WO2020196154A1

WO2020196154A1 - Arylamine compound and use thereof

Info

Publication number: WO2020196154A1
Application number: PCT/JP2020/011967
Authority: WO
Inventors: 圭介首藤; 歳幸遠藤
Original assignee: 日産化学株式会社
Priority date: 2019-03-27
Filing date: 2020-03-18
Publication date: 2020-10-01
Also published as: CN113614068A; TW202104181A; TWI839495B; JPWO2020196154A1; KR20210144758A; JP7491302B2

Abstract

This arylamine compound represented by formula (1) has good solubility in an organic solvent, and provides a thin film having excellent optical characteristics, wherein when said thin film is applied to a hole injection layer or the like, an organic EL element having good characteristics can be achieved. (In the formula, R1's each independently represent an aryl group having 6-20 carbon atoms, and R2's each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1-20 carbon atoms, a halogenated alkyl group having 1-20 carbon atoms, an alkoxy group having 1-20 carbon atoms, or an aryl group having 6-20 carbon atoms.)

Description

Arylamine compounds and their uses

The present invention relates to arylamine compounds and their use.

Organic electroluminescence (hereinafter referred to as organic EL) elements are expected to be put into practical use in fields such as displays and lighting, and various developments related to materials and element structures are expected for the purpose of low voltage drive, high brightness, long life, etc. Has been made.
A plurality of functional thin films are used in this organic EL element, and one of them, the hole injection layer, is responsible for the transfer of electric charge between the anode and the hole transport layer or the light emitting layer, and is low in the organic EL element. It plays an important role in achieving voltage drive and high brightness.

The method for producing the hole injection layer is roughly classified into a dry process represented by a vapor deposition method and a wet process represented by a spin coating method. Comparing these processes, the wet process can efficiently produce a thin film with a large area and high flatness.
For this reason, as the area of organic EL displays is being increased, a hole injection layer that can be formed by a wet process is desired.

In view of these circumstances, the present inventors have a charge transporting property that provides a thin film that can be applied to various wet processes and can realize excellent EL device characteristics when applied to a hole injection layer of an organic EL device. We have been developing compounds with good solubility in materials and organic solvents used for them (see Patent Documents 1 to 3).

On the other hand, various incorporations have been made so far in order to improve the performance of organic EL elements, but efforts are being made to adjust the refractive index of the functional film used for the purpose of improving the light extraction efficiency. .. Specifically, by using a hole injection layer or a hole transport layer having a relatively high or low refractive index in consideration of the overall configuration of the device and the refractive index of other adjacent members, the efficiency of the device is high. Attempts have been made to achieve this (see Patent Documents 4 and 5).
As described above, the refractive index is an important factor in the design of the organic EL element, and in the material for the organic EL element, the refractive index is also considered to be an important physical property value to be considered.

Further, since coloring of the charge transporting thin film used for the organic EL element lowers the color purity and color reproducibility of the organic EL element, in recent years, the charge transporting thin film for the organic EL element has been in the visible region. It is desired to have high transparency and high transparency (see Patent Document 6).
In this way, as the area of organic EL displays is increasing, the development of organic EL displays using a wet process is being energetically carried out, and charge transport with good transparency is being carried out. There is a constant demand for materials for wet processes that provide a thin film.

International Publication No. 2008/129947 International Publication No. 2015/050253 International Publication No. 2017/217457 Special Table 2007-536718 Special Table 2017-501585 Gazette International Publication No. 2013/0426223

The present invention has been made in view of such circumstances, and when a thin film having good solubility in an organic solvent and good optical characteristics is provided and this thin film is applied to a hole injection layer or the like. It is an object of the present invention to provide an arylamine compound capable of realizing an organic EL device having good properties.

As a result of diligent studies to achieve the above object, the present inventors have found that a predetermined arylamine compound having an arylcarbazole skeleton has good solubility in an organic solvent and a varnish containing the compound. The present invention has been completed by finding that an organic EL element having good characteristics can be obtained when a thin film having excellent optical characteristics is provided and the thin film is applied to a hole injection layer or the like.

That is, the present invention
1. 1. An arylamine compound, which is represented by the following formula (1).

(In the formula, R ¹ independently represents an aryl group having 6 to 20 carbon atoms, and R ² independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, and 1 to 20 carbon atoms. , An alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
2. 2. 1 arylamine compound represented by the following formula (1-1),

(In the formula, R ¹ and R ² have the same meanings as described above.)
3. 3. 2 arylamine compounds represented by the following formula (1-1A) or (1-1B),

(In the formula, R ¹ and R ² have the same meanings as described above.)
4. An arylamine compound according to any one of 1 to 3, wherein R ¹ is a phenyl group, a 1-naphthyl group or a 2-naphthyl group.
5. 4 arylamine compounds in which R ¹ is all phenyl groups,
6. An arylamine compound according to any one of 1 to 5, wherein R ² is an all hydrogen atom.
7. A charge-transporting varnish containing any of the arylamine compounds 1 to 6 and an organic solvent,
8. 7 charge-transporting varnishes containing dopant material,
9. Eight charge-transporting varnishes in which the dopant substance is an aryl sulfonic acid ester compound,
10. A charge-transporting thin film prepared by using any of the charge-transporting varnishes 7 to 9.
11. Electronic devices with 10 charge transport thin films,
12. Organic electroluminescence device with 10 charge transport thin films,
13. The charge transporting thin film provides twelve organic electroluminescence devices that are hole injection layers or hole transport layers.

The arylamine compound of the present invention has good solubility in an organic solvent, and by using a charge-transporting varnish containing this arylamine compound, high transparency (low k (disappearance coefficient)) and high A charge transporting thin film having a refractive index (high n) can be obtained.
This charge transporting thin film can be suitably used as a thin film for electronic devices such as organic EL devices, and in particular, by applying the charge transporting thin film of the present invention to a hole injection layer or the like of an organic EL device. , It is possible to manufacture an element having good characteristics.

Hereinafter, the present invention will be described in more detail.
The arylamine compound according to the present invention is characterized by being represented by the following formula (1), and a preferred embodiment is represented by the formula (1-1).

