JPWO2020027262A1 - Charge transporting composition - Google Patents

Abstract

For example, a charge transporting composition containing an aniline derivative represented by the following formula is provided. (In the formula, Ph is a phenyl group.)

Description

The present invention relates to charge transporting compositions.

In recent years, charge-transporting thin films used in organic electroluminescence (hereinafter, also referred to as organic EL) devices are transparent in the visible region because their coloring reduces the color purity and color reproducibility of organic EL devices. It is desired that the rate is high and the transparency is excellent (Patent Document 1). In view of this point, the applicant has already found a material for a wet process that provides a charge-transporting thin film having excellent transparency and suppressed coloring in the visible region (Patent Documents 1 and 2).

On the other hand, various incorporations have been made so far in order to improve the performance of organic EL elements, but efforts are being made to adjust the refractive index of the functional film used for the purpose of improving the light extraction efficiency. .. Specifically, by using a hole injection layer or a hole transport layer having a relatively high or low refractive index in consideration of the overall configuration of the device and the refractive index of other adjacent members, the efficiency of the device is high. Attempts have been made to achieve this (for example, Patent Documents 3 and 4). As described above, the refractive index is an important factor in the design of the organic EL element, and in the material for the organic EL element, the refractive index is also considered to be an important physical property value to be considered.

International Publication No. 2013/0426223 International Publication No. 2008/032616 Special table 2007-536718 Special table 2017-501585

The present invention has been made in view of the above circumstances, and provides a thin film having good charge transportability, low extinction coefficient (k), good transparency, and high refractive index (n). It is an object of the present invention to provide a charge transporting composition capable of realizing an organic EL device having excellent properties when applied to a hole injection layer or the like.

As a result of diligent studies to achieve the above object, the present inventor has determined a predetermined aniline having an N, N, N', N'-tetra (carbazole-2-yl) -paraphenylenediamine structure in the molecule. The charge transporting composition containing the derivative only provides a charge transporting thin film having a low extinction coefficient (k), good transparency, and a high refractive index (n) as compared with the case where an aniline derivative having a similar structure is used. The present invention has been completed by finding that the composition itself is excellent in storage stability and that an organic EL element having excellent properties is provided when the charge transporting thin film is applied to a hole injection layer or the like. I let you.

［式中、各Ａｒは、互いに独立に、下記式（Ａｒ１）〜（Ａｒ９）のいずれかで表される基である。

（式中、Ｒ¹〜Ｒ²¹は、互いに独立に、水素原子、Ｚ¹で置換されていてもよい炭素数１〜２０のアルキル基、Ｚ¹で置換されていてもよい炭素数２〜２０のアルケニル基、Ｚ¹で置換されていてもよい炭素数２〜２０のアルキニル基、Ｚ²で置換されていてもよい炭素数６〜２０のアリール基又はＺ²で置換されていてもよい素数２〜２０のヘテロアリール基であり、
Ｚ¹は、ハロゲン原子、ニトロ基、シアノ基、Ｚ³で置換されていてもよい炭素数６〜２０のアリール基又はＺ³で置換されていてもよい炭素数２〜２０のヘテロアリール基であり、
Ｚ²は、ハロゲン原子、ニトロ基、シアノ基、Ｚ³で置換されていてもよい炭素数１〜２０のアルキル基、Ｚ³で置換されていてもよい炭素数２〜２０のアルケニル基又はＺ³で置換されていてもよい炭素数２〜２０のアルキニル基であり、
Ｚ³は、ハロゲン原子、ニトロ基又はシアノ基である。）］
２．Ａｒが、全て同じ基である１の電荷輸送性組成物。
３．Ａｒが、式（Ａｒ１）〜（Ａｒ５）のいずれかで表される基である２の電荷輸送性組成物。
４．Ａｒが、式（Ａｒ１）で表される基である３の電荷輸送性組成物。
５．更に、ドーパントを含む１〜４のいずれかの電荷輸送性組成物。
６．前記ドーパントが、アリールスルホン酸エステル化合物である５の電荷輸送性組成物。
７．１〜５のいずれかの電荷輸送性組成物を用いて作製される電荷輸送性薄膜。
８．７の電荷輸送性薄膜を備える有機ＥＬ素子。Therefore, the present invention provides the following charge transporting compositions.
1. 1. A charge transporting composition containing an aniline derivative represented by the following formula (1).

[In the formula, each Ar is a group represented by any of the following formulas (Ar1) to (Ar9) independently of each other.

(Wherein, R ¹ to R ²¹ are each independently a hydrogen atom, an alkyl group having carbon atoms which may be have 1-20 substituted with Z ^1, Z ¹ carbon atoms which may be substituted with 2-20 alkenyl groups, Z ¹ in the optionally substituted alkynyl group having 2 to 20 carbon atoms also may prime be substituted by an aryl group, or Z ² having 6 to 20 carbon atoms which may be substituted with Z ² 2 to 20 heteroaryl groups,
Z ¹ is a halogen atom, a nitro group, a cyano group, a heteroaryl group Z ³ aryl group, or Z ³ may C2-20 optionally substituted with from 6 to 20 carbon atoms which may be substituted with can be,
Z ² is a halogen atom, a nitro group, a cyano group, Z ³ in the optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group which may C2-20 optionally substituted by Z ³ or Z It is an alkynyl group having 2 to 20 carbon atoms which may be substituted with ^3.
Z ³ is a halogen atom, a nitro group or a cyano group. )]
2. A charge-transporting composition in which Ar is the same group.
3. 3. A charge transporting composition of 2 in which Ar is a group represented by any of the formulas (Ar1) to (Ar5).
4. A charge-transporting composition of 3 in which Ar is a group represented by the formula (Ar1).
5. Further, any of 1 to 4 charge transporting compositions comprising a dopant.
6. 5 charge-transporting composition in which the dopant is an aryl sulfonic acid ester compound.
A charge-transporting thin film prepared by using any of the charge-transporting compositions of 7.1 to 5.
An organic EL device including a charge transporting thin film of 8.7.

By using the charge transporting composition of the present invention, a charge having high transparency (low extinction coefficient (k)) and high refractive index (n) as compared with the case of using a composition containing an aniline derivative having a similar structure. A transportable thin film can be produced. Further, the charge transporting composition of the present invention is excellent in storage stability as compared with the composition containing an aniline derivative having a similar structure. The charge-transporting thin film obtained from the charge-transporting composition of the present invention can be suitably used as a thin film for electronic devices such as organic EL devices, and is provided between the anode and the light emitting layer of the organic EL device. By using it as a functional layer, particularly a hole injection layer, an organic EL device having excellent characteristics can be obtained.

[Charge transporting composition]
The charge transporting composition of the present invention contains an aniline derivative represented by the following formula (1).

In the formula (1), each Ar is a group represented by any of the following formulas (Ar1) to (Ar9) independently of each other.

Wherein (Ar1) ~ (Ar9), R 1 ~R 21 independently represent a hydrogen atom, an alkyl group having carbon atoms which may be have 1-20 substituted with Z ^1, optionally substituted by Z ¹ an alkenyl group having 2 to 20 carbon atoms, substituted with an aryl group, or Z ² in Z ¹ in optionally substituted alkynyl group having 2 to 20 carbon atoms, Z ² carbon atoms which may be substituted with 6-20 It is a heteroaryl group having 2 to 20 carbon atoms which may be used. Z ¹ is a halogen atom, a nitro group, a cyano group, a heteroaryl group Z ³ aryl group, or Z ³ may C2-20 optionally substituted with from 6 to 20 carbon atoms which may be substituted with be. Z ² is a halogen atom, a nitro group, a cyano group, Z ³ in the optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group which may C2-20 optionally substituted by Z ³ or Z It is an alkynyl group having 2 to 20 carbon atoms which may be substituted with ^3. Z ³ is a halogen atom, a nitro group or a cyano group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

The alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group and isobutyl. Group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, etc. Chain or branched alkyl groups; cyclic alkyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group and the like can be mentioned.

