KR20210040081A - Charge transport composition - Google Patents

Abstract

(식 중, Ph는 페닐기이다.)For example, it provides a charge transport composition containing an aniline derivative represented by the following formula.

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

Description

Charge transport composition

The present invention relates to a charge transport composition.

Charge-transporting thin films used in organic electroluminescence (hereinafter, also referred to as organic EL) devices have recently had a transmittance in the visible region due to reasons such as lowering the color purity and color reproduction of the organic EL device due to their coloring. It is desired to be high and excellent in transparency (Patent Document 1). In view of this point, the present applicant has already discovered a material for a wet process that provides a charge-transporting thin film excellent in transparency in which coloration in the visible region is suppressed (Patent Documents 1 and 2).

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

International Publication No. 2013/042623 International Publication No. 2008/032616 Japanese Special Patent No. 2007-536718 Japan Special Issue 2017-501585

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

In order to achieve the above object, the inventors of the present invention have repeatedly studied, as a result, a predetermined aniline derivative having a structure of N,N,N',N'-tetra(carbazol-2-yl)-paraphenylenediamine in the molecule. Compared with the case of using an aniline derivative having a similar structure, the charge-transporting composition comprising a has a low extinction coefficient (k) and good transparency, and not only provides a charge-transporting thin film having a high refractive index (n), but also preserves the composition itself. The present invention has been completed by finding that an organic EL device having excellent stability is also excellent, and that when the charge-transporting thin film is applied to a hole injection layer or the like, has excellent properties.

Accordingly, the present invention provides the following charge transport composition.

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

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

(Wherein, R ¹ ~R ²¹ is, independently from each other, with an alkenyl group, Z ¹ of 2 to 20 carbon atoms that may be substituted with an alkyl group, Z ¹ of 1 to 20 carbon atoms that may be substituted with hydrogen atoms, Z ¹ of 2 to 20 carbon atoms that may be substituted with an alkynyl group, an aryl group of 6 to 20 carbon atoms optionally substituted by Z ² or heteroaryl group of 2 to 20 carbon atoms which may be substituted with Z ^2, and

Z ¹ is a heteroaryl group of 2 to 20 carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, an aryl group of 6 to 20 carbon atoms optionally substituted by Z ³ or Z ^3,

Z ² is two carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, Z ³ an alkyl group of 1 to 20 carbon atoms that may be substituted, Z ³ in the 2 to 20 carbon atoms that may be substituted with an alkenyl group, or Z ³ It is an alkynyl group of ∼20,

Z ³ is a halogen atom, a nitro group or a cyano group.)]

2. The charge-transporting composition of 1 in which all Ar are the same group.

3. The charge-transporting composition of group 2 wherein Ar is represented by any one of formulas (Ar1) to (Ar5).

4. The charge-transporting composition of group 3 wherein Ar is represented by the formula (Ar1).

5. The charge-transporting composition of any one of 1 to 4 further comprising a dopant.

6. The charge transport composition of 5, wherein the dopant is an arylsulfonic acid ester compound.

7. A charge-transporting thin film produced using the charge-transporting composition of any one of 1 to 5.

8. An organic EL device having a charge-transporting thin film of 7.

By using the charge-transporting composition of the present invention, a charge-transporting thin film having high transparency (low extinction coefficient (k)) and high refractive index (n) can be produced as compared to the case of using a composition containing an aniline derivative having a similar structure. . Further, the charge-transporting composition of the present invention is superior in storage stability compared to a composition containing an aniline derivative having a similar structure. In addition, 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 including organic EL devices, and as a functional layer provided between the anode of the organic EL device and the light emitting layer, particularly as a hole injection layer. By using, an organic EL device excellent in properties is obtained.

(Form for carrying out the invention)

[Charge transporting composition]

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

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

Formula (Ar1) ~ (Ar9) of, R ¹ ~R ²¹ are, independently, of 2 to 20 carbon atoms that may be substituted with an alkyl group, Z ¹ of 1 to 20 carbon atoms that may be substituted with hydrogen atoms, Z ¹ each alkenyl group, a heteroaryl group, a alkynyl group, having 2 to 20 carbon atoms which may be substituted with a carbon number of 6 to 20 aryl group, or Z ² of which may be substituted with Z ² of 2 to 20 carbon atoms which may be substituted with Z ^1. Z ¹ is a heteroaryl group of 2 to 20 carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, an aryl group of 6 to 20 carbon atoms optionally substituted by Z ³ or Z ^3. Z ² is two carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, Z ³ an alkyl group of 1 to 20 carbon atoms that may be substituted, Z ³ in the 2 to 20 carbon atoms that may be substituted with an alkenyl group, or Z ³ It is an alkynyl group of -20. 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, and an iodine atom, but 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, isobutyl group, s-butyl group , a linear or branched alkyl group having 1 to 20 carbon atoms such as t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and n-decyl group; Cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, and other cyclic alkyl groups having 3 to 20 carbon atoms are mentioned.

The alkenyl group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include ethenyl group, n-1-propenyl group, n-2-propenyl group, 1-methylethenyl group, and 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-1 -Prophenyl group, 1-methyl-2-propenyl group, n-1-pentenyl group, n-1-decenyl group, etc. are mentioned.

The alkynyl group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include ethynyl group, n-1-propynyl group, n-2-propynyl group, n-1-butynyl group, and 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, n-1-decy Neil group, etc. are mentioned.

