KR20230147645A - Charge-transporting ink composition - Google Patents

Abstract

A charge-transporting ink composition that has charge-transport properties and high transparency in the visible light region, produces a film excellent in flatness, and is stable against exposure to the atmosphere, comprising an amine compound represented by the following formula (P1), a charge-transport material, and an organic Provided is a charge-transporting ink composition comprising a solvent.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).)

Description

Charge-transporting ink composition

The present invention relates to charge transporting ink compositions.

Organic electroluminescence (hereinafter referred to as organic EL) devices are attracting attention for their various advantages such as high contrast, energy savings, and flexibility, and are being commercialized in fields such as displays and lighting. In organic EL devices, a plurality of functional thin films are used, one of which, the hole injection layer, is responsible for transferring charges between the anode and the hole transport layer or light emitting layer, and plays an important role in achieving low voltage driving and high brightness of the organic EL device. has

Manufacturing methods for organic EL devices are roughly divided into dry processes represented by vapor deposition methods, and wet processes represented by spin coating methods and inkjet methods. When comparing the two processes from the viewpoint of increasing the area of the device, the wet process can produce a film with high flatness over a large area more efficiently than the dry process. Therefore, at a time when large-area manufacturing of organic EL devices is required, it is important to provide a hole injection layer with excellent functionality that can be formed by a wet process.

One of the functions required for charge-transporting thin films such as hole injection layers is high transparency in the visible light region. For reasons such as the coloring of the charge-transporting thin film deteriorating the color purity and color reproduction of the organic EL device, it has recently been required to have high transparency in the visible light region.

Considering this, various studies have been conducted so far to achieve high transparency in the visible light region. In Patent Document 1, formation of a charge-transporting thin film with high transparency in the visible light region was achieved by using a composition containing metal oxide nanoparticles.

On the other hand, charge transport thin films such as hole injection layers require excellent charge transport properties and high transparency in the visible light region, as well as film flatness and stability of the ink composition. Non-patent Document 1 shows that the characteristics of an organic EL device are improved by reducing the surface roughness of the film. Additionally, charge-transporting inks are generally susceptible to the influence of oxygen and moisture, and there is a risk that their performance may change due to oxidation or decomposition of compounds in the ink. Therefore, it is important from a reliability standpoint that the charge-transporting ink is stable against atmospheric exposure.

International Publication No. 2018/135582

Korean Journal of Chemical Engineering 2005, Vol.22, p.643-647

With recent developments in the organic EL field, the performance requirements for functional thin films including a hole injection layer that can be formed by a wet process are increasing.

The present invention was made in view of the above background, and its purpose is to provide a charge-transporting ink composition that has charge-transport properties, produces a film excellent in flatness, and is stable against exposure to the atmosphere.

As a result of intensive study, the present inventors have found that when an amine compound is included in a charge-transporting ink composition containing a charge-transporting material and an organic solvent, such as the composition disclosed in Patent Document 1, an amine having a specific structure is used as the amine compound. It was discovered that by using the compound, the flatness of the charge-transporting thin film was improved and the stability of the ink to exposure to the atmosphere was improved, and the present invention was completed.

That is, the present invention provides the following charge-transporting ink composition.

1. A charge-transporting ink composition comprising an amine compound represented by the following formula (P1), a charge-transporting substance, and an organic solvent.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. When the kenylene group and the alkanetriyl group of R ^m and R ⁿ are combined with -NH ₂ in formula (P1), -CH ₂ -NH ₂ group is formed.)

2. The charge-transporting ink composition of 1, wherein R ^m is an alkyl group having 1 to 20 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms.

3. The charge-transporting ink composition of 1 or 2, wherein the charge-transporting material is a polythiophene derivative or an amine adduct thereof containing a repeating unit represented by the following formula (1).

(In the formula, R ¹ and R ² are independently of each other a hydrogen atom, an alkyl group with 1 to 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, an alkoxy group with 1 to 40 carbon atoms, or a fluoroalkoxy group with 1 to 40 carbon atoms. group, an aryloxy group having 6 to 20 carbon atoms, -O-[ZO] _p -R ^e , or a sulfonic acid group, or -OYO- formed by combining R ¹ and R ² , and Y contains an ether bond Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, R ^e is a hydrogen atom and has 1 carbon number. It is an alkyl group with ∼40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, or an aryl group with 6 to 20 carbon atoms.)

4. R ¹ is a sulfonic acid group, and R ² is an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] _p -R ^e , or -OYO- formed by combining R ¹ and R ² Charge transport ink composition of 3.

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

6. The charge-transporting ink composition of 5, wherein the dopant material includes at least one member selected from the group consisting of arylsulfonic acid compounds and heteropolyacid compounds.

7. The charge-transporting ink composition of any one of 1 to 6, further comprising metal oxide nanoparticles.

8. A charge-transporting thin film obtained from the charge-transporting ink composition of any one of 1 to 7.

9. Electronic device having a charge-transporting thin film of 8.

10. The electronic device of 9, which is an organic electroluminescence device.

11. A method of improving the storage stability of a charge-transporting ink composition containing an amine compound, a charge-transporting material, and an organic solvent, characterized in that, as the amine compound, an amine compound represented by the following formula (P1) is used. Method for improving storage stability of charge-transporting ink composition.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).)

12. A method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting material, and an organic solvent, comprising:

A method for improving the flatness of a charge-transporting thin film, characterized by using an amine compound represented by the following formula (P1) as the amine compound.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).)

By using the charge-transporting ink composition of the present invention, a charge-transporting thin film with excellent flatness can be obtained. Additionally, the charge-transporting ink composition of the present invention has excellent stability against atmospheric exposure. This charge-transporting thin film can be suitably used as a thin film for electronic devices, including organic EL devices.

1 is an absorption spectrum of a charge-transporting ink composition obtained in Examples and Comparative Examples.

(Form for carrying out the invention)

Hereinafter, the present invention will be described in more detail.

The charge-transporting ink composition of the present invention contains an amine compound represented by the following formula (P1), a charge-transporting substance, and an organic solvent. In addition, in the present invention, “solid content” regarding the charge-transporting ink composition of the present invention means components other than the solvent contained in the composition. Additionally, charge transport properties are the same as conductivity, and hole transport properties are also the same. The charge-transporting ink composition of the present invention may have charge-transporting properties itself, or the solid film obtained by using the composition may have charge-transporting properties.

In the formula, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms, an alkenylene group with 2 to 20 carbon atoms, or represents an arylene group with 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkantriyl group with 3 to 40 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms and an alkenyl group with 2 to 20 carbon atoms. The ren group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when bonded with -NH ₂ in formula (P1).

The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group , n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosanyl group, etc.

Alkenyl groups having 2 to 20 carbon atoms include ethenyl group, n-1-propenyl group, n-2-propenyl group, 1-methylethenyl group, n-1-butenyl group, n-2-butenyl group, and n-3- Butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, 1-methyl-1-propenyl group, 1-methyl-2-propenyl group, n-1- Pentenyl group, n-1-decenyl group, n-1-eicocenyl group, etc. can be mentioned.

Aryl groups 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, and 2-phenene. Examples include toryl group, 3-phenanthryl group, 4-phenanthryl group, and 9-phenanthryl group, and phenyl group, tolyl group, and naphthyl group are preferred.

The alkylene group having 1 to 20 carbon atoms is a divalent group derived from an alkane by removing two hydrogen atoms, and may be linear, branched, or cyclic, and specific examples include methylene group, ethylene group, propylene group, and tri-chain group. Methylene group, tetramethylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, Hexadecylene group, heptadecylene group, octadecylene group, nonadecylene group, and eicosanilene group.

The alkenylene group having 2 to 20 carbon atoms is a divalent group derived from an alkene by removing two hydrogen atoms, and includes vinylene group, propenylene group, butenylene group, pentenylene group, hexenylene group, heptenylene group, and octenyl group. Len group, nonenenylene group, decenylene group, undecenylene group, dodecenylene group, tridecenylene group, tetradecenylene group, pentadecenylene group, hexadecenylene group, heptadecenylene group, octadecenylene group, nonade A cenylene group, an icosenylene group, etc. are mentioned.

Examples of the arylene group having 6 to 20 carbon atoms include groups obtained by removing one hydrogen atom from the above specific examples of the aryl group having 6 to 12 carbon atoms, such as phenylene group, naphthylene group, biphenylene group, etc. there is.

The alkanetriyl group having 3 to 40 carbon atoms is a trivalent group derived by removing a hydrogen atom from an alkane, and examples include groups represented by the following formula (K1).

(In the formula, n ^r represents an integer from 0 to 10, n ^c represents an integer from 1 to 10, and * represents a bond.)

The above R ^m is preferably an alkyl group with 1 to 20 carbon atoms, more preferably an alkyl group with 1 to 10 carbon atoms, even more preferably an alkyl group with 1 to 8 carbon atoms, and even more preferably an alkyl group with 1 to 5 carbon atoms.

The above R ⁿ is preferably an alkylene group with 1 to 20 carbon atoms, more preferably an alkylene group with 1 to 10 carbon atoms, even more preferably an alkylene group with 1 to 8 carbon atoms, and even more preferably an alkylene group with 1 to 5 carbon atoms. .

The n ^r is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1, and the n ^c is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1. am.

As the combination of n ^r and n ^c , preferably both n ^r and n ^c are 1 to 3, more preferably both n ^r and n ^c are 1 to 2, and even more preferably n ^r is 1 to 2, n ^c is 1, and more preferably both n ^r and n ^c are 1.

Specific examples of the amine compound represented by formula (P1) include the following compounds, but are not limited to these.

In the charge-transporting ink composition of the present invention, the content of the amine compound represented by the formula (P1) is not particularly limited, but is expressed in mass ratio from the viewpoint of stability against exposure to the atmosphere and obtaining a thin film with good reproducibility and excellent flatness. It is about 0.01 to 10 times by mass relative to the charge-transporting material 1, preferably about 0.01 to 8 times by mass, more preferably about 0.01 to 6 times by mass, and even more preferably about 0.01 to 4 times by mass.

The charge transport material used in the present invention is not particularly limited and can be appropriately selected from charge transport compounds, charge transport oligomers, charge transport polymers, etc. used in the field of organic EL devices.