The alkenyl group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include an ethenyl group, an n-1-propenyl group, an n-2-propenyl group and 1-methylethenyl. Group, n-1-butenyl group, n-2-butenyl group, n-3-butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, 1-methyl- Examples thereof include 1-propenyl group, 1-methyl-2-propenyl group, n-1-pentenyl group, n-1-decenyl group and the like.

The alkynyl group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include an ethynyl group, an n-1-propynyl group, an n-2-propynyl group and an n-1. − Butynyl group, n-2-butynyl group, n-3-butynyl group, 1-methyl-2-propynyl group, n-1-pentynyl group, n-2-pentynyl group, n-3-pentynyl group, n- 4-pentynyl group, 1-methyl-n-butynyl group, 2-methyl-n-butynyl group, 3-methyl-n-butynyl group, 1,1-dimethyl-n-propynyl group, n-1-hexynyl group, Examples thereof include an n-1-decynyl group.

Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group and a 1-phenanthryl group. , 2-Phenyltril group, 3-Phenyltril group, 4-Phenyltril group, 9-Phenyltril group and the like.

Specific examples of the heteroaryl group having 2 to 20 carbon atoms include 2-thienyl group, 3-thienyl group, 2-furanyl group, 3-furanyl group, 2-oxazolyl group, 4-oxazolyl group and 5-oxazolyl group. , 3-Isooxazolyl group, 4-Ioxazolyl group, 5-Isooxazolyl group and other oxygen-containing heteroaryl groups, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5- Sulfur-containing heteroaryl group such as isothiazolyl group, 2-imidazolyl group, 4-imidazolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 3-pyrazyl group, 5-pyrazyl group, 6-Pyridyl group, 2-pyrimidyl group, 4-pyrimidyl group, 5-pyrimidyl group, 6-pyrimidyl group, 3-pyridadyl group, 4-pyridadyl group, 5-pyridadyl group, 6-pyridadyl group, 1,2,3 -Triazine-4-yl group, 1,2,3-triazine-5-yl group, 1,2,4-triazine-3-yl group, 1,2,4-triazine-5-yl group, 1,2 , 4-Triazine-6-yl group, 1,3,5-triazine-2-yl group, 1,2,4,5-tetrazine-3-yl group, 1,2,3,4-tetrazine-5-yl group Il group, 2-quinolinyl group, 3-quinolinyl group, 4-quinolinyl group, 5-quinolinyl group, 6-quinolinyl group, 7-quinolinyl group, 8-quinolinyl group, 1-isoquinolinyl group, 3-isoquinolinyl group, 4- Isoquinolinyl group, 5-isoquinolinyl group, 6-isoquinolinyl group, 7-isoquinolinyl group, 8-isoquinolinyl group, 2-quinoxanyl group, 5-quinoxanyl group, 6-quinoxanyl group, 2-quinazolinyl group, 4-quinazolinyl group, 5- Includes quinazolinyl group, 6-quinazolinyl group, 7-quinazolinyl group, 8-quinazolinyl group, 3-cinnolinyl group, 4-cinnolinyl group, 5-cinnolinyl group, 6-cinnolinyl group, 7-cinnolinyl group, 8-cinnolinyl group and the like. Examples thereof include a nitrogen heteroaryl group.

Among these, as R ¹ to R ^21, an aryl group of Z ² are carbon atoms which may have 6 to 20 substituted with a heteroaryl group optionally 2 to 20 carbon atoms optionally substituted by Z ² preferably, Z more preferably an aryl group having 6 to 20 carbon atoms optionally substituted by ² phenyl group which may be substituted with Z ^2, which may be substituted with Z ² 1-naphthyl group, substituted with Z ² 2-naphthyl groups, which may be used, are even more preferred. As the Z ^2, a halogen atom, Z ³ in the optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group of Z ³ may C2-20 optionally substituted with are preferred. As Z ³ , a halogen atom is preferable, and a fluorine atom is more preferable.

In the present invention, from the viewpoint of easiness of synthesizing the aniline derivative, it is preferable that Ar is all the same group. Further, from the viewpoint of improving the solubility of the aniline derivative in an organic solvent and obtaining a highly uniform composition with good reproducibility, the group represented by any of the formulas (Ar1) to (Ar5) is preferable, and the group represented by the formula (Ar1) to (Ar5) is preferable. The group represented by Ar1) is optimal.

（式中、Ｐｈは、フェニル基である。）Hereinafter, specific examples of aniline derivatives suitable in the present invention will be given, but the present invention is not limited thereto.

(In the formula, Ph is a phenyl group.)

The aniline derivative used in the present invention is a para-phenylenediamine (1,4-phenylenediamine) and a halogenated or pseudohalogenated carbazole derivative Ar-X (Ar is the same as above. X is a halogen atom) in the presence of a catalyst. Alternatively, it can be produced by reacting with a pseudohalogen group).

Examples of the halogen atom include the same as above, but chlorine atom, bromine atom and iodine atom are preferable. Examples of the pseudo-halogen group include (fluoro) alkylsulfonyloxy groups such as methanesulfonyloxy group, trifluoromethanesulfonyloxy group and nonafluorobutanesulfonyloxy group; aromatic sulfonyloxy groups such as benzenesulfonyloxy group and toluenesulfonyloxy group. And so on.

The charge ratio of 1,4-phenylenediamine to the halogenated or pseudohalogenated carbazole derivative shall be equal to or greater than the amount of the halogenated or pseudohalogenated carbazole derivative with respect to the amount of substance of the total NH groups of 1,4-phenylenediamine. However, about 1 to 1.2 equivalents are preferable.

Examples of the catalyst used in the reaction include copper catalysts such as copper chloride, copper bromide and copper iodide; tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ) and bis (triphenylphosphine) dichloropalladium. (Pd (PPh ₃ ) ₂ Cl ₂ ), bis (dibenzylideneacetone) palladium (Pd (dba) ₂ ), tris (dibenzylideneacetone) dipalladium (Pd ₂ (dba) ₃ ), bis [tri (t-butyl) Phosphine)] Palladium catalysts such as palladium (Pd (Pt-Bu ₃ ) ₂ ) and palladium acetate (Pd (OAc) ₂ ) can be mentioned. These catalysts may be used alone or in combination of two or more.

These catalysts may also be used with suitable known ligands. Examples of such ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-t-butylphosphine, and di-t-butyl ( Phosphine, di-t-butyl (4-dimethylaminophenyl) phosphine, 1,2-bis (diphenylphosphine) ethane, 1,3-bis (diphenylphosphine) "propane, 1,4-bis (diphenyl) Examples thereof include tertiary phosphine such as phosphine) butane, 1,1'-bis (diphenylphosphine) ferrocene, and tertiary phosphine such as trimethylphosphine, triethylphosphine, and triphenylphosphine.

The amount of the catalyst used can be about 0.01 to 0.2 mol with respect to 1 mol of the halogenated or pseudohalogenated carbazole derivative, but about 0.15 mol is preferable.
When a ligand is used, the amount used can be 0.1 to 5 equivalents with respect to the catalyst to be used, but 1 to 2 equivalents are preferable.