Specific examples of the aryl group having 6 to 20 carbon atoms include phenyl group, tolyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, etc. are mentioned.

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, 5-oxazolyl group, Oxygen-containing heteroaryl groups such as 3-isoxazolyl group, 4-isooxazolyl group, and 5-isoxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothia Sulfur heteroaryl groups, such as a zolyl group, 4-isothiazolyl group, and 5-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-Pyrazyl Group, 2-Pyrimidyl Group, 4-Pyramidyl Group, 5-Pyrimidyl Group, 6-Pyramidyl Group, 3-Pyri Poly, 4-pyridazyl, 5-pyridazyl, 6-pyridazyl, 1,2,3-triazine-4-yl, 1,2,3-triazine-5-yl, 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-tetrazin-3-yl group, 1,2,3,4-tetrazin-5-yl group, 2-quinolinyl group, 3-quinolinyl group, 4-quinolinyl group, 5-quinol Nolinyl 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-quinazolinyl group, 6-quinazolinyl group, 7-quinazolinyl group, 8-quinazolinyl group, 3-cinnolinyl group, 4-cinnolinyl group, 5-cinnolinyl group, 6-cinnolinyl group, 7- Nitrogen-containing heteroaryl groups, such as a cinnolinyl group and an 8-cinnolinyl group, etc. are mentioned.

Among them, R ¹ ~R ²¹ as the number of carbon atoms which may heteroaryl group of 2 to 20 carbon atoms which may be substituted with an aryl group 6 to 20 carbon atoms, Z ² of which may be substituted with Z ² group is preferred, and is substituted with Z ² 6 aryl groups of to 20 more preferred, and is substituted with 1-naphthyl group, Z ² is optionally substituted by a phenyl group, Z ² is optionally substituted by Z ² is preferably a 2-naphthyl which may incidentally. In addition, Z ² the halogen atom, the groups are alkenyl groups, 2 to 20 carbon atoms that may be substituted with Z ³ having 1 to 20 carbon atoms that may be substituted with Z ³ 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 ease of synthesis of the aniline derivative, it is preferable that all Ar are the same group. In addition, from the viewpoint of improving the solubility of the aniline derivative in an organic solvent and obtaining a composition having high uniformity with good reproducibility, a group represented by any one of formulas (Ar1) to (Ar5) is preferred, and a group represented by formula (Ar1) Giga is optimal.

Hereinafter, although the specific example of the aniline derivative suitable in this invention is given, it is not limited to this.

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

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

Examples of the halogen atom include those similar to those described above, but a chlorine atom, a bromine atom, and an iodine atom are preferable. Examples of the similar halogen group include (fluoro)alkylsulfonyloxy groups such as methanesulfonyloxy group, trifluoromethanesulfonyloxy group, and nonafluorobutanesulfonyloxy group; And aromatic sulfonyloxy groups such as a benzenesulfonyloxy group and a toluenesulfonyloxy group.

The charging ratio of 1,4-phenylenediamine and the halogenated or pseudohalogenated carbazole derivative can be made more than the equivalent of the halogenated or pseudohalogenated carbazole derivative with respect to the total amount of the NH group of 1,4-phenylenediamine. However, about 1 to 1.2 equivalents are suitable.

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 ), 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-butylphosphine)]palladium (Pd(Pt-Bu ₃ ) ₂ ), palladium acetate (Pd( Palladium catalysts, such as OAc) ₂ ), etc. are mentioned. These catalysts may be used alone or in combination of two or more.

In addition, these catalysts may be used together with a known suitable ligand. Examples of such ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-t-butylphosphine, di. -t-butyl(phenyl)phosphine, di-t-butyl(4-dimethylaminophenyl)phosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane Tertiary phosphine, such as 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, trimethylphosphite, triethylphosphite, triphenylphosphite, etc. Tea phosphite, etc. are mentioned.

The amount of the catalyst used may be about 0.01 to 0.2 mol per 1 mol of the halogenated or pseudohalogenated carbazole derivative, but about 0.15 mol is suitable.

In the case of using a ligand, the amount used can be 0.1 to 5 equivalents based on the catalyst to be used, but 1 to 2 equivalents are suitable.

When all the raw material compounds are solid or from the viewpoint of efficiently obtaining the target aniline derivative, each of the above reactions is carried out in a solvent. In the case of using a solvent, the kind 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.), aromatic hydrocarbons (benzene, nitrobenzene, etc.) Toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, etc.), ethers (Diethyl ether, diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), ketones (acetone, methyl ethyl ketone, methyl Isobutyl ketone, di-n-butyl ketone, cyclohexanone, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, etc.), lactams and lactones (N-methylpyrrolidone, γ-butyrolactone), urea (N,N-dimethylimidazolidinone, tetramethylurea, etc.), sulfoxides (dimethylsulfoxide, sulfolane, etc.), nitriles (acetonitrile, propionitrile, etc.) Butyronitrile, etc.) etc. are mentioned, but it is not limited to these. 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 according to a conventional method can be performed to obtain the desired aniline derivative.

The charge transport composition of the present invention contains an organic solvent. As such an organic solvent, a high-solubility solvent capable of satisfactorily dissolving the aniline derivative represented by formula (1) as a charge-transporting substance can be used. Specific examples of the solubility solvent include, for example, cyclohexanone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutylamide, N-methylpyrrolidone, 1,3 -Organic solvents, such as dimethyl-2-imidazolidinone and diethylene glycol monomethyl ether, are mentioned, but are not limited to these. These solvents may be used alone or in combination of two or more. The usage amount can be 5 to 100% by mass based on the entire solvent used in the composition.

