structure, resulting in a flat film. In this invention, the boiling point of the solvent is the value measured under 1 atmosphere.

[0088] The following are specific examples of compounds represented by general formula (1), but the present invention is not limited to these.

[0089] [ka]

[0090] [ka]

[0091] <Viscosity> The viscosity of solvent A is preferably between 3 mPas and 20 mPas. The viscosity of solvent B is preferably 5 mPas or less at 23°C. By keeping the viscosity of solvent B below the above upper limit, it becomes possible to select solvent A with higher viscosity or functional materials that easily increase viscosity when preparing the composition, thus broadening the range of choices for solvent A, functional materials, and ink concentration.

[0092] The viscosity of solvent B is preferably 4.5 mPas or less. On the other hand, from the viewpoint of easily retaining ink within the inkjet head when filled, the viscosity of solvent B is preferably 1.0 mPas or more.

[0093] In this invention, the viscosity of the solvent can be measured using an E-type viscometer RE85L (manufactured by Toki Sangyo Co., Ltd.) at a temperature 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 higher, and preferably 45 mN / m or lower. Having the surface tension of solvent A within this range is considered preferable because it maintains the overall surface tension of the ink within an appropriate range, enabling stable ejection in an inkjet device. Furthermore, having the surface tension of solvent A within this range is considered preferable because it facilitates the flattening of the liquid surface within the ink bank. When the surface tension of solvent A is above the lower limit, a certain level of tension is generated on the liquid surface during drying, causing the surface area to decrease, thus reducing the likelihood of wrinkles in the film. On the other hand, when the surface tension of solvent A is below the upper limit, surface tension differences are less likely to occur during drying, reducing unnecessary Marangoni convection, thus facilitating the formation of a flat film, which is preferable.

[0095] In this invention, the surface tension of the solvent can be measured at 23.0°C using a plate method with a platinum plate.

[0096] <Combinations of solvents> The solvents A and B contained in the composition of the present invention may each be one or more types.

[0097] In particular, the presence of two or more types of solvent A is preferable because it allows for adjustment of the surface tension, which facilitates solvent convection in front of the thin film, and further suppresses heterogeneity due to the asymmetric structure of solvent A, 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 ensuring that the functional material dissolves well and does not easily precipitate during the drying process, solvent B is preferably one of naphthalene, benzoic acid ester, or aromatic ether, each of which may have substituents.

[0100] [Contents of Solvent A and Solvent B] The content of solvent A in the composition of the present invention is 0.5 to 50% by weight relative to the total amount of solvent. In order to efficiently lower the temperature of solvent A by the volatilization of solvent B, it is necessary to have 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 solvent 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, especially preferably 90% by weight or more, most preferably 95% by weight or more, with an upper limit of 100% by weight. When the total content of solvent A and solvent B is above the lower limit mentioned above, it can be used as an ink that can be ejected from a micro nozzle, the drying of the solvent is easily controlled, and the effects of the present invention are easily obtained.

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

[0103] The functional material used in this invention can be a light-emitting layer material, a hole injection layer material, a hole transport layer material, or an electron transport layer material, as described below, and is preferably a light-emitting layer material, a hole injection layer material, or a hole transport layer material. More preferably, the light-emitting layer material is a low-molecular-weight light-emitting layer material.

[0104] Furthermore, 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 hole injection layer forming composition.

[0105] Furthermore, the functional material in the present invention is preferably a polymer compound. Preferably, the polymer compound is a hole-transport polymer compound, which is typically used as a material for a hole injection layer, a material for a hole transport layer, or a material for a light-emitting layer.

[0106] The composition of the present invention may contain only one functional material, or it may contain two or more functional materials. If the composition of the present invention contains an electron-accepting compound as a functional material, it is preferable that it further contains a hole-transporting polymer compound.

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

[0108] Electron-accepting compounds are preferably compounds that possess oxidizing power and the ability to accept one electron from the hole transport material mentioned above. Specifically, electron-accepting compounds are preferably those with an electron affinity of 4.0 eV or higher, and more preferably those with an electron affinity of 5.0 eV or higher.

[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 electron-accepting compounds include onium salts with substituted organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. 2005 / 089024, International Publication No. 2017 / 164268); high-valence inorganic compounds such as iron(III) chloride (Japanese Patent Publication No. 11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene and aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Publication No. 2003-31365); fullerene derivatives; iodine; and sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions.

[0110] [Tetraarylborate ion] The tetraarylborate ion is an anion with an ionic charge of 1, in which a boron atom is substituted with four optionally substituted aromatic hydrocarbon rings or optionally substituted aromatic heterocycles.

[0111] The tetraarylborate ion, which is preferably included in the composition of the present invention, has high stability because it has a fluorine atom or a fluorine-substituted alkyl group as a substituent on the aryl group. Furthermore, the tetraarylborate ion, which is preferably included 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 countercation. Having a 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 of these independently represents a monovalent group consisting of multiple structures selected from optionally substituted aromatic hydrocarbon ring groups, optionally substituted aromatic heterocyclic groups, or optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups. The substituent may also be a crosslinking group. Ar 1 Ar 2 Ar 3 and Ar 4 At least one of them has a fluorine atom or a fluorine-substituted alkyl group as a substituent.

[0114] Furthermore, Ar in formula (2) 1 Ar 2 Ar 3 and Ar 4 Preferably, at least one of these is a group represented by the following formula (3).

[0115] [ka]

[0116] (In formula (3), R 100 Each of these independently consists of a substituted aromatic hydrocarbon ring group, a substituted aromatic heterocyclic group, a monovalent group formed by linking multiple structures selected from a substituted aromatic hydrocarbon ring group and a substituted aromatic heterocyclic group, a fluorine-substituted alkyl group, or R 100 It is a group that contains a crosslinking group, F4 indicates that four fluorine atoms are substituted. F (5-m) Each of these independently represents that 5-m fluorine atoms are substituted, k represents an integer from 0 to 5, independently. (Each 'm' represents an independent integer between 0 and 5.)

[0117] Ar 1 Ar 2 Ar 3 and Ar 4 The aromatic hydrocarbon rings used in the aromatic hydrocarbon ring group are preferably monocyclic or 2-6 condensed rings. Specifically, examples include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, fluorene rings, biphenyl structures, terphenyl structures, or quaterphenyl structures.

[0118] Ar 1 Ar 2 Ar 3 and Ar 4 The aromatic heterocyclic rings used in the aromatic heterocyclic group are preferably monocyclic rings or 2-6 fused rings. Specifically, examples include furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, pyrroloimidazole rings, pyrrolopyrrole rings, pyrrolopyrrole rings, thienopyrrole rings, thienopyrrole rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenanthidine rings, perimidine rings, quinazoline rings, quinazolinone rings, or azulene rings.

[0119] Among these, monovalent groups or biphenyl groups derived from a benzene ring, naphthalene ring, fluorene ring, pyridine ring, or carbazole ring are more preferred due to their excellent stability and heat resistance. Particularly preferred are monovalent groups derived from a benzene ring, i.e., phenyl groups or biphenyl groups.

[0120] The number of monocyclic or 2- to 6-fused aromatic hydrocarbon ring groups and monocyclic or 2- to 6-fused aromatic heterocyclic ring groups included in a monovalent group, which is composed of multiple structures selected from optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic ring groups, 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 substituents that may be present include the groups listed in the substituent group W described later.

[0122] Ar 1 Ar 2 Ar 3 and Ar 4 As substituents, fluorine atoms or fluorine-substituted alkyl groups are preferred because they increase the stability of the anion and improve the effect of stabilizing the cation. Furthermore, fluorine atoms or fluorine-substituted alkyl groups are Ar 1 Ar 2 Ar 3 and Ar 4 It is preferable that two or more of these are substituted, more preferably three or more are substituted, and most preferably four are substituted.

[0123] Ar 1 Ar 2 Ar 3 and Ar 4 As the fluorine-substituted alkyl group as the substituent, a linear or branched alkyl group having 1 to 12 carbon atoms with a fluorine atom substituted is preferred, a perfluoroalkyl group is more preferred, a linear or branched perfluoroalkyl group having 1 to 5 carbon atoms is even more preferred, a linear or branched perfluoroalkyl group having 1 to 3 carbon atoms is particularly preferred, and a perfluoromethyl group is most preferred. This is because it stabilizes the hole injection layer containing a crosslinked product of an electron-accepting compound having a crosslinking group, and the coating film laminated on top thereof.

[0124] The tetraarylborate ion contained in the composition of the present invention further enhances the stability of the anion and further improves the effect of stabilizing the cation, 1 Ar 2 Ar 3 and Ar 4 It is more preferable that at least two of them are groups represented by formula (3) independently, Ar 1 Ar 2 Ar 3 and Ar 4 It is even more preferable that at least three of these are groups represented independently by formula (3), and Ar 1 Ar 2 Ar 3 and Ar 4 It is most preferable that all of them are bases that can be independently represented by equation (3).

[0125] k is preferably 1 or greater, and more preferably 2 or greater, as this further improves the stability of the anion. k is preferably 0 or 1, and more preferably 0, as this facilitates even dispersion.

[0126] m is preferably 0 in terms of superior durability, preferably 1 or more in terms of the ability to introduce various functions into the tetraarylborate ion, and even more preferably 1 or 2 in terms of compatibility with durability.

[0127] It is preferable that k+m≧1, and even more preferable that k+m≧2, as this improves the stability and durability of the anion.

[0128] R 100 The preferred structure and optional substituents of the aromatic hydrocarbon ring group or aromatic heterocyclic group are Ar 1 Ar 2 Ar 3 and Ar 4 It is similar to the structure and any substituents it may have.

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

[0130] In equation (3), the stability of the anion is further increased, and the effect of stabilizing the cation is further improved, with at least one R 100 The group is preferably a fluorine-substituted alkyl group, preferably a perfluoroalkyl group, and more preferably a trifluoromethyl group.

[0131] [Bridging group] In equation (3), at least one R 100 It is preferable that the crosslinking group includes a crosslinking group, and that the crosslinking group is represented by any of the following formulas (X1) to (X18) in the following crosslinking group group T.

[0132] (Bridging group T)

[0133] [ka]

[0134] (In formulas (X1) to (X4), the benzene ring and the naphthalene ring may have substituents. The substituents may also be bonded to each other to form a ring.) R in equations (X4), (X5), (X6), and (10) 110 (This represents a hydrogen atom or an alkyl group which may have a substituent.)

[0135] The groups represented by (X1) to (X4) may have substituents, and examples of such substituents include R 100 These are the same substituents that may be present. R 110 If the group is an alkyl group, an alkyl group having 1 to 5 carbon atoms is preferred, an alkyl group having 1 to 3 carbon atoms is more preferred, and a methyl group is even more preferred.

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

[0137] R 100 However, in the case where one or more groups represented by formula (X1), formula (X2), or formula (X4) are bonded to an aromatic hydrocarbon group, the aromatic hydrocarbon group is preferably a group containing a benzene ring, a naphthalene ring, or a structure in which two or more selected from a benzene ring and a naphthalene ring are linked, and the number of links is preferably 4 or less. A further preferred R in this case is 100 The group includes 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 monocycle or a naphthalene ring monocycle, and it is more preferable that the group includes 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 it is particularly preferable that the group includes 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 formulas (X1) to (X18) are preferred because they have crosslinking properties, and it is thought that the tetraarylborate ions and countercations do not diffuse to other layers.

[0139] (Substituent group W) The substituent group W consists of 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 alkylthio group, an arylthio group, an alkylketone group, or an arylketone group.

[0140] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine atoms being preferred due to the stability of the compound. It is particularly preferable for the compound to be substituted with four or more fluorine atoms for stability reasons.

[0141] Aromatic ring groups consisting of 1 to 5 aromatic rings include phenyl group, biphenyl group, terphenyl group, quaterphenyl group, naphthyl group, phenantrenyl group, triphenylene group, naphthylphenyl group, etc., with phenyl group, naphthyl group, biphenyl group, terphenyl group, or quaterphenyl group being preferred due to the stability of the compound.

[0142] Examples of hydrocarbon ring groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups.

[0143] The alkyl group typically has 1 or more carbon atoms, preferably 4 or more, typically 24 or less, preferably 12 or less, more preferably 8 or less, and more preferably 6 or less. Specifically, examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, octyl group, 2-ethylhexyl group, dodecyl group, and the like.

[0144] Alkenyl groups typically have 2 or more carbon atoms, usually 24 or fewer, and preferably 12 or fewer. Specifically, examples include vinyl groups, propenyl groups, and butenyl groups.

[0145] Alkynyl groups typically have 2 or more carbon atoms, usually 24 or fewer, and preferably 12 or fewer. Specifically, examples include acetyl groups, propynyl groups, and butynyl groups.

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

[0147] The alkoxy group typically has 1 or more carbon atoms, 24 or fewer carbon atoms, preferably 12 or fewer carbon atoms, and more preferably 6 or fewer carbon atoms. Specific examples include methoxy groups, ethoxy groups, butyloxy groups, hexyloxy groups, octyloxy groups, and the like.

[0148] The aryloxy group typically has 4 or more carbon atoms, preferably 5 or more, more preferably 6 or more, usually 36 or fewer, preferably 24 or fewer, and more preferably 12 or fewer. Specific examples include the phenoxy group and the naphthyloxy group.

[0149] Alkylthio groups typically have one or more carbon atoms, usually 24 or fewer, and preferably 12 or fewer. Specific examples include methylthio groups, ethylthio groups, butylthio groups, and hexylthio groups.

[0150] The arylthio group typically has 4 or more carbon atoms, preferably 5 or more, usually 36 or fewer, and preferably 24 or fewer. Specific examples include the phenylthio group and the naphthylthio group.

[0151] Alkyl ketone groups typically have 1 or more carbon atoms, 24 or fewer carbon atoms, preferably 12 or fewer carbon atoms, and more preferably 6 or fewer carbon atoms. Specific examples include acetyl groups, ethyl carbonyl groups, butyl carbonyl groups, octyl carbonyl groups, and the like.

[0152] The aryl ketone group typically has 5 or more carbon atoms, preferably 7 or more, usually 25 or fewer, and preferably 13 or fewer. Specific examples include the benzoyl group and the naphthylcarbonyl group.

[0153] Furthermore, adjacent substituents may bond to each other to form a ring. Examples of ring formations include cyclobutene rings and cyclopentene rings.

[0154] Furthermore, these substituents may be further substituted with substituents, and examples of such substituents include halogen atoms, alkyl groups, or aryl groups.

[0155] Among these substituents, halogen atoms or aryl groups are preferred in terms of compound stability. Halogen atoms are most preferred.

[0156] [Specific examples of tetraarylborate ions] The following are specific examples of tetraarylborate ions used in the compositions of the present invention, but are 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] Of the above specific examples, the compound represented by either (A-1) or (A-2) is preferred in terms of electron-accepting ability, heat resistance, and solubility. Furthermore, the compounds represented by any of (A-18), (A-19), (A-20), (A-21), (A-25), (A-26), and (A-28) are more preferred due to their high stability as a composition for charge transport films, and the compounds represented by any of (A-19), (A-21), (A-25), (A-26), and (A-28) are particularly preferred due to the stability of the composition.

[0168] [Electron-accepting ion compounds containing tetraarylborate ions] The tetraarylborate ion is also preferably used as an electron-accepting ion compound containing the tetraarylborate ion. The electron-accepting ion compound containing the tetraarylborate ion is referred to as the first ion compound. The first ion compound consists of the tetraarylborate ion, which is an anion, and a countercation. The first ion compound is used as an electron-accepting compound.