Specific examples thereof include arylamine derivatives such as oligoaniline derivatives, N,N'-diarylbenzidine derivatives, N,N, N',N'-tetraarylbenzidine derivatives, oligothiophene derivatives, thienothiophene derivatives, and thienobenzoate. Various charge-transporting compounds such as thiophene derivatives such as thiophene derivatives, pyrrole derivatives such as oligopyrrole, charge-transporting oligomers, and charge-transporting polymers such as polythiophene derivatives, polyaniline derivatives, and polypyrrole derivatives, and especially polythiophene derivatives. Offene derivatives are preferred.

In one preferred embodiment, the charge-transporting material is a polythiophene derivative or an amine adduct thereof containing a repeating unit represented by formula (1).

In the formula, R ¹ and R ² are independently of each other a hydrogen atom, an alkyl group with 1 to 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, an alkoxy group with 1 to 40 carbon atoms, or a fluoroalkoxy group with 1 to 40 carbon atoms. , an aryloxy group having 6 to 20 carbon atoms, -O-[ZO] _p -R ^e , or a sulfonic acid group, or -OYO- formed by combining R ¹ and R ² , and Y may contain an ether bond. , is an alkylene group having 1 to 40 carbon atoms which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, R ^e is a hydrogen atom and has 1 to 4 carbon atoms. It is an alkyl group with 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, or an aryl group with 6 to 20 carbon atoms.

The alkyl group having 1 to 40 carbon atoms may be linear, branched, or cyclic. Specific examples include behenyl, triacontyl, and tetracontyl groups in addition to the alkyl groups having 1 to 20 carbon atoms exemplified above. In the present invention, an alkyl group having 1 to 18 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms is more preferable.

The fluoroalkyl group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 40 carbon atoms in which at least one hydrogen atom on the carbon atom is replaced with a fluorine atom. Specific examples include fluoromethyl group, difluoromethyl group, perfluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,2-difluoroethyl group, 1,1-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, 1,2,2,2-tetrafluoroethyl group, perfluoro Roethyl group, 1-fluoropropyl group, 2-fluoropropyl group, 3-fluoropropyl group, 1,1-difluoropropyl group, 1,2-difluoropropyl group, 1,3-difluoro Lopropyl group, 2,2-difluoropropyl group, 2,3-difluoropropyl group, 3,3-difluoropropyl group, 1,1,2-trifluoropropyl group, 1,1, 3-trifluoropropyl group, 1,2,3-trifluoropropyl group, 1,3,3-trifluoropropyl group, 2,2,3-trifluoropropyl group, 2,3,3- Trifluoropropyl group, 3,3,3-trifluoropropyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,3-tetrafluoropropyl group, 1,2, 2,3-tetrafluoropropyl group, 1,3,3,3-tetrafluoropropyl group, 2,2,3,3-tetrafluoropropyl group, 2,3,3,3-tetrafluoropropyl group, 1,1,2,2,3-pentafluoropropyl group, 1,2,2,3,3-pentafluoropropyl group, 1,1,3,3,3-pentafluoropropyl group, 1,2,3,3,3-pentafluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, Perfluorohexyl group, perfluoroheptyl group, and perfluorooctyl group can be mentioned.

As an alkoxy group having 1 to 40 carbon atoms, the alkyl group therein may be linear, branched, or cyclic, and specific examples thereof include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, and c-propoxy group. group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, n-pentoxy group, n-hexoxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, n-tridecyloxy group, n-tetradecyloxy group, n-pentadecyloxy group, n-hexadecyloxy group, n-heptade Siloxy group, n-octadecyloxy group, n-nonadecyloxy group and n-eicosanyloxy group can be mentioned.

The fluoroalkoxy group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkoxy group having 1 to 40 carbon atoms in which at least one hydrogen atom on the carbon atom is replaced with a fluorine atom. Specific examples include fluoromethoxy group, difluoromethoxy group, and purple group. Fluoromethoxy group, 1-fluoroethoxy group, 2-fluoroethoxy group, 1,2-difluoroethoxy group, 1,1-difluoroethoxy group, 2,2-difluoro Ethoxy group, 1,1,2-trifluoroethoxy group, 1,2,2-trifluoroethoxy group, 2,2,2-trifluoroethoxy group, 1,1,2,2 -Tetrafluoroethoxy group, 1,2,2,2-tetrafluoroethoxy group, perfluoroethoxy group, 1-fluoropropoxy group, 2-fluoropropoxy group, 3-fluoro Propoxy group, 1,1-difluoropropoxy group, 1,2-difluoropropoxy group, 1,3-difluoropropoxy group, 2,2-difluoropropoxy group, 2, 3-difluoropropoxy group, 3,3-difluoropropoxy group, 1,1,2-trifluoropropoxy group, 1,1,3-trifluoropropoxy group, 1,2, 3-trifluoropropoxy group, 1,3,3-trifluoropropoxy group, 2,2,3-trifluoropropoxy group, 2,3,3-trifluoropropoxy group, 3, 3,3-trifluoropropoxy group, 1,1,2,2-tetrafluoropropoxy group, 1,1,2,3-tetrafluoropropoxy group, 1,2,2,3-tetra Fluoropropoxy group, 1,3,3,3-tetrafluoropropoxy group, 2,2,3,3-tetrafluoropropoxy group, 2,3,3,3-tetrafluoropropoxy group , 1,1,2,2,3-pentafluoropropoxy group, 1,2,2,3,3-pentafluoropropoxy group, 1,1,3,3,3-pentafluoropropoxyl group Period, 1,2,3,3,3-pentafluoropropoxy group, 2,2,3,3,3-pentafluoropropoxy group, perfluoropropoxy group, etc.

The alkylene group having 1 to 40 carbon atoms may be linear, branched, or cyclic, and specific examples include the same alkylene groups as those exemplified above.

Examples of the aryl group having 6 to 20 carbon atoms include the same ones as those exemplified above. In the present invention, phenyl group, tolyl group and naphthyl group are preferred.

Examples of the aryloxy group having 6 to 20 carbon atoms include phenoxy group, anthraceoxy group, naphthoxy group, phenanthrenoxy group, and fluorenoxy group.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

In the formula (1), R ¹ and R ² are independently of each other hydrogen atom, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, -O[C(R ^a R ^b )-C (R ^c R ^d )-O] _p -R ^e , -OR ^f , or a sulfonic acid group, or -OYO- formed by combining R ¹ and R ² is preferred.

R ^a to ^{R d} independently represent a hydrogen atom, an alkyl group with 1 to 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and specific examples of these groups are the same as those mentioned above. .

Among them, R ^a to R ^d are preferably, independently of each other, a hydrogen atom, an alkyl group with 1 to 8 carbon atoms, a fluoroalkyl group with 1 to 8 carbon atoms, or a phenyl group.

R ^e is a hydrogen atom, an alkyl group with 1 to 8 carbon atoms, a fluoroalkyl group with 1 to 8 carbon atoms, or a phenyl group, and is preferably a hydrogen atom, a methyl group, a propyl group, or a butyl group.

Moreover, p is preferably 1 to 5, and more preferably 1, 2, or 3.

R ^f is a hydrogen atom, an alkyl group with 1 to 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, or an aryl group with 6 to 20 carbon atoms; Alternatively, a phenyl group is preferable, and -CH ₂ CF ₃ is more preferable.

In the present invention, R ¹ is preferably a hydrogen atom or a sulfonic acid group, more preferably a sulfonic acid group, and R ² is preferably an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] _p -R ^e , more preferably -O[C(R ^a R ^b )-C(R ^c R ^d )-O] _p -R ^e or -OR ^f , even more preferably -O[C(R ^a R ^b )- C(R ^c R ^d )-O] _p -R ^e , -O-CH ₂ CH ₂ -O-CH ₂ CH ₂ -O-CH ₃ , -O-CH ₂ CH ₂ -O-CH ₂ CH ₂ - OH or -O-CH ₂ CH ₂ -OH, or -OYO- formed by R ¹ and R ² bonded to each other.

For example, the polythiophene derivative according to a preferred embodiment of the present invention is -OYO where R ¹ is a sulfonic acid group, R ² includes a repeating unit other than a sulfonic acid group, or R ¹ and R ² are combined to form -Contains a repeating unit.

Preferably, the polythiophene derivative contains a repeating unit where R ¹ is a sulfonic acid group and R ² is an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] _p -R ^e , or R ¹ and R It contains a repeating unit that is -OYO-, which is formed by combining ² .

More preferably, in the polythiophene derivative, R ¹ is a sulfonic acid group, and R ² is -O[C(R ^a R ^b )-C(R ^c R ^d )-O] _p -R ^e or -OR ^f contains repeat units.

Even more preferably, the polythiophene derivative has a repeating unit wherein R ¹ is a sulfonic acid group and R ² is -O[C(R ^a R ^b )-C(R ^c R ^d )-O] _p -R ^e or a repeating unit that is -OYO-, which is formed by combining R ¹ and R ² .

More preferably, in the polythiophene derivative, R ¹ is a sulfonic acid group, and R ² is -O-CH ₂ CH ₂ -O-CH ₂ CH ₂ -O-CH ₃ , -O-CH ₂ CH ₂ -O Contains a repeating unit of -CH ₂ CH ₂ -OH, or -O-CH ₂ CH ₂ -OH, or R ¹ and R ² are bonded to each other, and are groups represented by the following formulas (Y1) and (Y2). Includes units.

Preferred specific examples of the polythiophene derivative include polythiophene containing at least one repeating unit represented by the following formulas (1-1) to (1-5).

Additionally, a suitable structure of the polythiophene derivative includes, for example, a polythiophene derivative having a structure represented by the following formula (1a). In addition, in the following formula, each unit may be bonded randomly or may be bonded as a block polymer.

In the formula, a to d represent the molar ratio of each unit, 0≤a≤1, 0≤b≤1, 0<a+b≤1, 0≤c<1, 0≤d<1, a+b+ c+d=1 is satisfied.