In addition, the composition contains at least one high viscosity organic solvent having a viscosity of 10 to 200 mPa·s at 25°C, particularly 35 to 150 mPa·s, and a boiling point of 50 to 300°C at normal pressure (atmospheric pressure), especially 150 to 250°C. By doing so, it becomes easy to adjust the viscosity of the composition, and as a result, it becomes possible to prepare a composition according to the coating method to be used in which a thin film having high flatness is supplied with good reproducibility. As a high viscosity organic solvent, for example, cyclohexanol, ethylene glycol, ethylene glycol diglycidyl ether, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1, 3-butanediol, 2,3-butanediol, 1,4-butanediol, propylene glycol, hexylene glycol, etc. may be mentioned, but the present invention is not limited thereto. 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 a range in which no solid precipitates, and as long as no solid precipitates, the addition ratio is preferably 5 to 80% by mass.

In addition, for the purpose of improving the wettability to the substrate, adjusting the surface tension of the solvent, adjusting the polarity, adjusting the boiling point, etc., other solvents are used in an amount of 1 to 90% by mass, preferably based on the total solvent used in the composition. May be mixed in a ratio 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, and diethylene glycol monobutyl ether. Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diacetone alcohol, γ-butyrolactone, ethyl lactate, n-hexyl acetate, and the like, but are not limited to these. These solvents may be used alone or in combination of two or more.

In addition, the aniline derivative represented by formula (1) has a substituent on at least one nitrogen atom in the molecule, for example, in the case of having an aryl group on the nitrogen atom at position 9 of the carbazole moiety in the molecule. In the case, preferably, when all nitrogen atoms have substituents, preparation of a composition using only a low polarity solvent becomes easy. Specific examples of such a low-polarity solvent include chlorine-based solvents such as chloroform and chlorobenzene; Aromatic hydrocarbon solvents such as toluene, xylene, tetralin, cyclohexylbenzene, and decylbenzene; Aliphatic alcohol solvents such as 1-octanol, 1-nonanol, and 1-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 solvents such as ether; Methyl benzoate, ethyl benzoate, butyl benzoate, dimethyl phthalate, diethyl maleate, isoamyl benzoate, bis(2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, Ester solvents, such as diethylene glycol monobutyl ether acetate, etc. are mentioned, but are not limited to these. These solvents may be used alone or in combination of two or more.

The charge-transporting composition of the present invention may also contain water as a solvent, but from the viewpoint of obtaining a highly durable device with good reproducibility when the charge-transporting thin film obtained from the composition is used as a hole injection layer of an organic EL device, the content of water is 10 mass% or less is preferable, 5 mass% or less is more preferable, and it is optimal to use only an organic solvent as a solvent. In addition, "only organic solvent" in this case means that only an organic solvent is used as a solvent, and even the presence of "water" contained in a trace amount such as an organic solvent or solid content to be used is not denied. In addition, in the present invention, the solid content means components other than the solvent contained in the charge-transporting composition.

The charge-transporting composition of the present invention may contain other charge-transporting substances in addition to a charge-transporting substance composed of an aniline derivative represented by formula (1).

The charge transport composition of the present invention contains a charge transport material composed of an aniline derivative represented by formula (1) and an organic solvent, but depending on the application of the resulting thin film, a dopant ( Charge-accepting substances) may be included.

The dopant is not particularly limited as long as it is dissolved in at least one solvent used in the composition, and any of an inorganic dopant and an organic dopant can be used. Moreover, inorganic type and organic type dopant may be used individually by 1 type, and may be used in combination of 2 or more types. In addition, in the process of obtaining a charge-transporting thin film, which is a solid film from the composition, the dopant is partially released from the molecule due to external stimulation such as heating during firing, so that the function as a dopant is finally expressed or improved. A substance to be formed, for example, an aryl sulfonic acid ester compound in which a sulfonic acid group is easily removed may be used.

The amount of the dopant material in the composition cannot be uniformly defined because it varies depending on the degree of desired charge transportability or the type of dopant material, but usually, in terms of mass ratio, 0.0001 to 100 with respect to the aniline derivative 1 represented by formula (1). Is the range of.

In the present invention, as a preferable inorganic dopant, a heteropolyacid is mentioned. The heteropolyacid is typically a Keggin type represented by the following formula (H1) or a Dawson type chemical structure represented by the following formula (H2), and has a structure in which a hetero atom is located at the center of a molecule, and vanadium (V), molybdenum It is a polyacid formed by condensation with an oxygen acid such as (Mo) and tungsten (W), which is an oxygen acid, and an oxygen acid of a different element. As the oxygen acid of such a heterogeneous element, mainly oxygen acids of silicon (Si), phosphorus (P), and arsenic (As) are exemplified.

Specific examples of the heteropolyacid include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, and the like. These heteropolyacids may be used individually by 1 type, and may be used in combination of 2 or more types. In addition, these heteropolyacids are commercially available and can also be synthesized by a known method.

In particular, when one type of heteropolyacid is used, the one type of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and phosphotungstic acid is optimal. Moreover, when two or more types of heteropolyacids are used, one of the two or more types of heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, more preferably phosphotungstic acid.