[0169] Preferred countercations include iodonium cations, sulfonium cations, carbocations, oxonium cations, ammonium cations, phosphonium cations, cycloheptyltrienyl cations, or ferrocenium cations having a transition metal; iodonium cations, sulfonium cations, carbocations, and ammonium cations are more preferred, and iodonium cations are particularly preferred.

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

[0171] Specifically, preferred iodonium cations include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, 4-tert-butoxyphenylphenyliodonium cation, 4-methoxyphenylphenyliodonium cation, and 4-isopropylphenyl-4-methylphenyliodonium cation.

[0172] Specifically, preferred sulfonium cations 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] Specifically, preferred carbocations include trisubstituted carbocations such as triphenylcarbocation, tri(methylphenyl)carbocation, and tri(dimethylphenyl)carbocation.

[0174] Specifically, preferred ammonium cations 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] Specifically, 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, iodonium cations, carbocations, and sulfonium cations are preferred in terms of the film stability of the compound, with iodonium cations being more preferred.

[0177] The iodonium cation serving as the countercation for the first ionic compound is preferably structured as shown in formula (6) below.

[0178] [ka]

[0179] In formula (6), Ar 5 Ar 6 Each of these is independently an aromatic hydrocarbon group which may have substituents, or an aromatic heterocyclic group which may have substituents. 5 Ar 6 Aromatic hydrocarbon ring groups or aromatic heterocyclic groups as Ar 1 Ar 2 Ar 3 and Ar 4 The same structure can be selected as in the case of Ar 1 Ar 2 Ar 3 and Ar 4 You can choose from the same structure as in the previous case.

[0180] Furthermore, the countercation represented by formula (6) is preferably represented by the following formula (7).

[0181] [ka]

[0182] In formula (7), Ar 7 and Ar 8 This is the Ar in equation (6) mentioned above. 5 and Ar 6 This is similar to the substituents that may be present.

[0183] The molecular weight of the first ionic compound used in the present invention is usually in the range of 900 or more, preferably 1000 or more, more preferably 1200 or more, and usually 10000 or less, preferably 5000 or less, and more preferably 3000 or less. If the molecular weight is too small, the delocalization of positive and negative charges may be insufficient, which may reduce the electron-accepting ability, and if the molecular weight is too large, it may hinder charge transport.

[0184] [Specific example] The following are specific examples of ionic compounds with iodonium cations 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] Of the above specific examples, the compound represented by either (B-1) or (B-2) is preferred in terms of electron-accepting ability, heat resistance, and solubility. Furthermore, the compound represented by any of (B-18), (B-19), (B-20), (B-21), (B-25), (B-26), or (B-28) is more preferred due to its high stability as a composition for charge transport films, and the compound represented by any of (B-19), (B-21), (B-25), (B-26), or (B-28) is particularly preferred due to the stability of the composition.

[0198] Mixing such electron-accepting compounds is preferable to obtain a flatter film. Electron-accepting compounds typically use highly electronegative materials to achieve high electron affinity. This results in a relatively large polarity parameter in Hansen's solubility parameters, making them poorly soluble in non-polar solvents. When the solvent compound shown in general formula (1) is applied, the compatibility between the two benzene rings and the electron-accepting compound is very poor, and the electron-accepting compound tends to accumulate on the outermost surface of the ink. During hole injection layer formation, the electron-accepting compound, which precipitates slightly during the drying process, is distributed on the outermost surface of the ink. This reduces flow due to Laplace pressure and suppresses Marangoni convection caused by surface tension differences, thus favoring the acquisition of a flatter film.

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

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

[0201] [Preferred polymer] When the functional material included in the composition of the present invention contains a hole-transport polymer compound, the hole-transport polymer compound is preferably a polymer having a triarylamine structure as a repeating unit. The repeating unit of the triarylamine structure is represented by the following formula (50).

[0202] [ka]

[0203] (In formula (50), Ar 51 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a group formed by linking multiple groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups. Ar 52 This represents a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked directly or via linking groups. Ar 51 and Ar 52 Ar may form a ring via single bonds or linking groups. 51 Ar 52 (It may have a crosslinking group.)

[0204] The crosslinking base is Ar 51 Or Ar 52 It is preferable that the linkage is direct or via a linking group. The linking group is preferably an aromatic hydrocarbon group which may have substituents, an aromatic hydrocarbon group which may have substituents, or a structure in which multiple aromatic hydrocarbon groups which may have substituents are linked, and the phenyl group is preferred as the aromatic hydrocarbon group. The substituents that the aromatic hydrocarbon group as a linking group may have are selected from the substituent group Z below. It is preferable that the aromatic hydrocarbon group as a linking group does not have substituents.

[0205] (crosslinking group) Here, a crosslinking group refers to a group that, upon irradiation with heat and / or active energy rays, reacts with other crosslinking groups located in its vicinity to form a new chemical bond. In this case, the reacting group may be the same as the crosslinking group or a different group.

[0206] Examples of crosslinking groups, though not limited to them, include groups containing alkenyl groups, groups containing conjugated diene structures, groups containing alkynyl groups, groups containing oxirane structures, groups containing oxetane structures, groups containing aziridine structures, azide groups, groups containing maleic anhydride structures, groups containing alkenyl groups bonded to aromatic rings, and cyclobutene rings fused to aromatic rings. Specific examples of preferred crosslinking groups include those selected from the above-mentioned group T of crosslinking groups.

[0207] (Ar 52 )[main chain] In the repeating unit represented by the above formula (50), Ar 52 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a group formed by linking multiple groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group. Here, the substituents that the aromatic hydrocarbon group and the optionally substituted aromatic heterocyclic group may have are preferably the same groups as those in substituent group Z described later.

[0208] The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms, and specifically includes a 6-membered monocyclic or 2- to 5-fused ring divalent group, 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, fluorantene ring, and fluorene ring, or a group in which multiple such groups are linked. When multiple groups are linked, examples include a divalent group with 2 to 10 linked groups, and a divalent group with 2 to 5 linked groups is preferred. For example, "divalent group of a benzene ring" means "a benzene ring having a divalent free valence," i.e., a phenylene group. Preferred aromatic hydrocarbon groups are 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 quarterphenyl 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 is preferably one with 3 to 60 carbon atoms, specifically a furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, phlopyrrole ring, phlofuran ring, thienofuran ring, benzo Examples include divalent groups of 5-6 membered monocyclic or 2-4 fused rings, such as soxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, and azulene rings, or groups in which multiple such groups are linked. When multiple groups are linked, examples include divalent groups linked in groups of 2-10, and preferably divalent groups linked in groups of 2-5. Preferred aromatic heterocyclic groups are divalent groups of thiophene rings, benzothiophene rings, carbazole rings, and triazine rings.

[0210] The divalent group, which is formed by the direct or via linking groups of multiple aromatic hydrocarbon groups or aromatic heterocyclic groups that may have substituents, may be a group in which multiple identical groups are linked, or a group in which multiple different groups are linked. Examples of groups to be linked include divalent groups with 2 to 10 linked groups, and preferably divalent groups with 2 to 5 linked groups.

[0211] (Ar 51 )[side chain] In the repeating unit represented by the above formula (50), Ar 51 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a group formed by linking multiple groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group. The substituents are preferably the same as those in substituent group Z described later.

[0212] The aromatic hydrocarbon group is preferably one with 6 to 60 carbon atoms, and specifically, examples include monovalent groups of 6-membered rings or 2- to 5-fused rings, such as benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, and fluorene rings, or groups in which multiple such groups are linked. When multiple groups are linked, examples include monovalent groups linked in groups of 2 to 10, and monovalent groups linked in groups of 2 to 5 are preferred. For example, "monovalent group of a benzene ring" means "a benzene ring with a monovalent free valency," i.e., a phenyl group.

[0213] The aromatic heterocyclic group is preferably one with 3 to 60 carbon atoms, specifically a furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, phlopyrrole ring, phlofuran ring, thienofuran ring, benzo Examples include monovalent groups of 5-6 membered rings or 2-4 fused rings, such as soxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, and azulene rings, or groups in which multiple such groups are linked. When multiple groups are linked, examples include monovalent groups linked in groups of 2-10, and preferably monovalent groups linked in groups of 2-5.

[0214] The monovalent group, which is formed by the direct or via linking groups of multiple aromatic hydrocarbon groups or aromatic heterocyclic groups that may have substituents, may be a group in which multiple identical groups are linked, or a group in which multiple different groups are linked. Examples of groups to be linked include monovalent groups with 2 to 10 linked groups, and preferably monovalent groups with 2 to 5 linked groups.

[0215] Ar51 It is preferable that the compound contains a monovalent or divalent group consisting of 2 to 5 linked aromatic hydrocarbon groups, which may have substituents, due to its excellent charge transport properties and durability, and it is even more preferable that the compound contains a monovalent or divalent group consisting of 2 to 5 linked benzene rings, which may have substituents. 51 If the group contains a divalent group consisting of 2 to 5 linked aromatic hydrocarbon groups which may have substituents, the terminal end is a monovalent aromatic hydrocarbon group which may have substituents or a monovalent aromatic heterocyclic group which may have substituents. Preferably, the substituent is a group selected from substituent group Z described below or a bridging group selected from the bridging group group T.

[0216] Ar 51 If it has a bridging group as a substituent, Ar 51 Preferably, the structure has a bridging group selected from the bridging group group T at the end of a monovalent group in which 2 to 5 benzene rings, which may have substituents, are linked. 51 More preferably, the structure has a monovalent group consisting of 2 to 5 linked benzene rings without substituents, with a bridging group selected from the bridging group group T at the end of each group.

[0217] Ar 51 From the standpoint of excellent charge transport properties and durability, optionally substituted aromatic hydrocarbon groups are preferred, among which optionally substituted monovalent groups of an optionally substituted benzene ring or fluorene ring, i.e., optionally substituted phenyl groups or fluorenyl groups, even more preferably optionally substituted fluorenyl groups, and optionally substituted 2-fluorenyl groups are 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 reduce the properties of the polymer. Preferably, the substituents are groups selected from the substituent group Z described below, 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 From the viewpoint of solubility in the 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 in which at least one of the 9th and 9' positions is substituted with an alkyl group tends to have improved solubility in solvents and durability of the fluorene ring. Furthermore, the fluorenyl group in which both the 9th and 9' positions are substituted with alkyl groups tends to have even improved solubility in solvents and durability of the fluorene ring.

[0221] Also, Ar 51 From the viewpoint of solubility in the coating solvent, it is also preferable that it be a spirobifluorenyl group.

[0222] (Content of repeating units 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 consist only of repeating units represented by formula (50), but may also have repeating units other than those represented by formula (50) in order to balance the various performance characteristics when used as an organic electroluminescent element. In that 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, an end group refers to the structure of the end portion of a polymer formed by an end capping agent used at the end of polymerization. In the compositions of the present invention, the end groups of a polymer containing repeating units represented by formula (50) are preferably hydrocarbon groups. From the viewpoint of charge transport properties, hydrocarbon groups having 1 to 60 carbon atoms are preferred, hydrocarbon groups having 1 to 40 carbon atoms are more preferred, and hydrocarbon groups having 1 to 30 carbon atoms are even more preferred.

[0225] Examples of hydrocarbon groups include, Linear, branched, or cyclic alkyl groups having typically 1 or more carbon atoms, preferably 4 or more, typically 24 or less, and preferably 12 or less carbon atoms, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, and dodecyl groups; A linear, branched, or cyclic alkenyl group, such as a vinyl group, having typically 2 to 24 carbon atoms, preferably 12 or fewer; A linear or branched alkynyl group, such as an ethynyl group, having typically 2 to 24 carbon atoms, preferably 12 or fewer; Examples include aromatic hydrocarbon groups such as phenyl groups and naphthyl groups, which typically have 6 to 36 carbon atoms, preferably 24 or fewer.

[0226] These hydrocarbon groups may have further substituents, and the substituents that may be present are preferably alkyl groups or aromatic hydrocarbon groups. If there are multiple such substituents, they may be bonded to each other to form a ring.

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

[0228] (substituent group Z) The substituent group Z consists 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 include linear, branched, or cyclic structures.

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

[0230] The substituents may include linear, branched, or cyclic structures. When the above substituents are adjacent, adjacent substituents may bond to each other to form a ring. Preferred ring sizes are 4-membered, 5-membered, and 6-membered rings, with specific examples being cyclobutane rings, cyclopentane rings, and cyclohexane rings.

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

[0232] Furthermore, each substituent in the substituent group Z may have further substituents. Examples of these substituents are the same as those in substituent group Z. Preferably, there are no further substituents, or the substituents are alkyl groups having 8 or fewer carbon atoms, alkoxy groups having 8 or fewer carbon atoms, or phenyl groups, more preferably alkyl groups having 6 or fewer carbon atoms, alkoxy groups having 6 or fewer carbon atoms, or phenyl groups. From the viewpoint of charge transport, it is more preferable to have no further substituents.

[0233] (Preferred Ar 51 ) Furthermore, as a polymer, the repeating unit represented by formula (50) is Ar 51 Preferably, at least one of the groups is a group comprising a monovalent or divalent group in which 2 to 5 optionally substituted benzene rings are linked, an optionally substituted fluorenyl group, 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 the bond with the nitrogen atom of the main chain in equation (50), Ar 53 Ar 54Each of these independently represents a divalent aromatic hydrocarbon group which may have substituents, a heterocyclic aromatic group which may have substituents, or a divalent group in which multiple heterocyclic aromatic hydrocarbon groups which may have substituents are linked directly or via linking groups. Ar 55 This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group is directly or via a linking group. Ar 56 represents a hydrogen atom or substituent.

[0237] Here, each aromatic hydrocarbon group and each aromatic heterocyclic group may have substituents, and Ar when it is a substituent. 56 It may have a crosslinking group. As the crosslinking group, a group selected from the crosslinking group T can be used.

[0238] (Ar 53 Ar 54 ) In the repeating unit represented by the above formula (51), Ar 53 Ar 54 Each of these independently represents a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which a plurality of aromatic hydrocarbon groups which may have substituents or an aromatic heterocyclic group which may have substituents are linked directly or via linking groups. Preferably, it is a divalent aromatic hydrocarbon group which may have substituents or a group in which a plurality of divalent aromatic hydrocarbon groups which may have substituents are linked. Here, the substituents which the aromatic hydrocarbon group and the aromatic heterocyclic group may have may have a bridging group, and groups similar to those of substituent group Z are preferred. As the bridging group, a group selected from the bridging group group T can be used.

[0239] Ar 53 and Ar 54 The aromatic hydrocarbon group and aromatic heterocyclic group are the Ar 52Similar aromatic hydrocarbon groups and aromatic heterocyclic groups can be used.

[0240] A divalent group formed by the direct or via linking groups of multiple aromatic hydrocarbon groups or aromatic heterocyclic groups that may have substituents may be a group in which multiple identical groups are linked, or a group in which multiple different groups are linked.

[0241] When multiple divalent groups are linked together, examples include 2 to 10 linked divalent groups, and preferably 2 to 5 linked divalent groups.

[0242] Ar 53 The group is preferably a group consisting of 1 to 6 linked divalent aromatic hydrocarbon groups, which may have substituents; more preferably a group consisting of 2 to 4 linked divalent aromatic hydrocarbon groups, most preferably a group consisting of 1 to 4 linked phenylene rings, which may have substituents, and particularly preferably a biphenylene consisting of 2 linked phenylene rings, which may have substituents.