Each of the above reactions is carried out in a solvent when all the raw material compounds are solid or from the viewpoint of efficiently obtaining the desired aniline derivative. When a solvent is used, the type is not particularly limited as long as it does not adversely affect the reaction. Specific examples include aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decalin, etc.), halogenated aliphatic hydrocarbons (chloroform, dichloromethane, dichloroethane, carbon tetrachloride, etc.), and aromatics. Group hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesityrene, etc.), halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, etc.) p-dichlorobenzene, etc.), ethers (diethyl ether, diisopropyl ether, t-butylmethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), ketones (acetone, methylethylketone, etc.) Methylisobutyl ketone, di-n-butyl ketone, cyclohexanone, etc.), amides (N, N-dimethylformamide, N, N-dimethylacetamide, etc.), lactam and lactones (N-methylpyrrolidone, γ-butyrolactone, etc.), urea Classes (N, N-dimethylimidazolidinone, tetramethylurea, etc.), sulfoxides (dimethylsulfoxide, sulfolane, etc.), nitriles (acetoyl, propionitrile, butyronitrile, etc.), and the like, but are not limited thereto. These solvents may be used alone or in combination of two or more.

The reaction temperature may be appropriately set in the range from the melting point to the boiling point of the solvent to be used, but is usually in the range of about 0 to 200 ° C, preferably in the range of 20 to 150 ° C. After completion of the reaction, post-treatment can be carried out according to a conventional method to obtain the desired aniline derivative.

The charge transporting composition of the present invention contains an organic solvent. As such an organic solvent, a highly soluble solvent capable of satisfactorily dissolving the aniline derivative represented by the formula (1), which is a charge transporting substance, can be used. Specific examples of the highly soluble solvent include, for example, cyclohexanone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylisobutyramide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazole. Examples include, but are not limited to, organic solvents such as lydinone and diethylene glycol monomethyl ether. These solvents may be used alone or in combination of two or more. The amount used can be 5 to 100% by mass based on the total amount of the solvent used in the composition.

Further, the composition has a viscosity of 10 to 200 mPa · s at 25 ° C., particularly 35 to 150 mPa · s, and a high viscosity organic solvent having a boiling point of 50 to 300 ° C., particularly 150 to 250 ° C. at normal pressure (atmospheric pressure). By containing at least one of the above, the viscosity of the composition can be easily adjusted, and as a result, the composition can be prepared according to the coating method to be used, which gives a thin film having high flatness with good reproducibility. Examples of the high-viscosity organic solvent include cyclohexanol, ethylene glycol, ethylene glycol diglycidyl ether, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and 1,3-butanediol. Examples thereof include, but are not limited to, 2,3-butanediol, 1,4-butanediol, propylene glycol, and hexylene glycol. These solvents may be used alone or in combination of two or more. The addition ratio of the high-viscosity organic solvent to the entire solvent used in the composition is preferably within the range in which the solid does not precipitate, and the addition ratio is preferably 5 to 80% by mass as long as the solid does not precipitate.

Further, for the purpose of improving the wettability with respect to the substrate, adjusting the surface tension of the solvent, adjusting the polarity, adjusting the boiling point, etc., other solvents are preferably added in an amount of 1 to 90% by mass, preferably 1 to 90% by mass, based on the total amount of the solvent used in the composition. Can also be mixed in a proportion of 1 to 50% by mass. Examples of such a solvent include propylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and diethylene glycol. Examples thereof include, but are not limited to, monoethyl ether, diacetone alcohol, γ-butylollactone, ethyllactate, n-hexyl acetate and the like. These solvents may be used alone or in combination of two or more.

Further, the aniline derivative represented by the formula (1) is substituted on at least one nitrogen atom in the molecule, for example, when it has an aryl group on the nitrogen atom at the 9-position of the carbazole moiety in the molecule. When it has a group, preferably when it has a substituent on all nitrogen atoms, it is easy to prepare a composition using only a low polar solvent. Specific examples of such low-polarity solvents include chlorine-based solvents such as chloroform and chlorobenzene; aromatic hydrocarbon-based solvents such as toluene, xylene, tetraline, cyclohexylbenzene and decylbenzene; 1-octanol, 1-nonanol, 1 -Adioxide-based solvent such as decanol; tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, etc. Ether-based solvents; methyl benzoate, ethyl benzoate, butyl benzoate, dimethyl phthalate, diethyl maleate, isoamyl benzoate, bis (2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol Examples thereof include, but are not limited to, ester solvents such as monoethyl ether acetate and diethylene glycol monobutyl ether acetate. These solvents may be used alone or in combination of two or more.

The charge transporting composition of the present invention may contain water as a solvent, but when the charge transporting thin film obtained from the composition is used as the hole injection layer of the organic EL device, a highly durable device can be reproduced with good reproducibility. From the viewpoint of obtaining water, the content of water is preferably 10% by mass or less, more preferably 5% by mass or less of the total solvent, and it is optimal to use only an organic solvent as the solvent. In this case, "only the organic solvent" means that only the organic solvent is used as the solvent, and even the existence of "water" contained in a trace amount in the organic solvent used, the solid content, etc. is denied. It's not something to do. Further, in the present invention, the solid content means a component other than the solvent contained in the charge transporting composition.

The charge-transporting composition of the present invention may contain other charge-transporting substances as well as the charge-transporting substance composed of the aniline derivative represented by the formula (1).

The charge-transporting composition of the present invention contains a charge-transporting substance composed of an aniline derivative represented by the formula (1) and an organic solvent, and its charge-transporting ability is improved depending on the use of the obtained thin film. A dopant (charge-accepting substance) may be contained for the purpose of the above.

The dopant is not particularly limited as long as it is soluble in at least one solvent used in the composition, and either an inorganic dopant or an organic dopant can be used. Further, the inorganic and organic dopants may be used alone or in combination of two or more. Further, in the process of obtaining a charge-transporting thin film which is a solid film from the composition, the dopant first exhibits its function as a dopant by removing a part of the molecule due to an external stimulus such as heating during firing. Alternatively, it may be a substance that improves, for example, an aryl sulfonic acid ester compound protected by a group in which a sulfonic acid group is easily eliminated.

The amount of the dopant substance in the composition cannot be unconditionally specified because it varies depending on the desired degree of charge transportability and the type of the dopant substance, but usually, the mass of the aniline derivative 1 represented by the formula (1) is increased. The ratio is in the range of 0.0001 to 100.

In the present invention, a preferred inorganic dopant is a heteropolyacid. The heteropolyacid has a structure in which a hetero atom is located at the center of a molecule, which is typically represented by a Keggin type chemical structure represented by the following formula (H1) or a Dawson type chemical structure represented by the following formula (H2). However, it is a polyacid formed by condensing isopolyacid, which is an oxygen acid such as vanadium (V), molybdenum (Mo), and tungsten (W), and oxygen acid, which is a heterogeneous element. Oxygen acids of such dissimilar elements mainly include oxygen acids of silicon (Si), phosphorus (P), and arsenic (As).

Specific examples of the heteropolyacid include phosphomolybdic acid, silicate molybdic acid, phosphotungstic acid, silicate tungstic acid, phosphotungstic acid, and the like. These heteropolyacids may be used alone or in combination of two or more. In addition, these heteropolyacids are available as commercial products, and can also be synthesized by a known method.