In formulas (1) and (1-1), R ¹ independently represents an aryl group having 6 to 20 carbon atoms, and R ² independently represents a hydrogen atom, a halogen atom, and a nitro group. It represents a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkyl halide group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic, and may be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl or t-butyl. , N-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl group and other linear or branched alkyl groups having 1 to 20 carbon atoms; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl. , Cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, bicyclodecyl group and other cyclic alkyl groups having 3 to 20 carbon atoms.

Alkoxy groups having 1 to 20 carbon atoms may have linear, branched, or cyclically displaced alkyl groups, and specific examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, and n-butoxy. , Isobutoxy, s-butoxy, t-butoxy, n-pentoxy, n-hexyloxy, n-octyloxy, n-decyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, 2-n-propylhexyloxy, 2- Examples thereof include n-butylhexyloxy, 2-ethyldecyloxy, and 3-ethylhexyloxy group.

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

The alkyl halide group having 1 to 20 carbon atoms is a group in which at least one hydrogen atom of the alkyl group having 1 to 20 carbon atoms is substituted with a halogen atom, and specific examples thereof include fluoromethyl, difluoromethyl, and tri. Fluoromethyl, bromodifluoromethyl, 2-chloroethyl, 2-bromoethyl, 1,1-difluoroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, 2-chloro-1, 1,2-Trifluoroethyl, pentafluoroethyl, 3-bromopropyl, 2,2,3,3-tetrafluoropropyl, 1,1,2,3,3,3-hexafluoropropyl, 1,1,1 , 3, 3,3-Hexafluoropropane-2-yl, 3-bromo-2-methylpropyl, 4-bromobutyl, perfluoropentyl, 2- (perfluorohexyl) ethyl group and the like.

In particular, considering the solubility of the compound in an organic solvent, R ¹ is preferably an aryl group having 6 to 14 carbon atoms, more preferably a phenyl group, a 1-naphthyl group, and a 2-naphthyl group, all of which are phenyl groups. A 1-naphthyl or 2-naphthyl group is even more preferred, and a phenyl group is even more preferred.

Considering the solubility of the compound in an organic solvent, R ² is preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, preferably a hydrogen atom. , Alkyl groups having 1 to 10 carbon atoms are more preferable, and all hydrogen atoms are even more preferable.

In the formula (1-1), the bonding positions of the three nitrogen atoms of the central carbazole skeleton and the carbazole ring of the arylcarbazole skeleton are not particularly limited, and even if they are bonded at the same position, they are different. However, as represented by the following formula (1-1A) or (1-1B), the 3-position (meta-position) or 4-position (para-position) with respect to the nitrogen atom of the arylcarbazole skeleton ) Is preferred, and the one bonded at the 3-position is more preferable.

(In the equation, R ¹ and R ² have the same meaning as above.)

Examples of the arylamine compound suitable in the present invention include those represented by the following formulas (2) or (3), but are not limited thereto.

As shown in the scheme below, the arylamine compound represented by the formula (1) or (1-1) catalyzes the diaminocarbazole compound [Ia] or [Ib] and the halide arylcarbazole compound [II]. It can be produced by reacting in the presence.

(In the formula, X represents a halogen atom or a pseudohalogen group, and R ¹ and R ² have the same meanings as above.)

(In the formula, X, R ¹ and R ² have the same meanings as above.)

Examples of the halogen atom include the same as above.
Examples of the pseudohalogen group include (fluoro) alkylsulfonyloxy groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy and nonafluorobutanesulfonyloxy groups; aromatic sulfonyloxy groups such as benzenesulfonyloxy and toluenesulfonyloxy groups. ..

The charging ratio of the diaminocarbazole compound [Ia] or [Ib] to the halide arylcarbazole compound [II] is such that the amount of the halide arylcarbazole compound is 5 equivalents or more with respect to the amount of substance of the total NH groups of the diaminocarbazole compound. However, an amount of about 5 to 5.5 equivalents is preferable.

Examples of the catalyst used in the above reaction include copper catalysts such as copper chloride, copper bromide and copper iodide; Pd (PPh ₃ ) ₄ (tetrax (triphenylphosphine) palladium), Pd (PPh ₃ ) ₂ Cl ₂ (Bis (triphenylphosphine) dichloropalladium), Pd (dba) ₂ (bis (dibenzylideneacetone) palladium), Pd ₂ (dba) ₃ (tris (dibenzylideneacetone) dipalladium), Pd (Pt-Bu) ₃ ) Examples thereof include palladium catalysts such as ₂ (bis (tri (t-butylphosphine)) palladium) and Pd (OAc) ₂ (palladium acetate). These catalysts may be used alone or in combination of two or more. These catalysts may also be used with suitable known ligands.

Examples of such ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-t-butylphosphine, di-t-butyl ( Phenyl) phosphine, di-t-butyl (4-dimethylaminophenyl) phosphine, 1,2-bis (diphenylphosphine) ethane, 1,3-bis (diphenylphosphine) propane, 1,4-bis (diphenylphos) Tertiary phosphine such as fino) butane, 1,1'-bis (diphenylphosphine) ferrocene, tertiary phosphine such as trimethylphosphine, triethylphosphine, triphenylphosphine, John Phos commercially available from Aldrich. , CyjohnPhos, DavePhos, XPhos, SPhos , tBuXPhos, RuPhos, Me4tBuXPhos, sSPhos, tBuMePhos, MePhos, tBuDavePhos, PhDavePhos, 2'-Dicyclohexylphosphino-2,4,6-trimethoxybiphenyl, BrettPhos, tBuBrettPhos, AdBrettPhos, Me 3 (OMe) tBuXPhos , (2-Biphenyl) di-1-adamantylphosphine, RockPhos, CPhos and other biphenylphosphine compounds.

The amount of the catalyst used can be about 0.01 mol to 0.5 mol with respect to 1 mol of the arylcarbazole compound [II], but is preferably about 0.05 to 0.2 mol.
When a ligand is used, the amount used can be 0.1 to 5 equivalents with respect to the metal complex to be used, but 1 to 2 equivalents are preferable.