[0243] Furthermore, when multiple divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are linked together, it is preferable that the linked divalent aromatic hydrocarbon groups are bonded in such a way that they are not conjugated. Specifically, it is preferable to include a 1,3-phenylene group or a group having substituents that form a twisted structure due to the steric effect of the substituents.

[0244] Ar 53 The substituents that may be present are preferably the same groups as substituent group Z. Preferably, Ar 53 It has no substituents.

[0245] Ar 54From the standpoint of excellent charge transport properties and durability, a group consisting of one or more linked divalent aromatic hydrocarbon groups, which may be the same or different, is preferred, and the divalent aromatic hydrocarbon groups may have substituents. When multiple groups are linked, 2 to 10 is preferred, 6 or less is more preferred, and 3 or less is particularly preferred from the viewpoint of film stability. Preferred aromatic hydrocarbon structures are benzene rings, naphthalene rings, anthracene rings, and fluorene rings, with benzene rings and fluorene rings being more preferred. As for the multiple linked groups, a group consisting of one to four linked phenylene rings, which may have substituents, or a group consisting of a phenylene ring, which may have substituents, and a fluorene ring, which may have substituents, is preferred. From the viewpoint of expanding the LUMO, biphenylene, which consists of two linked phenylene rings, which may have substituents, is particularly preferred.

[0246] Ar 54 The substituents that may be present can be any of the substituent group Z mentioned above, or a combination thereof. Preferably, the substituents are not N-carbazolyl, indrocarbazolyl, or indenocarbazolyl groups, and more preferably, phenyl, naphthyl, or fluorenyl groups. It is also preferable that the substituent has no substituents.

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

[0248] Here, the substituents that the aromatic hydrocarbon group and the aromatic heterocyclic group may have may be bridging groups, and groups similar to those of substituent group Z are preferred. As the bridging group, a group selected from the bridging group group T can be used.

[0249] When multiple units are linked, it is preferable that they be divalent groups linked in groups of 2 to 10, and monovalent groups linked in groups of 2 to 5. As for aromatic hydrocarbons and aromatic heterocycles, the Ar 51 Similar aromatic hydrocarbon groups and aromatic heterocyclic groups can be used.

[0250] Ar 55 Preferably, the structure is represented by one of the following schemes 2. Furthermore, from the viewpoint of distributing the molecular LUMO, 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 preferred. Furthermore, from the viewpoint of promoting the expansion of the molecular LUMO by having electron-withdrawing groups, a structure selected from a-1 to a-4, b-1 to b-9, d-1 to d-12, and e1 to e4 is preferred. Furthermore, from the viewpoint of a high triplet level and the effect of confining excitons formed in the luminescence layer, a structure selected from a-1 to a-4, d-1 to d-12, and e1 to e4 is preferred. In addition, from the viewpoint of being easy to synthesize and having excellent stability, d-1 and d-10 are even more preferred, and the benzene ring structure of d-1 is particularly preferred. Furthermore, substituents may be present in these structures. Note that "-*" in the figure represents Ar 54 This indicates the connection position with Ar, and if there are multiple "-*", one of them is Ar 54 This indicates the connection point with [the other element].

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] <R 31 and R 32 > R in Scheme 2 31 and R 32 Each of these is preferably an independently linear, branched, or cyclic alkyl group, which may have substituents. 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 6 or less, more preferably 3 or less, and even more preferably a methyl group or an ethyl group.

[0255] R 31 and R 32 They may be the same or different, but since they can uniformly distribute the charge around the nitrogen atom and are also easy to synthesize, all R 31 and R 32 It is preferable that they are the same group.

[0256] Ar 55 As substituents that may be present, any of the substituent group Z or combinations thereof can be used. From the viewpoint of durability and charge transport, the above Ar 54 It is preferable that the substituents be selected from the same substituents that may be present in the other substituents.

[0257] (Ar 56 ) Ar 56 Ar represents a hydrogen atom or substituent. 56 When is a substituent, it is not particularly limited, but preferably an aromatic hydrocarbon group which may have substituents or an aromatic heterocyclic group which may have substituents. A preferred structure is the Ar 53 ~Ar 54 This structure is similar to the aromatic hydrocarbon structure and aromatic heterocyclic structure mentioned above, and is monovalent.

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

[0259] Ar 56If it is a substituent, it is preferable that it is bonded to the 3-position of carbazole from the viewpoint of improving durability. 56 From the viewpoint of ease of synthesis and charge transport properties, it is preferable that it be a hydrogen atom. 56 From the viewpoint of improving durability and charge transport, it is preferable that the component is an aromatic hydrocarbon group that may have substituents or an aromatic heterocyclic group that may have substituents, and more preferably an aromatic hydrocarbon group that may have substituents.

[0260] Ar 56 From the viewpoint of ease of synthesis and charge transport properties, it is preferable that the atom be a hydrogen atom.

[0261] Ar 56 When is an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, the substituents are the same as those listed in substituent group Z, the preferred substituents are the same, and the substituents that those substituents may further have are also the same.

[0262] (Formula (52)) Ar in the repeating unit represented by the above formula (50) 51 It is also preferable that at least one of the groups is represented by the following formula (52). This is because, in the two carbazole structures in formula (52), the LUMO is distributed between the nitrogen atoms of each other in the aromatic hydrocarbon group or aromatic heterocyclic group, which suppresses the influence on the main chain amine in formula (50) and improves the durability of the main chain amine against electrons and excitons.

[0263] [ka]

[0264] (In formula (52), Ar 61 and Ar 62Each of these is independently a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which multiple aromatic hydrocarbon groups or aromatic heterocyclic groups which may have substituents are linked directly or via linking groups. Ar 63 ~Ar 65 Each of these is independently a hydrogen atom or a substituent. * indicates the bond position of the main chain to the nitrogen atom in equation (50).

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

[0266] (Ar 63 ~Ar 65 ) Ar 63 ~Ar 65 Each of them independently, the aforementioned Ar 56 It is similar to that.

[0267] (Ar 62 ) Ar 62 This is a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which a plurality of optionally substituted aromatic hydrocarbon groups or optionally substituted aromatic heterocyclic groups are linked directly or via linking groups. Preferably, it is a divalent aromatic hydrocarbon group which may have substituents or a group in which a plurality of optionally substituted divalent aromatic hydrocarbon groups are linked.

[0268] Ar 62 The specific structure is, 54 It is similar to that.

[0269] Ar 62Specific preferred groups are divalent groups of a benzene ring, naphthalene ring, anthracene ring, or fluorene ring, or groups in which multiple such groups are linked; more preferably, divalent groups of a benzene ring, or groups in which multiple such groups are linked; particularly preferably, a 1,4-phenylene group in which a benzene ring is linked at the 1,4 positions with divalentity; a 2,7-fluorenylene group in which a fluorene ring is linked at the 2,7 positions with divalentity; or a group in which multiple such groups are linked; 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 has no substituents other than at the linking position, which is due to the steric effect of substituents on Ar 62 It is preferable that no twisting occurs. Furthermore, it is preferable for the fluorenylene group to have substituents at the 9,9' position, from the viewpoint of improving solubility and the durability of the fluorene structure.

[0271] (Ar 61 ) Ar 61 The Ar 53 It is a similar group, and the preferred structure is also similar. (Formula (53)) Ar in the repeating unit represented by the above formula (50) 51 It is also preferable that at least one of these is a group represented by the following formula (53).

[0272] [ka]

[0273] In formula (53), * represents the bond with the nitrogen atom of the main chain in equation (50), Ar 71 This represents a divalent aromatic hydrocarbon group which may have substituents, Ar 72 and Ar 73Each of these independently represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group are linked directly or via linking groups. The HA ring is an aromatic heterocycle containing a nitrogen atom. X 2 , Y 2 Each of these independently represents a carbon atom or a nitrogen atom, and X 2 and Y 2 If at least one of them is a carbon atom, that carbon atom may have substituents.

[0274] <Ar 71 > Ar 71 The Ar 53 It is a similar base. Ar 71 Preferably, the group consists of one divalent aromatic hydrocarbon group which may have substituents, or a group in which 2 to 10 divalent aromatic hydrocarbon groups which may have substituents are linked together. More preferably, the group consists of one divalent aromatic hydrocarbon group which may have substituents, or a group in which 2 to 8 divalent aromatic hydrocarbon groups which may have substituents are linked together. In particular, a group in which two or more divalent aromatic hydrocarbon groups which may have substituents are linked together is preferred.

[0275] Ar 71 In particular, a group consisting of 2 to 6 linked benzene rings, which may have substituents, is preferred, and a quaterphenylene group consisting of 4 linked benzene rings, which may have substituents, is most preferred.

[0276] Also, Ar 71 It is preferable that it contains at least one benzene ring linked at the 1,3 positions, which are non-conjugated sites, and more preferably two or more.

[0277] Ar 71In the case of a group consisting of multiple linked divalent aromatic hydrocarbon groups, which may have substituents, it is preferable that all of them are directly bonded together from the viewpoint of charge transport or durability.

[0278] Therefore, Ar 71 The preferred structures connecting the nitrogen atom of the polymer's main chain to the ring HA in formula (53) are shown in schemes 2-1 and 2-2 below. "-*" represents a bonding site with either the nitrogen atom of the polymer's main chain or the ring HA in formula (53). Either of the two "-*"s may be bonded to the nitrogen atom of the polymer's main chain or to the ring HA.

[0279] [ka]

[0280] [ka]

[0281] Ar 71 As substituents that may be present, any of the substituent group Z or a combination thereof can be used. 71 The preferred range of substituents that G may have is the same as the substituents that G may have when G is an aromatic hydrocarbon group.

[0282] <X 2 and Y 2 > X 2 and Y 2 Each of these independently represents either a carbon (C) atom or a nitrogen (N) atom. 2 and Y 2 If at least one of them is a C atom, it may have substituents.

[0283] From the perspective of making it easier to localize LUMO around the ring HA, X 2 and Y 2 Preferably, all of these are N atoms.

[0284] X 2 and Y 2 As substituents that may be present when at least one of them is a C atom, any of the substituent group Z or a combination thereof can be used. From the viewpoint of charge transport, X 2 and Y 2 It is even more preferable that it does not have substituents.

[0285] <Ar 72 and Ar 73 > Ar 72 and Ar 73 Each of these is independently a monovalent group consisting of an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or two or more groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group, linked directly or via linking groups.

[0286] From the perspective of distributing the LUMO of molecules, Ar 72 and Ar 73 Preferably, each of these structures is independently 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.

[0287] Furthermore, from the viewpoint of promoting the expansion of the molecular LUMO by having electron-withdrawing groups, 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 having a high triplet level and the effect of confining excitons formed in the luminescent layer, structures selected from a-1 to a-4, d-1 to d-12, and e-1 to e-4 are preferred.

[0289] To prevent molecular aggregation, structures selected from d-1 to d-12 and e-1 to e-4 are even more preferable. From the viewpoint of being easy to synthesize and having excellent stability, Ar 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 substituents. "-*" represents a binding site to the ring HA. If there are multiple "-*" symbols, each one represents a binding site to the ring HA.

[0291] Ar 72 and Ar 73 As substituents that may be present, any of the substituent group Z or a combination thereof can be used. From the viewpoint of durability and charge transport, substituents that are similar to those of substituent group Z are preferred.

[0292] (Preferred main chain) The repeating units represented by formula (50) are preferably the repeating units represented by formula (54), formula (55), formula (56), and formula (57). Polymers having a triarylamine structure as a repeating unit may also preferably include multiple repeating units of different structures in each of these formulas.

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

[0294] [ka]

[0295] (In formula (54), Ar 51 This is Ar in formula (50) above. 51 It is similar to, 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 of these is an alkyl group which may have substituents, R 207 ~R 209 and R 211 ~R 214 Each of these is independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aromatic hydrocarbon group. a and b are independent integers between 0 and 4. c is an integer between 0 and 3. d is an integer between 0 and 4. i and j are independent integers between 0 and 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 Each of these is an alkyl group which may have substituents.

[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 to maintain the solubility of the polymer, it is preferably 1 or more, 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 They may be the same or different, R 202 If there are multiple R 202 They may be the same or different. Since the charge can be uniformly distributed around the nitrogen atom and it is also easy to synthesize, all R 201 and R 202 It is preferable that they are the same group.

[0299] R 221 If there are multiple R 221 They may be the same or different, R 222 If there are multiple R 222 They may be the same or different. Because synthesis is easy, all R 221 and R 222 It is preferable that they are the same group.

[0300] (R 207 ~R 209 and R 211 ~R 214 ) R 207 ~R 209 and R 211 ~R 214 Each of these is independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aromatic hydrocarbon group.

[0301] The alkyl group is not particularly limited, but it is preferable that it has 1 or more carbon atoms, preferably 24 or fewer, more preferably 8 or fewer, and even more preferably 6 or fewer, as it tends to improve the solubility of the polymer. The alkyl group may also have a linear, branched, or cyclic structure.

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

[0303] The aralkyl group is not particularly limited, but it tends to improve the solubility of the polymer, so it is preferable that it has 5 or more carbon atoms, preferably 60 or fewer, and more preferably 40 or fewer.

[0304] Examples of the aralkyl group include 1,1-dimethyl-1-phenylmethyl group, 1,1-di(n-butyl)-1-phenylmethyl group, 1,1-di(n-hexyl)-1-phenylmethyl group, 1,1-di(n-octyl)-1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1-n-heptyl group, 8-phenyl-1-n-octyl group, and 4-phenylcyclohexyl group.

[0305] The aromatic hydrocarbon group is not particularly limited, but it is preferable that it has 6 or more carbon atoms, preferably 60 or fewer, and more preferably 30 or fewer, as it tends to improve the solubility of the polymer.

[0306] Examples of the aromatic hydrocarbon group include monovalent groups of 6-membered rings or 2- to 5-fused rings, such as benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, and fluorene rings, or groups in which multiple such groups are linked together.

[0307] From the viewpoint of improving charge transport and durability, R 207 and R 208 R is preferably a methyl group or an aromatic hydrocarbon group. 207 and R 208 It is more preferably a methyl group, R 209 It is more preferable that it be a phenyl group.

[0308] R 201 , R 202 , R 221 , R 222 Alkyl, R 207 ~R 209 and R 211 ~R 214The alkyl group, aralkyl group, and aromatic hydrocarbon group may have substituents. The substituents are as follows: 207 ~R 209 and R 211 ~R 214 The groups listed above are preferred alkyl groups, aralkyl groups, and aromatic hydrocarbon groups.

[0309] R 201 , R 202 , R 221 , R 222 Alkyl, R 207 ~R 209 and R 211 ~R 214 From the viewpoint of lowering the voltage, it is most preferable that the alkyl group, aralkyl group, and aromatic hydrocarbon group in the given molecule are free of substituents.

[0310] (a, b, c, and d) In the repeating unit represented by the above formula (54), a and b are each independent integers between 0 and 4. It is preferable that a + b is 1 or greater, and more preferably that a and b are each 2 or less, and more preferably that both a and b are 1. Here, if b is 1 or greater, then d is also 1 or greater. Also, if c is 2 or greater, the multiple a's may be the same or different, and if d is 2 or greater, the multiple b's may be the same or different.

[0311] When a+b is 1 or greater, the aromatic rings of the main chain are twisted due to steric hindrance, resulting in excellent solubility of the polymer in the solvent. Furthermore, coatings formed by wet deposition and heat-treated tend to exhibit excellent solvent insolubility. Therefore, when a+b is 1 or greater, if another organic layer (e.g., a light-emitting layer) is formed on this coating using a wet deposition method, the elution of the polymer into the organic layer-forming composition containing the organic solvent is suppressed.