In particular, when one kind of heteropolyacid is used, the one kind of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and phosphotungstic acid is most suitable. When two or more kinds of heteropolyacids are used, one of the two or more kinds of heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.

In addition, in quantitative analysis such as elemental analysis, heteropolyacids have a large number of elements or a small number of elements from the structure represented by the general formula, but they are commercially available products or known synthetics. As long as it is properly synthesized according to the method, it can be used in the present invention. That is, for example, in general, phosphotungstic acid is represented by the chemical formulas H ₃ (PW ₁₂ O ₄₀ ) and nH ₂ O, and phosphomolybdic acid is represented by the chemical formulas H ₃ (PMo ₁₂ O ₄₀ ) and nH ₂ O, respectively. , Even if the number of P (phosphorus), O (oxygen) or W (tungsten) or Mo (molybdenum) in this formula is large or small in the quantitative analysis, it is obtained as a commercial product. Alternatively, it can be used in the present invention as long as it is appropriately synthesized according to a known synthesis method. In this case, the mass of the heteropolyacid defined in the present invention is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in the synthetic product or the commercially available product, but the form available as the commercially available product and the known synthesis. In a form that can be isolated by the method, it means the total mass in a state containing hydrated water and other impurities.

When a heteropolyacid is used as the dopant, the amount used can be about 0.001 to 50.0 in terms of mass ratio with respect to the aniline derivative 1 represented by the formula (1), but is preferably 0. It is about .01 to 20.0, more preferably about 0.1 to 10.0.

On the other hand, preferred organic dopants include tetracyanoquinodimethane derivatives and benzoquinone derivatives. Specific examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ), halotetracyanoquinodimethane represented by the following formula (H3), and the like. Specific examples of benzoquinone derivatives include tetrafluoro-1,4-benzoquinone (F4BQ), tetrachloro-1,4-benzoquinone (chloranil), tetrabromo-1,4-benzoquinone, 2,3-dichloro-5, 6-Dicyano-1,4-benzoquinone (DDQ) and the like can be mentioned.

In formula (H3), R ^{101 to} R ¹⁰⁴ represent hydrogen atoms or halogen atoms independently of each other, but at least one is a halogen atom, at least two are preferably halogen atoms, and at least three are halogen atoms. It is more preferably an atom, and most preferably all of them are halogen atoms. Examples of the halogen atom include the same ones as described above, but a fluorine atom or a chlorine atom is preferable, and a fluorine atom is more preferable.

Specific examples of such halotetracyanoquinodimethane include 2-fluoro-7,7,8,8-tetracyanoquinodimethane and 2-chloro-7,7,8,8-tetracyanoquinodimethane. 2,5-Difluoro-7,7,8,8-Tetracyanoquinodimethane, 2,5-Dichloro-7,7,8,8-Tetracyanoquinodimethane, 2,3,5,6-Tetra Examples thereof include chloro-7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ).

When a tetracyanoquinodimethane derivative or a benzoquinone derivative is used as the dopant, the amount used is 0.01 to 20.0 in terms of the amount of substance (molar) ratio to the aniline derivative 1 represented by the formula (1). It can be about 0.1 to 10.0, more preferably about 0.5 to 5.0.

In addition, examples of other preferable organic dopants include aryl sulfonic acid compounds. Specific examples thereof include benzenesulfonic acid, tosylic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2 , 5-Dihexylbenzene sulfonic acid, dibutylnaphthalene sulfonic acid, 6,7-dibutyl-2-naphthalene sulfonic acid, dodecylnaphthalene sulfonic acid, 3-dodecyl-2-naphthalene sulfonic acid, hexylnaphthalene sulfonic acid, 4-hexyl-1 -Naphthalene Sulfonic Acid, Octyl Naphthalene Sulfonic Acid, 2-octyl-1-naphthalene Sulfonic Acid, Hexyl Naphthalene Sulfonic Acid, 7-Hexyl-1-naphthalene Sulfonic Acid, 6-Hexyl-2-naphthalene Sulfonic Acid, Dinonyl Naphthalene Sulfonic Acid Acid, 2,7-Dinonyl-4-naphthalene Sulfonic Acid, Dinonyl Naphthalenedi Sulfonic Acid, 2,7-Dinonyl-4,5-Naphthalenedi Sulfonic Acid, 1,4-benzodioxane disulfon described in International Publication No. 2005/000832. Examples thereof include acid compounds, aryl sulfonic acid compounds described in International Publication No. 2006/025342, and aryl sulfonic acid compounds described in International Publication No. 2009/09632.

More specifically, an aryl sulfonic acid compound represented by the following formula (H4) or (H5) can be mentioned.

In the formula (H4), A ¹ represents O or S, but O is preferable. A ² is a (q + 1) -valent group derived from naphthalene or anthracene (that is, a group obtained by removing (q + 1) hydrogen atoms from naphthalene or anthracene), but those derived from naphthalene are preferable. A ³ is a p-valent group derived from perfluorobiphenyl (that is, a group obtained by removing p fluorine atoms from perfluorobiphenyl). p ^{represents the number of bonds between A 1} and A ^3, and is an integer satisfying 2 ≦ p ≦ 4, but 2 is preferable. At this time, A ³ is a perfluorobiphenyldiyl group, preferably a perfluorobiphenyl-4,4'-diyl group. q ^{represents the number of sulfonic acid groups bonded to A 2} , and is an integer satisfying 1 ≦ q ≦ 4, but 2 is optimal.

In the formula (H5), A ^{4 to} A ⁸ are independent of each other, such as a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkyl halide group having 1 to 20 carbon atoms, or 2 to 2 carbon atoms. There are 20 halogenated alkenyl groups, but at least 3 of ^{A 4 to} A ^{8 are halogen atoms.}

Alkyl halide groups having 1 to 20 carbon atoms include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl. 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4 , 4-Pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group and the like. Be done. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include a perfluorovinyl group, a perfluoro-1-propenyl group, a perfluoro-2-propenyl group, a perfluorobutenyl group and the like. Other examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms include the same as described above, but the halogen atom is preferably a fluorine atom.

Among these, A ^{4 to} A ⁸ include a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkyl halide group having 1 to 10 carbon atoms, or an alkenyl halide having 2 to 10 carbon atoms. a group, and a ⁴ is preferably at least three fluorine atoms of to a ^8, a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 5 carbon atoms, fluoride of 1 to 5 carbon atoms It is more preferably an alkyl group or a fluorinated alkenyl group having 2 to 5 carbon atoms, and ^{at least 3 of A 4 to} A ⁸ are fluorine atoms, and hydrogen atom, fluorine atom, cyano group and carbon number. It is even more preferable that it is a perfluoroalkyl group of 1 to 5 or a perfluoroalkenyl group having 1 to 5 carbon atoms, and that A ⁴ , A ⁵ and A ^{8 are fluorine atoms.} The perfluoroalkyl group is a group in which all the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and the perfluoroalkyl group is a group in which all the hydrogen atoms of the alkenyl group are substituted with fluorine atoms.

In the formula (H5), r represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1 ≦ r ≦ 4, but 2 to 4 is preferable, and 2 is optimal.

Hereinafter, specific examples of suitable aryl sulfonic acid compounds will be given, but the present invention is not limited thereto.

When an aryl sulfonic acid compound is used as the dopant, the amount used is preferably about 0.01 to 20.0 in terms of the amount of substance (molar) ratio with respect to the aniline derivative 1 represented by the formula (1). It is preferably about 0.4 to 5.0. A commercially available product may be used as the aryl sulfonic acid compound, but it can also be synthesized by a known method described in International Publication No. 2006/025342, International Publication No. 2009/09632, and the like.