In addition, in quantitative analysis such as elemental analysis, even if the number of elements is large or small from the structure represented by the general formula, the heteropolyacid is obtained as a commercial item, or appropriately synthesized according to a known synthesis method. As long as it is one, it can be used in the present invention. That is, for example, in general, phosphotungstic acid is represented by the formula H ₃ (PW ₁₂ O ₄₀ )·nH _{2 O} , and phosphomolybdic acid is represented by the formula H ₃ (PMo ₁₂ O ₄₀ )·nH ₂ O, respectively, but quantitative analysis In this formula, even if the number of P (phosphorus), O (oxygen) or W (tungsten) or Mo (molybdenum) is large or small, it is appropriately obtained as a commercial product or according to a known synthesis method. As long as it is synthesized, it can be used in the present invention. In this case, the mass of the heteropolyacid specified in the present invention is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in the composite or commercial product, but in the form available as a commercial product and in a form that can be isolated by a known synthetic method, hydration It means the total mass in the state including water or other impurities.

In the case of using a heteropolyacid as a dopant, the amount used may 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 it is preferably about 0.01 to 20.0, more preferably 0.1 It is about -10.0.

On the other hand, as a preferable organic dopant, a tetracyanoquinodimethane derivative and a benzoquinone derivative are mentioned. Specific examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ) and halotetracyanoquinodimethane represented by the following formula (H3). In addition, specific examples of the benzoquinone derivative include tetrafluoro-1,4-benzoquinone (F4BQ), tetrachloro-1,4-benzoquinone (chloranyl), tetrabromo-1,4-benzoquinone, 2,3 -Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), etc. are mentioned.

In formula (H3), R ¹⁰¹ to ^{R 104} each independently represent a hydrogen atom or a halogen atom, 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 preferable that it is more preferable, and it is most preferable that all are halogen atoms. Examples of the halogen atom include those 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, 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-tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), etc. Can be mentioned.

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

Moreover, an arylsulfonic acid compound is mentioned as another preferable organic type dopant. 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, dibutylnaphthalenesulfonic acid, 6,7-dibutyl-2-naphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, 3-dodecyl-2-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 4-hexyl-1-naphthalenesulfonic acid, octylnaphthalenesulfonic acid , 2-octyl-1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 7-hexyl-1-naphthalenesulfonic acid, 6-hexyl-2-naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, 2,7-dinonyl-4-naphthalenesulfonic acid, dino Nylnaphthalenedisulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, 1,4-benzodioxane disulfonic acid compound described in International Publication No. 2005/000832, aryl described in International Publication No. 2006/025342 Sulfonic acid compounds and arylsulfonic acid compounds described in International Publication No. 2009/096352, and the like.

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

In formula (H4), A ¹ represents O or S, but O is preferred. 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 is preferably derived from naphthalene. A ³ is a p-valent group derived from perfluorobiphenyl (ie, 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, but is preferably a perfluorobiphenyl-4,4'-diyl group. q represents the number of sulfonic acid groups bonded to A2, and is an integer satisfying 1≦q≦4, but 2 is optimal.

In formula (H5), A ^{4 to} A ⁸ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogenated alkenyl group having 2 to 20 carbon atoms, And at least 3 of ^{A 4 to} A ^{8 are halogen atoms.}

Examples of halogenated alkyl 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-nonafluoro Butyl group, etc. are mentioned. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include perfluorovinyl group, perfluoro-1-propenyl group, perfluoro-2-propenyl group, perfluorobutenyl group, and the like. In addition, examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms are the same as those described above, but the halogen atom is preferably a fluorine atom.

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

In formula (H5), r represents the number of sulfonic acid groups bonded to the naphthalene ring, and is an integer that satisfies 1 ≤ r ≤ 4, but 2 to 4 are preferred, and 2 is optimal.

Hereinafter, although a specific example of a suitable arylsulfonic acid compound is given, it is not limited to these.

In the case of using an arylsulfonic acid compound as a dopant, the amount of the arylsulfonic acid compound is used in terms of a substance amount (molar) ratio with respect to the aniline derivative 1 represented by the formula (1), preferably about 0.01 to 20.0, more preferably about 0.4 to 5.0. to be. The arylsulfonic acid compound may be commercially available, but it can also be synthesized by a known method described in International Publication No. 2006/025342, International Publication No. 2009/096352, and the like.

Moreover, an aryl sulfonic acid ester compound is mentioned as another preferable organic type dopant. Specific examples thereof include an aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217455, an 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 represented by any one of the following formulas (H6) to (H8).

In 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 is preferably derived from naphthalene.

R ^s1 to ^{R s4} are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and R ^s5 is an optionally substituted monovalent hydrocarbon group having 2 to 20 carbon atoms. Examples of the linear or branched C1-C6 alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, etc. Can be mentioned. Among these, a C1-C3 alkyl group is preferable. The monovalent hydrocarbon group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and t-butyl group. Alkyl groups such as; Aryl groups, such as phenyl, naphthyl, and phenanthryl group, etc. are mentioned.

In particular, R ^s1 and ^s4 of the ~R, R ^s1 or ^s3 R is a straight chain alkyl group having a carbon number of 1 to 3, or the rest is a hydrogen atom, and R ^s1 is a straight chain alkyl group having a carbon number of 1 to 3, R is a hydrogen atom ^{s4 s2} ~R It is preferable to be. In this case, as a C1-C3 linear alkyl group, a methyl group is preferable. Moreover, as ^Rs5 , a C2-C4 linear alkyl group or a phenyl group is preferable.