[0312] In the repeating unit represented by the above formula (54), c is an integer between 0 and 3, and d is an integer between 0 and 4. Preferably, c and d are each 2 or less, more preferably c and d are equal, and particularly preferably both c and d are 1, or both c and d are 2.

[0313] If both c and d in the repeating unit represented by the above formula (54) are 1, or if both c and d are 2, and both a and b are 2 or 1, then R 201 and R 202 It is most preferable that they are joined in positions symmetrical to each other.

[0314] Here, R 201 and R 202 The bond between them in symmetrical positions means that, relative to the fluorene ring, carbazole ring, or 9,10-dihydrophenanthrene derivative structure in formula (54), R 201 and R 202 This refers to the symmetrical positioning of the bonded elements. In this case, a 180-degree rotation around the main chain axis is considered to result in the same structure.

[0315] R 221 and R 222 If present, it is preferable that each of them be 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 The condensed ring to which the polymer is bonded and the adjacent benzene ring on the main chain are twisted due to steric hindrance, resulting in excellent solubility of the polymer in solvents. Furthermore, the coating film formed by the wet film formation method and heat-treated tends to have excellent insolubility in solvents, which is preferable.

[0316] (X) In equation (54) above, X is -C(R) because of its high stability during charge transport. 207 )(R 208 )- or -N(R 209 )- is preferred, -C(R 207 )(R 208 ) - is more preferable.

[0317] (Preferred repeating unit) The repeating unit represented by formula (54) above is particularly preferably a repeating unit shown by any of the following formulas (54-1) to (54-8).

[0318] [ka]

[0319] [ka]

[0320] In the above formula, R 201 and R 202 They are identical, and R 201 and R 202 They are joined in positions symmetrical to each other.

[0321] <A preferred example of a repeating main chain represented by formula (54)> The main chain structure excluding the nitrogen atom in formula (54) above is not particularly limited, but the following structure is preferred, for example.

[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 This is Ar in equation (54) above. 51 It is similar to, R 303 and R 306 Each of these is an alkyl group which may have substituents, R 304 and R 305 Each of these is independently an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group. l is either 0 or 1. m is either 1 or 2. n is either 0 or 1. p is either 0 or 1, q is either 0 or 1.

[0333] (R 303 , R 306 ) R in the repeating unit represented by the above formula (55) 303 and R 306Each of these is an alkyl group which may have substituents.

[0334] As an alkyl group, R in formula (54) above 201 and R 202 Similar examples include substituents that may be present and preferred structures of R. 201 and R 202 Similar examples include the above.

[0335] R 303 If there are multiple R 303 They may be the same or different, R 306 If there are multiple R 306 They 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 Each of these is independently an optionally substituted alkyl group, an optionally substituted alkoxy group, or an optionally substituted aralkyl group. Preferably, it is an optionally substituted alkyl group. R 304 and R 304 It is preferable that they are 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 it is preferably 1 or more, preferably 24 or less, more preferably 8 or less, and even more preferably 6 or less, as this tends to improve the solubility of the polymer.

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

[0339] The alkoxy group is not particularly limited, and is an alkoxy group (-OR 10 ) of R 10 The alkyl group represented by may have a linear, branched, or cyclic structure, and tends to improve the solubility of the polymer. Therefore, the number of carbon atoms is preferably 1 or more, preferably 24 or less, and more preferably 12 or less.

[0340] Examples of such alkoxy groups include methoxy, ethoxy, n-propoxy, n-butoxy, hexyloxy, 1-methylpentyloxy, and cyclohexyloxy groups.

[0341] The aralkyl group is not particularly limited, but it is preferable to have 5 or more carbon atoms, preferably 60 or fewer, and more preferably 40 or fewer, as it tends to improve the solubility of the polymer.

[0342] Examples of such aralkyl groups include 1,1-dimethyl-1-phenylmethyl group, 1,1-di(n-butyl)-1-phenylmethyl group, 1,1-di(n-hexyl)-1-phenylmethyl group, 1,1-di(n-octyl)-1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1-n-heptyl group, 8-phenyl-1-n-octyl group, and 4-phenylcyclohexyl group.

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

[0344] l and n are independent of each other, 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 can also be suppressed.

[0345] m represents either 1 or 2, and is preferably 1 because the organic electroluminescent element of the present invention can be driven at a low voltage, and hole injection capability, transport capability, and durability tend to improve.

[0346] (p and q) p represents 0 or 1, and q represents 0 or 1. When l is 2 or greater, multiple p values ​​may be the same or different, and when n is 2 or greater, multiple q values ​​may be the same or different. When l=n=1, p and q cannot be 0 at the same time. The fact that p and q cannot be 0 at the same time tends to increase the solubility of the polymer contained in the composition of the present invention and suppress precipitation from the second composition containing the polymer. Also, for the same reasons as in a and b above, when p+q is 1 or greater, the aromatic ring of the main chain is twisted due to steric hindrance, resulting in excellent solubility of the polymer in the solvent, and the coating film formed by the wet film formation method and heat-treated tends to have excellent insolubility in the solvent. Therefore, when p+q is 1 or greater, if another organic layer (e.g., a light-emitting layer) is formed on this coating film by the wet film formation method, the elution of the polymer into the other organic layer-forming composition containing an organic solvent is suppressed.

[0347] <Specific example of a repeating main chain represented by formula (55)> The main chain structure excluding the nitrogen atom in formula (55) is not particularly limited, but examples 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 This is Ar in equation (54) above. 51 It is similar to, Ar 41 This is a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is directly or via a linking group, R 441 and R 442 Each of these is an alkyl group which may have substituents, t is either 1 or 2. u is either 0 or 1, r and s are independent integers between 0 and 4.

[0358] (R 441 , R 442 ) R in the repeating unit represented by the above formula (56) 441 , R 442 Each of these is an alkyl group which may have substituents.

[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 to maintain the solubility of the polymer, it is preferable to have 1 or more carbon atoms, preferably 10 or fewer, more preferably 8 or fewer, and even more preferably 6 or fewer. The alkyl group is even more preferably a methyl group or a hexyl group.

[0360] R 441 and R 442 If there are multiple R in the repeating unit represented by the above formula (56), then multiple R 441 and R 442 They may be the same or different.

[0361] (r, s, t, and u) In the repeating unit represented by equation (56), r and s are each independent integers between 0 and 4. When t is 2 or greater, multiple r values ​​may be the same or different, and when u is 2 or greater, multiple s values ​​may be the same or different. It is preferable that r+s is 1 or greater, and furthermore, it is preferable that r and s are each 2 or less. When r+s is 1 or greater, the driving life of the organic electroluminescent element is considered to be further extended for the same reasons as a and b in equation (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 41This is a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is directly or via a linking group.

[0364] Ar 41 The aromatic hydrocarbon group in and of the aromatic hydrocarbon group is Ar in formula (50). 52 Similar groups can be cited. Furthermore, the aromatic hydrocarbon group and the substituents that the aromatic hydrocarbon group may have are preferably the same as those in substituent group Z, and it is even more preferable that the substituents that may be present are the same as those in substituent group Z.

[0365] <Specific examples of repeating units represented by formula (56)> The repeating unit represented by equation (56) is not particularly limited, but for example, the following structure can be considered.

[0366] [ka]

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

[0368] [ka]

[0369] (In formula (57), Ar 51 This is Ar in equation (54) above. 51 It is similar to, R 517 ~R 519 Each of these independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aralkyl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. f, g, and h each independently represent integers from 0 to 4. e represents an integer from 0 to 3. However, if g is 1 or greater, then e is 1 or greater.

[0370] (R 517 ~R 519 ) R 517 ~R 519 In this, the aromatic hydrocarbon group and the aromatic heterocyclic group are each independently of the Ar 51 The substituents are similar to those listed above, and the substituents that these groups may have are preferably the same as those in substituent group Z.

[0371] R 517 ~R 519 The alkyl and aralkyl groups in the R 207 Groups similar to those listed above are preferred, and substituents that may also be present are also R 207 A similar base is preferred.

[0372] R 517 ~R 519 The alkoxy group in is preferably one of the alkoxy groups listed in substituent group Z, and any further substituents that may be present are the same as those in substituent group Z.

[0373] (f, g, h) f, g, and h each independently represent integers from 0 to 4. If e is 2 or greater, the multiple gs may be the same or different. It is preferable that f+g+h is 1 or greater. It is preferable that f+h is 1 or greater. It is more preferable that f+h is 1 or greater, and f, g, and h are 2 or less. It is even more preferable that f+h is 1 or greater, and f and h are 1 or less. It is most preferable that both f and h are 1.

[0374] If both f and h are 1, R 517 and R 519 It is preferable that they are joined in positions symmetrical to each other. Also, R 517 and R 519 It is preferable that it be identical to the above.

[0375] It is more preferable that g is 2. If g is 2, then the two R 518 It is most preferable that they are bonded to each other in the para position. If g is 2, then the two R 518 It is most preferable that they be identical.

[0376] Here, R 517 and R 519 The term "bonding in symmetrical positions" refers to the following bond positions. However, for notation purposes, a 180-degree rotation around the main chain axis is considered to represent the same structure.

[0377] [ka]

[0378] Furthermore, if the polymer of this embodiment contains repeating units represented by formula (57), the ratio of the compound represented by formula (1) to the repeating units represented by formula (57) 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. In addition, this ratio is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0379] Furthermore, the repeating unit represented by formula (57) is preferably the repeating unit represented by formula (58) below.

[0380] The preferred equation is (57) = equation (58).

[0381] [ka]

[0382] In the case of the repeating unit represented by formula (58) above, it is preferable that g = 0 or 2. When g = 2, the bond positions are at positions 2 and 5. When g = 0, i.e., R 518 When there is no steric hindrance, and when g=2 and the bond positions are at positions 2 and 5, i.e., when there are two R's steric hindrances 518 If it is at a diagonal position on the benzene ring to which it is bonded, then R 517 and R 519 It is possible for them to be joined in positions symmetrical to each other.

[0383] Furthermore, it is even more preferable that the repeating unit represented by formula (58) is the repeating unit shown in formula (59) below, where e=3.

[0384] The preferred equation (58) = equation (59)

[0385] [ka]

[0386] In the case of the repeating unit represented by formula (59) above, it is preferable that g = 0 or 2. When g = 2, the bond positions are at positions 2 and 5. When g = 0, i.e., R 518 When there is no steric hindrance, and when g=2 and the bond positions are at positions 2 and 5, that is, when there are two R's steric hindrances 518 If it is at a diagonal position on the benzene ring to which it is bonded, then R 517 and R 519 It is possible for them to be joined in positions symmetrical to each other.

[0387] <Specific example of a repeating main chain represented by formula (57)> The main chain structure of the repeating unit represented by equation (57) is not particularly limited, but examples include the following structures.

[0388] [ka]

[0389] It is preferable that the repeating units represented by formulas (50) to (59) do not have crosslinking groups. When crosslinking groups are absent, distortion of the polymer chain is less likely to occur during heating and drying or baking (heating and firing) after wet film formation. This is because volume changes may occur when crosslinking groups react, causing distortion of the polymer chain. Furthermore, distortion of the polymer chain can occur even if no volume change occurs.

[0390] (Preferred repeating unit) In the case where 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 the repeating unit represented by formula (54), the repeating unit represented by formula (55), the repeating unit represented by formula (56), or the repeating unit represented by formula (57).

[0391] Among these, A repeating unit represented by formula (54) including a substructure represented by formula (61) below, A repeating unit represented by formula (55) including a substructure represented by formula (61) below, A repeating unit represented by formula (56) including a substructure represented by formula (61) below, Alternatively, it is preferable that the repeating unit represented by formula (57) includes a substructure represented by formula (61) below.

[0392] [ka]

[0393] (In equations (61) and (61'), R 601 R in equation (54) 201 or R 202 , R in equation (55) 303 , R 304 , R 305 , or R 406 , R in equation (56) 441 Or R+, R in equation (57) 517 , R518 or R 519 This represents a bond with an adjacent atom, and -* indicates a bond with a neighboring atom. If formula (61) is a substructure of formula (54) or formula (56), then Ring B may be part of a fused ring. The substructures represented by equations (61) and (61') are R 601 In addition, if Ring A and Ring B are substructures of formula (54), then R 201 or R 202 If it is a substructure of equation (55), then R 303 , R 304 , R 305 , or R 406 If it is a substructure of equation (56), then R 441 Or, if it is R442, a substructure of formula (57), then R 517 , R 518 or R 519 (May have.)

[0394] The substructure represented by formula (61) or formula (61') is a substantially planar structure of Ring A and Ring B formed by π-conjugation, R 601 The steric hindrance causes distortion, resulting in a twisted main chain structure compared to a normal π-conjugated bond. In other words, it has a higher degree of freedom. When the solvent compound represented by formula (1) is applied, the solvent compound represented by formula (1) has a high degree of freedom and moderate flexibility because the two benzene rings are bonded by quaternary carbon atoms. These two highly flexible benzene rings have high compatibility with the functional material, making them easier to penetrate and improving solubility. As a result, even if the solvent evaporates and the concentration of the functional material increases in the coated wet film, it is presumed that the solute will disperse more uniformly in the solvent, improving flatness.

[0395] In a display panel using organic electroluminescent elements, pixels are partitioned into banks. To form a film within the minute regions partitioned by the banks, a composition of a functional material dissolved in a solvent is applied using an inkjet device, and the solvent is dried to form a functional material film within the bank. Here, if the solvent compound represented by formula (1) is used as the solvent, as described above, the solvent compound represented by formula (1) penetrates the functional material easily, so even if the solvent evaporates and the concentration of the functional material 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)) Particularly preferred is the repeating unit of formula (54). The composition of the present invention further preferably contains a solvent compound represented by formula (1) and a polymer having this repeating unit in order to form a flat thin film. The repeating unit represented by formula (54) is preferably the repeating unit represented by the following formula (62).

[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 formula (54) above. 51 X, R 201 , R 202 , R 221 , R 222 , are the same as a, b, c, d, i, j, a 1 a 2 , b 1 , b 2 i 1 i 2 , j 1 , j 2 Each of these is independently either 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 more, b 1 , b 2 And at least one of b is 1 or more, c and d are 1 or greater, If c is 1, then a 1 or a 2 At least one of them 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 them is 1. Ring A1 is R 201 This refers to a divalent benzene ring that may have a specific position. Ring A2 is R 201 A divalent group consisting of c-1 linked benzene rings, where c=1 refers to a monocyclic divalent benzene ring. Ring A3 refers to a divalent fused ring in which a biphenyl structure is further bonded by X. Ring A4 is R 202 A divalent group having d-1 linked benzene rings, where d=1 refers to a monocyclic divalent benzene ring. Ring A5 is R 202 (This refers to a divalent benzene ring that may have a specific position.) Here, in equation (54), a is greater than or equal to 1 if, in equation (62), a 1 a 2 And at least one of a is 1 or greater, and in equation (54) b being 1 or greater means that in equation (62), b 1 , b 2 (This is equivalent to saying that at least one of b is 1 or greater.)