Additionally, the polythiophene derivative may be a homopolymer or copolymer (including statistical, random, gradient, and block copolymers). As polymers containing monomer A and monomer B, block copolymers include, for example, AB diblock copolymer, ABA triblock copolymer, and (AB) _m -multiblock copolymer. Polythiophenes are made up of different types of monomers (e.g., thienothiophene, selenophen, pyrrole, furan, tellurophene, aniline, arylamine, and arylene (e.g., phenylene, phenylenevinylene, and It may contain repeating units derived from fluorene, etc.).

In the present invention, the content of the repeating unit represented by formula (1) in the polythiophene derivative is preferably more than 50 mol%, and more than 80 mol%, based on the total repeating units contained in the polythiophene derivative. It is preferable, 90 mol% or more is more preferable, 95 mol% or more is still more preferable, and 100 mol% is most preferable.

In the present invention, depending on the purity of the starting monomer used in polymerization, the formed polymer may contain repeating units derived from impurities. In the present invention, the term "homopolymer" above refers to a polymer containing a repeating unit derived from one type of monomer, but may also contain a repeating unit derived from an impurity. In the present invention, the polythiophene derivative is preferably a polymer in which all repeating units are basically repeating units represented by the formula (1), and are represented by the formulas (1-1) to (1-5). It is more preferable that it is a polymer containing at least one repeating unit.

In the present invention, when the polythiophene derivative contains a repeating unit having a sulfonic acid group, from the viewpoint of further improving solubility and dispersibility in organic solvents, at least a portion of the sulfonic acid group contained in the polythiophene derivative is added with an amine. It is preferable to use an amine adduct to which the compound is added.

Amine compounds that can be used to form amine adducts include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, s-butylamine, t-butylamine, and n-pentylamine. , n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, Monoalkylamine compounds such as n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, and n-eicosanylamine; Aniline, tolylamine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenane Primary amine compounds such as monoarylamine compounds such as torylamine, 4-phenanthrylamine, and 9-phenanthrylamine; N-ethylmethylamine, N-methyl-n-propylamine, N-methylisopropylamine, N-methyl-n-butylamine, N-methyl-s-butylamine, N-methyl-t-butylamine, N -Methylisobutylamine, diethylamine, N-ethyl-n-propylamine, N-ethylisopropylamine, N-ethyl-n-butylamine, N-ethyl-s-butylamine, N-ethyl-t- Butylamine, dipropylamine, N-n-propylisopropylamine, N-n-propyl-n-butylamine, N-n-propyl-s-butylamine, diisopropylamine, N-n-butylisopropylamine, N-t-butylisopropylamine , di(n-butyl)amine, di(s-butyl)amine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2,2-dimethylaziridine, azetidine ( Trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2,6-dimethylpiperidine dialkylamine compounds such as , 3,5-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, and octamethyleneimine; Diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-dinaphthylamine, 2,2'-dinaphthylamine, 1,2'-di Naphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H-dibenzo[a,i]carbazole, etc. diarylamine compounds; N-methylaniline, N-ethylaniline, N-n-propylaniline, N-isopropylaniline, N-n-butylaniline, N-s-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl -1-naphthylamine, N-n-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, etc. secondary amine compounds such as alkylarylamine compounds; N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethyl-n-butylamine, N,N-dimethyl-s-butylamine, N,N-dimethyl-t-butylamine, N,N-dimethylisobutylamine, N,N-diethylmethylamine, N-methyldi(n-propyl)amine, N-methyldiisopropylamine, N- Methyldi(n-butyl)amine, N-methyldiisobutylamine, triethylamine, N,N-diethyl-n-butylamine, N,N-diisopropylethylamine, N,N-di(n) -Butyl)ethylamine, tri(n-propyl)amine, tri(i-propyl)amine, tri(n-butyl)amine, tri(i-butyl)amine, 1-methylacetidine, 1-methylpyrroli trialkylamine compounds such as dine and 1-methylpiperidine; triarylamine compounds such as triphenylamine; Alkyldiarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole, and 9-ethylcarbazole; Dialkylarylamine compounds such as N,N-diethylaniline, N,N-di(n-propyl)aniline, N,N-di(i-propyl)aniline, N,N-di(n-butyl)aniline, etc. tertiary amine compounds such as tertiary amine compounds, but considering the balance of the solubility of the amine adduct and the charge transportability of the resulting charge transport thin film, tertiary amine compounds are preferable, trialkylamine compounds are more preferable, and triethyl Amines are even more preferred.

Amine adducts can be obtained by adding a polythiophene derivative to the amine itself or its solution and stirring well.

In the present invention, the polythiophene derivative or its amine adduct treated with a reducing agent may be used.

In polythiophene derivatives or their amine adducts, some of the repeating units constituting them may have an oxidized chemical structure called a “quinoid structure.” The term “quinoid structure” is used for the term “benzenoid structure,” and the latter is a structure containing an aromatic ring, while the former is a structure in which the double bond within the aromatic ring moves to the outside of the ring (as a result, the aromatic ring disappears). ), refers to a structure in which two extra-ring double bonds are formed that conjugate with other double bonds remaining in the ring. For those skilled in the art, the relationship between these two structures can be easily understood from the relationship between the structures of benzoquinone and hydroquinone. The quinoid structures for the repeat units of various conjugated polymers are well known to those skilled in the art. As an example, the quinoid structure corresponding to the repeating unit of the polythiophene derivative containing the repeating unit represented by the above formula (1) is shown in the following formula (1').

(Wherein, R ¹ and R ² are as defined in formula (1) above.)

This quinoid structure is created by a process in which a polythiophene derivative containing the repeating unit represented by the above formula (1) undergoes an oxidation reaction with a dopant, the so-called doping reaction, and imparts charge transport properties to the polythiophene derivative. It forms part of the structure called “polaron structure” and “bipolaron structure”. These structures are known. In the production of an organic EL device, the introduction of a “polaron structure” and/or a “bipolaron structure” is essential, and in fact, when creating an organic EL device and baking a thin film formed from a charge-transporting ink composition, the above This is achieved by intentionally causing a doping reaction. The fact that the polythiophene derivative before causing this doping reaction contains a quinoid structure means that the polythiophene derivative is subject to an unintended oxidation reaction equivalent to the doping reaction during the production process (particularly, the sulfonation process). It is thought that this is because it caused.

There is a correlation between the amount of quinoid structure contained in the polythiophene derivative and the solubility and dispersibility of the polythiophene derivative in organic solvents. As the amount of quinoid structure increases, the solubility and dispersibility tend to decrease. There is. For this reason, the introduction of the quinoid structure after the thin film is formed from the charge-transporting ink composition does not cause a problem, but if the quinoid structure is excessively introduced into the polythiophene derivative due to the above-mentioned unintended oxidation reaction, In some cases, this may cause problems in the production of charge-transporting ink compositions. It is known that polythiophene derivatives have variations in solubility and dispersibility in organic solvents, but one of the reasons for this is the amount of quinoid structure introduced into polythiophene through the unintended oxidation reaction described above. It is thought that it fluctuates depending on differences in manufacturing conditions of polythiophene derivatives.

Therefore, when the polythiophene derivative is subjected to a reduction treatment using a reducing agent, even if the quinoid structure is excessively introduced into the polythiophene derivative, the quinoid structure is reduced by reduction, thereby reducing the organic content of the polythiophene derivative. Since solubility and dispersibility in solvents are improved, it becomes possible to stably produce an ink composition with good charge transport properties that produces a thin film with excellent homogeneity.

The conditions for the reduction treatment are to reduce the quinoid structure and appropriately convert it into a non-oxidized structure, that is, the benzenoid structure (e.g., a polythiophene derivative containing a repeating unit represented by the formula (1) above) There is no particular limitation as long as the quinoid structure represented by the formula (1') can be converted to the structure represented by the formula (1), for example, in the presence or absence of a suitable solvent. However, this treatment can be performed simply by contacting the polythiophene derivative or amine adduct with a reducing agent.

There is no particular limitation to this reducing agent as long as the reduction is appropriate, but for example, ammonia water and hydrazine, which are readily available as commercial products, are suitable.

In addition, the amount of reducing agent cannot be uniformly specified because it varies depending on the amount of reducing agent used, but from the viewpoint of appropriate reduction, usually 0.1 mass parts per 100 parts by mass of polythiophene derivative or amine adduct to be treated. parts or more, and from the viewpoint of preventing excess reducing agent from remaining, it is 10 parts by mass or less.

As an example of a specific method of reduction treatment, the polythiophene derivative or amine adduct is stirred in 28% aqueous ammonia at room temperature overnight. By reduction treatment under these relatively mild conditions, the solubility and dispersibility of the polythiophene derivative or amine adduct in organic solvents are sufficiently improved.

In the charge-transporting ink composition of the present invention, when an amine adduct of a polythiophene derivative is used, the reduction treatment may be performed before forming the amine adduct or after forming the amine adduct.

In addition, as a result of this reduction treatment, the solubility and dispersibility of the polythiophene derivative or its amine adduct in the solvent is changed, so that the polythiophene derivative or its amine adduct that was not dissolved in the reaction system at the start of the treatment is treated. It may be dissolved upon completion. In such cases, an organic solvent incompatible with the polythiophene derivative or its amine adduct (in the case of sulfonated polythiophene, acetone, isopropyl alcohol, etc.) is added to the reaction system to form a polythiophene derivative or its amine adduct. The polythiophene derivative or its amine adduct can be recovered by methods such as precipitation and filtration.

The weight average molecular weight of the polythiophene derivative or its amine adduct containing the repeating unit represented by formula (1) is preferably about 1,000 to 1,000,000, more preferably about 5,000 to 100,000, and even more preferably about 10,000 to about 50,000. desirable. By setting the weight average molecular weight above the lower limit, good conductivity can be obtained with good reproducibility, and by setting it below the upper limit, solubility in solvents is improved. In addition, the weight average molecular weight is a value converted to polystyrene by gel permeation chromatography.

The polythiophene derivative or its amine adduct contained in the charge-transporting ink composition of the present invention may be only one polythiophene derivative or its amine adduct containing a repeating unit represented by formula (1), or may be two or more types. do.