In addition, examples of other preferable organic dopants include aryl sulfonic acid ester compounds. Specific examples thereof include the aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217455, the aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217457, and the like.

More specifically, the aryl sulfonic acid ester compound is preferably one represented by any of the following formulas (H6) to (H8).

In the formulas (H6) to (H8), m is an integer satisfying 1 ≦ m ≦ 4, but 2 is preferable. n is an integer satisfying 1 ≦ n ≦ 4, but 2 is preferable.

In formula (H6), A ¹¹ is an m-valent group derived from perfluorobiphenyl. A ¹² is -O- or -S-, but -O- is preferable. A ¹³ is a (n + 1) -valent group derived from naphthalene or anthracene, but those derived from naphthalene are preferable.

R ^{s1 to} R ^s4 are hydrogen atoms or linear or branched alkyl groups having 1 to 6 carbon atoms independently of each other, and R ^s5 is 1 of 2 to 20 carbon atoms which may be substituted. It is a valent hydrocarbon group. The linear or branched alkyl group having 1 to 6 carbon atoms includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group and a t-butyl group. , N-hexyl group and the like. Of these, alkyl groups having 1 to 3 carbon atoms are preferable. The monovalent hydrocarbon group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and isobutyl. Examples include an alkyl group such as a group and a t-butyl group; and an aryl group such as a phenyl, naphthyl and phenanthryl group.

In particular, ^{among R s1 to} R ^s4 , R ^s1 or R ^s3 is a linear alkyl group having 1 to 3 carbon atoms, and the rest is a hydrogen atom, or R ^s1 is a linear alkyl group having 1 to 3 carbon atoms. It is ^{preferable that R s2 to} R ^s4 are hydrogen atoms. In this case, the methyl group is preferable as the linear alkyl group having 1 to 3 carbon atoms. Further, as R ^s5 , a linear alkyl group or a phenyl group having 2 to 4 carbon atoms is preferable.

In formula (H7), A ¹⁴ is an m-valent hydrocarbon group having 6 to 20 carbon atoms containing one or more aromatic rings which may be substituted, and the hydrocarbon group is one or more. It is a group obtained by removing m hydrogen atoms from a hydrocarbon compound having 6 to 20 carbon atoms containing an aromatic ring. Examples of such hydrocarbon compounds include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, phenanthrene and the like. A part or all of the hydrogen atom of the hydrocarbon group may be further substituted with a substituent, and examples of such a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and a nitro. Group, cyano group, hydroxy group, amino group, silanol group, thiol group, carboxy group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, ester group, thioester group, amide group, monovalent hydrocarbon group, organo Examples thereof include an oxy group, an organoamino group, an organosilyl group, an organothio group, an acyl group and a sulfo group. Among these, ^{as A 14} , a group derived from benzene, biphenyl or the like is preferable.

In the formula (H7), A ¹⁵ is −O− or −S−, but −O− is preferable.

In the formula (H7), A ¹⁶ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group is an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing (n + 1) hydrogen atoms from the ring. Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like. Among them, as A ¹⁶ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

In formula (H7), R ^s6 and R ^s7 are hydrogen atoms or linear or branched monovalent aliphatic hydrocarbon groups independently of each other, and R ^s8 is a linear or branched 1 It is an aliphatic hydrocarbon group. However, the total number of carbon atoms of ^{R s6} , R ^s7 and R ^{s8 is 6 or more.} The upper limit of the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is not particularly limited, but is preferably 20 or less, and more preferably 10 or less. Specific examples of the linear or branched monovalent aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, and a t-. Alkyl groups having 1 to 20 carbon atoms such as butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, decyl group; vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1- Examples thereof include alkenyl groups having 2 to 20 carbon atoms such as methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group and hexenyl group. Among these, R ^s6 is preferably a hydrogen atom, and R ^s7 and R ^s8 are preferably alkyl groups having 1 to 6 carbon atoms independently of each other.

In the formula (H8), R ^{s9 to} R ^s13 are independent of each other, such as a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms. It is a halogenated alkenyl group having 2 to 10 carbon atoms.

The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Group, s-butyl group, t-butyl group, n-pentyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group and the like. Be done.

The alkyl halide group having 1 to 10 carbon atoms is not particularly limited as long as it is a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are substituted with a halogen atom. Specific examples thereof include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 3,3,3-trifluoropropyl group, and a 2,2. 2,3,3,3-pentafluoropropyl group, 1,1,2,2,3,3,3-heptafluoropropyl group, 4,4,4-trifluorobutyl group, 3,3,4,4 , 4-Pentafluorobutyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, etc. Can be mentioned.

The halogenated alkenyl group having 2 to 10 carbon atoms is not particularly limited as long as it is a group in which a part or all of the hydrogen atoms of the alkenyl group having 2 to 10 carbon atoms are substituted with halogen atoms. Specific examples thereof include a perfluorovinyl group, a perfluoro-1-propenyl group, a perfluoro-2-propenyl group, a perfluoro-1-butenyl group, a perfluoro-2-butenyl group, and a perfluoro-3-butenyl group. And so on.

Among these, ^{as R s9} , a nitro group, a cyano group, an alkyl halide group having 1 to 10 carbon atoms, and an alkenyl halide group having 2 to 10 carbon atoms are preferable, and a nitro group, a cyano group, and 1 to 4 carbon atoms are preferable. The alkyl halide group and the alkenyl halide group having 2 to 4 carbon atoms are more preferable, and the nitro group, the cyano group, the trifluoromethyl group and the perfluoropropenyl group are even more preferable.

In the formula (H8), as R ^{s10 to} R ^s13 , a halogen atom is preferable, and a fluorine atom is more preferable.

In formula (H8), A ¹⁷ is -O-, -S- or -NH-, but -O- is preferable.

In the formula (H8), A ¹⁸ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group is an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing (n + 1) hydrogen atoms from the ring. Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like. Among these, ^{as A 18} , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

In the formula (H8), R ^{s14 to} R ^s17 are hydrogen atoms or linear or branched monovalent aliphatic hydrocarbon groups having 1 to 20 carbon atoms independently of each other. Specific examples of the monovalent aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group and an n-pentyl group. Alkyl group having 1 to 20 carbon atoms such as cyclopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group and n-dodecyl group. 2 to 2 carbon atoms of vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, hexenyl group, etc. 20 alkenyl groups and the like can be mentioned. Of these, an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable, and an alkyl group having 1 to 8 carbon atoms is even more preferable.

In formula (H8), R ^s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or OR ^s19 . R ^s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted. ^Examples of the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R s18 include the same groups as described above. When R ^s18 is a monovalent aliphatic hydrocarbon group, R ^s18 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and an alkyl group having 1 to 8 carbon atoms. Even more preferable. The ^{monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R s19} includes an aryl group such as a phenyl group, a naphthyl group, and a phenanthryl group in addition to the above-mentioned monovalent aliphatic hydrocarbon groups other than the methyl group. And so on. Among these, ^{as R s19} , a linear alkyl group or a phenyl group having 2 to 4 carbon atoms is preferable. Examples of the substituent that the monovalent hydrocarbon group may have include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, and a cyano group.

Specific examples of suitable aryl sulfonic acid ester compounds include, but are not limited to, those shown below.

When an aryl sulfonic acid ester compound is used as the dopant, the amount used should be about 0.01 to 20.0 with respect to the aniline derivative 1 represented by the formula (1) in terms of the amount of substance (molar). However, it is preferably about 0.1 to 10.0, and more preferably about 0.5 to 5.0.