Moreover, you may use a base for the said reaction. Examples of the base include lithium, sodium, potassium, lithium hydride, sodium hydride, lithium hydroxide, potassium hydroxide, t-butoxylithium, t-butoxysodium, t-butoxypotassium, sodium hydroxide, potassium hydroxide. , Sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, etc., alkali metal hydride, alkali metal hydroxide, alkoxy alkali metal, alkali metal carbonate, alkali metal carbonate; alkali carbonate soil such as calcium carbonate Kinds of metals: n-butyl lithium, s-butyl lithium, t-butyl lithium, lithium diisopropylamide (LDA), lithium 2,2,6,6-tetramethylpiperidin (LiTMP), hexamethyldisilazane lithium (LHMDS), etc. Organic lithium; amines such as triethylamine, diisopropylethylamine, tetramethylethylenediamine, triethylenediamine, pyridine and the like can be mentioned.
When a base is used, the amount used can be 0.1 to 5 equivalents with respect to the arylcarbazole compound [II] used, but 1 to 2 equivalents are preferable.

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

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

The above-mentioned arylamine compound of the present invention can be suitably used as a charge transporting substance. In this case, it can be used as a charge-transporting varnish containing the arylamine compound of the present invention and an organic solvent, and the charge-transporting varnish can be used to improve its charge-transporting ability depending on the use of the obtained thin film. It may contain a dopant substance for the purpose of. Further, the arylamine compound of the present invention can be used in combination with other conventionally known charge-transporting substances such as an aniline derivative and a thiophene derivative, but the arylamine compound of the present invention alone can be used as a charge-transporting substance. preferable.
In the present invention, charge transportability is synonymous with conductivity. The charge-transporting varnish may be a varnish having a charge-transporting property by itself, or the solid film obtained thereby may have a charge-transporting property.

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

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

Specific examples of the heteropolyacid include phosphomolybdic acid, silicate molybdic acid, phosphotungstic acid, silicate tungstic acid, phosphotungstic acid, and the like, and these may be used alone or in combination of two or more. Good. In addition, these heteropolyacids are available as commercial products, and can also be synthesized by a known method.
In particular, when one kind of heteropolyacid is used, the one kind of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and phosphotungstic acid is most suitable. When two or more types of heteropolyacids are used, one of the two or more types of heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.
In addition, in quantitative analysis such as elemental analysis, heteropolyacids have a large number of elements or a small number of elements from the structure represented by the general formula, but they are commercially available products or known synthetics. As long as it is properly synthesized according to the method, it can be used in the present invention.
That is, for example, in general, phosphotungstic acid is represented by the chemical formulas H ₃ (PW ₁₂ O ₄₀ ) and nH ₂ O, and phosphomolybdic acid is represented by the chemical formulas H ₃ (PMo ₁₂ O ₄₀ ) and nH ₂ O, respectively. , In quantitative analysis, even if the number of P (phosphorus), O (oxygen) or W (tungsten) or Mo (molybdenum) in this formula is large or small, it is obtained as a commercial product. Alternatively, it can be used in the present invention as long as it is appropriately synthesized according to a known synthesis method. In this case, the mass of the heteropolyacid defined in the present invention is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in the synthetic product or the commercially available product, but the form available as the commercially available product and the known synthesis. In a form that can be isolated by the method, it means the total mass in a state containing hydrated water and other impurities.

The amount of the heteropolyacid used can be about 0.001 to 50.0 with respect to the charge transporting substance 1 in terms of mass ratio, but is preferably about 0.01 to 20.0, more preferably 0. It is about 1 to 10.0.

On the other hand, as the organic dopant substance, a tetracyanoquinodimethane derivative or a benzoquinone derivative can be particularly used.
Specific examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ) and halotetracyanoquinodimethane represented by the formula (H3).
Specific examples of the benzoquinone derivative include tetrafluoro-1,4-benzoquinone (F4BQ), tetrachloro-1,4-benzoquinone (chloranil), tetrabromo-1,4-benzoquinone, 2,3-dichloro-5, and so on. 6-Dicyano-1,4-benzoquinone (DDQ) and the like can be mentioned.

In the formula, R ⁵⁰⁰ to R ⁵⁰³ each independently represent a hydrogen atom or a halogen atom, but at least one is a halogen atom, at least two are preferably halogen atoms, and at least three are halogen atoms. More preferably, all are halogen atoms.
Examples of the halogen atom include the same ones as described above, but a fluorine atom or a chlorine atom is preferable, and a fluorine atom is more preferable.

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

The amount of the tetracyanoquinodimethane derivative and the benzoquinone derivative used is preferably 0.0001 to 100 equivalents, more preferably 0.01 to 50 equivalents, and even more preferably 1 to 20 equivalents, relative to the charge transporting substance. is there.

The organic dopant substance is an electrically neutral onium composed of a monovalent or divalent anion represented by the following formula (a1) and a counter cation represented by the formulas (c1) to (c5). Borate salts can also be used.

(In the formula, Ar independently represents an aryl group having 6 to 20 carbon atoms which may have a substituent or a heteroaryl group having 2 to 20 carbon atoms which may have a substituent, and L. Represents an alkylene group having 1 to 20 carbon atoms, -NH-, an oxygen atom, a sulfur atom or -CN ⁺ -.)

In the formula (a1), the alkylene group having 1 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include methylene, methylmethylene, dimethylmethylene, ethylene, trimethylene and propylene. , Tetramethylene, pentamethylene, hexamethylene group and the like. Examples of the aryl group and the heteroaryl group include the same as above.

Preferable examples of the anion of the above formula (a1) include, but are not limited to, those represented by the formula (a2).

The amount of the onium borate salt used can be about 0.1 to 10 with respect to the charge-transporting substance in terms of the amount of substance (molar).
The onium borate salt can be synthesized by referring to, for example, a known method described in Japanese Patent Application Laid-Open No. 2005-314682.

Further, as an organic dopant substance, an aryl sulfonic acid compound or an aryl sulfonic acid ester compound can also be preferably used.

Specific examples of the aryl sulfonic acid compound include benzene sulfonic acid, tosylic acid, p-styrene sulfonic acid, 2-naphthalene sulfonic acid, 4-hydroxybenzene sulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzene sulfonic acid, and dihexyl benzene. Sulfonic acid, 2,5-dihexylbenzene sulfonic acid, dibutylnaphthalene sulfonic acid, 6,7-dibutyl-2-naphthalene sulfonic acid, dodecylnaphthalene sulfonic acid, 3-dodecyl-2-naphthalene sulfonic acid, hexylnaphthalene sulfonic acid, 4 -Hexyl-1-naphthalene sulfonic acid, octylnaphthalene sulfonic acid, 2-octyl-1-naphthalene sulfonic acid, hexylnaphthalene sulfonic acid, 7-hexyl-1-naphthalene sulfonic acid, 6-hexyl-2-naphthalene sulfonic acid, Dinonylnaphthalene sulfonic acid, 2,7-dinonyl-4-naphthalene sulfonic acid, dinonylnaphthalenedisulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, International Publication No. 2005/000832, 1,4 -Benzodioxane disulfonic acid compounds, aryl sulfonic acid compounds described in International Publication No. 2006/0254342, aryl sulfonic acid compounds described in International Publication No. 2009/096322, and the like can be mentioned.