In addition, the polythiophene derivative containing the repeating unit represented by formula (1) may be a commercial product or one polymerized by a known method using a thiophene derivative or the like as a starting material. In either case, It is also preferable to use those purified by methods such as reprecipitation or ion exchange. By using a purified ink composition, the characteristics of an organic EL device with a thin film obtained from the charge-transporting ink composition of the present invention can be further improved.

Additionally, sulfonation of conjugated polymers and sulfonated conjugated polymers (including sulfonated polythiophenes) are described in US Pat. No. 8,017,241 to Seshadri et al. In addition, sulfonated polythiophene is described in International Publication No. 2008/073149 and International Publication No. 2016/171935.

In the present invention, at least a portion of the polythiophene derivative containing the repeating unit represented by formula (1) or its amine adduct contained in the charge-transporting ink composition is dissolved in an organic solvent.

In the present invention, as the charge transport material, a polythiophene derivative or an amine adduct thereof containing a repeating unit represented by formula (1) and a charge transport material composed of other charge transport compounds may be used in combination, but the charge transport material may be used in combination with the charge transport material of the formula (1). It is preferable that only polythiophene derivatives or amine adducts thereof containing the repeating unit represented by 1) are included.

The content of the charge-transporting material in the charge-transporting ink composition of the present invention is usually in the range of 0.05 to 40% by mass, preferably 0.1 to 35% by mass, based on the solid content, taking into account the desired film thickness and viscosity of the ink composition, etc. It is decided appropriately.

The charge-transporting ink composition of the present invention includes an organic solvent. These organic solvents are not particularly limited as long as they disperse or dissolve solid content. Specific examples thereof include aromatic or halogenated aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and chlorobenzene; Aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclohexane; Ether-based solvents such as diethyl ether, tetrahydrofuran, dioxane, and 1,2-dimethoxyethane; Ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Ester solvents such as ethyl acetate, normalhexyl acetate, ethyl lactate, γ-butyrolactone, propylene carbonate, and diisopropyl malonate; Halogenated hydrocarbon solvents such as methylene chloride, dichloromethane, 1,2-dichloroethane, and chloroform; amide-based solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone; Alcohol-based solvents such as methanol, ethanol, isopropanol, n-propanol, cyclohexanol, diacetone alcohol, and 2-benzooxyethanol; Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol diglycidyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol Glycol ethers such as dimethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate. menstruum; Ethylene glycol, propylene glycol, hexylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4- It may be used by appropriately selecting from among glycol-based solvents such as butanediol.

In the present invention, among these, amide-based solvents, glycol ether-based solvents and glycol-based solvents are preferred, and 1,3-dimethyl-2-imidazolidinone, dipropylene glycol and dipropylene glycol monomethyl ether are more preferred. .

In addition, these organic solvents can be used individually or in mixture of two or more types.

The charge-transporting ink composition of the present invention may also contain water as a solvent, but the water content is preferably 10% by mass or less, and more preferably 5% by mass or less, of the total solvent, from the viewpoint of obtaining a durable organic EL device with good reproducibility. It is preferable and optimal to use only organic solvents as solvents. In addition, “only organic solvent” in this case means that only organic solvents are used as solvents, and does not deny the existence of “water” contained in trace amounts in the organic solvents or solids used.

The charge-transporting ink composition of the present invention may contain metal oxide nanoparticles. Nanoparticles refer to fine particles whose average particle diameter relative to the primary particle is the size of nanometers (typically 500 nm or less). Metal oxide nanoparticles refer to metal oxides formed into nanoparticles.

The primary particle diameter of the metal oxide nanoparticles used in the present invention is not particularly limited as long as it is nano-sized, but considering obtaining a thin film with good reproducibility and excellent flatness, 2 to 150 nm is preferable, and 3 to 100 nm is more preferable. 5 to 50 nm is even more preferable. In addition, the particle diameter is a measured value using the nitrogen adsorption isotherm by the BET method.

The metals constituting the metal oxide nanoparticles used in the present invention include metals in the ordinary sense as well as semimetals.

Metals in the ordinary sense are not particularly limited, but include tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten ( It is preferable to use one or two or more types selected from the group consisting of W).

Meanwhile, a semimetal refers to an element whose chemical and/or physical properties are intermediate between metals and nonmetals. Although a universal definition of semimetals has not been established, in the present invention, a total of six elements are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). is considered a semimetal. These semimetals may be used individually, may be used in combination of two or more types, and may be used in combination with metals in the ordinary sense.

The metal oxide nanoparticles used in the present invention include boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), tin (Sn), and titanium (Ti). , aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten (W). In addition, when two or more metals are combined, the metal oxide may be a mixture of oxides of individual metals, or may be a complex oxide containing a plurality of metals.

Specific examples of metal oxides include B ₂ O ₃ , B ₂ O, SiO ₂ , SiO, GeO ₂ , GeO, As ₂ O ₄ , As ₂ O ₃ , As ₂ O ₅ , Sb ₂ O ₃ , Sb ₂ O ₅ , TeO ₂ , SnO ₂ , ZrO ₂ , Al ₂ O ₃ , ZnO, etc., but B ₂ O ₃ , B ₂ O, SiO ₂ , SiO, GeO ₂ , GeO, As ₂ O ₄ , As ₂ O ₃ , As _{2O 5} , SnO ₂ , SnO, Sb ₂ O ₃ , TeO ₂ , and mixtures thereof are preferred, and SiO ₂ is more preferred.

The metal oxide nanoparticles contained in the charge-transporting ink composition of the present invention may be one type or two or more types.

It is preferable that the metal oxide nanoparticles contained in the charge-transporting ink composition of the present invention are uniformly dispersed in the composition.

Additionally, the metal oxide nanoparticles may include one or more organic capping groups. This organic capping group may be reactive or non-reactive. Examples of reactive organic capping groups include organic capping groups that can be crosslinked by ultraviolet rays or radical initiators.

In the charge-transporting ink composition of the present invention, the content of metal oxide nanoparticles is not particularly limited, but from the viewpoint of suppressing agglomeration of particles in the charge-transporting ink composition, obtaining a thin film with good reproducibility and excellent flatness, etc. Of the solid content contained in the charge-transporting ink composition, 40 to 95 mass% is preferable, 50 to 95 mass% is more preferable, and 60 to 90 mass% is most preferable.

In particular, in the present invention, by using a metal oxide nanoparticle sol in which metal oxide nanoparticles are dispersed, a composition in which metal oxide nanoparticles are uniformly dispersed can be prepared with good reproducibility.

That is, by mixing and dispersing the metal oxide nanoparticles themselves in a solvent together with a charge-transporting material, etc., a metal oxide nanoparticle sol is prepared in advance, and the sol is mixed with a mixture in which the charge-transporting material, etc. is dissolved or dispersed in a solvent, thereby dispersing the metal oxide nanoparticles in a solvent. A charge-transporting ink composition in which oxide nanoparticles are uniformly dispersed can be manufactured with good reproducibility.

Such a metal oxide nanoparticle sol may be a commercially available product or may be prepared by a known method using a solvent and metal oxide nanoparticles that may be included in the charge-transporting ink composition of the present invention.

In particular, when preparing the charge-transporting ink composition of the present invention, it is suitable to use silica sol in which SiO ₂ nanoparticles are dispersed in a dispersion medium.

The silica sol is not particularly limited and can be appropriately selected and used from known silica sol.

Commercially available silica sol is usually in the form of a dispersion. As a commercially available silica sol, SiO ₂ nanoparticles can be dissolved in various solvents, such as water, methanol, methyl ethyl ketone, methyl isobutyl ketone, N,N-dimethylacetamide, ethylene glycol, isopropanol, methanol, and ethylene glycol monopropyl ether. , cyclohexanone, ethyl acetate, toluene, propylene glycol monomethyl ether acetate, etc.

In particular, in the present invention, silica sol whose dispersion medium is an alcohol-based solvent, glycol-based solvent, or water is preferable, and silica sol whose dispersion medium is an alcohol-based solvent or glycol-based solvent is more preferable. As the alcohol-based solvent or glycol-based solvent, a water-soluble alcohol or glycol-based solvent is preferable, and methanol, 2-propanol, and ethylene glycol are more preferable.

Specific examples of commercially available silica sol include Snowtex (registered trademark) ST-O, ST-OS, ST-O-40, ST-OL manufactured by Nissan Chemical Co., Ltd., and Silica Dole 20 manufactured by Nippon Chemical Co., Ltd. , 30, 40, etc. water-dispersed silica sol; Methanol silica sol manufactured by Nissan Chemical Co., Ltd., organo silica sol such as MA-ST-M, MA-ST-L, IPA-ST, IPA-ST-L, IPA-ST-ZL, EG-ST, etc. can be mentioned, but are not limited to these.

The concentration of SiO ₂ nanoparticles in silica sol is usually about 5 to 50% by mass, but when the concentration of SiO ₂ nanoparticles is high, when silica sol is mixed with a mixture in which charge-transporting substances, etc. are dissolved or dispersed in a solvent, the mixture Depending on the type of solvent it contains, SiO ₂ nanoparticles may aggregate, so keep that in mind when preparing the composition.

The charge-transporting ink composition of the present invention contains an amine compound represented by formula (P1), a charge-transporting material, and an organic solvent. However, in order to improve the charge-transporting ability, etc., a dopant material may be included as necessary. do. The dopant material is not particularly limited as long as it is dispersed or dissolved in at least one solvent used in the charge-transporting ink composition, and either an inorganic dopant material or an organic dopant material can be used.

When the charge-transporting ink composition of the present invention contains a dopant material, its content is appropriately set in consideration of the type and amount of the charge-transporting material, but is usually 0.1 to 20.0 per 1 charge-transporting material in mass ratio. is the range.

Examples of inorganic dopant materials include inorganic acids such as hydrogen chloride, sulfuric acid, nitric acid, and phosphoric acid; Aluminum (III) chloride (AlCl ₃ ), titanium (IV) tetrachloride (TiCl ₄ ), boron tribromide (BBr ₃ ), boron trifluoride ether complex (BF ₃ ·OEt ₂ ), iron (III) chloride (FeCl ₃ ), Copper(II) chloride (CuCl ₂ ), antimony (V) pentafluoride (SbCl ₅ ), antimony (V) pentafluoride (SbF ₅ ), arsenic (V) pentafluoride (AsF ₅ ), phosphorus pentafluoride (PF ₅ ). metal halides such as tris(4-bromophenyl)aluminum hexachloroantimonate (TBPAH); Halogens such as Cl ₂ , Br ₂ , I ₂ , ICl, ICl ₃ , IBr, IF ₄ ; Heteropoly acids such as phosphomolybdic acid and phosphotungstic acid can be mentioned.