[0399] As follows, formula (62) includes formula (61) or formula (61') as a substructure. a 1 a2 And if at least one of a is 1 or more, a 1 or a 2 If at least one of them is 1, then if c is 2 or more, Ring A1 and Ring A2, and if c is 1, Ring A1 and Ring A3, If a is 1, then Ring A2 and Ring A1, or Ring A2 and Ring A3, The above formula (61) or formula (61') is included as a substructure. Similarly, b 1 , b 2 It can be seen that formula (61) or formula (61') is included as a substructure if at least one of b is 1 or more. Also, i 1 i 2 , j 1 and j 2 If at least one of them is 1, i 1 and i 2 If one or both of them are 1, then Ring A3's R 221 The ring to which is bonded and the benzene ring of RingA2 form a substructure of formula (61'), j 1 and j 2 If one or both of them are 1, then Ring A3's R 222 It can be seen that formula (61) is formed as a substructure between the bonded ring and the benzene ring of RingA4. In other words, it can be seen that Ring A3 and Ring A2, or Ring A3 and Ring A4, have a twisted structure. Therefore, formula (62) is preferable because, as mentioned above, it is easier to obtain a flat film due to the twisted aromatic ring in the main chain.

[0400] [Molecular weight of polymer] The molecular weights of the polymers contained in the composition of the present invention are described below.

[0401] The weight-average molecular weight (Mw) of polymers having the above-described triarylamine structure as a repeating unit is typically 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. Furthermore, the weight-average molecular weight is typically 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 a polymer having the aforementioned triarylamine structure as a repeating unit is below the upper limit, solubility in solvents is obtained, and it tends to have excellent film-forming properties. Furthermore, when the weight-average molecular weight of the polymer is above the lower limit, the decrease in the polymer's glass transition temperature, melting point, and vaporization temperature is suppressed, and its heat resistance may be improved.

[0403] Furthermore, the number-average molecular weight (Mn) of polymers having the aforementioned triarylamine structure as a repeating unit is typically 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, and particularly preferably 100,000 or less. In addition, the number-average molecular weight is typically 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 degree of dispersion (Mw / Mn) in the polymer having the aforementioned 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 a smaller degree of dispersion is better, the lower limit is ideally 1. When the degree of dispersion of the polymer is below the above upper limit, it is easy to purify and has good solubility in solvents and charge transport ability.

[0405] Typically, the weight-average molecular weight and number-average molecular weight of polymers are determined by SEC (size exclusion chromatography) measurement. In SEC measurement, components with higher molecular weights have shorter elution times, while components with lower molecular weights have longer elution times. However, by using a calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the weight-average molecular weight and number-average molecular weight can be calculated by converting the sample's elution time to molecular weight.

[0406] [Specific example] Specific examples of polymers containing repeating units 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 ratio of the repeating units, where n represents the number of repeating units.

[0407] These polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and are not limited to the order of monomer arrangement.

[0408] [ka]

[0409] A polymer containing repeating units represented by formula (55), and Ar 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. n represents the number of repeats.

[0410] These polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and the order of monomer arrangement is not limited.

[0411] [ka]

[0412] [ka]

[0413] [ka]

[0414] [ka]

[0415] Specific examples of polymers containing repeating units 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 formulas represent the molar ratio of the repeating units, where n represents the number of repeating units.

[0416] These polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and are not limited to the order of monomer arrangement.

[0417] [ka]

[0418] [ka]

[0419] <Method for producing polymers> The method for producing the polymer contained in the composition of the present invention is not particularly limited and is arbitrary. Examples include polymerization by the Suzuki reaction, polymerization by the Grignard reaction, polymerization by the Yamamoto reaction, polymerization by the Ullmann reaction, polymerization by the Buchwald-Hartwig reaction, and so on.

[0420] In the polymerization methods by the Ullmann reaction and the Buchwald-Hartwig reaction, for example, a polymer containing the repeating unit represented by formula (54) is synthesized by reacting an aryl dihalide represented by the following formula (2a) (where Z represents a halogen atom such as I, Br, Cl, or F) with a primary aminoaryl represented by the following formula (2b).

[0421] [ka]

[0422] (In the above reaction equation, Ar 51 , R 201 , R 202 X, a-d are equivalent to the definitions in equation (54) above.

[0423] Furthermore, in the polymerization methods by the Ullmann reaction and the Buchwald-Hartwig reaction, for example, a polymer containing repeating units represented by formula (55) is synthesized by reacting an aryl dihalide represented by formula (3a) (where 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 equation, Ar 51 , R 303 ~R 306 n, m, l, p, and q are the same as their definitions in equation (55) above.

[0426] In the polymerization method described above, the reaction that forms the N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, tert-butoxysodium, or triethylamine. It can also be carried out in the presence of a transition metal catalyst such as a copper or palladium complex.

[0427] [Sol and functional ingredient content] There are no particular restrictions on the content of the functional material in the composition of the present invention, but it is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, more preferably 1.0% by weight or more, preferably 20% by weight or less, more preferably 15% by weight or less, and more preferably 10% by weight or less.

[0428] Specifically, the compositions of the present invention include the compositions for forming an emissive layer, a hole injection layer, a hole transport layer, and an electron transport layer, as described below. The preferred content of the solvent is as described later for each layer-forming composition. The content of the functional materials is also as described later for each layer-forming composition, corresponding to the content of the emissive layer material, hole injection layer material, hole transport layer material, and electron transport layer material.

[0429] [Film deposition by wet deposition method] The composition of the present invention is suitably used for forming functional films in the manufacture of organic electroluminescent devices. The configuration of the organic electroluminescent device is as described below.

[0430] The organic electroluminescent element in the present invention typically has a substrate on which electrodes are provided, with a minute region where light-emitting pixels are partitioned by partitions called banks. The composition of the present invention is extruded into this minute region partitioned by banks, dried, and heated as appropriate to form a functional film.

[0431] The ejection method involves ejecting droplets smaller than the micro-regions partitioned by a bank from a minute nozzle, and it is preferable to fill the micro-regions partitioned by the bank with the composition of the present invention by ejecting multiple droplets. The ejection method is preferably an inkjet method.

[0432] In the wet film deposition method, a micro-region partitioned by a bank is filled with the composition of the present invention, and then vacuum-dried. Vacuum drying is the process of volatilizing the solvent by reducing the pressure.

[0433] Although both solvent A and solvent B can be mostly evaporated by vacuum drying, heating is then performed to ensure thorough drying. The heating temperature and duration 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 more, preferably 3 minutes or more, more preferably 5 minutes or more, and usually 120 minutes or less, preferably 90 minutes or less, and more preferably 60 minutes or less.

[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 more, preferably 3 minutes or more, more preferably 5 minutes or more, and usually 120 minutes or less, preferably 90 minutes or less, and more preferably 60 minutes or less.

[0436] Heating can be carried out using methods such as a hot plate, oven, or infrared irradiation. In the case of infrared irradiation, which directly imparts molecular vibrations, a heating time close to the lower limit mentioned above is sufficient. However, in the case of hot plate heating, where the substrate is in direct contact with the heat source or the heat source and substrate are placed very close together, a longer heating time is required than with infrared irradiation. In the case of oven heating, that is, heating with gas inside 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 upper limit mentioned above is preferable. The heating time is adjusted as appropriate depending on the heating method.

[0437] [Functional membranes] 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, particularly preferably 95% by weight or more, and most preferably substantially 100% by weight, with an upper limit of 100% by weight. Substantially 100% by weight means that the functional film may contain trace amounts of additives, residual solvents, and impurities. By having the functional material content in the functional film within this range, the functionality of the functional material can be expressed more effectively.

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

[0439] Figure 1 is a schematic cross-sectional diagram showing an example of the structure of the organic electroluminescent element 10 of the present invention. In Figure 1, 1 represents the substrate, 2 the anode, 3 the hole injection layer, 4 the hole transport layer, 5 the light-emitting layer, 6 the hole blocking layer, 7 the electron transport layer, 8 the electron injection layer, and 9 the cathode.

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

[0441] [substrate] Substrate 1 serves as a support for the organic electroluminescent element. Substrate 1 can be a plate of quartz or glass, a metal plate or foil, a plastic film or sheet, etc. Glass plates, or transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, or polysulfone are particularly preferred. When using a synthetic resin substrate, it is preferable to pay attention to its gas barrier properties. A high gas barrier property of the substrate is desirable because it reduces the likelihood of degradation of the organic electroluminescent element due to outside air passing through the substrate. Therefore, a method of ensuring gas barrier properties by providing a dense silicon oxide film or the like on at least one side of the synthetic resin substrate is also a preferred method.

[0442] [anode] Anode 2 is an electrode that plays the role of injecting holes into the layer on the light-emitting layer 5 side. The anode 2 is typically composed of metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and / or tin oxides; metal halides such as copper iodide; carbon black; or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline.

[0443] The formation of anode 2 is usually carried out by methods such as sputtering or vacuum deposition. When forming anode 2 using metal nanoparticles such as silver, nanoparticles such as copper iodide, carbon black, conductive metal oxide nanoparticles, conductive polymer fine powder, etc., the anode 2 can also be formed by dispersing these nanoparticles in a suitable binder resin solution and coating it onto substrate 1.

[0444] In the case of conductive polymers, a thin film can also be formed directly on the substrate 1 by electrolytic polymerization. A conductive polymer can also be applied to substrate 1 to form anode 2 (Appl. Phys. Lett., Vol. 60, p. 2711, 1992). Anode 2 is usually a single-layer structure, but it can also be a multilayer structure consisting of multiple materials if desired.

[0445] The thickness of anode 2 can be appropriately selected depending on the required transparency. If transparency is required, the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness of anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably around 500 nm or less. If opacity is acceptable, the thickness of anode 2 is arbitrary. A substrate 1 that also functions as anode 2 may be used. It is also possible to laminate different conductive materials on top of the above anode 2.

[0446] To remove impurities adhering to anode 2 and adjust the ionization potential to improve hole injection performance, it is preferable to treat the surface of anode 2 with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma.

[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, it is usually formed on the anode 2.

[0448] The method for forming the hole injection layer 3 can be either vacuum deposition or wet deposition, and there are no particular restrictions. The hole injection layer 3 is preferably formed by a wet deposition method from the viewpoint of reducing dark spots.

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

[0450] (Hole transport material) Compositions for forming hole injection layers typically contain a hole transport material and a solvent as constituent materials for the hole injection layer 3. The hole transport material is typically used in the hole injection layer 3 of an organic electroluminescent device. Any compound with hole transport properties may be a polymer or other high-molecular-weight compound, or a monomer or other low-molecular-weight compound, but a polymer is preferred.

[0451] As hole transport materials, compounds having an ionization potential of 4.5 eV to 6.0 eV are preferred from the viewpoint of a charge injection barrier from anode 2 to hole injection layer 3. Examples of hole transport materials include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by fluorene groups, hydrazone derivatives, silazane derivatives, silanamin derivatives, phosphatamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon, and the like.

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

[0453] The hole transport material used as the material for the hole injection layer 3 may contain one of these compounds alone, or two or more. When two or more hole transport materials are included, the combination is arbitrary, 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] As hole transport materials, aromatic amine compounds are preferred among those exemplified above in terms of amorphous nature and visible light transmittance, and aromatic tertiary amine compounds are particularly preferred. Aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure, and also include compounds having groups derived from aromatic tertiary amines.

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

[0456] [ka]

[0457] (In formula (20), Ar 3 This represents an aromatic hydrocarbon group or an aromatic heterocyclic group, which may have substituents. Ar 4 This represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group, which may have substituents, or a divalent group formed by the direct or mediated linkage of multiple such aromatic hydrocarbon and aromatic heterocyclic groups.

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

[0459] Among the linking groups, Ar in formula (20) is superior in that it is excellent at hole injection into the light-emitting layer. 4 However, it is preferable that the aromatic hydrocarbon group or aromatic heterocyclic group is linked together via a linking group represented by the following formula (30).

[0460] [ka]

[0461] (In formula (30), d represents an integer between 1 and 10. R 8 and R 9 Each of these independently represents an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group, which may have a hydrogen atom or a substituent. R 8 , R 9 If multiple instances exist, they may be the same or different.

[0462] [ka]

[0463] In equation (11) above, j, k, l, m, n, and p each independently represent a non-negative integer, where l + m ≥ 1. 11 Ar 12 Ar 14 Each of these independently represents a divalent aromatic ring group having 30 or fewer carbon atoms, which may have substituents. 13 Q represents a divalent aromatic ring group having 30 or fewer carbon atoms, which may have substituents, or a divalent group represented by the following formula (12), 11 Q 12 Each of these independently represents an oxygen atom, a sulfur atom, or a hydrocarbon chain having 6 or fewer carbon atoms, which may have substituents. 1 ~S 4 Each of these is independently represented by the group shown in formula (13) below.

[0464] In this context, "aromatic ring group" refers to aromatic hydrocarbon ring groups and aromatic heterocyclic ring groups. Ar 11 Ar 12 Ar 14Examples of aromatic ring groups include monocyclic rings, 2-6 fused rings, or groups in which two or more of these aromatic rings are linked. Specific examples of monocyclic or 2-6 fused ring aromatic ring groups include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, fluorene rings, biphenyl groups, terphenyl groups, quaterphenyl groups, furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, and pyrrolymidazole rings. Examples of divalent groups derived from benzene rings, pyrrolopyrazole rings, pyrrolopyrrole rings, thienopyrrole rings, thienothiophene rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, cinolinoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, or azulene rings. Among these, divalent groups derived from benzene rings, naphthalene rings, fluorene rings, pyridine rings, or carbazole rings, or biphenyl groups, are preferred because they efficiently delocalize negative charges and have excellent 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 previous case.

[0465] [ka]

[0466] In the above equation (12), R 11 R represents an alkyl group, an aromatic ring group, or a trivalent group consisting of an alkyl group having 40 or fewer carbon atoms and an aromatic ring group, and these may have substituents. 12 represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group with 40 or fewer carbon atoms and an aromatic ring group, which may have substituents. 31R represents a monovalent aromatic ring group or a monovalent bridging group, and these groups may have substituents. q represents 1 to 4. If q is 2 or greater, multiple R 12 They may be the same or different, and multiple Ar 31 These may be the same or different. An asterisk (*) indicates a bond with the nitrogen atom in equation (11).

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

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

[0469] R 12 Specific examples of aromatic ring groups include benzene rings, fluorene rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and divalent groups derived from linked rings with 30 or fewer carbon atoms.

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

[0471] Ar 31Specific examples of aromatic ring groups include benzene rings, fluorene rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and monovalent groups derived from linked rings with 30 or fewer carbon atoms.

[0472] Examples of preferred structures of formula (12) include the following structure, R 11 In the following substructure, the benzene ring or fluorene ring in the main chain may have further substituents.

[0473] [ka]

[0474] Ar 31 Examples of crosslinking groups include groups derived from benzocyclobutene rings, naphthocyclobutene rings, or oxetane rings, vinyl groups, acrylic groups, etc. Due to the stability of the compound, groups derived from benzocyclobutene rings or naphthocyclobutene rings are preferred.

[0475] [ka]

[0476] In equation (13) above, x and y represent integers greater than or equal to 0. 21 Ar 23 Each of these independently represents a divalent aromatic ring group, and these groups may have substituents. 22 R represents a monovalent aromatic ring group which may have substituents, 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 substituents.

[0477] Ar 32 represents a monovalent aromatic ring group or a monovalent bridging group, and these groups may have substituents. 32 If is a monovalent crosslinking group, the crosslinking group is the Ar 31A bridging group similar to the one that can be used in [the formula] is preferred. An asterisk (*) indicates a bond with 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 previous case. Ar 22 Ar 32 Examples of aromatic ring groups include monocyclic rings, 2-6 fused rings, or groups in which two or more of these aromatic rings are linked. Specific examples include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, fluorene rings, biphenyl groups, terphenyl groups, quaterphenyl groups, furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, pyrroloimidazole rings, pyrrolopy Examples include monovalent groups derived from razole rings, pyrrolopyrrole rings, thienopyrrole rings, thienothiophene rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, cinolinic rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, or azulene rings. Among these, monovalent groups derived from benzene rings, naphthalene rings, fluorene rings, pyridine rings, or carbazole rings, or biphenyl groups, are preferred because they efficiently delocalize negative charges and have excellent stability and heat resistance.