When an organic dopant is used as the dopant, its molecular weight is not particularly limited, but when used together with the aniline derivative represented by the formula (1), good solubility in an organic solvent is ensured and uniformity is achieved. From the viewpoint of obtaining a high composition with good reproducibility, it is preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less. In particular, the molecular weight of the aryl sulfonic acid compound used as the dopant is preferably 2,000 or less, more preferably 1,500 or less, from the same viewpoint.

In the present invention, considering that a thin film having high charge transportability can be obtained with good reproducibility, availability of a dopant, and the like are taken into consideration, the dopants include aryl sulfonic acid compound, aryl sulfonic acid ester compound, halotetracyanoquinodimethane, and benzoquinone. It is preferable to use at least one of the derivatives, and further considering that a more transparent charge-transporting thin film can be obtained with good reproducibility, it is more preferable to use at least one of an aryl sulfonic acid compound and an aryl sulfonic acid ester compound. It is even more preferable to use an aryl sulfonic acid ester compound in consideration of obtaining a charge transporting composition having excellent stability.

The charge-transporting substance and the dopant are preferably completely dissolved or uniformly dispersed in the solvent, and most preferably completely dissolved.

The charge-transporting composition of the present invention is an organic silane for the purpose of improving the injection property into the hole-transporting layer when the obtained thin film is used as the hole-injecting layer of the organic EL device, and improving the life characteristics of the device. A compound or a nonionic fluorine-containing surfactant may be contained, and the content thereof is usually about 1 to 30 parts by mass with respect to 100 parts by mass of the total of the charge-transporting substance and the dopant.

The solid content concentration in the charge-transporting composition of the present invention is usually about 0.1 to 20% by mass, preferably 0.5, from the viewpoint of ensuring a sufficient film thickness while suppressing precipitation of the charge-transporting substance. ~ 15% by mass.

The viscosity of the charge transporting composition of the present invention is usually 1 to 50 mPa · s at 25 ° C., and the surface tension is usually 20 to 50 mN / m at 25 ° C. For the viscosity and surface tension of the charge transporting composition of the present invention, the types of organic solvents used, their ratios, solid content concentration, etc. should be changed in consideration of various factors such as the coating method used and the desired film thickness. It can be adjusted with.

The charge transporting composition of the present invention can be produced by dissolving the aniline derivative represented by the formula (1) in an organic solvent. The aniline derivative may be dissolved in an organic solvent in advance, and other organic solvents may be added thereto in sequence, or a mixed solvent of all the solvents to be used may be prepared in advance and the aniline derivative may be dissolved therein. Further, if necessary, care may be taken not to decompose or deteriorate the components contained in the composition, and heating may be carried out to promote the dissolution of the aniline derivative or the like. When the charge transporting composition of the present invention contains components other than the aniline derivative and the solvent, the same method is followed. Further, in the charge transporting composition of the present invention, from the viewpoint of obtaining a thin film having higher flatness with good reproducibility, the charge transporting substance is dissolved in an organic solvent and then filtered using a filter on the order of submicrometers or the like. You may.

[Charge transport thin film]
By applying the charge transporting composition of the present invention on a base material and firing it, a charge transporting thin film can be formed on the base material.

The coating method of the composition is not particularly limited, and examples thereof include a dip method, a spin coating method, a transfer printing method, a roll coating method, an inkjet method, a spray method, and a slit coating method. It is preferable to adjust the viscosity and surface tension of the composition according to the coating method.

The firing atmosphere is not particularly limited, and a thin film having a uniform film-forming surface and charge transportability can be obtained not only in the atmospheric atmosphere (under air) but also under an inert gas such as nitrogen or in a vacuum, but usually in the atmosphere. Bake in the atmosphere.

Further, the firing conditions are not particularly limited, but for example, heating and firing using a hot plate is performed. Usually, the firing temperature is appropriately determined within the range of 100 to 260 ° C., and the firing time is appropriately determined within the range of 1 minute to 1 hour in consideration of desired charge transportability and the like. Further, if necessary, multi-step firing may be performed at two or more different temperatures.

The film thickness of the charge transporting thin film is not particularly limited, but is preferably 5 to 300 nm when used as a functional layer of an organic EL element. As a method of changing the film thickness, for example, there is a method of changing the solid content concentration in the charge transporting composition or changing the amount of liquid at the time of coating.

[Organic EL element]
The organic EL device of the present invention has a pair of electrodes, and the charge-transporting thin film of the present invention is provided as a functional layer between these electrodes.

Typical configurations of the organic EL element include, but are not limited to, the following (a) to (f). In the following configuration, if necessary, an electron block layer or the like may be provided between the light emitting layer and the anode, and a hole block layer or the like may be provided between the light emitting layer and the cathode. Further, the hole injection layer, the hole transport layer or the hole injection transport layer may also have a function as an electron block layer or the like, and the electron injection layer, the electron transport layer or the electron injection transport layer is a hole (hole). It may also have a function as a block layer or the like. Further, if necessary, an arbitrary functional layer can be provided between the layers.
(A) Antenna / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (b) anode / hole injection layer / hole transport layer / light emitting layer / electron injection transport layer / Cathode (c) Electron / hole injection transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (d) anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (e) anode / positive Hole injection layer / hole transport layer / light emitting layer / cathode (f) anode / hole injection transport layer / light emitting layer / cathode

The "hole injection layer", "hole transport layer" and "hole injection transport layer" are layers formed between the light emitting layer and the anode, and transport holes from the anode to the light emitting layer. It has a function. When only one layer of hole transporting material is provided between the light emitting layer and the anode, it is a "hole injection transport layer", and a layer of hole transporting material between the light emitting layer and the anode. When two or more layers are provided, the layer close to the anode is the "hole injection layer", and the other layers are the "hole transport layers". In particular, as the hole injection (transport) layer, a thin film having excellent not only hole acceptability from the anode but also hole injection property into the hole transport (emission) layer is used.

The "electron injection layer", "electron transport layer" and "electron transport layer" are layers formed between the light emitting layer and the cathode and have a function of transporting electrons from the cathode to the light emitting layer. Is. When only one layer of electron transporting material is provided between the light emitting layer and the cathode, it is an "electron injection transporting layer", and two layers of electron transporting material are provided between the light emitting layer and the cathode. When the above is provided, the layer close to the cathode is the "electron injection layer", and the other layers are the "electron transport layer".

The "light emitting layer" is an organic layer having a light emitting function, and includes a host material and a dopant material when a doping system is adopted. At this time, the host material mainly has a function of promoting recombination of electrons and holes and confining excitons in the light emitting layer, and the dopant material efficiently emits excitons obtained by recombination. Has a function. In the case of a phosphorescent device, the host material mainly has a function of confining excitons generated by the dopant in the light emitting layer.

The charge transporting thin film of the present invention is suitable as a functional layer provided between the anode and the light emitting layer in an organic EL device, and is more suitable as a hole injection layer, a hole transport layer, and a hole injection transport layer. , It is more suitable as a hole injection layer.

Examples of materials and methods used when producing an organic EL device using the charge transporting composition of the present invention include, but are not limited to, the following.

An example of a method for producing an OLED device having a hole transport layer made of a thin film obtained from the charge transporting composition of the present invention is as follows. It is preferable that the electrodes are preliminarily cleaned with alcohol, pure water, or the like, or surface-treated with UV ozone treatment, oxygen-plasma treatment, or the like, as long as the electrodes are not adversely affected.