In addition, organic dopant materials include 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, etc. tetracyanoquinodimethane; Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8 ,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodi Halotetracyanoquinodimethane (haloTCNQ) such as methane and 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane; Benzoquinone derivatives such as tetrachloro-1,4-benzoquinone (chloranyl) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ); Benzenesulfonic acid, tosylic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2,5-dihexylbenzenesulfonic acid, dihexylbenzenesulfonic acid Butylnaphthalenesulfonic 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, dinonylnaphthalenedi. Sulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, 1,4-benzodioxanedisulfonic acid derivative described in International Publication No. 2005/000832, arylsulfonic acid derivative described in International Publication No. 2006/025342, Arylsulfonic acid compounds such as dinonylnaphthalenesulfonic acid derivatives described in Japanese Patent Laid-Open No. 2005-108828, and aromatic sulfone compounds such as polystyrenesulfonic acid; and non-aromatic sulfone compounds such as 10-camphasulfonic acid.

These inorganic and organic dopant substances may be used individually or in combination of two or more types.

In the present invention, among these dopant substances, arylsulfonic acid compounds are suitable, and examples of preferable arylsulfonic acid compounds include arylsulfonic acid compounds represented by formula (H1) or (H2).

A ¹ represents O or S, but O is preferred.

A ² represents a naphthalene ring or an anthracene ring, but a naphthalene ring is preferred.

A ³ represents a divalent to tetravalent perfluorobiphenyl group, s represents the number of bonds between A ¹ and A ³ , and is an integer satisfying 2≤s≤4, but A ³ is preferably a perfluorobiphenyldiyl group. It is preferably a perfluorobiphenyl-4,4'-diyl group, and s is preferably 2.

q represents the number of sulfonic acid groups bonded to A ² and is an integer satisfying 1≤q≤4, but 2 is optimal.

A ⁴ to ^{A 8} independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group with 1 to 20 carbon atoms, a halogenated alkyl group with 1 to 20 carbon atoms, or a halogenated alkenyl group with 2 to 20 carbon atoms, but A ⁴ At least three of ~A ⁸ are halogen atoms.

Halogenated alkyl groups having 1 to 20 carbon atoms include trifluoromethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2,2-pentafluoroethyl group, and 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-nonafluorobutyl group, etc. can be mentioned.

Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include perfluorovinyl group, perfluoropropenyl group (allyl group), and perfluorobutenyl group.

In addition, examples of the halogen atom and an alkyl group having 1 to 20 carbon atoms include the same as above, but the halogen atom is preferably a fluorine atom.

Among these, A ⁴ to ^{A 8} is a hydrogen atom, a halogen atom, a cyano group, an alkyl group with 1 to 10 carbon atoms, a halogenated alkyl group with 1 to 10 carbon atoms, or a halogenated alkenyl group with 2 to 10 carbon atoms, and A ⁴ to A At least 3 of ^{the 8} are preferably fluorine atoms, and are hydrogen atom, fluorine atom, cyano group, alkyl group of 1 to 5 carbon atoms, fluoroalkyl group of 1 to 5 carbon atoms, or alkenyl fluoride group of 2 to 5 carbon atoms. At least three of A ⁴ to ^{A 8} are more preferably fluorine atoms, and are a hydrogen atom, a fluorine atom, a cyano group, a perfluoroalkyl group with 1 to 5 carbon atoms, or a perfluoroalkenyl group with 1 to 5 carbon atoms, Moreover, it is further preferable that A ⁴ , A ⁵ and A ⁸ are fluorine atoms.

In addition, a perfluoroalkyl group is a group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms, and a perfluoroalkenyl group is a group in which all hydrogen atoms of an alkenyl group are substituted with fluorine atoms.

r represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1≤r≤4, with 2 to 4 being preferable and 2 being optimal.

When using an organic compound as a dopant material, its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, considering its solubility in organic solvents.

In particular, the molecular weight of the arylsulfonic acid compound used as the dopant material is not particularly limited, but considering solubility in organic solvents, it is preferably 2,000 or less, more preferably 1,500 or less.

In the present invention, examples of arylsulfonic acid compounds that can be suitably used include the following compounds, but are not limited to these.

In the charge-transporting ink composition of the present invention, for the purpose of improving the dispersibility and solubility of charge-transporting substances such as polythiophene derivatives or amine adducts thereof, the amine compound represented by formula (P1) and other An amine compound may be included.

These other amine compounds are not particularly limited as long as they are soluble in at least one type of solvent used in the ink composition, and may be one type alone or two or more types.

Specific examples of primary amine compounds include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, s-butylamine, t-butylamine, n-pentylamine, and n-hexylamine. , n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine , monoalkylamine compounds such as n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, and n-eicosanylamine; Aniline, tolylamine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenane and monoarylamine compounds such as torylamine, 4-phenanthrylamine, and 9-phenanthrylamine.

Specific examples of secondary amine compounds include N-ethylmethylamine, N-methyl-n-propylamine, N-methylisopropylamine, N-methyl-n-butylamine, N-methyl-s-butylamine, and N-methylamine. -t-Butylamine, N-methylisobutylamine, diethylamine, N-ethyl-n-propylamine, N-ethylisopropylamine, N-ethyl-n-butylamine, N-ethyl-s-butylamine , N-ethyl-t-butylamine, dipropylamine, N-n-propylisopropylamine, N-n-propyl-n-butylamine, N-n-propyl-s-butylamine, diisopropylamine, N-n-butylisopropylamine , N-t-butylisopropylamine, di(n-butyl)amine, di(s-butyl)amine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2,2- Dimethylaziridine, azetidine (trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2 dialkylamine compounds such as 6-dimethylpiperidine, 3,5-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, and octamethyleneimine; Diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-dinaphthylamine, 2,2'-dinaphthylamine, 1,2'-di Naphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H-dibenzo[a,i]carbazole, etc. diarylamine compounds; N-methylaniline, N-ethylaniline, N-n-propylaniline, N-isopropylaniline, N-n-butylaniline, N-s-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl -1-naphthylamine, N-n-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, etc. Alkylarylamine compounds, etc. can be mentioned.

Specific examples of tertiary amine compounds include N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethyl-n-butylamine, N,N- Dimethyl-s-butylamine, N,N-dimethyl-t-butylamine, N,N-dimethylisobutylamine, N,N-diethylmethylamine, N-methyldi(n-propyl)amine, N-methyl Diisopropylamine, N-methyldi(n-butyl)amine, N-methyldiisobutylamine, triethylamine, N,N-diethyl-n-butylamine, N,N-diisopropylethylamine, N,N-di(n-butyl)ethylamine, tri(n-propyl)amine, tri(i-propyl)amine, tri(n-butyl)amine, tri(i-butyl)amine, 1-methylacety trialkylamine compounds such as dine, 1-methylpyrrolidine, and 1-methylpiperidine; triarylamine compounds such as triphenylamine; Alkyldiarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole, and 9-ethylcarbazole; Dialkylarylamine compounds such as N,N-diethylaniline, N,N-di(n-propyl)aniline, N,N-di(i-propyl)aniline, N,N-di(n-butyl)aniline, etc. etc. can be mentioned.

In particular, when the charge transport ink composition of the present invention contains other amine compounds, the ability to improve the dispersibility and solubility of charge transport materials such as polythiophene derivatives or amine adducts thereof used in the present invention is excellent. , the other amine compound preferably contains a primary amine compound, and preferably contains a monoalkylamine, especially a monoalkylamine having 2 to 20 carbon atoms.

When the charge-transporting ink composition of the present invention contains other amine compounds, the content thereof is usually about 10 times by mass or less relative to the charge-transporting material such as polythiophene derivatives or amine adducts thereof used in the present invention. am.

Additionally, heteropoly acid can also be suitably used as a dopant material. Heteropoly acids are typically represented by a Keggin-type chemical structure represented by formula (A) or a Dawson-type chemical structure represented by formula (B), and have a structure in which the hetero atom is located at the center of the molecule, and contain vanadium (V) and molybdenum (Mo ), isopoly acid, which is an oxyacid such as tungsten (W), and a polyacid formed by condensation of an oxyacid of a different element. Examples of oxyacids of these heterogeneous elements mainly include oxyacids of silicon (Si), phosphorus (P), and arsenic (As).

Specific examples of heteropoly acids include phosphomolybdic acid, silicolybdic acid, phosphotungstic acid, silicotungstic acid, and phosphotungstomolybdic acid, and these may be used individually or in combination of two or more types. In addition, the heteropoly acid used in the present invention is available as a commercial item and can also be synthesized by a known method.

In particular, when it contains only one type of heteropoly acid, it is preferable that the one type of heteropoly acid contains tungsten. That is, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, etc. are preferable, and phosphotungstic acid and silicotungstic acid are more preferable.

In addition, in quantitative analysis such as elemental analysis, heteropolyacids, even if they have a large or small number of elements based on the structure expressed by the general formula, are obtained as commercial products or synthesized appropriately according to a known synthesis method. As long as it is, it can be used in the present invention.

That is, for example, phosphotungstic acid is generally represented by the formula H ₃ (PW ₁₂ O ₄₀ )·nH _2O , but in quantitative analysis, P (phosphorus), O (oxygen), or W (tungsten) in this formula ) Even if the number is large or small, it can be used in the present invention as long as it is obtained as a commercial product or synthesized appropriately according to a known synthesis method. In this case, the mass of heteropoly acid specified in the present invention is not the mass (phosphotungstic acid content) of pure phosphotungstic acid in the composite or commercial product, but is in the form available as a commercial product and in a form that can be isolated by known synthetic methods, such as water of hydration or It refers to the total mass including other impurities.