Examples of preferable aryl sulfonic acid compounds include aryl sulfonic acid compounds represented by the formula (H4) or (H5).

A ¹ represents O or S, with O being preferred.
A ² represents a naphthalene ring or an anthracene ring, but a naphthalene ring is preferable.
A ³ represents a 2- to tetravalent perfluorobiphenyl group, p represents the number of bonds between A ¹ and A ^3, and is an integer satisfying 2 ≦ p ≦ 4, where A ³ is perfluorobiphenyldiyl. The group, preferably a perfluorobiphenyl-4,4'-diyl group, preferably has a p of 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 are independently hydrogen atom, halogen atom, cyano group, alkyl group having 1 to 20 carbon atoms, alkyl halide group having 1 to 20 carbon atoms, or halogenation having 2 to 20 carbon atoms. Representing an alkenyl group, at least three of A ⁴ to A ⁸ are halogen atoms.

As the alkyl halide group having 1 to 20 carbon atoms, trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl. , 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4 , 4-Pentafluorobutyl, 2,2,3,3,4,5,4-heptafluorobutyl, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, etc. Be done.

Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include perfluorovinyl, perfluoropropenyl (allyl), perfluorobutenyl group and the like.
Other examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms include the same as above, but the halogen atom is preferably a fluorine atom.

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

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

The molecular weight of the aryl sulfonic acid compound used as the dopant substance is not particularly limited, but is preferably 2000 or less, more preferably 2000 or less, considering the solubility in an organic solvent when used together with the arylamine compound of the present invention. It is 1500 or less.

Specific examples of suitable aryl sulfonic acid compounds will be given below, but the present invention is not limited to these.

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

On the other hand, as the aryl sulfonic acid ester compound, the aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217455, the aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217457, and Japanese Patent Application No. 2017-243631. The above-mentioned aryl sulfonic acid ester compounds and the like can be mentioned, and specifically, those represented by any of the following formulas (H6) to (H8) are preferable.

(In the formula, m is an integer satisfying 1 ≦ m ≦ 4, preferably 2. n is an integer satisfying 1 ≦ n ≦ 4, but 2 is preferable.)

In formula (H6), A ¹¹ is an m-valent group derived from perfluorobiphenyl.
A ¹² is —O— or —S—, but —O— is preferred.
A ¹³ is a (n + 1) -valent group derived from naphthalene or anthracene, but a group derived from naphthalene is preferable.
R ^s1 to R ^s4 are each independently a hydrogen atom or a linear or branched chain alkyl group having 1 to 6 carbon atoms, and R ^s5 is an optionally substituted alkyl group having 2 to 20 carbon atoms. It is a monovalent hydrocarbon group of.

Specific examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-hexyl group and the like. , An alkyl group having 1 to 3 carbon atoms is preferable.
The monovalent hydrocarbon group having 2 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include ethyl, n-propyl, isopropyl, n-butyl, isobutyl and t-butyl. Alkyl groups such as groups; aryl groups such as phenyl, naphthyl and phenanthryl groups can be mentioned.

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

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

Further, A ¹⁵ is —O— or —S—, but —O— is preferable.
A ¹⁶ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the aromatic hydrocarbon group is (n + 1) from the aromatic ring of the aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing individual hydrogen atoms.
Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like.
Among them, as A ¹⁶ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

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

In the formula (H8), R ^s9 to R ^s13 independently represent a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, and an alkyl halide group having 1 to 10 carbon atoms. Alternatively, it is a halogenated alkenyl group having 2 to 10 carbon atoms.
The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and s-butyl. Examples thereof include t-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl group and the like.

The alkyl halide group having 1 to 10 carbon atoms is not particularly limited as long as it is a group in which a part or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms is substituted with a halogen atom. Specific examples include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3. , 3-Pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,5,4-pentafluorobutyl, 2 , 2,3,3,4,5,4-heptafluorobutyl, 1,1,2,2,3,3,4,4-nonafluorobutyl group and the like.

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

Among these, as R ^s9 , a nitro group, a cyano group, an alkyl halide group having 1 to 10 carbon atoms, and an alkenyl halide group having 2 to 10 carbon atoms are preferable, and a nitro group, a cyano group, and 1 to 4 carbon atoms are preferable. The alkyl halide group and the alkenyl halide group having 2 to 4 carbon atoms are more preferable, and the nitro group, the cyano group, the trifluoromethyl group and the perfluoropropenyl group are even more preferable.
As R ^s10 to R ^s13 , a halogen atom is preferable, and a fluorine atom is more preferable.

A ¹⁷ is -O-, -S- or -NH-, but -O- is preferable.
A ¹⁸ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the aromatic hydrocarbon group is (n + 1) from the aromatic ring of the aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing individual hydrogen atoms.
Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like.
Among these, as A ¹⁸ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

R ^s14 to R ^s17 are independently hydrogen atoms or linear or branched chain monovalent aliphatic hydrocarbon groups having 1 to 20 carbon atoms.
Specific examples of the monovalent aliphatic hydrocarbon group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl and n. -Alkyl groups having 1 to 20 carbon atoms such as heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl groups; vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl Examples thereof include alkenyl groups having 2 to 20 carbon atoms such as -2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl groups, but alkyl groups having 1 to 20 carbon atoms are preferable, and alkyl groups having 1 to 20 carbon atoms are preferable. An alkyl group of 10 is more preferable, and an alkyl group having 1 to 8 carbon atoms is even more preferable.