[0479] R 13 Examples of alkyl groups or aromatic ring groups include R 12 It is similar to that. Ar 32The crosslinking group is not particularly limited, but preferred examples include groups derived from benzocyclobutene rings, naphthocyclobutene rings or oxetane rings, vinyl groups, acrylic groups, 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 these may have further substituents, as long as 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, but examples include one or more types selected from the substituent group W below.

[0481] [Substituent group W] Alkyl groups having 1 or more carbon atoms, preferably 10 or less, and more preferably 8 or less, such as methyl and ethyl groups; alkenyl groups having 2 or more carbon atoms, preferably 11 or less, and more preferably 5 or less, such as vinyl groups; alkynyl groups having 2 or more carbon atoms, preferably 11 or less, and more preferably 5 or less, such as ethynyl groups; alkoxy groups having 1 or more carbon atoms, preferably 10 or less, and more preferably 6 or less, such as methoxy and ethoxy groups; phenoxy, naphthoxy, pyridyloxy groups, etc. having 4 or more carbon atoms, preferably 5 or more, preferably 25 or less, and more preferably 14 or fewer aryloxy groups; methoxycarbonyl groups, ethoxycarbonyl groups, etc., with 2 or more carbon atoms, preferably 11 or fewer, more preferably 7 or fewer; dialkylamino groups, etc., with 2 or more carbon atoms, preferably 20 or fewer, more preferably 12 or fewer; diarylamino groups, etc., with 10 or more carbon atoms, preferably 12 or more, preferably 30 or fewer, more preferably 22 or fewer; phenylmethylamino groups, etc., with 6 or more carbon atoms. , more preferably 7 or more, preferably 25 or less, and more preferably 17 or less arylalkylamino groups; acetyl groups, benzoyl groups, etc., with 2 or more carbon atoms, preferably 10 or less, and more preferably 7 or less acyl groups; halogen atoms such as fluorine atoms and chlorine atoms; haloalkyl groups such as trifluoromethyl groups, with 1 or more carbon atoms, preferably 8 or less, and more preferably 4 or less haloalkyl groups; methylthio groups, ethylthio groups, etc., with 1 or more carbon atoms, preferably 10 or less, and more preferably 6 or less alkylthio groups; phenylthio groups, naphthylthio groups, pyridylthio groups, etc. arylthio groups having 4 or more carbon atoms, preferably 5 or more, preferably 25 or less, and more preferably 14 or less; silyl groups having 2 or more carbon atoms, preferably 3 or more, preferably 33 or less, and more preferably 26 or less, such as trimethylsilyl group and triphenylsilyl group; siloxy groups having 2 or more carbon atoms, preferably 3 or more, preferably 33 or less, and more preferably 26 or less, such as trimethylsiloxy group and 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 phenyl group and naphthyl group;Aromatic heterocyclic groups such as thienyl groups and pyridyl groups, having 3 or more carbon atoms, preferably 4 or more, preferably 28 or fewer, and more preferably 17 or fewer.

[0482] Of the substituent group W described above, 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 transport and stability. In particular, among polymer compounds having repeating units represented by formula (11), polymer compounds having repeating units represented by formula (14) below are preferred because they exhibit very high hole injection and transport properties.

[0483] [ka]

[0484] In the above equation (14), R 21 ~R 25 Each of these independently represents an arbitrary substituent. 21 ~R 25 Specific examples of substituents are the same as those listed in [substituent group W] above. s and t each independently represent integers between 0 and 5, inclusive. u, v, and w each independently represent integers between 0 and 4, inclusive.

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

[0486] [ka]

[0487] In equations (15) and (16) above, Ar 45 Ar 47 and Ar 48 Each of these independently represents a potentially substituted monovalent aromatic hydrocarbon group or a potentially substituted monovalent aromatic heterocyclic group. 44 and Ar46 Each of these independently represents a divalent aromatic hydrocarbon group which may have substituents, or a divalent aromatic heterocyclic group which may have substituents.

[0488] R 41 ~R 43 Each of these independently represents a hydrogen atom or any substituent.

[0489] Ar 45 Ar 47 and Ar 48 Examples of specific examples, preferred examples, examples of substituents that may be present, and examples of preferred substituents are given by Ar 22 It is similar to Ar 44 and Ar 46 Examples of specific examples, preferred examples, examples of optional substituents, and examples of preferred substituents are given by Ar 11 Ar 12 and Ar 14 It is similar to R. 41 ~R 43 Preferably, the substituent is a hydrogen atom or one of the substituents listed in [substituent group W] above, and more preferably, it is a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

[0490] The following are some preferred examples of repeating units represented by formulas (15) and (16) that are applicable to the present invention, but the present invention is not limited to these.

[0491] [ka]

[0492] In the structure of a hole transport material, it is preferable to further include repeating units of the following formula (a-1) to form a stable film.

[0493] [ka]

[0494] (In formula (a-1), Ar 1 Each of these independently represents a divalent group consisting of multiple structures selected from optionally substituted aromatic hydrocarbon ring groups, optionally substituted aromatic heterocyclic groups, or optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups. Ar 4 This represents a monovalent group formed by linking multiple structures selected from optionally substituted aromatic hydrocarbon ring groups, optionally substituted aromatic heterocyclic groups, or optionally substituted aromatic hydrocarbon ring groups and optionally substituted aromatic heterocyclic groups. R is a monovalent group in which multiple structures selected from optionally substituted alkyl groups, optionally substituted alkyloxy groups, optionally substituted alkylthio groups, fluorine atoms, optionally substituted aromatic hydrocarbon ring groups, optionally substituted aromatic heterocyclic groups, optionally substituted aromatic hydrocarbon ring groups, and optionally substituted aromatic heterocyclic groups are linked together. The subscript n represents an integer from 2 to 5. The subscript m represents an integer from 0 to 4, independently. The sum of multiple independent values ​​of m is 1 or greater.

[0495] In formula (a-1), it is particularly preferable for the repeating unit to be that of formula (54) below, in order to form an even 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 cause distortion, resulting in a higher degree of freedom compared to a normal π-conjugated bond. When a solvent represented by general formula (1) is applied, the two free benzene rings in the solvent can more easily interpenetrate each other, increasing solubility and improving flatness as the solute becomes more uniformly dispersed in the solvent.

[0498] (Electron-accepting compounds for hole injection layers) The hole injection layer forming composition preferably contains an electron-accepting compound for the 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 that has oxidizing power and the ability to accept one electron from the hole transport material mentioned above. Specifically, the electron-accepting compound for the hole injection layer is preferably a compound with an electron affinity of 4.0 eV or more, and more preferably a compound with an electron affinity of 5.0 eV or more.

[0500] Examples of electron-accepting compounds for hole injection layers 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 electron-accepting compounds for the hole injection layer include organically substituted onium salts such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. 2005 / 089024, International Publication No. 2017 / 164268); high-valence inorganic compounds such as iron(III) chloride (Japanese Patent Publication No. 11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene and aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Publication No. 2003-31365); fullerene derivatives; iodine; and sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions.

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

[0502] Electron-accepting compounds can improve the conductivity of the hole injection layer 3 by oxidizing the hole transport material. Furthermore, mixing such electron-accepting compounds is preferable to obtain a flatter film.

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

[0504] (solvent) It is preferable that at least one of the solvents in the hole injection layer formation composition used in the wet film deposition method is a compound capable of dissolving the constituent materials of the hole injection layer 3 described above.

[0505] If the hole injection layer forming composition is the composition of the present invention, the solvents are solvent A and solvent B of the present invention. Since solvent A has the property of being poor in dissolving the electron-accepting compound, in order for solvent B to be a solvent that ensures overall solubility as an ink, it is preferable that solvent B is a solvent that is relatively good at dissolving 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 solvents include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

[0507] Examples of ether-based solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0508] Examples of ester solvents 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 amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide. Other substances such as dimethyl sulfoxide can also be used.

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

[0512] The concentration of the hole transport material in the hole injection layer forming composition is arbitrary as long as it does not significantly impair the effects of the present invention. From the viewpoint of uniformity of film thickness, the concentration of the hole transport material in the hole injection layer forming composition is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 0.5% by weight or more. The concentration of the hole transport material in the hole injection layer forming composition is preferably 70% by weight or less, more preferably 60% by weight or less, and even more preferably 50% by weight or less. This concentration is preferable in that it is less likely to cause unevenness in film thickness. This concentration is also preferable in that it is less likely to cause defects in the formed hole injection layer.

[0513] (Formation of hole injection layer by wet deposition method) When forming a hole injection layer 3 by a wet deposition method, a composition for film formation (composition for forming the hole injection layer) is usually prepared by mixing the materials constituting the hole injection layer 3 with a suitable solvent (solvent for the hole injection layer). This composition for forming the hole injection layer 3 is then applied to the layer corresponding to the layer below the hole injection layer (usually the anode 2) using an appropriate method, deposited, and dried to form the hole injection layer 3.

[0514] (Formation of hole injection layer 3 by vacuum deposition method) When forming the hole injection layer 3 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 aforementioned hole transport material, electron-accepting compound, etc.) are placed in crucibles set up inside a vacuum vessel (if two or more materials are used, each is placed in its own crucible), and the inside of the vacuum vessel is pumped with a suitable vacuum pump for 10°C. -4 The air is evacuated to approximately Pa. After this, the crucible is heated (each crucible is heated if two or more materials are used), and the evaporation rate is controlled to evaporate the material (each material is evaporated independently if two or more materials are used) to form a hole injection layer 3 on the anode 2 of the substrate 1, which is placed facing the crucible. If two or more materials are used, a mixture of these materials can also be placed in the crucible, heated, and evaporated to form the hole injection layer 3.

[0515] The vacuum level during deposition is not limited as long as it does not significantly impair the effects of the present invention. The vacuum level during deposition is typically 0.1 × 10⁻⁶. -6 Torr(0.13×10 -4 Pa) or more, 9.0×10 -6 Torr(12.0× -4 The vapor deposition rate is less than or equal to Pa. 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 deposition temperature during vapor deposition is not limited as long as it does not significantly impair the effects of the present invention. The film deposition temperature during vapor 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 element of the present invention, but when the hole transport layer 4 is provided, it is usually formed on the hole injection layer 3 if there is a hole injection layer 3, and on the anode 2 if there is no hole injection layer 3.

[0517] The method for forming the hole transport layer 4 can be either vacuum deposition or wet deposition, and there are no particular restrictions. The hole transport layer 4 is preferably formed by a wet deposition method from the viewpoint of reducing dark spots.

[0518] The material forming the hole transport layer 4 is preferably a material that has high hole transport properties and can efficiently transport the injected holes. For this reason, the material forming the hole transport layer 4 is preferably one that has a low ionization potential, high transparency to visible light, high hole mobility, excellent stability, and is less likely to generate trapping impurities during manufacturing or use. In most cases, the hole transport layer 4 is in contact with the light-emitting layer 5, so it is preferable that it does not quench the light emission from the light-emitting layer 5 or form an excyplex with the light-emitting layer 5, thereby reducing efficiency.

[0519] The material for the hole transport layer 4 can be any material that has been conventionally used as a constituent material for the hole transport layer 4. Examples of materials for 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 ethersulfone derivatives containing tetraphenylbenzidine, polyarylenevinylene derivatives, polysiloxane derivatives, polythiophene derivatives, and poly(p-phenylenevinylene) derivatives. These may be alternating copolymers, random polymers, block polymers, or graft copolymers. They may also be polymers with branched main chains and three or more terminal ends, or so-called dendrimers.

[0521] In particular, polyarylamine derivatives and polyarylene derivatives are preferred as the material for the hole transport layer 4. Specific examples of polyarylamine derivatives and polyarylene derivatives include those described in Japanese Patent Publication No. 2008-98619. As the polyarylamine derivative, it is preferable to use the aforementioned aromatic tertiary amine polymer compound.

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

[0523] If the hole transport layer forming composition is the composition of the present invention, the solvent is solvent A and solvent B of the present invention. When forming the hole transport layer 4 by vacuum deposition, the film formation conditions are the same as those for forming the hole injection layer 3. 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 the penetration of low molecular weight material in the light-emitting layer and the swelling of the hole transport material.

[0524] [Luminous layer] The light-emitting layer 5 is the main light-emitting layer, excited by the recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes under an applied electric field. The light-emitting layer 5 is usually formed on top of the hole transport layer 4 if one is present, on top of the hole injection layer 3 if one is present but one is not, and on top of the anode 2 if neither the hole transport layer 4 nor the hole injection layer 3 is present.

[0525] <Materials for luminescent layers> Materials for light-emitting layers typically include a light-emitting material and a host charge transport material.

[0526] <Luminescent materials> As the light-emitting material, any known material commonly used as a light-emitting material in organic electroluminescent devices can be applied, and there are no particular restrictions. Any material that emits light at a desired emission wavelength and has good luminescence efficiency should be used. The light-emitting material may be a fluorescent material or a phosphorescent material, but from the viewpoint of internal quantum efficiency, a phosphorescent material is preferred. 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 exhibit light emission from an excited triplet state. Typical examples include metal complex compounds containing Ir, Pt, Eu, etc., and materials with a metal complex structure are preferred.

[0529] Among metal complexes, examples of phosphorescent organometallic complexes that emit light via a triplet state include Werner-type complexes or organometallic complex compounds containing a metal selected from groups 7 to 11 of the long-period periodic table (hereinafter, unless otherwise specified, "periodic table" refers to the long-period periodic table) as the central metal. Examples of such phosphorescent materials include the phosphorescent materials described in International Publication No. 2014 / 024889, International Publication No. 2015-087961, International Publication No. 2016 / 194784, and Japanese Patent Publication No. 2014-074000. Preferably, the compound is represented by the following formula (201), or by the following formula (205), and more preferably by the following formula (201).

[0530] [ka]

[0531] In formula (201), ring A1 represents an aromatic hydrocarbon ring structure which may have substituents or an aromatic heterocyclic structure which may have substituents. Ring A2 represents an aromatic heterocyclic structure that may have substituents. R 201 , R 202 Each of these is an independent structure represented by formula (202), and "*" indicates the bond position with ring A1 or ring A2. 201 , R 202 R can be the same or different, 201 , R 202 If there are multiple instances of each, they may be the same or different.

[0532] Ar 201 Ar 203Each of these independently represents an aromatic hydrocarbon ring structure that may have substituents, or an aromatic heterocyclic ring structure that may have substituents. Ar 202 This represents an optionally substituted aromatic hydrocarbon ring structure, an optionally substituted aromatic heterocyclic structure, or an optionally substituted aliphatic hydrocarbon structure. Substituents bonded to ring A1 may bond to each other, substituents bonded to ring A2 may bond to each other, or substituents bonded to ring A1 and substituents bonded to ring A2 may bond to each other to form a ring.

[0533] B 201 -L 200 -B 202 This represents an anionic bidentate ligand. 201 and B 202 Each of these independently represents a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms that constitute a ring. 200 is a single bond, or B 201 and B 202 B represents the group of atoms that together constitute a bidentate ligand. 201 -L 200 -B 202 If multiple instances exist, they may be identical or different.