In formula (H7), A ¹⁴ is an m-valent hydrocarbon group having 6 to 20 carbon atoms, which may be substituted, containing one or more aromatic rings, and this hydrocarbon group is a hydrocarbon group having 6 to 20 carbon atoms containing one or more aromatic rings. It is a group obtained by removing m number of hydrogen atoms from a compound. Examples of such hydrocarbon compounds include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, and phenanthrene. In addition, some or all of the hydrogen atoms in the hydrocarbon group may be further substituted with a substituent, and such substituents include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxy group, an amino group, a silanol group, a thiol Group, carboxyl group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, ester group, thioester group, amide group, monovalent hydrocarbon group, organooxy group, organoamino group, organosilyl group, organothio group, acyl group, alcohol Such as giving up. Among these, A ¹⁴ is preferably a group derived from benzene, biphenyl, or the like.

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

In formula (H7), A ¹⁶ is a (n+1) valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group contains (n+1) hydrogen atoms on the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing. Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. 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 each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group, and R ^s8 is a linear or branched monovalent aliphatic hydrocarbon group. However, the total number of carbon atoms of ^{R s6} , R ^s7 and R ^{s8 is 6 or more.} Although ^{the upper limit of the total number of carbon atoms of R s6} , R ^s7 and R ^s8 is not particularly limited, 20 or less is preferable and 10 or less is more preferable. Specific examples of the linear or branched monovalent aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group , an alkyl group having 1 to 20 carbon atoms such as an n-octyl group, a 2-ethylhexyl group, and a decyl group; 2 to 20 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, and hexenyl group And alkenyl groups of. Among these, R ^s6 is preferably a hydrogen atom, and R ^s7 and R ^s8 are, independently of each other, preferably an alkyl group having 1 to 6 carbon atoms.

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

The alkyl group having 1 to 10 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, isobutyl 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.

The halogenated alkyl group having 1 to 10 carbon atoms is not particularly limited as long as some or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are substituted with halogen atoms. Specific examples thereof include trifluoromethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2,2-pentafluoroethyl group, 3,3,3-trifluoropropyl group, 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-nonafluoro Lobutyl group, etc. are mentioned.

The halogenated alkenyl group having 2 to 10 carbon atoms is not particularly limited as long as some 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 perfluorovinyl group, perfluoro-1-propenyl group, perfluoro-2-propenyl group, perfluoro-1-butenyl group, perfluoro-2-butenyl group, perfluoro-3 -Butenyl group, etc. are mentioned.

Among these, R ^s9 is preferably a nitro group, a cyano group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated alkenyl group having 2 to 10 carbon atoms, and a nitro group, a cyano group, a halogenated alkyl group having 1 to 4 carbon atoms, and 2 to 4 carbon atoms. Halogenated alkenyl group of is more preferable, and a nitro group, a cyano group, a trifluoromethyl group, and a perfluoropropenyl group are still more preferable.

In formula (H8), as ^Rs10 to ^Rs13 , 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 formula (H8), A ¹⁸ is a (n+1) valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group contains (n+1) hydrogen atoms on the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing. Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. Among these, as A ¹⁸ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

In formula (H8), R ^s14 to ^{R s17} are each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. Specific examples of the monovalent aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, cyclopentyl group, n -C1-C20 alkyl groups such as 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 20 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, and hexenyl group And alkenyl groups of. Among these, a C1-C20 alkyl group is preferable, a C1-C10 alkyl group is more preferable, and a C1-C8 alkyl group is still 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 an optionally substituted monovalent hydrocarbon group having 2 to 20 carbon atoms. Examples of the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ^{s18 include those similar to those 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 even more preferably an alkyl group having 1 to 8 carbon atoms. Examples of the monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R ^s19 include aryl groups such as a phenyl group, a naphthyl group, and a phenanthryl group in addition to those other than the methyl group among the aforementioned monovalent aliphatic hydrocarbon groups. Among these, R ^s19 is preferably a C 2 to C 4 linear alkyl group or a phenyl group. Further, examples of the substituent which the monovalent hydrocarbon group may have include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a cyano group, and the like.

Specific examples of suitable arylsulfonic acid ester compounds include those shown below, but are not limited thereto.

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

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

In the present invention, in consideration of obtaining a thin film having high charge transport properties with good reproducibility and availability of a dopant, at least one of an arylsulfonic acid compound, an arylsulfonic acid ester compound, halotetracyanoquinodimethane and benzoquinone derivatives as dopants It is preferable to use one type, and in consideration of obtaining a more transparent charge-transporting thin film with good reproducibility, it is more preferable to use at least one of an arylsulfonic acid compound and an arylsulfonic acid ester compound, and a charge-transporting composition having excellent stability is prepared. In consideration of obtaining, it is more preferable to use an aryl sulfonic acid ester compound.

The charge-transporting substance and the dopant are preferably completely dissolved in the solvent or uniformly dispersed, and it is optimal that they are completely dissolved.

The charge-transporting composition of the present invention is an organic silane compound or nonionic compound for the purpose of improving the injectability into the hole-transporting layer when the resulting thin film is used as a hole injecting layer of an organic EL device, and improving the life characteristics of the device. A fluorinated surfactant may be included, and the content thereof is usually about 1 to 30 parts by mass based on 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 to 15% by mass, from the viewpoint of securing a sufficient film thickness while suppressing the precipitation of the charge-transporting substance.

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. The viscosity and surface tension of the charge-transporting composition of the present invention can be adjusted by changing the type of organic solvent used, their ratio, solid content concentration, etc. in consideration of various factors such as the coating method to be used and the desired film thickness.