R ^s18 is a linear or branched chain monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or OR ^s19 . R ^s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.
^Examples of the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms of R ^s18 include the same as above.
When R ^s18 is a monovalent aliphatic hydrocarbon group, R ^s18 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and an alkyl group having 1 to 8 carbon atoms. Even more preferable.
^Examples of the monovalent hydrocarbon group having 2 to 20 carbon atoms of R ^s19 include those other than the methyl group among the above-mentioned monovalent aliphatic hydrocarbon groups, and aryl groups such as phenyl, naphthyl and phenanthryl groups.
Among these, R ^s19 is preferably a linear alkyl group or a phenyl group having 2 to 4 carbon atoms.
Examples of the substituent that the monovalent hydrocarbon group may have include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, and a cyano group.

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

The amount of the aryl sulfonic acid ester compound used is preferably about 0.01 to 20, more preferably about 0.05 to 10 with respect to the charge transporting substance 1 in terms of the amount of substance (molar).

In the present invention, considering the production of a charge-transporting thin film having excellent transparency and a high refractive index, it is preferable to use an aryl sulfonic acid compound or an aryl sulfonic acid ester compound as the dopant substance, and the solubility in a solvent is preferable. In addition, it is more preferable to use an aryl sulfonic acid ester compound in consideration of obtaining a thin film having a smaller extinction coefficient.

Further, when the obtained thin film is used as the hole injection layer of the organic EL device, the charge transport varnish is an organic silane compound for the purpose of improving the injection property into the hole transport layer and the life characteristics of the device. May include. Its content is usually about 1 to 30% by mass with respect to the total mass of the charge transporting substance and the dopant substance.

As the organic solvent used when preparing the charge transporting varnish of the present invention, a highly polar solvent capable of satisfactorily dissolving the arylamine compound of the present invention can be used. The arylamine compound of the present invention can be dissolved in a solvent regardless of the polarity of the solvent. Further, if necessary, a low-polarity solvent may be used because it is superior in process compatibility to a high-polarity solvent. In the present invention, a low polar solvent is defined as a solvent having a relative permittivity of less than 7 at a frequency of 100 kHz, and a high polar solvent is defined as a solvent having a relative permittivity of 7 or more at a frequency of 100 kHz.

Examples of low polar solvents include, for example.
Chlorine-based solvents such as chloroform and chlorobenzene;
Aromatic hydrocarbon solvents such as toluene, xylene, tetralin, cyclohexylbenzene, decylbenzene;
Aliphatic alcohol solvents such as 1-octanol, 1-nonanol, 1-decanol;
Ethereal solvents such as tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether;
Esters such as methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, bis (2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, etc. Examples include a solvent.

Further, as a highly polar solvent, for example,
Amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylisobutyramide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone;
Ketone solvents such as ethyl methyl ketone, isophorone, cyclohexanone;
Cyan-based solvents such as acetonitrile and 3-methoxypropionitrile;
Polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butanediol, and 2,3-butanediol;
Other than aliphatic alcohols such as diethylene glycol monomethyl ether, diethylene glycol monophenyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3-phenoxybenzyl alcohol, and tetrahydrofurfuryl alcohol. Monohydric alcohol solvent;
Examples thereof include sulfoxide-based solvents such as dimethyl sulfoxide.

The viscosity of the charge-transporting varnish is appropriately determined depending on the thickness of the thin film to be produced and the solid content concentration, but is usually 1 to 50 mPa · s at 25 ° C. In the present invention, the solid content means a component other than the solvent contained in the charge transport varnish.
The solid content concentration of the charge-transporting varnish is appropriately set in consideration of the viscosity and surface tension of the varnish, the thickness of the thin film to be produced, etc., but is usually 0.1 to 10.0 mass. It is about%, preferably about 0.5 to 5.0% by mass, and more preferably about 1.0 to 3.0% by mass in consideration of improving the coatability of the varnish.

The method for preparing the charge-transporting varnish is not particularly limited, but for example, a solid content such as a charge-transporting substance containing the arylamine compound of the present invention is dissolved in a high-polarity solvent, and a low-polarity solvent is dissolved therein. A method of adding a charge, a method of mixing a high polar solvent and a low polar solvent, and a method of dissolving a charge transporting substance therein.

In particular, when preparing a charge transporting varnish, from the viewpoint of obtaining a thin film with higher flatness with good reproducibility, after dissolving a charge transporting substance, a dopant substance, etc. in an organic solvent, a submicrometer order filter or the like is used. It is desirable to use and filter.

Since the charge-transporting varnish described above can easily produce a charge-transporting thin film by using the varnish, it can be suitably used when manufacturing an electronic device, particularly an organic EL device.
In this case, the charge-transporting thin film can be formed by applying the above-mentioned charge-transporting varnish on a substrate and firing it.
The varnish coating method is not particularly limited, and examples thereof include a dip method, a spin coating method, a transfer printing method, a roll coating method, a brush coating, an inkjet method, a spray method, and a slit coating method. It is preferable to adjust the viscosity and surface tension of the varnish accordingly.

Further, the firing atmosphere of the charge-transporting varnish after coating is not particularly limited, and a thin film having a uniform film-forming surface and high charge-transporting property not only in the air atmosphere but also in an inert gas such as nitrogen or in a vacuum can be obtained. Although it can be obtained, depending on the type of dopant substance used, a thin film having charge transportability may be obtained with good reproducibility by firing the varnish in an air atmosphere.

The firing temperature is appropriately set within the range of about 100 to 260 ° C. in consideration of the intended use of the obtained thin film, the degree of charge transportability applied to the obtained thin film, the type of solvent, the boiling point, etc., for example, the obtained thin film. When is used as a hole injection layer of an organic EL device, it is preferably about 140 to 250 ° C., more preferably about 145 to 240 ° C., but the arylamine compound represented by the above formula (1) is used as a charge transporting substance. When used, a thin film having good charge transportability can be obtained even at a low temperature of 200 ° C. or lower.
In addition, at the time of firing, a temperature change of two or more steps may be applied for the purpose of exhibiting higher uniform film forming property or allowing the reaction to proceed on the substrate. It may be carried out using an appropriate device such as an oven.

The thickness of the charge transporting thin film is not particularly limited, but when it is used as a functional layer provided between an anode and a light emitting layer such as a hole injection layer, a hole transport layer, and a hole injection transport layer of an organic EL element. It is preferably 5 to 300 nm. As a method of changing the film thickness, there are methods such as changing the solid content concentration in the varnish and changing the amount of the solution on the substrate at the time of coating.