A hole injection layer made of the charge-transporting thin film of the present invention is formed on the anode substrate by the above method. This is introduced into a vacuum vapor deposition apparatus, and a hole transport layer, a light emitting layer, an electron transport layer, an electron transport layer / hole block layer, and a cathode metal are sequentially vapor-deposited. Alternatively, instead of forming the hole transport layer and the light emitting layer by vapor deposition in the method, a composition for forming a hole transport layer containing a hole transport polymer and a composition for forming a light emitting layer containing a light emitting polymer. These layers are formed by a wet process using. If necessary, an electron block layer may be provided between the light emitting layer and the hole transport layer.

Examples of the anode material include transparent electrodes typified by indium tin oxide (ITO) and indium zinc oxide (IZO), and metal anodes composed of metals typified by aluminum and alloys thereof, which are flat. Those that have undergone chemical treatment are preferable. Polythiophene derivatives and polyaniline derivatives having high charge transport properties can also be used. Examples of other metals constituting the metal anode include, but are not limited to, gold, silver, copper, indium, and alloys thereof.

Examples of the material forming the light emitting layer include an aluminum complex of 8-hydroxyquinoline such as tris (8-quinolinolate) aluminum (III) (Alq ₃ ) and bis (8-quinolinolate) zinc (II), and a metal complex such as a zinc complex. Low molecular weight luminescent materials such as metal complexes of 10-hydroxybenzo [h] quinoline, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl) benzothiazole, silol derivatives; poly (p-phenylene vinylene) ), Poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene], poly (3-alkylthiophene), polyvinylcarbazole and other polymer compounds mixed with a luminescent material and an electron transfer material. Systems and the like can be mentioned, but the present invention is not limited to these. When the light emitting layer is formed by vapor deposition, it may be co-deposited with a light emitting dopant, and the light emitting dopant is a metal complex such _{as tris (2-phenylpyridine) iridium (III) (Ir (PPy) 3).} , A naphthacene derivative such as rubrene, a quinacridone derivative, a condensed polycyclic aromatic ring such as perylene, and the like, but are not limited thereto.

Examples of the material for forming the electron transport layer / whole block layer include, but are not limited to, an oxydiazole derivative, a triazole derivative, a phenanthroline derivative, a phenylquinoxaline derivative, a benzimidazole derivative, and a pyrimidine derivative.

Materials for forming the electron injection layer _{include metal oxides such as lithium oxide (Li 2} O), magnesium oxide (Mg O), and alumina (Al ₂ O ₃ ), lithium fluoride (LiF), and sodium fluoride (NaF). Metal fluoride, but is not limited to these.

Examples of the cathode material include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, and the like.

Examples of the material for forming the electron block layer include, but are not limited to, tris (phenylpyrazole) iridium and the like.

Examples of the hole-transporting polymer include poly [(9,9-dihexylfluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,4-diaminophenylene). )], Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,1'-biphenylene-4,4-diamine) )], Poly [(9,9-bis {1'-penten-5'-yl} fluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,4 -Diaminophenylene)], poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) -benzidine] -endcapped with polysilsesquioxane, poly [(9,9) -Didioctylfluorenyl-2,7-diyl) -co- (4,4'-(N- (p-butylphenyl)) diphenylamine)] and the like.

Examples of the luminescent polymer include polyfluorene derivatives such as poly (9,9-dialkylfluorene) (PDAF) and poly (2-methoxy-5- (2'-ethylhexoxy) -1,4-phenylene vinylene) (MEH-). Examples thereof include polyphenylene vinylene derivatives such as PPV), polythiophene derivatives such as poly (3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

The material constituting the anode and the cathode and the layer formed between them differs depending on whether the element having the bottom emission structure or the top emission structure is manufactured. Therefore, the material is appropriately selected in consideration of this point.

Normally, in the element of the bottom emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side, whereas in the element of the top emission structure, a reflective anode made of metal is used and the direction is opposite to that of the substrate. Since light is extracted from a certain transparent electrode (cathode) side, regarding the anode material, when manufacturing an element having a bottom emission structure, a transparent anode such as ITO is used, and when manufacturing an element having a top emission structure, Al / A reflecting anode such as Nd is used respectively.

The organic EL device of the present invention may be sealed together with a water catching agent or the like, if necessary, in accordance with a conventional method in order to prevent deterioration of characteristics.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. The devices used are as follows.
(1) LDI-MS: Bruker's AutoFlex
(2) ¹ H-NMR: JNM-ECP300 FT NMR SYSTEM manufactured by JEOL Ltd.
(3) Substrate cleaning: Substrate cleaning equipment manufactured by Choshu Industry Co., Ltd. (decompression plasma method)
(4) Application of composition: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.
(5) Film thickness measurement: Fine shape measuring machine surf coder ET-4000 manufactured by Kosaka Laboratory Co., Ltd.
(6) Manufacture of element: Multi-function vapor deposition equipment system C-E2L1G1-N manufactured by Choshu Industry Co., Ltd.
(7) Measurement of element current density, etc .: Multi-channel IVL measuring device manufactured by EHC Co., Ltd. (8) Measurement of refractive index (n) and extinction coefficient (k): manufactured by JA Woolam Japan Co., Ltd. Multi-entry angle spectroscopic ellipsometer VASE

[1] Production of compound [Synthesis example 1]

In a flask, 0.520 g of 1,4-phenylenediamine, 6.26 g of 2-bromo-9-phenyl-9H-carbazole, 0.106 g of bis (dibenzylideneacetone) palladium and 2.24 g of sodium t-butoxide were placed. The inside of the flask was replaced with nitrogen. To this, 10 mL of toluene and 1.3 mL (concentration: 62.5 g / L) of a separately prepared toluene solution of phenyldi-t-butylphosphine were added, and the mixture was stirred at 90 ° C. for 3 hours. After cooling the reaction mixture to room temperature, toluene and saturated brine were placed in a separatory funnel together with the cooled reaction mixture to perform a separation treatment, and the organic layer was recovered. Activated carbon was added to the recovered organic layer, the mixture was stirred at room temperature for 0.5 hours, and then silica gel filtration was performed to concentrate the obtained filtrate.
The obtained concentrate was added dropwise to a mixed solvent of methanol and ethyl acetate, and the mixture was stirred for a while. The obtained slurry solution was filtered, and the obtained filtrate was dried to obtain 2.96 g (yield: 59%) of the target aniline derivative A. The obtained target product was ^{identified by 1} H-NMR.
^{1 1} H-NMR (500MHz, DMSO-d6) δ [ppm]: 8.09-8.15 (m, 8H), 7.54-7.57 (m, 8H), 7.43-7.47 (m, 12H), 7.33-7.37 (m, 4H) ), 7.24-7.30 (m, 8H), 7.05 (m, 8H), 6.92-6.94 (m, 4H).

[2] Preparation of Charge Transporting Composition and Evaluation of Storage Stability [Example 1-1]
To a mixture of 0.243 g of the aniline derivative A and 0.283 g of the aryl sulfonic acid ester represented by the following formula, 10 g of xylene was added and dissolved by stirring at room temperature, and the obtained solution was dissolved with a syringe filter having a pore size of 0.2 μm. Filtration was performed to obtain a charge transporting composition. The aryl sulfonic acid ester B was synthesized according to the method described in International Publication No. 2017/217457 (the same applies hereinafter).