The charge-transporting composition of the present invention can be prepared by dissolving an aniline derivative represented by formula (1) in an organic solvent. The aniline derivative may be dissolved in advance in an organic solvent, and other organic solvents may be sequentially added thereto, or a mixed solvent of all solvents to be used may be prepared in advance, and the aniline derivative may be dissolved therein. In addition, if necessary, care may be taken not to decompose or deteriorate the components contained in the composition, and heating may be performed to promote 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 a solvent, the same method is followed. In addition, the charge-transporting composition of the present invention may be filtered using a submicron filter or the like after dissolving a charge-transporting substance in an organic solvent from the viewpoint of obtaining a thin film having higher flatness with good reproducibility.

[Charge transport thin film]

By applying and firing the charge transport composition of the present invention on a substrate, a charge transport thin film can be formed on the substrate.

The method of applying the composition is not particularly limited, and includes a dipping method, a spin coating method, a transfer printing method, a roll coating method, an ink jet method, a spray method, a slit coating method, and the like. Depending on the application method, it is desirable to control the viscosity and surface tension of the composition.

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

In addition, the firing conditions are also not particularly limited, but heat firing is performed using, for example, a hot plate. Usually, considering the desired charge transport property, etc., the firing temperature is suitably determined within the range of 100 to 260°C and the firing time within the range of 1 minute to 1 hour. Further, if necessary, multi-stage firing may be performed at two or more different temperatures.

The film thickness of the charge-transporting thin film is not particularly limited, but when used as a functional layer of an organic EL device, it is preferably 5 to 300 nm. 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 application.

[Organic EL device]

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

Typical configurations of the organic EL device include the following (a) to (f), but are not limited thereto. Further, 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 (hole) block layer or the like may be provided between the light emitting layer and the cathode. In addition, the hole injection layer, the hole transport layer, or the hole injection transport layer may have a function as an electron block layer or the like, and the electron injection layer, an electron transport layer, or the electron injection transport layer may have a function as a hole (hole) block layer or the like. . Moreover, it is also possible to provide an arbitrary functional layer between each layer as needed.

(a) anode/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) anode/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/hole injection layer/hole transport layer/light emitting layer/cathode

(f) anode/hole injection transport layer/light emitting layer/cathode

The "hole injection layer", the "hole transport layer" and the "hole injection transport layer" are layers formed between the light emitting layer and the anode, and have a function of transporting holes from the anode to the light emitting layer. If only one layer of a hole transport material is provided between the light emitting layer and the anode, it is a ``hole injection transport layer,'' and when two or more layers of hole transport material are provided between the light emitting layer and the anode, close to the anode. The layer is a "hole injection layer", and the layer other than that is a "hole transport layer". In particular, as the hole injection (transport) layer, a thin film excellent in not only accepting holes from the anode but also injecting holes into the hole transport (light emitting) layer is used.

The "electron injection layer", the "electron transport layer", and the "electron injection 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. When only one layer of electron transport material is provided between the light-emitting layer and the cathode, it is a "electron injection and transport layer", and when two or more layers of electron-transport material are provided between the light-emitting layer and the cathode, a layer close to the cathode This is the "electron injection layer", and other layers are the "electron transport layer".

The "light-emitting layer" is an organic layer having a light-emitting function, and when a doping system is employed, a host material and a dopant material are included. At this time, the host material mainly promotes recombination of electrons and holes and has a function of confining excitons in the emission layer, and the dopant material has a function of efficiently emitting excitons obtained through recombination. In the case of a phosphorescent device, the host material mainly has a function of confining excitons generated from a dopant in the light emitting layer.

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

Examples of materials and manufacturing methods used in the case of manufacturing an organic EL device using the charge-transporting composition of the present invention include the following, but are not limited thereto.

An example of a method of manufacturing an OLED device having a hole transport layer made of a thin film obtained from the charge transport composition of the present invention is as follows. In addition, the electrode is preferably washed with alcohol, pure water or the like, or surface treatment by UV ozone treatment, oxygen-plasma treatment, or the like in advance within a range that does not adversely affect the electrode.

On the anode substrate, a hole injection layer made of the charge-transporting thin film of the present invention is formed 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 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 transporting polymer and a composition for forming a light emitting layer containing a light emitting polymer are used to form these layers by a wet process. To form. Further, if necessary, an electron blocking layer may be provided between the light emitting layer and the hole transport layer.

Examples of the anode material include a transparent electrode typified by indium tin oxide (ITO) and indium zinc oxide (IZO), or a metal anode composed of a metal typified by aluminum or an alloy thereof, and a planarization treatment is preferred. . Polythiophene derivatives or polyaniline derivatives having high charge transport properties can also be used. Further, examples of other metals constituting the metal anode include gold, silver, copper, indium, and alloys thereof, but are not limited thereto.

Materials for forming the light-emitting layer include aluminum complexes of 8-hydroxyquinoline, zinc complexes such as tris(8-quinolinolate)aluminum(III)(Alq ₃ ) and bis(8-quinolinolate)zinc(II). Metal complexes such as, 10-hydroxybenzo[h]quinoline metal complexes, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, silol derivatives, etc. Luminescent material; Poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), polyvinylcar A system in which a light-emitting material and an electron transfer material are mixed with a high molecular compound such as bisol may be mentioned, but the present invention is not limited thereto. In the case of forming a light-emitting layer by evaporation, it may be co-deposited with a light-emitting dopant, and as a light-emitting dopant, a metal complex such as _{tris(2-phenylpyridine)iridium(III)(Ir(PPy) 3 ), rubrene, etc.} And condensed polycyclic aromatic rings such as naphthacene derivatives, quinacridone derivatives, and perylene, but are not limited thereto.