The charge-transporting thin film of the present invention described above usually exhibits a refractive index (n) of 1.50 or more and an extinction coefficient (k) of 0.10 or less with an average value in the wavelength region of 400 to 800 nm. In some embodiments, it exhibits a refractive index (n) of 1.60 or higher, in other embodiments it exhibits a refractive index (n) of 1.70 or higher, and in some embodiments it has an extinction coefficient of 0.07 or lower. (K) shows an extinction coefficient (k) of 0.02 or less in some other embodiments.

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

The "hole injection layer", the "hole transport layer" and the "hole injection transport layer" are layers formed between the light emitting layer and the anode, and transport holes from the anode to the light emitting layer. When it has a function and only one layer of a hole transporting material is provided between the light emitting layer and the anode, it is a "hole injection transport layer", and between the light emitting layer and the anode, When two or more layers of the hole transporting material are provided, the layer close to the anode is the "hole injection layer" and the other layers are the "hole transport layer". In particular, as the hole injection (transport) layer, a thin film having excellent not only hole acceptability from the anode but also hole injection property into the hole transport (emission) layer is used.
The "electron injection layer", "electron transport layer" and "electron injection transport layer" are layers formed between the light emitting layer and the cathode and have a function of transporting electrons from the cathode to the light emitting layer. When only one layer of electron transporting material is provided between the light emitting layer and the cathode, it is an "electron injection transporting layer", and a layer of electron transporting material is provided between the light emitting layer and the cathode. When two or more layers are provided, the layer close to the cathode is the "electron injection layer", and the other layers are the "electron transport layers".
The "light emitting layer" is an organic layer having a light emitting function, and includes a host material and a dopant material when a doping system is adopted. At this time, the host material mainly promotes the recombination of electrons and holes and has a function of confining excitons in the light emitting layer, and the dopant material efficiently emits excitons obtained by recombination. Has a function. In the case of a phosphorescent device, the host material mainly has a function of confining excitons generated by the dopant in the light emitting layer.

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

Examples of materials and methods used when manufacturing an EL device using the charge-transporting varnish of the present invention 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 varnish of the present invention is as follows. It is preferable that the electrodes are preliminarily cleaned with alcohol, pure water, or the like, or surface-treated with UV ozone treatment, oxygen-plasma treatment, or the like, as long as the electrodes are not adversely affected.
A hole injection layer made of the charge-transporting thin film of the present invention is formed on the anode substrate by the above method. This is introduced into a vacuum vapor deposition apparatus, and a hole transport layer, a light emitting layer, an electron transport layer, an electron transport layer / hole block layer, and a cathode metal are sequentially vapor-deposited. Alternatively, instead of forming the hole transport layer and the light emitting layer by vapor deposition in the method, a composition for forming a hole transport layer containing a hole transport polymer and a composition for forming a light emitting layer containing a light emitting polymer are used. These layers are formed by a wet process using. If necessary, an electron block layer may be provided between the light emitting layer and the hole transport layer.

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

Materials for forming the hole transport layer include (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spirodimers, and 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 -Triarylamines such as -naphthyl (phenyl) amino] triphenylamine (1-TNATA), 5,5 "-bis- {4- [bis (4-methylphenyl) amino] phenyl} -2,2': Examples thereof include oligothiophenes such as 5', 2 "-turthiophene (BMA-3T).

Examples of the material forming the light emitting layer include a metal complex such as an aluminum complex of 8-hydroxyquinoline, a metal complex of 10-hydroxybenzo [h] quinoline, a bisstyrylbenzene derivative, a bisstyrylarylene derivative, and (2-hydroxyphenyl) benzo. Low molecular weight luminescent materials such as thiazole metal complexes and silol derivatives; poly (p-phenylene vinylene), poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene], poly (3-alkyl Examples thereof include, but are not limited to, a system in which a light emitting material and an electron transfer material are mixed with a polymer compound such as thiophene) and polyvinylcarbazole.
When the light emitting layer is formed by vapor deposition, it may be co-deposited with a light emitting dopant, and the light emitting dopant is a metal complex such as tris (2-phenylpyridine) iridium (III) (Ir (ppy) ₃ ). , A naphthacene derivative such as rubrene, a quinacridone derivative, a condensed polycyclic aromatic ring such as perylene, and the like, but are not limited thereto.

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

Materials for forming the electron injection layer include metal oxides such as lithium oxide (Li ₂ O), magnesium oxide (Mg O), and alumina (Al ₂ O ₃ ), lithium fluoride (LiF), and sodium fluoride (NaF). Metal fluorides, but are not limited to these.
Examples of the cathode material include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, and the like.
Examples of the material for forming the electron block layer include, but are not limited to, tris (phenylpyrazole) iridium and the like.

As the 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] -endcapped with polysilsis quinoxane, poly [(9,9-) Didioctylfluorenyl-2,7-diyl) -co- (4,4'-(N- (p-butylphenyl)) diphenylamine)] and the like can be mentioned.

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

As described above, the charge transporting varnish of the present invention is suitable for forming a functional layer provided between an anode and a light emitting layer such as a hole injection layer, a hole transport layer, and a hole injection transport layer of an organic EL device. In addition to being used, organic photoelectric conversion elements, organic thin film solar cells, organic perovskite photoelectric conversion elements, organic integrated circuits, organic field effect transistors, organic thin films, organic light emitting transistors, organic optical inspection devices, organic photoreceivers, organic It can also be used to form a charge transporting thin film in electronic devices such as electric field extinguishing devices, light emitting electronic chemical batteries, quantum dot light emitting diodes, quantum lasers, organic laser diodes and organic Plasmon light emitting devices.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The devices used are as follows.
(1) MALDI-TOF-MS: autoflex III smart beam manufactured by Bruker Co., Ltd.
(2) ^{1 1} H-NMR: JNM-ECP300 FT NMR SYSTEM manufactured by JEOL Ltd.
(3) Substrate cleaning: Substrate cleaning equipment manufactured by Choshu Sangyo Co., Ltd. (decompression plasma method)
(4) Application of varnish: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.
(5) Film thickness measurement: Kosaka Laboratory Co., Ltd. Fine shape measuring machine Surfcoder ET-4000
(6) Manufacture of element: Multi-function vapor deposition equipment system C-E2L1G1-N manufactured by Choshu Sangyo Co., Ltd.
(7) Measurement of element current density and brightness: Multi-channel IVL measuring device manufactured by EHC Co., Ltd. (8) Life measurement of EL element (brightness half-life measurement): Organic EL brightness life manufactured by EHC Co., Ltd. Evaluation system PEL-105S
(9) Measurement of refractive index (n) and extinction coefficient (k): Multi-incident angle spectroscopic ellipsometer VASE manufactured by JA Woolam Japan