[0534] In addition, in equations (201) and (202), i1 and i2 each independently represent integers between 0 and 12 (inclusive). i3 is Ar 202 Represents a non-negative integer with an upper limit of the number that can be substituted for, i4 is Ar 201 Represents a non-negative integer with an upper limit of the number that can be substituted for, k1 and k2 each independently represent non-negative integers up to the number of numbers that can be permuted in rings A1 and A2, respectively. z represents an integer between 1 and 3.

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

[0536] <Substituent group S> Alkyl alkyl groups, preferably C1 to C20 alkyl groups, more preferably C1 to C12 alkyl groups, even more preferably C1 to C8 alkyl groups, and particularly preferably C1 to C6 alkyl groups.

[0537] • Alkoxy groups, preferably alkoxy groups having 1 to 20 carbon atoms, more preferably alkoxy groups having 1 to 12 carbon atoms, and even more preferably alkoxy groups 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. • 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] Aralkyl groups, preferably aralkyl groups having 7 to 40 carbon atoms, more preferably aralkyl groups having 7 to 18 carbon atoms, and even more preferably aralkyl groups having 7 to 12 carbon atoms. • Heteroaralkyl group, preferably a heteroaralkyl group having 7 to 40 carbon atoms, more preferably a heteroaralkyl group having 7 to 18 carbon atoms. Alkenyl groups, preferably alkenyl groups having 2 to 20 carbon atoms, more preferably alkenyl groups having 2 to 12 carbon atoms, even more preferably alkenyl groups having 2 to 8 carbon atoms, and particularly preferably alkenyl groups having 2 to 6 carbon atoms.

[0540] • 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. • Alkylsilyl group, preferably an alkylsilyl group having 1 to 20 carbon atoms in the alkyl group, more preferably an alkylsilyl group having 1 to 12 carbon atoms in the alkyl group.

[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. • Alkylcarbonyl group, preferably an alkylcarbonyl group having 2 to 20 carbon atoms. • Arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms. The above groups may have one or more hydrogen atoms replaced by fluorine atoms, or one or more hydrogen atoms replaced by deuterium atoms. Unless otherwise specified, aryls are aromatic hydrocarbon rings, and heteroaryls are aromatic heterocycles. • Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF6 5。

[0543] Of the above substituent group S, preferably are alkyl groups, alkoxy groups, aryloxy groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, alkylsilyl groups, arylsilyl groups, and groups in which one or more hydrogen atoms of these groups are replaced by fluorine atoms, fluorine atoms, cyano groups, or -SF5. More preferably 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 by fluorine atoms, fluorine atoms, cyano groups, or -SF5. More preferably, 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 preferably, the group is an alkyl group, an arylamino group, an aralkyl group, an aryl group, or a heteroaryl group.

[0544] These substituent groups S may further contain substituents selected from substituent group S. The preferred groups, more preferred groups, even more preferred groups, particularly preferred groups, and most preferred groups of the substituents that may be present are the same as the preferred groups in substituent group S.

[0545] (Ring A1) Ring A1 represents an aromatic hydrocarbon ring structure or an aromatic heterocyclic structure that may have substituents.

[0546] The aromatic hydrocarbon ring is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, benzene rings, naphthalene rings, anthracene rings, triphenylyl rings, acenaphthene rings, fluorantene rings, and fluorene rings are preferred.

[0547] As the aromatic heterocycle, a C3 to C30 aromatic heterocycle containing a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom is preferred. More preferably, it is a furan ring, a benzofuran ring, a thiophene ring, or a benzothiophene ring.

[0548] More preferably, ring A1 is 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 that may have substituents. The aromatic heterocycle is preferably an aromatic heterocycle having 3 to 30 carbon atoms, which contains one of the following as a heteroatom: a nitrogen atom, an oxygen atom, or a sulfur atom. Specifically, examples include pyridine rings, pyrimidine rings, pyrazine rings, triazine rings, imidazole rings, oxazole rings, thiazole rings, benzothiazole rings, benzoxazole rings, benzimidazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, quinazoline rings, naphthyridine rings, and phenanthidine rings. Preferably, these are pyridine rings, pyrazine rings, pyrimidine rings, imidazole rings, benzothiazole rings, benzoxazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, and quinazoline rings. More preferably, these are pyridine rings, imidazole rings, benzothiazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, and quinazoline rings. Most preferably, these are pyridine rings, imidazole rings, benzothiazole rings, quinoline rings, quinoxaline rings, and quinazoline rings.

[0550] (Combination of ring A1 and ring A2) Preferred combinations of ring A1 and ring A2, when denoted 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 rings A1 and A2 may have can be arbitrarily selected, but preferably one or more substituents selected from the substituent group S.

[0552] (Ar 201 Ar 202 Ar 203 ) Ar 201 Ar 203 Each of these independently represents an aromatic hydrocarbon ring structure that may have substituents, or an aromatic heterocyclic ring structure that may have substituents.

[0553] Ar 202 This represents an optionally substituted aromatic hydrocarbon ring structure, an optionally substituted aromatic heterocyclic structure, or an optionally substituted aliphatic hydrocarbon structure.

[0554] Ar 201 Ar 202 Ar 203 If any of the elements is an aromatic hydrocarbon ring structure which may have substituents, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, a benzene ring, naphthalene ring, anthracene ring, triphenylyl ring, acenaphthene ring, fluorantene ring, or fluorene ring is preferred, more preferably a benzene ring, naphthalene ring, or fluorene ring, and most preferably a benzene ring.

[0555] Ar 201 Ar 202 If any of the elements is a benzene ring which may have substituents, it is preferable that at least one benzene ring is bonded to an adjacent structure at the ortho or meta position, and more preferably that at least one benzene ring is bonded to an adjacent structure at the meta position.

[0556] Ar 201 Ar 202 Ar 203 If either of the elements is a fluorene ring which may have substituents, it is preferable that the 9th and 9' positions of the fluorene ring have substituents or are bonded to adjacent structures.

[0557] Ar 201 Ar 202 Ar 203In the case of an aromatic heterocyclic structure in which any of the elements may have substituents, 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. Specifically, examples include pyridine rings, pyrimidine rings, pyrazine rings, triazine rings, imidazole rings, oxazole rings, thiazole rings, benzothiazole rings, benzoxazole rings, benzimidazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, quinazoline rings, naphthyridine rings, phenantholidine rings, carbazole rings, dibenzofuran rings, and dibenzothiophene rings, and preferably pyridine rings, pyrimidine rings, triazine rings, carbazole rings, dibenzofuran rings, and dibenzothiophene rings.

[0558] Ar 201 Ar 202 Ar 203 If either of the elements is a carbazole ring which may have substituents, it is preferable that the N-position of the carbazole ring has a substituent or is bonded to an adjacent structure.

[0559] Ar 202 If the aliphatic hydrocarbon structure may have substituents, it is a linear, branched, or cyclic aliphatic hydrocarbon structure, preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms.

[0560] (i1, i2, i3, i4, k1, k2) i1 and i2 each independently represent integers from 0 to 12, preferably from 1 to 12, more preferably from 1 to 8, and more preferably from 1 to 6. This range is expected to improve solubility and charge transport. i3 preferably represents an integer between 0 and 5, more preferably between 0 and 2, and more preferably 0 or 1.

[0561] i4 preferably represents an integer between 0 and 2, and more preferably 0 or 1. k1 and k2 each independently represent an integer preferably between 0 and 3, more preferably between 1 and 3, more preferably 1 or 2, and particularly preferably 1.

[0562] (Ar 201 Ar 202 Ar 203 Preferred substituents) Ar 201 Ar 202 Ar 203 The substituents that may be present can be arbitrarily selected, but preferably one or more substituents selected from the substituent group S, and the preferred groups are also as in the substituent group S, but more preferably unsubstituted (hydrogen atom), alkyl, or aryl group, particularly preferably unsubstituted (hydrogen atom) or alkyl, and most preferably unsubstituted (hydrogen atom) or tertiary butyl group, where the tertiary butyl group is Ar 203 If Ar 203 Ar 203 If it does not exist, Ar 202 Ar 202 and Ar 203 If it does not exist, Ar 201 It is preferable that it be substituted with

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

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

[0565] (II)(phenylene)-aralkyl(alkyl) A structure having an aromatic hydrocarbon group or an aromatic heterocyclic group to which an alkyl group or aralkyl group is bonded to 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 The structure is an aliphatic hydrocarbon, i2 is 1 to 12, preferably 3 to 8, Ar 203 The structure is a benzene ring structure, i3 is 0 or 1, preferably Ar 201 This is the aforementioned aromatic hydrocarbon structure, more preferably a structure in which 1 to 5 benzene rings are linked together, and more preferably a single benzene ring. This structure is expected to improve both solubility and charge transport.

[0566] (III) Dendron A structure in which a dendron is attached to ring A1 or ring A2, for example, Ar 201 Ar 202 The benzene ring structure, Ar 203 The structure is biphenyl or terphenyl, i1 and i2 are 1 to 6, i3 is 2, and j is 2. This structure is expected to improve both solubility and charge transport.

[0567] (IV)B 201 -L 200 -B 202 B 201 -L 200 -B 202 The structure represented by is preferably the structure represented by the following formula (203) or formula (204).

[0568] [ka]

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

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

[0571] [ka]

[0572] [ka]

[0573] Furthermore, phosphorescent materials represented by the following formula (205) are also preferred.

[0574] [ka]

[0575] [In formula (205), M 2 R represents a metal, and T represents a carbon or nitrogen atom. 92 ~R 95 Each of these independently represents a substituent. However, if T is a nitrogen atom, then R 94 and R 95 There isn't one.

[0576] In formula (205), M 2 Specific examples include metals selected from groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold are preferred, and divalent metals such as platinum and palladium are particularly preferred.

[0577] Also, in equation (205), R 92 and R 93Each of these 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, if T is a carbon atom, R 94 and R 95 Each of them is independent of R 92 and R 93 This represents substituents represented by similar examples. Furthermore, if T is a nitrogen atom, R is directly bonded to T. 94 or R 95 It does not exist. Also, R 92 ~R 95 It may further have substituents. The substituents can be the substituents mentioned above. Furthermore, R 92 ~R 95 Any two or more of these groups may be linked together 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. Furthermore, the molecular weight of the phosphorescent material is preferably 800 or more, more preferably 1000 or more, and even more preferably 1200 or more. This molecular weight range allows the phosphorescent materials to mix uniformly with the charge transport material without agglomerating, resulting in a highly efficient luminescent layer.

[0580] A large molecular weight is preferable for phosphorescent materials because it results in high Tg, melting point, and decomposition temperature, providing excellent heat resistance for the phosphorescent material and the formed luminescent layer, and reducing the likelihood of deterioration of film quality due to gas generation, recrystallization, and molecular migration, as well as an increase in impurity concentration due to thermal decomposition of the material. On the other hand, a small molecular weight is preferable for phosphorescent materials because it facilitates the purification of organic compounds.

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

[0582] As an electron transport material, from the viewpoint of having excellent electron transport properties and a relatively stable structure, compounds having pyridine, pyrimidine, or triazine structures are more preferred, and compounds having pyrimidine or triazine structures are even more preferred.

[0583] A hole-transporting material is a compound having a structure that exhibits excellent hole transport properties. Among the central skeletons exhibiting 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 even 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 molecular rigidity, making it easier to suppress the degree of molecular motion that responds to heat. Furthermore, the fused rings of three or more rings and the fused rings of five or more rings preferably have aromatic hydrocarbon rings or aromatic heterocycles, in terms of charge transport properties and material durability.

[0585] Examples of condensed ring structures with three or more rings include anthracene structures, phenanthrene structures, pyrene structures, chrysene structures, naphthacene structures, triphenylene structures, fluorene structures, benzofluorene structures, indenofluorene structures, indolofluorene structures, carbazole structures, indenocarbazole structures, indolocarbazole structures, dibenzofuran structures, and dibenzothiophene structures. From the viewpoint of charge transport and solubility, at least one selected from the group consisting of phenanthrene structures, fluorene structures, indenofluorene structures, carbazole structures, indenocarbazole structures, indolocarbazole structures, dibenzofuran structures, and dibenzothiophene structures is preferred, and from the viewpoint of resistance to charge, carbazole structures or indolocarbazole structures are more preferred.

[0586] In the present invention, from the viewpoint of the durability of the organic electroluminescent element against charge, 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] From the viewpoint of excellent flexibility, the charge transport material of the light-emitting layer is preferably a polymer material. A light-emitting layer formed using a material with excellent flexibility is preferred as a light-emitting layer for an organic electroluminescent device 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 low molecular weight, from the viewpoint of ease of synthesis and purification, ease of designing electron transport performance and hole transport performance, and ease of viscosity adjustment 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, most preferably 2,000 or less, 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 compounds represented by the following formula (211) are preferred.

[0590] [ka]

[0591] In the above equation (211), Ar 241 represents an aromatic hydrocarbon condensed ring structure which may have substituents, and Ar 242 Ar 243 Each of these independently represents an alkyl group, an aromatic hydrocarbon group, an aromatic heterogroup, or a group formed by bonding these together, which may each have substituents. n41 is an integer from 1 to 4.

[0592] Ar 241 Preferably, it represents an aromatic hydrocarbon condensed ring structure having 10 to 30 carbon atoms. Specific examples of ring structures include naphthalene, acenaphthene, fluorene, anthracene, phenathrene, fluorantene, pyrene, tetracene, chrysene, and perylene.

[0593] Ar 241 More preferably, it is an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms. Specific examples of ring structures include acenaphthene, fluorene, anthracene, phenathrene, fluorantene, pyrene, tetracene, chrysene, and perylene.

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

[0595] n41 is 1 to 4, preferably 1 to 3, more preferably 1 to 2, and most preferably 2. Ar 242 Ar 243 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and 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 heterogroup is preferably an aromatic heterogroup having 3 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 5 to 24 carbon atoms, specifically a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group, with the dibenzofuranyl group being more preferred.

[0598] Ar 241 Ar 242 Ar 243 The substituents that may be present are preferably groups selected from the substituent group S, more preferably hydrocarbon groups included in the substituent group S, and even more preferably hydrocarbon groups among the groups preferred as substituent group S.

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

[0600] [ka]

[0601] In the above equation (212), R 251 , R 252 Each of these is a structure that can be independently represented by equation (213), and R 253 R represents a substituent, 253 If there are multiple values, they may be the same or different, and n43 is an integer between 0 and 8.

[0602] [ka]

[0603] In the above equation (213), * represents the bond with the anthracene ring in equation (212), and Ar 254 Ar 255 Each of these independently represents an aromatic hydrocarbon structure which may have substituents, or a heteroaromatic ring structure which may have substituents, and Ar 254 Ar 255 If there are multiple instances of each, they may be the same or different, n44 is an integer from 1 to 5, and n45 is an integer from 0 to 5.

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

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

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

[0607] R is a substituent. 253 Ar 254 and Ar 255 The substituents that may be present are preferably groups selected from the substituent group S. More preferably, they are hydrocarbon groups included in substituent group S, and even more preferably, they are hydrocarbon groups among the groups preferred as 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. It is also 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 injection layer 8, which will be described later. The hole blocking layer 6 is a layer within the electron transport layer that also plays a role in preventing holes moving from the anode 2 from reaching the cathode 9. The hole blocking layer 6 is a layer that is laminated on top of 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 moving 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 required properties 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-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum dinuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Publication No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Publication No. 7-41759), and phenanthroline derivatives such as basocuproine (Japanese Patent Publication No. 10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2,4, and 6 positions, as described in International Publication No. 2005 / 022962, are also preferred as materials for the hole blocking layer 6.