Examples of the material for forming the electron transport layer/hole block layer include, but are not limited to, an oxidiazole derivative, a triazole derivative, a phenanthroline derivative, a phenylquinoxylin derivative, a benzimidazole derivative, a pyrimidine derivative, and the like.

Materials for forming the electron injection layer include _{metal oxides such as lithium oxide (Li 2} O), magnesium oxide (MgO), and alumina (Al ₂ O ₃ ), and metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF). However, it 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.

Although tris(phenylpyrazole) iridium etc. are mentioned as a material for forming an electron blocking layer, it is not limited to this.

As a hole-transporting polymer, 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'-pentene-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]-end capped with polysilsesquioxane, poly[ (9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] and the like.

As a luminescent polymer, polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene ) Polyphenylenevinylene derivatives such as (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbisol (PVCz).

Since the material constituting the anode, the cathode, and the layer formed therebetween differs depending on whether an element having a bottom emission structure or a top emission structure is to be manufactured, the material is appropriately selected in consideration of that point.

In general, in a device having a bottom emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side, whereas in a device having a top emission structure, a reflective anode made of metal is used, and in the opposite direction to the substrate. Since light is extracted from the side of the transparent electrode (cathode) in the anode material, a transparent anode such as ITO is used when manufacturing a device having a bottom emission structure, and Al is used when manufacturing a device having a top emission structure. Reflective anodes such as /Nd are used respectively.

The organic EL device of the present invention may be sealed with a desiccant or the like according to a conventional method in order to prevent deterioration of characteristics.

Example

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. In addition, the apparatus used is as follows.

(1) LDI-MS: AutoFlex manufactured by Bruker

(2) ¹ H-NMR: JNM-ECP300 FT NMRSYSTEM manufactured by Nihon Denshi Co., Ltd.

(3) Substrate cleaning: Substrate cleaning device made by Choshu Sangyo (Co., Ltd.) (pressure-sensitive plasma method)

(4) Application of the composition: MS-A100 spin coater manufactured by Mikasa (Co., Ltd.)

(5) Membrane thickness measurement: Kosaka Kenkyusho Co., Ltd. micro-shape measuring instrument, Surf Coda ET-4000

(6) Fabrication of device: C-E2L1G1-N, a multifunctional vapor deposition system system manufactured by Choshu Sangyo Co., Ltd.

(7) Measurement of device current density, etc.: Multi-channel IVL measuring device manufactured by HCC Co., Ltd.

(8) Measurement of refractive index (n) and extinction coefficient (k): Multi-incidence spectral ellipsometer VASE manufactured by J.Ulam Japan

[1] Preparation of compound

[Synthesis Example 1]

In the flask, 0.502 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 added, The inside of the flask was purged with nitrogen. To there, 10 mL of toluene and 1.3 mL of a toluene solution of phenyldi-t-butylphosphine prepared separately in advance (concentration: 62.5 g/L) were added, and the mixture was stirred at 90°C for 3 hours. After the reaction mixture was cooled to room temperature, toluene and saturated saline were placed in a separating funnel together with the cooled reaction mixture, followed by liquid separation treatment to recover the organic layer. Activated carbon was added to the recovered organic layer and stirred at room temperature for 0.5 hours, followed by silica gel filtration, and the obtained filtrate was concentrated.

The obtained concentrated solution was added dropwise to a mixed solvent of methanol and ethyl acetate, and 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.

[2] Preparation of charge-transporting composition and evaluation of storage stability thereof

[Example 1-1]

To a mixture of 0.243 g of aniline derivative A and 0.283 g of arylsulfonic acid ester B represented by the following formula, 10 g of xylene was added and dissolved by stirring at room temperature, and the resulting solution was filtered through a syringe filter having a pore diameter of 0.2 μm to obtain a charge-transporting composition. . In addition, 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 arylsulfonic acid ester B, 5 g of triethylene glycol butyl methyl ether, 3 g of butyl benzoate and 2 g of dimethyl phthalate were added, stirred at room temperature to dissolve, and the resulting solution was dissolved in a syringe filter having a pore diameter of 0.2 μm Filtered to obtain a charge-transporting composition.

[Example 1-3]

To a mixture of 0.243 g of aniline derivative A and 0.283 g of aryl sulfonic acid ester B, 3 g of 3-phenoxytoluene and 7 g of butyl benzoate were added, stirred at room temperature to dissolve, and the resulting solution was filtered through a syringe filter having a pore diameter of 0.2 μm, and charged. A transportable composition was obtained.

[Comparative Example 1-1]

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

[Comparative Example 1-2]

Preparation of a charge-transporting composition was attempted 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 did not dissolve even when stirred at room temperature, and the solid content did not dissolve even when heated and stirred at any temperature of 50° C. or 80° C., and a charge-transporting composition uniform enough to produce a charge-transporting thin film was not obtained. .

[Comparative Example 1-3]

Preparation of a charge-transporting composition was attempted 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 to 50° C. and stirred, and the solid content dissolved when heated to 80° C. and stirred. The obtained solution was filtered through a syringe filter having a pore diameter of 0.2 µm to obtain a charge-transporting composition.