[1] Production of arylamine compound [Example 1-1] Synthesis of arylamine compound A

Four-necked flask, 3,6-diaminocarbazole 0.3 g, 2-bromophenyl carbazole _{_{2.570g, Pd 2 (dba) 2}} 0.086g, [(tBu) 3 PH] BF 4 0.087g, tBuONa1. 05 g and 10 g of toluene were added, and the mixture was stirred at 80 ° C. for 3 hours. Then, it was returned to room temperature and filtered through Celite. Toluene and saturated brine were added to the filtrate to separate the filtrates, and the aqueous layer was removed. An appropriate amount of magnesium ₄ was added to the obtained organic layer, and the mixture was allowed to stand at room temperature for 10 minutes. Silica gel ₄ was filtered through silica gel, and the filtrate was concentrated. The obtained concentrated solution was added dropwise to a mixed solvent of ethyl acetate and methanol, and the mixture was stirred at room temperature for 30 minutes, and the precipitated solid was filtered off. The obtained solid was dried to obtain 0.82 g of arylamine compound A (yield 38%).

^{1 1} H-NMR (500 MHz, THF-d ₈ ) δ [ppm]: 7.95-7.92 (m, 10H), 7.72-7.55 (m, 20H), 7.54-7.41 (M, 5H), 7.35-7.20 (m, 25H), 7.16-7.09 (m, 6H).

[Example 1-2] Synthesis of arylamine compound B

Four-necked flask, 3,6-diaminocarbazole 0.502 g, 3- bromophenyl carbazole _{_{4.441g, Pd 2 (dba) 2}} 0.037g, [(tBu) 3 PH] BF 4 0.037g, tBuONa1. 346 g and 15 g of toluene were added, and the mixture was stirred at 80 ° C. for 5.5 hours. After completion of the reaction, Celite filtration was performed and the target portion was concentrated by silica gel chromatography. The activated carbon was added to the concentrate, and the mixture was stirred at room temperature for 1 hour, and then the activated carbon was removed by filtration through Celite. The obtained filtrate was added dropwise to a mixed solvent of ethyl acetate and methanol, and the mixture was stirred at room temperature for 1 hour. The precipitated solid was separated by filtration and the obtained solid was dried to obtain 3.50 g of arylamine compound B (yield 98%).

^{1 1} H-NMR (500 MHz, THF-d ₈ ) δ [ppm]: 8.12-7.92 (m, 10H), 7.85-7.67 (m, 20H), 7.66-7.53 (M, 5H), 7.37-7.24 (m, 25H), 7.19-7.10 (m, 6H).

[2] Preparation of charge-transporting varnish [Example 2-1]
Arylamine compound A (0.027 g) obtained in Example 1-1 and an arylsulfonic acid ester represented by the following formula synthesized in chloroform (10 g) according to the method described in International Publication No. 2017/217455. The solution obtained by adding A (0.024 g) and stirring at room temperature to dissolve the solution was filtered through a syringe filter having a pore size of 0.2 μm to obtain a charge-transporting varnish A1.

[Example 2-2]
A charge-transporting varnish B1 was obtained in the same manner as in Example 2-1 except that the arylamine compound A was changed to the arylamine compound B obtained in Example 1-2.

[Example 2-3]
A charge-transporting varnish A2 was obtained in the same manner as in Example 2-1 except that the amount of the arylamine compound A used was changed to 0.040 g.

[Example 2-4]
A charge-transporting varnish B2 was obtained in the same manner as in Example 2-2, except that the amount of the arylamine compound B used was changed to 0.040 g.

[3] Production of thin film and evaluation of film physical properties [Example 3-1 and Example 3-2]
The varnishes obtained in Example 2-1 and Example 2-2 were each applied to a quartz substrate using a spin coater, dried in air at 120 ° C. for 1 minute, and then dried in air at 200 ° C. at 15 ° C. It was fired for a minute to form a uniform thin film of 50 nm on a quartz substrate.
Using the obtained quartz substrate with a film, the visible region average refractive index n and the visible region average extinction coefficient k at a wavelength of 400 to 800 nm were measured. The results are shown in Table 1.

As shown in Table 1, it can be seen that the thin film obtained from the charge-transporting varnish of the present invention has a high refractive index and a low extinction coefficient.

[4] Preparation and characterization of hole-only device (HOD) 1 [Preparation of solution for hole injection layer formation]
0.137 g of the aniline derivative represented by the formula (T) synthesized according to the method described in WO2013 / 084664 and the aryl represented by the formula (N) synthesized according to the method described in WO 2006/025432. 0.271 g of sulfonic acid was dissolved in 6.7 g of 1,3-dimethyl-2-imidazolidinone under a nitrogen atmosphere. To the obtained solution, 10 g of cyclohexanol and 3.3 g of propylene glycol were sequentially added and stirred to prepare a solution for forming a hole injection layer.

[Example 4-1]
As the ITO substrate, a 25 mm × 25 mm × 0.7 t glass substrate in which indium tin oxide (ITO) is patterned on the surface with a thickness of 150 nm is used, and before use, an O ₂ plasma cleaning device (150 W, 30 seconds) is used. Impurities on the surface were removed. Subsequently, the hole injection layer forming solution prepared as described above is applied onto the ITO substrate by spin coating, heated to 80 ° C. on a hot plate in the air, dried for 1 minute, and then further dried at 230 ° C. for 15 ° C. The hole injection layer (film thickness: 30 nm) was formed by heating and firing for 1 minute.
Next, the charge-transporting varnish A2 obtained in Example 2-3 was applied onto the hole injection layer using a spin coater, and then calcined at 130 ° C. for 10 minutes in an air atmosphere to obtain holes of 40 nm. A transport layer thin film was formed.
A hole-only element (HOD) was obtained by forming an aluminum thin film of 80 nm at 0.2 nm / sec using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa).