[Example 1-2]
To a mixture of 0.243 g of aniline derivative A and 0.283 g of aryl sulfonic acid ester B, 5 g of triethylene glycol butyl methyl ether, 3 g of butyl benzoate and 2 g of dimethyl phthalate were added and dissolved by stirring at room temperature, and the obtained solution was dissolved. A charge transporting composition was obtained by filtering with a syringe filter having a pore size of 0.2 μm.

[Example 1-3]
A solution obtained by adding 3 g of 3-phenoxytoluene and 7 g of butyl benzoate to a mixture of 0.243 g of the aniline derivative A and 0.283 g of the aryl sulfonic acid ester and stirring at room temperature to dissolve the solution was prepared. A charge transporting composition was obtained by filtering with a 2 μm syringe filter.

[Comparative Example 1-1]
An attempt was made to prepare a charge transporting composition in the same manner as in Example 1-1 except that the aniline derivative C represented by the following formula was used instead of the aniline derivative A. However, the solid content did not dissolve even when stirred at room temperature, and the solid content did not dissolve even when heated at 50 ° C. and stirred, and the solid content was dissolved when heated and stirred at 80 ° C. The obtained solution was filtered through a syringe filter having a pore size of 0.2 μm to obtain a charge transporting composition. The aniline derivative C was synthesized according to the method described in International Publication No. 2015/137395.

[Comparative Example 1-2]
An attempt was made to prepare a charge transporting composition in the same manner as in Example 1-2 except that the aniline derivative C was used instead of the aniline derivative A. However, the solid content does not dissolve even when stirred at room temperature, and the solid content does not dissolve even when heated and stirred at any temperature of 50 ° C. or 80 ° C., so that a charge-transporting thin film can be produced. No uniform charge transporting composition was obtained.

[Comparative Example 1-3]
An attempt was made to prepare a charge transporting composition in the same manner as in Example 1-3 except that the aniline derivative C was used instead of the aniline derivative A. However, the solid content did not dissolve even when stirred at room temperature, and the solid content did not dissolve even when heated at 50 ° C. and stirred, and the solid content was dissolved when heated and stirred at 80 ° C. The obtained solution was filtered through a syringe filter having a pore size of 0.2 μm to obtain a charge transporting composition.

The obtained composition was stored at 0 ° C. for 1 week, and it was confirmed whether or not the solid content of the composition after storage was precipitated. The results are shown in Table 1, along with the solubility of the solids in the preparation of each composition.

As is clear from Table 1, no precipitation was confirmed in any of the solvent compositions of the composition of the present invention. On the other hand, precipitation was confirmed in the composition of Comparative Example containing the aniline derivative C having a structure similar to that of the aniline derivative A used in the present invention. From this result, it was found that the composition of the present invention was superior in storage stability to the composition of Comparative Example.

[3] Evaluation of Optical Properties of Thin Film [Example 2 and Comparative Example 2]
The charge-transporting compositions obtained in Example 1-1 and Comparative Example 1-1 were each applied to a quartz substrate using a spin coater, dried in an air atmosphere at 80 ° C. for 1 minute, and then 200. A uniform thin film of 60 nm was prepared on the substrate by firing at ° C. for 15 minutes.
The extinction coefficient k (average extinction coefficient at a wavelength of 400 nm to 800 nm) and the refractive index n (average refractive index at a wavelength of 400 nm to 800 nm) of each thin film were measured. The results are shown in Table 2.

As is clear from Table 2, it was found that the thin film obtained from the composition of the present invention showed a lower extinction coefficient, was highly transparent, and had a high refractive index as compared with the thin film obtained from the composition of the comparative example. rice field.

[4] Fabrication and Evaluation of Hole-Only Element In the following example, a 25 mm × 25 mm × 0.7 t glass substrate in which indium tin oxide (ITO) is patterned on the surface with a film thickness of 150 nm is used as the ITO substrate. Before use _{, impurities on the surface were removed by an O 2} plasma cleaning device (150 W, 30 seconds).

[Example 3]
The composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, dried in the air at 80 ° C. for 1 minute, and then calcined at 200 ° C. for 15 minutes to form a 60 nm film thickness. A charge-transporting thin film was prepared.
On top of that, an α-NPD (N, N'-di (1-naphthyl) (1-naphthyl) was used as a hole transport layer using a thin-film deposition device (vacuum degree 1.0 × 10 ^{-5 Pa, vapor deposition rate 0.2 nm / sec).} ) -N, N'-diphenylbenzidine) was formed into a film at 0.2 nm / sec at 30 nm, and an aluminum thin film of 80 nm was further formed on the film to prepare an element.

[Comparative Example 3]
The device was produced in the same manner as in Example 3 except that the composition obtained in Comparative Example 1-1 was used instead of the composition obtained in Example 1-1.

[Example 4]
A charge-transporting thin film was prepared on the ITO substrate by the same method as in Example 3.
A 0.6 mass% xylene solution of a TFB polymer (LT-N148 manufactured by Luminescence Technology) was applied thereto by spin coating in a glove box having a nitrogen atmosphere, and then fired at 130 ° C. for 10 minutes to have a charge of 20 nm. A transportable thin film was formed as a hole transport layer. Further, an aluminum thin film having an diameter of 80 nm was formed on the aluminum thin film in the same manner as in Example 3 to produce an element.

[Comparative Example 4]
The device was produced in the same manner as in Example 4 except that the composition obtained in Comparative Example 1-1 was used instead of the composition obtained in Example 1-1.

The current density when the manufactured element was driven with a drive voltage of 5 V was measured. The results are shown in Table 3.

As shown in Table 3, the charge-transporting thin film obtained from the composition of the present invention is superior in hole-injectability into the hole-transporting layer as compared with the charge-transporting thin film obtained from the composition of Comparative Example. .. By using the charge-transporting thin film obtained from the composition of the present invention, an organic EL device having high characteristics can be expected.

Claims (8)

A charge transporting composition containing an aniline derivative represented by the following formula (1).

[In the formula, each Ar is a group represented by any of the following formulas (Ar1) to (Ar9) independently of each other.

(Wherein, R ¹ to R ²¹ are each independently a hydrogen atom, an alkyl group having carbon atoms which may be have 1-20 substituted with Z ^1, Z ¹ carbon atoms which may be substituted with 2-20 alkenyl groups, Z ¹ in the optionally substituted alkynyl group having 2 to 20 carbon atoms also may prime be substituted by an aryl group, or Z ² having 6 to 20 carbon atoms which may be substituted with Z ² 2 to 20 heteroaryl groups,
Z ¹ is a halogen atom, a nitro group, a cyano group, a heteroaryl group Z ³ aryl group, or Z ³ may C2-20 optionally substituted with from 6 to 20 carbon atoms which may be substituted with can be,
Z ² is a halogen atom, a nitro group, a cyano group, Z ³ in the optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group which may C2-20 optionally substituted by Z ³ or Z It is an alkynyl group having 2 to 20 carbon atoms which may be substituted with ^3.
Z ³ is a halogen atom, a nitro group or a cyano group. )] The charge transporting composition according to claim 1, wherein Ar is the same group. The charge transporting composition according to claim 2, wherein Ar is a group represented by any of the formulas (Ar1) to (Ar5). The charge transporting composition according to claim 3, wherein Ar is a group represented by the formula (Ar1). The charge transporting composition according to any one of claims 1 to 4, further comprising a dopant. The charge transporting composition according to claim 5, wherein the dopant is an aryl sulfonic acid ester compound. A charge-transporting thin film produced by using the charge-transporting composition according to any one of claims 1 to 5. The organic electroluminescence device including the charge transporting thin film according to claim 7.