The charge-transporting ink composition of the present invention may contain a known organosilane compound. By including such an organic silane compound in the charge-transporting ink composition, when the charge-transporting thin film obtained from the ink composition is used as a hole injection layer of an organic EL device, the hole injection property to the hole transport layer provided in contact with it can be improved. there is.

As the organic silane compound, alkoxysilanes are preferable, and trialkoxysilanes and tetraalkoxysilanes are more preferable. Examples of the alkoxysilanes include tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, 3,3,3- Trifluoropropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, etc. are mentioned. In the present invention, among these, tetraethoxysilane (TEOS), tetramethoxysilane, and tetraisopropoxysilane can be suitably used. These organosilane compounds can be used individually or in combination of two or more types.

When the charge-transporting ink composition of the present invention contains an organic silane compound, its content is usually about 0.1 to 50% by mass of the solid content, but the balance of improving the flatness of the resulting thin film and suppressing the decline in charge-transporting properties is taken into consideration. In this case, it is preferably about 0.5 to 40 mass%, more preferably about 0.8 to 30 mass%, and even more preferably about 1 to 20 mass%.

The viscosity of the charge-transporting ink 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 ink composition of the present invention can be adjusted by taking into account various factors such as the application method used and the desired film thickness, and changing the type of organic solvent used, their ratio, solid concentration, etc.

In addition, the solid content concentration of the charge-transporting ink composition of the present invention is appropriately set in consideration of the viscosity and surface tension of the charge-transporting ink composition and the thickness of the thin film to be produced, but is usually about 0.1 to 15% by mass, and the ink From the viewpoint of suppressing aggregation of charge-transporting substances or metal oxide nanoparticles in the composition, it is preferably 10 mass% or less, more preferably 8 mass% or less, and even more preferably 6 mass% or less.

When preparing the charge-transporting ink composition of the present invention, as long as the solid content is uniformly dissolved or dispersed in the solvent, the amine compound represented by formula (P1), the charge-transporting material and the solvent, and, if necessary, metal oxide nanoparticles and Dopant materials, etc. can be mixed in any order. That is, for example, after obtaining a solution in which a charge transport material and an amine compound represented by formula (P1) are dissolved in a solvent, a dopant material is dissolved in the solution, and then a dopant material is dissolved in a solvent. A method of dissolving a charge-transporting material and an amine compound represented by formula (P1) in the solution. After mixing the amine compound represented by formula (P1), a charge-transporting material, and a dopant material, the mixture is dissolved in a solvent. Any method of adding and dissolving can be adopted as long as the solid content is uniformly dissolved or dispersed in the solvent.

When using metal oxide nanoparticles, in the above method, the aqueous dispersion or organic solvent dispersion of the metal oxide nanoparticles is added at an arbitrary timing, or the aqueous dispersion or organic solvent dispersion of the metal oxide nanoparticles is prepared in advance. A method of adding a solution containing an amine compound and a charge-transporting substance represented by formula (P1) and other components or a solution thereof is included.

Additionally, keep in mind that charge-transporting substances or metal oxide nanoparticles may aggregate or precipitate when mixed, depending on the type or amount of solvent with which they are mixed.

When preparing a charge-transporting ink composition, it may be heated appropriately as long as the components do not decompose or deteriorate.

In the present invention, the charge-transporting ink composition is prepared by using a submicrometer-sized filter, etc. during the production of the charge-transporting ink composition or after mixing all the components, for the purpose of obtaining a thin film with higher flatness with good reproducibility. You can filter it.

A charge-transporting thin film can be formed on a substrate by applying the charge-transporting ink composition described above onto the substrate and baking it.

The application method of the ink composition is not particularly limited and includes dipping method, spin coating method, transfer printing method, roll coating method, brush coating, inkjet method, spray method, and slit coating method. Depending on the application method, the ink may be applied. It is desirable to control the viscosity and surface tension of the composition.

Additionally, when using the charge-transporting ink composition of the present invention, the firing atmosphere is not particularly limited, and a thin film with a uniform film-forming surface and high charge-transporting property can be obtained not only in an air atmosphere but also in an inert gas such as nitrogen or in a vacuum. there is. The firing temperature is set appropriately within the range of about 100 to 260°C, taking into account the use of the resulting thin film, the degree of charge transport properties imparted to the resulting thin film, the type and boiling point of the solvent, etc.; however, the resulting thin film can be used as an organic EL device. When using it as a hole injection layer, about 140 to 250°C is preferable, and about 145 to 240°C is more preferable. In addition, during firing, a temperature change of two or more stages may be applied for the purpose of achieving higher uniform film forming properties or advancing the reaction on the substrate, and heating may be performed using a suitable device such as a hot plate or oven. This can be done using .

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 provided between the anode and the light-emitting layer, such as a hole injection layer, hole transport layer, or hole injection transport layer of an organic EL device. Methods for changing the film thickness include changing the solid concentration in the charge-transporting ink composition or changing the amount of solution on the substrate at the time of application.

The organic EL device of the present invention has a pair of electrodes, and between these electrodes, it has a charge transport layer made of the charge transport thin film of the present invention.

Representative structures of organic EL elements include (a) to (f) below, but are not limited to these. Additionally, in the following configuration, an electron blocking layer, etc. may be provided between the light emitting layer and the anode, and a hole blocking layer, etc. may be provided between the light emitting layer and the cathode, as needed. Additionally, the hole injection layer, the hole transport layer, or the hole injection transport layer may have a function as an electron blocking layer, etc., and the electron injection layer, the electron transport layer, or the electron injection transport layer may have a function as a hole blocking layer, etc. . Additionally, it is possible to provide arbitrary functional layers 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

“Hole injection layer,” “hole transport layer,” and “hole injection transport layer” are layers formed between the light-emitting layer and the anode, and have the function of transporting holes from the anode to the light-emitting layer. Between the light-emitting layer and the anode, holes are When only one layer of the hole-transporting material is provided, it is a “hole injection transport layer,” and when two or more layers of the hole-transporting material are provided between the light-emitting layer and the anode, the layer close to the anode is the “hole injection layer.” , the other layer is the “hole transport layer”. In particular, the hole injection (transport) layer is a thin film that not only has excellent hole acceptance from the anode, but also has excellent hole injection properties into the hole transport (light emitting) layer.

“Electron injection layer,” “electron transport layer,” and “electron injection transport layer” are layers formed between the light-emitting layer and the cathode, and have the function of transporting electrons from the cathode to the light-emitting layer. Between the light-emitting layer and the cathode, an electron-transporting material is added. When only one layer is provided, it is an “electron injection transport layer,” and when two or more layers of electron transport material are provided between the light-emitting layer and the cathode, the layer close to the cathode is the “electron injection layer.” The layer is the “electron transport layer.”

The “light-emitting layer” is an organic layer with a light-emitting function, and when a doping system is used, it contains a host material and a dopant material. At this time, the host material mainly has the function of promoting recombination of electrons and holes and confining excitons in the light-emitting layer, and the dopant material has the function of efficiently emitting excitons obtained through recombination. In the case of phosphorescent devices, the host material mainly has the function of confining excitons generated from the dopant within the light-emitting layer.

The charge-transporting thin film produced from the charge-transporting ink composition of the present invention can be used as a functional layer formed between an anode and a light-emitting layer in an organic EL device, and is suitable as a hole injection layer, a hole transport layer, and a hole injection and transport layer. It is more suitable as an injection layer and a hole transport layer, and is even more suitable as a hole injection layer.

When producing an EL element using the charge-transporting ink composition of the present invention, materials and production methods to be used include, but are not limited to, the following.

An example of a method for manufacturing an OLED device having a hole injection layer made of a thin film obtained from the charge-transporting ink composition of the present invention is as follows. In addition, it is desirable to previously clean the electrode with alcohol, pure water, etc., or surface treat it with UV ozone treatment, oxygen-plasma treatment, etc., to the extent that it does not adversely affect the electrode.

On the anode substrate, a hole injection layer is formed using the charge-transporting ink composition by the method described above. This is introduced into a vacuum deposition apparatus, and a hole transport layer, a light emitting layer, an electron transport layer/hole blocking layer, an electron injection layer, and a cathode metal are sequentially deposited. Alternatively, in this method, instead of forming the hole transport layer and the light-emitting layer by vapor deposition, these layers are formed by a wet process using 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. do. Additionally, 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 transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes made of metals such as aluminum, and alloys thereof, and those that have been subjected to planarization treatment are preferred. do. Polythiophene derivatives or polyaniline derivatives having high charge transport properties can also be used.

Additionally, other metals constituting the metal anode include gold, silver, copper, indium, and alloys thereof, but are not limited to these.

Materials forming the hole transport layer include (triphenylamine)dimer derivatives, [(triphenylamine)dimer]spirodimer, N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)- Benzidine (α-NPD), 4,4',4''-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), 4,4',4''-tris[1-naphthyl (phenyl)amino]triarylamines such as triphenylamine (1-TNATA), 5,5''-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5', and oligothiophenes such as 2''-terthiophene (BMA-3T).

Materials forming the emitting layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bistyrylbenzene derivatives, bistyrylarylene derivatives, (2-hydroxy low-molecular-weight luminescent materials such as metal complexes of phenyl)benzothiazole and silol derivatives; Poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), polyvinylcarboxylic Examples include, but are not limited to, systems in which a light-emitting material and an electrotransfer material are mixed with a polymer compound such as Bazole.

In addition, when forming the light-emitting layer by vapor deposition, it may be co-deposited with a light-emitting dopant, and the light-emitting dopant may be a metal complex such as tris(2-phenylpyridine)iridium(III) (Ir(ppy) ₃ ), rubrene, etc. naphthacene derivatives, quinacridone derivatives, condensed polycyclic aromatic rings such as perylene, etc., but are not limited to these.

Materials forming the electron transport layer/hole blocking layer include, but are not limited to, oxidiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, and pyrimidine derivatives.

Materials that form 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.

Cathode materials include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, etc.

Materials that form the electron blocking layer include, but are not limited to, tris(phenylpyrazole)iridium.

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'-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]-end capped with polysilsesquinoxane, poly[ (9,9-didioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] and the like.