[0612] There are no restrictions on the method of forming the hole blocking layer 6. The hole blocking layer 6 can be formed by wet deposition, vapor deposition, 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. Typically, the electron transport material used for the electron transport layer 7 is a compound that has high electron injection efficiency from the cathode 9 or the adjacent layer on the cathode 9 side, and also has high electron mobility, enabling efficient transport of injected electrons. Examples of compounds that satisfy these conditions include metal complexes such as aluminum and lithium complexes of 8-hydroxyquinoline (Japanese Patent 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, trisbenzimidazolbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Patent 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] As the electron transport material used in the electron transport layer 7, electron transporting organic compounds, such as nitrogen-containing heterocyclic compounds like bathophenanthroline or metal complexes like aluminum complexes of 8-hydroxyquinoline, are preferred because they can be doped with alkali metals such as sodium, potassium, cesium, lithium, and rubidium (as described in Japanese Patent Publication No. 10-270171, Japanese Patent Publication No. 2002-100478, Japanese Patent Publication No. 2002-100482, etc.) to achieve both electron injection transport properties and excellent film quality. Furthermore, doping the above-mentioned electron transporting organic compounds with inorganic salts such as lithium fluoride or cesium carbonate is also effective.

[0616] There are no restrictions on the method of forming the electron transport layer 7. The electron transport layer 7 can be formed by wet deposition, vapor deposition, 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 is typically 300 nm or less, preferably 100 nm or less.

[0618] [Electron injection layer] To efficiently inject electrons 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, which will be described later. 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 (MgF2), lithium oxide (Li2O), and cesium(II) carbonate (CsCO3) (see Applied Physics Letters, 1997, Vol. 70, pp. 152; Japanese Patent Publication No. 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154, etc.).

[0620] Since the electron injection layer 8 often does not have charge transport properties, it is preferable to use it as an ultrathin film in order to efficiently perform electron injection, and its film thickness is usually 0.1 nm or more, preferably 5 nm or less.

[0621] [cathode] The cathode 9 is an electrode that plays the role of injecting electrons into the layer on the light-emitting layer 5 side. Common materials for the cathode 9 include metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and / or tin oxides; metal halides such as copper iodide; carbon black; or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. Of these, metals with low work functions 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 material may consist of only one type, or two or more types may be used in any combination and ratio. The thickness of the cathode 9 varies depending on the required transparency. If transparency is required, the transmittance of visible light 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 around 500 nm or less. If opacity is acceptable, 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 different conductive materials on top of cathode 9. For example, to protect a cathode made of a metal with a low work function, such as alkali metals like sodium or cesium, or alkaline earth metals like barium or calcium, it is preferable to further laminate a metal layer with a high work function and stability to the atmosphere on top of it, as this increases the stability of the device. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum are used. These materials may be used individually or in any combination and ratio of two or more.

[0624] [Other layers] The organic electroluminescent element of the present invention may have other configurations without departing from the spirit of the invention. For example, as long as its performance is not impaired, there may be any additional layers between the anode 2 and the cathode 9 in addition to the layers described above, and non-essential layers among the layers described above may be omitted.

[0625] In the layer configuration described above, it is also possible to stack the components other than the substrate in the reverse order. For example, in the layer configuration shown in Figure 1, the other components may be placed 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 element of the present invention may be configured as a single organic electroluminescent element, or it may be applied to a configuration in which multiple organic electroluminescent elements are arranged in an array, or it may be applied to a configuration in which the anode and cathode 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 they do not significantly impair the effects of the present invention.

[0628] <Organic electroluminescent devices> By providing two or more organic electroluminescent elements that emit light in different colors, an organic electroluminescent device such as an organic EL display device or organic EL lighting can be created. In this organic electroluminescent device, by providing at least one, preferably all, organic electroluminescent elements of the present invention, a high-quality organic electroluminescent device can be provided.

[0629] <Organic EL display device> There are no particular restrictions on the type or structure of the organic EL display device using the organic electroluminescent element of the present invention, and it can be assembled according to conventional methods using the organic electroluminescent element of the present invention. For example, an organic EL display device can be formed using the method described in "Organic EL Display" (Ohmsha, published August 20, 2004, authored by Shizuka Tokito, Chihaya Adachi, and Hideyuki Murata).

[0630] <Organic EL lighting> There are no particular restrictions on the type or structure of the organic EL lighting using the organic electroluminescent element of the present invention, and it can be assembled according to conventional methods using the organic electroluminescent element of the present invention. [Examples]

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

[0632] <Preparing the circuit board> A substrate was prepared by depositing an Ag alloy film on a 0.5 mm thick glass substrate using the sputtering method, and then depositing an indium tin oxide (ITO) film on the Ag film using the sputtering method, followed by patterning using a general photolithography method. A liquid-repellent acrylic resin was coated onto this substrate to a thickness of 1.1 μm, and openings were created using a general photolithography method. The size of the openings was approximately 180 μm along the long axis and approximately 60 μm along the short axis, with a corner radius of 30 μm.

[0633] The prepared substrates were ultrasonically cleaned with ultrapure water for 15 minutes, then the remaining water was removed with an air blower, and they were dried in a clean oven set to 130°C for 10 minutes. In all the following examples and comparative examples, the dried substrates were baked on a hot plate at 230°C for 10 minutes immediately before ink application before use.

[0634] (Example 1) <Preparing the ink> A hole transport material P-1 with an average molecular weight of 15k and an electron-accepting compound D-1 were mixed in a weight ratio of 100:12.5. Meanwhile, butyl benzoate and 1,1-diphenylpentane were mixed as solvents in a weight ratio of 75:25 to prepare solvent 1. The content of this mixture was adjusted to 2.0% by weight relative to solvent 1, and composition 1 was prepared by heating at 110°C for 3 hours while stirring at 420 rpm using a stirring bar.

[0635] [Chemical formula]

[0636] [Chemical formula]

[0637] <Coating and drying process> Composition 1 was filled into a cartridge for an inkjet printer (DMCLCP - 11610), 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 where 21 openings in the long - axis direction and 65 openings in the short - axis direction were applied, and for every 5 applications in the short - axis direction, 1 application was skipped, forming Pixel Group 1. As a result, Pixel Group 1 has a periodic structure in the short - axis direction with a period of 6 openings, repeating between the applied openings and the non - applied openings. 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 the coating film> Using a stylus - type step profiler (ET - 200 manufactured by Kosaka Laboratory), seven measurements in the short - axis direction of the obtained organic film were taken. One with less noise was selected from the three measurement results excluding the organic film next to the non - applied opening, and used as 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, with the length of the organic film satisfying the condition Tm < T < Tm + 15 nm defined as Lf and the length of the opening defined as Lо, the flatness F was derived from the following formula (1).

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

[0641] (Example 2) Except for using hole transport material P-2 with an average molecular weight of 40k instead of hole transport material P-1 used in Example 1, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0642] [ka]

[0643] (Example 3) Except for using hole transport material P-3 with an average molecular weight of 15k instead of hole transport material P-1 used in Example 1, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0644] [ka]

[0645] (Example 4) Except for using hole transport material P-4 with an average molecular weight of 40k instead of hole transport material P-1 used in Example 1, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0646] [ka]

[0647] (Example 5) Except for the fact that the ratio of hole transport material P-1 and electron acceptor compound D-1 used in Example 1 was set to 100:0 by weight, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0648] (Example 6) Except for using electron-accepting compound D-2 instead of electron-accepting compound D-1 as in Example 1, the organic film was manufactured using the same procedure as in Example 1, and the flatness was quantified.

[0649] [ka]

[0650] (Example 7) The organic film was manufactured using the same procedure as in Example 1, except that 1,1-diphenylpentane was replaced with mixed solvent 1 of 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) Except for replacing butyl benzoate with diphenyl ether in solvent 1 used in Example 1, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0653] (Example 9) Except for changing the ratio of 1,1-diphenylpentane to butyl benzoate in solvent 1 used in Example 1 to 50:50, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0654] (Example 10) Except for changing the ratio of 1,1-diphenylpentane to butyl benzoate in solvent 1 used in Example 1 to 5:95, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0655] (Example 11) Except for changing the hole transport material used in Example 1 to P-5 and changing the weight ratio of the hole transport material P-5 to the electron acceptor compound D-1 to 100:0, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0656] [ka]

[0657] (Comparative Example 1) Except for replacing 1,1-diphenylpentane with 4-butylbiphenyl in solvent 1 used in Example 1, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

[0658] (Comparative Example 2) Except for changing the weight ratio of the hole transport material P-1 and electron acceptor compound D-1 used in Example 1 to 100:0, and replacing 1,1-diphenylpentane in the mixed solvent used in Example 1 with 4-butylbiphenyl, the organic film was manufactured using the same process as in Example 1, and the flatness was quantified.

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

[0660] [Table 1]

[0661] [Table 2]

[0662] [Table 3]

[0663] [Table 4]

[0664] As shown in the table above, organic films prepared using the solvent represented by formula (1) exhibit higher flatness compared to organic films prepared 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 invention. This application is based on Japanese Patent Application No. 2020-165309 and Japanese Patent Application No. 2020-165310, filed on September 30, 2020, the contents of which are incorporated herein by reference. [Explanation of Symbols]

[0666] 1 circuit board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6. Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent element

Claims

1. The material comprises a functional material and a solvent compound for organic electroluminescent devices represented by the following formula (1), The functional material includes at least a hole transport polymer compound, A composition for an organic electroluminescent element, wherein the hole-transport polymer compound is a polymer having a triarylamine structure as a repeating unit. 【Chemistry 1】 (In formula (1), R １ , R ２ , R ３ , n １ , m １ It satisfies either (i) or (ii) below. (i) R １ This represents an alkyl group with 1 to 6 carbon atoms. R ２ Each of these independently represents an alkyl group having 1 to 3 carbon atoms. n １ The integers 1 through 5 represent integers from 1 to 5. R ３ does not exist, that is, m １ = 0. (ii) R １ This represents an alkyl group with 2 to 6 carbon atoms. R ２ , R ３ Each of these independently represents an alkyl group having 1 to 3 carbon atoms. n １ , m １ (This represents an integer between 0 and 5.)

2. The organic electroluminescent device composition according to claim 1, wherein the repeating unit triarylamine structure comprises at least a repeating unit selected from the repeating units represented by the following formula (54), the repeating unit represented by the following formula (55), the repeating unit represented by the following formula (56), and the repeating unit represented by the following formula (57). 【Transformation 5】 (In formula (54), Ar ５１ This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a group formed by linking multiple groups selected from optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups. X is -C(R ２０７ ) (Caution ２０８ )-,-N(R ２０９ ) - or - C (R ２１１ ) (Caution ２１２ )-C(R ２１３ ) (Caution ２１４ ) - and R ２０１ , R ２０２ , R ２２１ and R ２２２ Each of these is an alkyl group which may have substituents, R ２０７ ~R ２０９ and R ２１１ ~R ２１４ Each of these is independently 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 independent integers between 0 and 4. c is an integer between 0 and 3. d is an integer between 0 and 4. i and j are independent integers between 0 and 3. 【Transformation 6】 (In formula (55), Ar ５１ Ar in formula (54) ５１ It is similar to, R ３０３ and R ３０６ Each of these is an alkyl group which may have substituents, R ３０４ and R ３０５ Each of these is an alkyl group which may have substituents, An alkoxy group which may have substituents or an aralkyl group which may have substituents, l is either 0 or 1. m is either 1 or 2. n is either 0 or 1, p is either 0 or 1, q is either 0 or 1. 【Transformation 7】 (In formula (56), Ar ５１ Ar in formula (54) ５１ It is similar to, Ar ４１ This is a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is directly or via a linking group, R ４４１ and R ４４２ Each of these is an alkyl group which may have substituents, t is either 1 or 2. u is either 0 or 1, r and s are each independent integers between 0 and 4. 【Transformation 8】 (In formula (57), Ar ５１ Ar in formula (54) ５１ It is similar to, R ５１７ ~R ５１９ Each of these independently represents an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aralkyl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. f, g, and h each independently represent integers from 0 to 4. e represents an integer between 0 and 3. However, if g is 1 or greater, then e is 1 or greater.

3. In the repeating unit represented by formula (54), the repeating unit represented by formula (55), the repeating unit represented by formula (56), and the repeating unit represented by formula (57), Ar ５１ The organic electroluminescent element composition according to claim 2, wherein the group is selected from a group comprising a monovalent or divalent group having 2 to 5 linked benzene rings which may have substituents, a fluorenyl group which may have substituents, 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 the bond with the nitrogen atom of the main chain in formulas (54), (55), (56), and (57). Ar ５３ Ar ５４ Each of these independently represents a divalent aromatic hydrocarbon group which may have substituents, a heterocyclic aromatic group which may have substituents, or a divalent group in which a plurality of heterocyclic aromatic hydrocarbon groups which may have substituents are directly or via linking groups. Ar ５５ This represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group is directly or via a linking group. Ar ５６ (This represents a hydrogen atom or substituent.) 【Chemistry 10】 (In formula (52), Ar ６１ and Ar ６２ Each of these is independently a divalent aromatic hydrocarbon group which may have substituents, a divalent aromatic heterocyclic group which may have substituents, or a divalent group in which a plurality of aromatic hydrocarbon groups or aromatic heterocyclic groups which may have substituents are linked directly or via linking groups. Ar ６３ ~Ar ６５ Each of these is independently a hydrogen atom or a substituent. * indicates the bond position of the main chain to the nitrogen atom in formulas (54), (55), (56), and (57). 【Chemistry 11】 (In formula (53), * represents the bond with the nitrogen atom of the main chain in formulas (54), (55), (56), and (57). Ar ７１ This represents a divalent aromatic hydrocarbon group which may have substituents, Ar ７２ and Ar ７３ Each of these independently represents an optionally substituted aromatic hydrocarbon group, an optionally substituted aromatic heterocyclic group, or a monovalent group in which two or more groups selected from an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group are linked directly or via linking groups. The ring HA is an aromatic heterocycle containing a nitrogen atom. X ２ , Y ２ Each of these independently represents a carbon atom or a nitrogen atom, and X ２ and Y ２ If at least one of them is a carbon atom, that carbon atom may have substituents.

4. The organic electroluminescent element composition according to any one of claims 1 to 3, wherein the weight-average molecular weight of the polymer having the triarylamine structure as a repeating unit is 50,000 or less.

5. The organic electroluminescent light-emitting composition according to claim 2 or 3, wherein the repeating unit triarylamine structure includes a repeating unit represented by formula (54).

6. Furthermore, it contains solvent B, The composition for an organic electroluminescent element according to any one of claims 1 to 5, wherein the solvent B is a solvent compound with a boiling point of 200°C or higher that is different from the solvent compound.

7. The organic electroluminescent element composition according to claim 6, wherein the total content of the solvent compound and the solvent B relative to the total amount of solvent contained in the composition is 50% by weight or more.

8. The organic electroluminescent element composition according to claim 6 or claim 7, wherein the viscosity of solvent B at 23°C is 5 mPas or less.

9. The organic electroluminescent element composition according to any one of claims 6 to 8, wherein the boiling point a of the solvent compound and the boiling point b of the solvent B satisfy boiling point b < boiling point a.

10. The organic electroluminescent element composition according to claim 9, wherein the difference between the boiling point a and the boiling point b is 10°C or more.

11. The organic electroluminescent element composition according to claim 9 or 10, wherein the boiling point a is in the range of 270°C to 340°C, and the boiling point b is in the range of 250°C to 340°C.

12. A method for manufacturing an organic electroluminescent element, comprising the step of wet-forming a film using the organic electroluminescent element composition described in any one of claims 1 to 11.

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