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

Solubility of solids Presence or absence of precipitation after preservation Example 1-1 Dissolved at room temperature. No precipitation Example 1-2 Dissolved at room temperature. No precipitation Example 1-3 Dissolved at room temperature. No precipitation Comparative Example 1-1 Dissolved at 80° C. heating. There is precipitation Comparative Example 1-2 It did not dissolve even at 80 degreeC heating. Comparative Example 1-3 Dissolved at 80° C. heating. There is precipitation

As is clear from Table 1, in the composition of the present invention, precipitation was not observed in any solvent composition. On the other hand, in the composition of the comparative example containing the aniline derivative C having a structure similar to the aniline derivative A used in the present invention, precipitation was confirmed. From this result, it was found that the composition of the present invention has superior storage stability compared to the composition of the comparative example.

[3] Evaluation of optical properties of thin films

[Example 2 and Comparative Example 2]

The charge-transporting compositions obtained in Example 1-1 and Comparative Example 1-1 were each coated on a quartz substrate using a spin coater, and then dried at 80°C for 1 minute in an air atmosphere, followed by firing at 200°C for 15 minutes. Thus, a uniform thin film of 60 nm was produced on the substrate.

The extinction coefficient k (average extinction coefficient at a wavelength of 400 nm to 800 nm) and a refractive index n (average refractive index at a wavelength of 400 nm to 800 nm) of each thin film were measured. Table 2 shows the results.

k n Example 2 0.021 1.70 Comparative Example 2 0.038 1.63

As is clear from Table 2, it was found that the thin film obtained from the composition of the present invention exhibits a low extinction coefficient, high transparency, and has a high refractive index compared to the thin film obtained from the composition of the comparative example.

[4] Hall-only device fabrication and evaluation

In the following example, as the ITO substrate, a glass substrate of 25 mm × 25 mm × 0.7t in which indium tin oxide (ITO) was patterned with a film thickness of 150 nm on the surface was used, and an O ₂ plasma cleaning device (150 W, 30 seconds) before use. To remove impurities on the surface.

[Example 3]

The composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, and then dried at 80° C. for 1 minute under air, and then fired at 200° C. for 15 minutes to form a charge-transporting thin film with a thickness of 60 nm. Made.

On top of that, using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa, vapor deposition rate 0.2 nm/sec), α-NPD(N,N'-di(1-naphthyl)-N,N'- Diphenylbenzidine) was formed into a 30 nm film at 0.2 nm/sec, and an 80 nm aluminum thin film was formed thereon to fabricate a device.

[Comparative Example 3]

A 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]

In the same manner as in Example 3, a charge-transporting thin film was formed on the ITO substrate.

On top of that, in a glove box in a nitrogen atmosphere, a 0.6% by mass xylene solution of TFB polymer (LT-N148 manufactured by Luminescence Technology) was applied by spin coating, and then baked at 130° C. for 10 minutes to form a 20 nm charge-transporting thin film. It was formed as a hole transport layer. Further, on it, an 80 nm aluminum thin film was formed in the same manner as in Example 3 to fabricate an element.

[Comparative Example 4]

A 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 in the case of driving the fabricated device with a drive voltage of 5 V was measured. Table 3 shows the results.

Current density (mA/cm ² ) Example 3 610 Comparative Example 3 340 Example 4 330 Comparative Example 4 26

As shown in Table 3, the charge-transporting thin film obtained from the composition of the present invention was superior to the charge-transporting thin film obtained from the composition of the comparative example, and the hole injection property into the hole transporting layer was excellent. By using the charge-transporting thin film obtained from the composition of the present invention, an organic EL device with 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 each independently a group represented by any one of the following formulas (Ar1) to (Ar9).

(Wherein, R ¹ ~R ²¹ is, independently from each other, with an alkenyl group, Z ¹ of 2 to 20 carbon atoms that may be substituted with an alkyl group, Z ¹ of 1 to 20 carbon atoms that may be substituted with hydrogen atoms, Z ¹ of 2 to 20 carbon atoms that may be substituted with an alkynyl group, an aryl group of 6 to 20 carbon atoms optionally substituted by Z ² or heteroaryl group of 2 to 20 carbon atoms which may be substituted with Z ^2, and
Z ¹ is a heteroaryl group of 2 to 20 carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, an aryl group of 6 to 20 carbon atoms optionally substituted by Z ³ or Z ^3,
Z ² is two carbon atoms that may be substituted with a halogen atom, a nitro group, a cyano group, Z ³ an alkyl group of 1 to 20 carbon atoms that may be substituted, Z ³ in the 2 to 20 carbon atoms that may be substituted with an alkenyl group, or Z ³ It is an alkynyl group of ∼20,
Z ³ is a halogen atom, a nitro group or a cyano group.)] The method of claim 1,
A charge transport composition in which all Ar are the same group. The method of claim 2,
The charge transport composition in which Ar is a group represented by any one of formulas (Ar1) to (Ar5). The method of claim 3,
The charge transport composition where Ar is a group represented by the formula (Ar1). The method according to any one of claims 1 to 4,
Charge-transporting composition further comprising a dopant. The method of claim 5,
The charge transport composition in which the dopant is an arylsulfonic acid ester compound. A charge-transporting thin film produced using the charge-transporting composition according to any one of claims 1 to 5. An organic electroluminescence device comprising the charge-transporting thin film according to claim 7.