Light-emitting polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), and poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene. ), polyphenylenevinylene derivatives such as (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

The materials constituting the anode, the cathode, and the layer formed between them differ depending on whether an element having a bottom emission structure or a top emission structure is to be manufactured, so the material is appropriately selected by taking that into consideration.

Typically, in devices with a bottom emission structure, a transparent anode is used on the substrate side, and light is extracted from the substrate side, whereas in devices with a top emission structure, a reflective anode made of metal is used, and the light is extracted from the substrate side. Since light is extracted from the transparent electrode (cathode) side, for example, regarding the anode material, a transparent anode such as ITO is used when manufacturing devices with a bottom emission structure, and Al is used when manufacturing devices with a top emission structure. Each reflective anode such as /Nd is used.

In order to prevent deterioration of properties, the organic EL device of the present invention may be sealed with a desiccant or the like according to a conventional method as necessary.

As described above, the charge-transporting ink composition of the present invention is suitably used for forming a functional layer formed between the anode and the light-emitting layer of an organic EL device, but is also used in organic photoelectric conversion devices, organic thin-film solar cells, and organic perovskite. Photoelectric conversion device, organic integrated circuit, organic field effect transistor, organic thin-film transistor, organic light-emitting transistor, organic optical inspection device, organic photoreceptor, organic electric field quenching device, light-emitting electrochemical cell, quantum dot light-emitting diode, quantum laser, organic laser diode It can also be used to form a charge-transporting thin film in electronic devices such as organic plasmon light-emitting devices.

The method of improving the storage stability of a charge-transporting ink composition of the present invention is a method of improving the storage stability of a charge-transporting ink composition comprising an amine compound, a charge-transporting material, and an organic solvent, wherein the amine compound has the formula (P1) The amine compound represented by is used, and suitable conditions such as solid content of the amine compound and charge-transporting material and the type and amount of the organic solvent are as above.

Improvement of the storage stability of the charge-transporting ink composition can be evaluated by the change in absorbance. Specifically, at the maximum absorption (e.g., wavelength 620 nm), the absorbance of the charge-transporting ink composition before exposure to air is a (initial), the absorbance of the charge-transporting ink composition after exposure for 10 days is a (exposure to air), When the difference in absorbance before and after exposure to the atmosphere (a (initial) - a (exposure to the atmosphere)) is taken as Δa, the rate of change in absorbance (%) = absolute value of Δa/a (initial), usually 10% or less, preferably 10% or less. In one embodiment, it is 9% or less, in a more preferred embodiment it is 8% or less, in an even more preferred embodiment it is 7% or less, and in an even more preferred embodiment it is 6% or less.

The method for improving the flatness of a charge-transporting thin film of the present invention is a method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting material, and an organic solvent. Suitable conditions, such as the type and amount of solid content and organic solvent, and the formation conditions of the charge-transporting thin film, are as described above.

Improvement of the flatness of the charge-transporting thin film can be evaluated by the average surface roughness Ra. Specifically, when the charge-transporting thin film formed on the substrate is measured using an atomic force microscope with a measurement range of 3 μm × 3 μm, the average surface roughness Ra (nm) is usually 2.80 nm or less, a preferred embodiment. is 2.70 nm or less, in a more preferred embodiment is 2.60 nm or less, and in a preferred embodiment is 2.50 nm or less.

In the present invention, the average surface roughness (Ra) of the charge-transporting thin film is measured, for example, using an atomic force microscope Park-NX10 manufactured by Park Systems and an average surface roughness measurement cantilever OMCL-AC 160TS 10M manufactured by Olympus Corporation. It can be measured.

Example

Hereinafter, the present invention will be described in more detail through examples and comparative examples, but the present invention is not limited to the following examples. Additionally, the device used is as follows.

(1) Application of charge-transporting ink composition: Spin coater MS-A100, manufactured by MIKASA Co., Ltd.

(2) Measurement of the average surface roughness (Ra) of the charge-transporting thin film: Park-NX10 atomic force microscope manufactured by Park Systems and cantilever OMCL-AC 160TS 10M for measuring average surface roughness manufactured by Olympus Corporation.

(3) Measurement of solution absorption spectrum of ink composition: UV-visible-near-infrared spectrophotometer UV-3600 manufactured by Shimadzu Science Co., Ltd.

(4) Production of organic EL device: Choshu Sangyo Co., Ltd., multifunctional deposition equipment system C-E2L1G1-N

(5) Measurement of luminance, etc. of organic EL elements: Multi-channel IVL measurement device manufactured by EHC Co., Ltd.

[1] Synthesis of compounds

[Production Example 1]

According to the method described in US Patent No. 8017241 and International Publication No. 2016/171935, an amine adduct of a polythiophene derivative, which is a polymer containing a repeating unit represented by formula (1a), was synthesized.

(In the formula, a to d are the same as above.)

[Production Example 2]

According to the method described in International Publication No. 2006/025342, arylsulfonic acid compound A represented by formula (b-1) was synthesized.

[2] Preparation of solutions and dispersions for preparing charge-transporting ink compositions

[Preparation example 1]

A 1,3-dimethyl-2-imidazolidinone solution containing 10% by mass of arylsulfonic acid compound A was prepared. The solution was prepared by stirring at 400 rpm and 50°C for 1 hour using a hot stirrer.

[Preparation example 2]

100 g of water-dispersed silica sol (manufactured by Nissan Chemical Co., Ltd.) of ST-OS (manufactured by Nissan Chemical Co., Ltd.) and dipropylene glycol monomethyl ether (manufactured by Kanto Chemical Co., Ltd., the same hereinafter) were placed in an eggplant flask, using an evaporator. The water contained in ST-OS was replaced with dipropylene glycol monomethyl ether, and silica sol (silica concentration 9.43% by mass) was obtained using dipropylene glycol monomethyl ether as a dispersion medium.

[3] Preparation of charge-transporting ink composition

[Example 1-1]

Add 3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol (manufactured by Junsei Chemical Co., Ltd., same hereinafter) and 3.55 g of dipropylene glycol monomethyl ether to an Erlenmeyer flask, and stirrer. and stirred at room temperature for 30 minutes. After that, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer.

To the resulting mixture, 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone (manufactured by Kanto Chemical Co., Ltd., the same hereinafter), and 3- 0.15 g of toxypropylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was stirred at 80°C for 3 hours using a hot stirrer, and 1.05 g of the resulting solution was added and stirred at room temperature for 30 minutes.

Next, 1.78 g of silica sol using dipropylene glycol monomethyl ether obtained in Preparation Example 2 as a dispersion medium was added to the obtained mixture, and the mixture was stirred at room temperature for 30 minutes.

Finally, the obtained mixture was filtered through a PP syringe filter with a pore diameter of 0.2 μm to obtain a charge-transporting ink composition.

[Example 1-2]

3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were added to an Erlenmeyer flask, and stirred at room temperature for 30 minutes using a stirrer. After that, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer.

To the resulting mixture, 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 3-isopropoxypropylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) ) 0.15 g was stirred at 80°C for 3 hours using a hot stirrer, 1.05 g of the resulting mixture was added, and stirred at room temperature for 30 minutes.

Next, 1.78 g of silica sol using dipropylene glycol monomethyl ether obtained in Preparation Example 2 as a dispersion medium was added to the obtained mixture, and the mixture was stirred at room temperature for 30 minutes.

Finally, the obtained mixture was filtered through a PP syringe filter with a pore diameter of 0.2 μm to obtain a charge-transporting ink composition.

[Comparative Example 1-1]

3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were added to an Erlenmeyer flask, and stirred at room temperature for 30 minutes using a stirrer. After that, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer.

To the resulting mixture, 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 0.15 g of n-butylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 1.05 g of the mixture obtained by stirring at 80°C for 3 hours using a hot stirrer was added, and stirred at room temperature for 30 minutes.

Next, 1.78 g of silica sol using dipropylene glycol monomethyl ether obtained in Preparation Example 2 as a dispersion medium was added to the obtained mixture, and the mixture was stirred at room temperature for 30 minutes.

Finally, the obtained mixture was filtered through a PP syringe filter with a pore diameter of 0.2 μm to obtain a charge-transporting ink composition.

[Comparative Example 1-2]

3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were added to an Erlenmeyer flask, and stirred at room temperature for 30 minutes using a stirrer. After that, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer.

To the resulting mixture, 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 0.15 g of isoamylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added. 1.05 g of the mixture obtained by stirring at 80°C for 3 hours using a hot stirrer was added, and stirred at room temperature for 30 minutes.

Next, 1.78 g of silica sol using dipropylene glycol monomethyl ether obtained in Preparation Example 2 as a dispersion medium was added to the obtained mixture, and the mixture was stirred at room temperature for 30 minutes.

Finally, the obtained mixture was filtered through a PP syringe filter with a pore diameter of 0.2 μm to obtain a charge-transporting ink composition.

[Comparative Example 1-3]

0.10 g of the amine adduct of the polythiophene derivative obtained in Preparation Example 1 was added to 4.75 g of 1,3-dimethyl-2-imidazolidinone and 0.15 g of 3-aminopropanol (manufactured by Tokyo Kasei Kogyo Co., Ltd.), Although the mixture was stirred at 80°C for 3 hours using a hot stirrer, the amine adduct of the polythiophene derivative was neither sufficiently soluble nor dispersed, and a composition uniform enough to be used for forming a charge-transporting thin film could not be prepared.

[Comparative Example 1-4]

0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1 was mixed with 4.75 g of 1,3-dimethyl-2-imidazolidinone and 2-amino-1-methoxybutane (manufactured by Tokyo Kasei Kogyo Co., Ltd.) It was added to 0.15 g and stirred at 80°C for 3 hours using a hot stirrer, but the amine adduct of the polythiophene derivative was neither sufficiently soluble nor dispersed, so a composition uniform enough to be used for forming a charge-transporting thin film was prepared. I couldn't do it.

[Comparative Example 1-5]

0.10 g of the amine adduct of the polythiophene derivative obtained in Preparation Example 1 was mixed with 4.75 g of 1,3-dimethyl-2-imidazolidinone and bis(2-ethoxyethyl)amine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) It was added to 0.15 g and stirred at 80°C for 3 hours using a hot stirrer, but the amine adduct of the polythiophene derivative was neither sufficiently soluble nor dispersed, so a composition uniform enough to be used for forming a charge-transporting thin film was prepared. I couldn't do it.