[Example 4-2]
HOD was prepared in the same manner as in Example 4-1 except that the charge transporting varnish B2 obtained in Example 2-4 was used instead of the charge transporting varnish A2.

The current density of the HOD produced above was measured at a drive voltage of 4 V. The results are shown in Table 2.

As shown in Table 2, it can be seen that the thin film prepared from the charge transporting varnish of the present invention exhibits excellent charge transporting property as a hole transporting layer.

[5] Fabrication of Single-Layer Element (SLD) [Example 5-1]
The charge-transporting varnish A1 obtained in Example 2-1 was applied on an ITO substrate similar to that in Example 4-1 by spin coating, dried in air at 120 ° C. for 1 minute, and then further in the air atmosphere. Below, it was fired at 200 ° C. for 15 minutes to form a hole injection layer (film thickness: 50 nm).
On this, an aluminum thin film of 80 nm was formed at 0.2 nm / sec using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa) to obtain a single-layer element (SLD).

[Example 5-2]
An SLD was prepared in the same manner as in Example 5-1 except that the charge transporting varnish A2 obtained in Example 2-2 was used instead of the charge transporting varnish A1.

The current density of the SLD produced above was measured at a drive voltage of 4 V. The results are shown in Table 3.

As shown in Table 3, it can be seen that the thin film prepared from the charge-transporting varnish of the present invention exhibits good charge-transporting property.

[6] Preparation of HOD2 [Example 6-1]
The charge-transporting varnish A1 obtained in Example 2-1 was applied onto an ITO substrate similar to that in Example 4-1 using a spin coater, dried in the air at 120 ° C. for 1 minute, and then The hole injection layer (film thickness: 50 nm) was formed by firing at 200 ° C. for 15 minutes.
On top of this, a thin film of α-NPD and aluminum was sequentially laminated using a vapor deposition apparatus (vacuum degree 2.0 × 10 ^-5 Pa) to obtain HOD. The vapor deposition was carried out under the condition of a vapor deposition rate of 0.2 nm / sec. The film thicknesses of the α-NPD and aluminum thin films were 30 nm and 80 nm, respectively.

[Example 6-2]
HOD was prepared in the same manner as in Example 6-1 except that the charge transporting varnish A2 obtained in Example 2-2 was used instead of the charge transporting varnish A1.

The current density of the HOD produced above was measured at a drive voltage of 4 V. The results are shown in Table 4.

As shown in Table 4, it can be seen that the thin film prepared from the charge-transporting varnish of the present invention exhibits good hole-injecting properties into the hole-transporting layer as the hole-injecting layer.

[7] Fabrication of organic EL device and evaluation of characteristics [Example 7-1]
The charge-transporting varnish A1 obtained in Example 2-1 was applied onto an ITO substrate similar to that in Example 4-1 using a spin coater, dried in the air at 120 ° C. for 1 minute, and then It was calcined at 200 ° C. for 15 minutes to form a thin film of 50 nm.
Next, on the ITO substrate on which the thin film was formed, α-NPD was deposited at 0.2 nm / sec at 30 nm using a thin film deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa). Next, a 10 nm film was formed on the electronic block material HTEB-01 manufactured by Kanto Chemical Co., Inc. Next, the light emitting layer host material NS60 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and the light emitting layer dopant material Ir (ppy) ₃ were co-deposited. For co-evaporation, the vapor deposition rate was controlled so that the concentration of Ir (ppy) ₃ was 6%, and 40 nm was laminated. Next, thin films of Alq ₃ , lithium fluoride and aluminum were sequentially laminated to obtain an organic EL device. At this time, the vapor deposition rate was 0.2 nm / sec for Alq ₃ and aluminum, and 0.02 nm / sec for lithium fluoride, respectively, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.
In order to prevent the deterioration of the characteristics due to the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate and then the characteristics were evaluated. Sealing was performed by 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, an organic EL element is placed between the sealing substrates, and the sealing substrate is an adhesive (Matsumura Oil Research Corp., Moresco Moisture Cut WB90US (P)). It was pasted together. At this time, a water catching agent (HD-071010W-40 manufactured by Dynic Co., Ltd.) was housed in the sealing substrate together with the organic EL element. The bonded 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 cure the adhesive.

[Example 7-2]
An organic EL device was produced in the same manner as in Example 7-1 except that the charge transporting varnish A2 obtained in Example 2-2 was used instead of the charge transporting varnish A1.

The drive voltage, current density, current efficiency, luminous efficiency, external emission quantum yield (EQE), and LT85 (initial brightness 5,000 cd /) when the obtained organic EL element is made to emit light at 5,000 cd / m ^2. The time required for a 15% reduction in m ² ) was measured. The results are shown in Table 5.

As shown in Table 5, it can be seen that all of the organic EL devices of the present invention exhibit high current efficiency and high EQE, and also exhibit good life characteristics.

Claims

An arylamine compound represented by the following formula (1).

(In the formula, R 1 independently represents an aryl group having 6 to 20 carbon atoms, and R 2 independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, and 1 to 20 carbon atoms. , An alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
The arylamine compound according to claim 1, which is represented by the following formula (1-1).

(In the formula, R 1 and R 2 have the same meanings as described above.)
The arylamine compound according to claim 2, which is represented by the following formula (1-1A) or (1-1B).

(In the formula, R 1 and R 2 have the same meanings as described above.)
The arylamine compound according to any one of claims 1 to 3, wherein R 1 is a phenyl group, a 1-naphthyl group or a 2-naphthyl group.
The arylamine compound according to claim 4, wherein R 1 is all a phenyl group.
The arylamine compound according to any one of claims 1 to 5, wherein R 2 is an all hydrogen atom.
A charge-transporting varnish containing the arylamine compound according to any one of claims 1 to 6 and an organic solvent.
The charge transporting varnish according to claim 7, which contains a dopant substance.
The charge transporting varnish according to claim 8, wherein the dopant substance is an aryl sulfonic acid ester compound.
A charge-transporting thin film produced by using the charge-transporting varnish according to any one of claims 7 to 9.
An electronic device including the charge transporting thin film according to claim 10.
The organic electroluminescence device including the charge transporting thin film according to claim 10.
The organic electroluminescence device according to claim 12, wherein the charge transporting thin film is a hole injection layer or a hole transport layer.