[4] Fabrication of charge-transporting thin films and evaluation of average surface roughness Ra

[Example 2-1]

The charge-transporting ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, heated at 120°C for 1 minute under air, and then heated at 230°C for 15 minutes to coat the ITO substrate with a uniform thickness of 30 nm. A thin film was formed.

In addition, as the ITO substrate, _a 25 mm Impurities on the surface were removed.

[Example 2-2, Comparative Example 2-1 to Comparative Example 2-2]

In the same manner as in Example 2-1, except that the charge transport ink compositions obtained in Example 1-2 and Comparative Examples 1-1 to 1-2 were used instead of the charge transport ink composition of Example 1-1, respectively. A uniform thin film with a thickness of 30 nm was formed on the ITO substrate.

The average surface roughness Ra was evaluated for the charge-transporting thin films on the ITO substrate formed in Example 2-1, Example 2-2, Comparative Example 2-1, and Comparative Example 2-2 using an atomic force microscope. In addition, the measurement range of the atomic force microscope was 3 μm × 3 μm. The results are shown in Table 1.

Average surface roughness Ra (nm) Example 2-1 2.31 Example 2-2 2.39 Comparative Example 2-1 2.94 Comparative Example 2-2 3.08

As shown in Table 1, the average surface roughness of the thin film formed from the charge-transporting ink composition of the present invention was low compared to the thin film formed from the charge-transporting ink composition of the comparative example. This means that by using the amine compound represented by the formula (P1) contained in the charge-transporting ink composition of the present invention, a more stable interaction between the amine compound and the charge-transporting material can be realized, and the heating after application of the composition becomes possible. This is presumed to be because aggregation of charge-transporting substances during the process was alleviated or suppressed.

[5] Stability evaluation of charge-transporting ink compositions against atmospheric exposure

[Example 3-1]

0.2 g of the charge transport ink composition obtained in Example 1-1 was mixed with 4.14 g of 1,3-dimethyl-2-imidazolidinone, 4.83 g of dipropylene glycol, and 4.83 g of dipropylene glycol monomethyl ether, and the resulting mixture The absorption spectrum was measured.

Next, 3.0 g of the charge-transporting ink composition obtained in Example 1-1 was placed in a 20 mL glass vial, and the vial was exposed to air at room temperature for 10 days with the cap of the vial open. 0.2 g of the charge-transporting ink composition exposed to the atmosphere was mixed with 4.14 g of 1,3-dimethyl-2-imidazolidinone, 4.83 g of dipropylene glycol, and 4.83 g of dipropylene glycol monomethyl ether, and the absorption spectrum of the resulting mixture was measured. was done. Additionally, a quartz cell with an optical path length of 1 cm was used to measure the absorption spectrum.

[Example 3-2, Comparative Examples 3-1 to 3-2]

In the same manner as Example 3-1, except that the charge transport ink compositions obtained in Example 1-2 and Comparative Examples 1-1 to 1-2 were used instead of the charge transport ink composition obtained in Example 1-1. , absorption spectrum measurements were performed.

The measured absorption spectrum is shown in Figure 1. In addition, at the wavelength of 620 nm where there is maximum absorption, the absorbance of the charge-transporting ink composition before exposure to the atmosphere (A (initial)), the absorbance of the charge-transporting ink composition after exposure for 10 days (A (exposure to the atmosphere)), before and after exposure to the atmosphere The difference in absorbance (Δa) and the rate of change in absorbance (%) are shown in Table 2, respectively.

a (initial) a (atmospheric exposure) Δa Example 3-1 0.371 0.352 0.019 Example 3-2 0.352 0.344 0.007 Comparative Example 3-1 0.425 0.326 0.099 Comparative Example 3-2 0.348 0.300 0.048

As shown in Figure 1 and Table 2, the change in absorbance of the charge-transporting ink composition of the present invention was small compared to the charge-transporting ink composition of the comparative example. This means that by using the amine compound represented by the formula (P1) contained in the charge-transporting ink composition of the present invention, it becomes possible to realize a stable interaction between the amine compound in the composition and the charge-transporting material, and the charge-transporting material It is presumed that this is because oxidation was suppressed.

[6] Fabrication and characteristic evaluation of organic EL devices

[Example 4-1]

The charge-transporting ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, heated at 120°C for 1 minute under air, and then heated at 230°C for 15 minutes to form a 30 nm thick layer on the ITO substrate. A uniform charge-transporting thin film was formed.

In _addition , as the ITO substrate, a 25 mm .

Subsequently, α-NPD (N,N'-di(1-naphthyl)-N,N'-diphenyl was deposited on the charge-transporting thin film formed on the ITO substrate using a vapor deposition device (vacuum degree 1.0×10 ^-5 Pa). Benzidine) was formed into a 30 nm film at 0.2 nm/sec.

On the α-NPD film, a 10 nm film of electronic block material HTEB-01 manufactured by Kanto Chemical Co., Ltd. was deposited, and further on top of this were the emitting layer host material NS60 manufactured by Nippon Steel Chemical Co., Ltd. and the emitting layer dopant material Ir. (ppy) ₃ was co-deposited. For co-deposition, the deposition rate was controlled so that the concentration of Ir(ppy) ₃ was 6%, and a 40 nm layer was deposited. Next, thin films of Alq ₃ , lithium fluoride, and aluminum were sequentially laminated to obtain an organic EL device. At this time, the deposition rate was 0.2 nm/sec for Alq ₃ and aluminum, and 0.02 nm/sec for lithium fluoride, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.

In addition, in order to prevent property deterioration due to the influence of oxygen, water, etc. in the air, the organic EL device was sealed with a sealing substrate and then its properties were evaluated. Sealing was performed in the following procedure. In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, the organic EL element was placed between the sealing substrates, and the sealing substrates were bonded together with an adhesive (Moresco Moisture Cut WB90US(P), manufactured by Moresco Co., Ltd.). . At this time, a desiccant (HD-071010W-40, manufactured by Dynic Co., Ltd.) was placed in the sealing substrate together with the organic EL element. The bonded sealing substrate was irradiated with UV light (wavelength: 365 nm, irradiation amount: 6,000 mJ/cm ² ) and then annealed at 80°C for 1 hour to harden the adhesive.

[Example 4-2]

An organic EL device was obtained in the same manner as in Example 4-1, except that the charge-transporting ink composition obtained in Example 1-2 was used instead of the charge-transporting ink composition obtained in Example 1-1.

The driving voltage, current density, and luminous efficiency, and half-life of luminance when the devices obtained in Example 4-1 and Example 4-2 were driven at a luminance of 10,000 cd/m ² (initial luminance 10,000 cd) The time required for /m ² to reach half was measured. The results are shown in Table 3.

driving voltage
(V) current density
(mA/ ^cm2 ) current efficiency
(cd/A) external quantum efficiency
(%) Luminance half-life
(hour) Example 4-1 6.1 20.0 50.1 14.3 418 Example 4-2 6.4 20.4 49.0 14.0 386

The organic EL devices obtained in Examples 4-1 and 4-2 all exhibited good device characteristics.

Claims (12)

A charge-transporting ink composition comprising an amine compound represented by the following formula (P1), a charge-transporting substance, and an organic solvent.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).) According to paragraph 1,
A charge-transporting ink composition wherein R ^m is an alkyl group having 1 to 20 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms. According to claim 1 or 2,
A charge-transporting ink composition wherein the charge-transporting material is a polythiophene derivative or an amine adduct thereof containing a repeating unit represented by the following formula (1).

(In the formula, R ¹ and R ² are independently of each other a hydrogen atom, an alkyl group with 1 to 40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, an alkoxy group with 1 to 40 carbon atoms, or a fluoroalkoxy group with 1 to 40 carbon atoms. group, an aryloxy group having 6 to 20 carbon atoms, -O-[ZO] _p -R ^e , or a sulfonic acid group, or -OYO- formed by combining R ¹ and R ² , and Y contains an ether bond Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, R ^e is a hydrogen atom and has 1 carbon number. It is an alkyl group with ∼40 carbon atoms, a fluoroalkyl group with 1 to 40 carbon atoms, or an aryl group with 6 to 20 carbon atoms.) According to paragraph 3,
Wherein R ¹ is a sulfonic acid group, and R ² is an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] _p -R ^e , or -OYO- formed by combining R ¹ and R ² Ink composition. According to any one of claims 1 to 4,
A charge-transporting ink composition further comprising a dopant material. According to clause 5,
A charge-transporting ink composition wherein the dopant material includes at least one member selected from the group consisting of arylsulfonic acid compounds and heteropoly acid compounds. According to any one of claims 1 to 6,
A charge-transporting ink composition further comprising metal oxide nanoparticles. A charge-transporting thin film obtained from the charge-transporting ink composition according to any one of claims 1 to 7. An electronic device having a charge-transporting thin film as expected in claim 8. According to clause 9,
An electronic device that is an organic electroluminescence device. A method for improving the storage stability of a charge-transporting ink composition comprising an amine compound, a charge-transporting material, and an organic solvent, comprising:
A method for improving the storage stability of a charge-transporting ink composition, characterized by using an amine compound represented by the following formula (P1) as the amine compound.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).) A method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting material, and an organic solvent, comprising:
A method for improving the flatness of a charge-transporting thin film, characterized by using an amine compound represented by the following formula (P1) as the amine compound.

(Wherein, R ^m represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms, and R ⁿ represents an alkylene group with 1 to 20 carbon atoms or an alkenylene group with 2 to 20 carbon atoms. or an arylene group having 6 to 20 carbon atoms, or R ^m and R ⁿ are bonded together to represent an alkanetriyl group having 3 to 40 carbon atoms, and R ⁿ is an alkylene group having 1 to 20 carbon atoms and an alkylene group having 2 to 20 carbon atoms. The kenylene group and the alkanetriyl group of R ^m and R ⁿ are limited to those that form -CH ₂ -NH ₂ group when combined with -NH ₂ in formula (P1).)