Arylamine compounds and their use

Abstract

The arylamine compound represented by the following formula (1) has good solubility in organic solvents and can provide a thin film with good optical properties. When the thin film is applied to a hole injection layer, etc., an organic EL element with good properties can be realized. (wherein, R 1 Each independently represents an aryl group having 6 to 20 carbon atoms, R 2 Each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, a haloalkyl 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.

Description

Technical Field

[0001] The present invention relates to arylamine compounds and their utilization. Background Art

[0002] Organic electroluminescent (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 being conducted for the purpose of low-voltage driving, high brightness, and long life.

[0003] In the organic EL element, a plurality of functional thin films are used, and a hole injection layer, one of which is responsible for transferring charges between the anode and the hole transport layer or the light emitting layer, plays an important role in achieving low voltage driving and high brightness of the organic EL element.

[0004] The methods for forming the hole injection layer are roughly divided into a dry method represented by a vapor deposition method and a wet method represented by a spin coating method. Comparing these methods, the wet method can efficiently form a thin film with high flatness over a large area.

[0005] Therefore, at present, when the area of ​​organic EL displays is being increased, a hole injection layer that can be formed by a wet method is desired.

[0006] In view of such actual conditions, the present inventors have developed charge transporting materials and compounds having good solubility in organic solvents for use therein, which can be applied to various wet processes and provide a thin film capable of achieving excellent EL element characteristics when applied to a hole injection layer of an organic EL element (see patent documents 1 to 3).

[0007] On the other hand, various studies have been conducted so far to improve the performance of organic EL elements, and studies have been conducted on adjusting the refractive index of the functional film used for the purpose of improving light extraction efficiency, etc. Specifically, considering the overall structure of the element and the refractive index of other adjacent components, attempts have been made to achieve high efficiency of the element by using a hole injection layer or a hole transport layer with a higher or lower refractive index (see Patent Documents 4 and 5).

[0008] Therefore, the refractive index is an important factor in the design of an organic EL element, and is also regarded as an important physical property value to be considered for materials for organic EL elements.

[0009] In addition, with regard to the coloring of charge transport films used in organic EL elements, due to the actual situation that the color purity and color reproducibility of the organic EL elements are reduced, in recent years, it is desired that the charge transport films used in organic EL elements have high transmittance in the visible region and high transparency (see Patent Document 6).

[0010] Therefore, at present, as the area of ​​organic EL displays is being increased, efforts are being focused on the development of organic EL displays using a wet process toward practical use, and materials for the wet process that provide a charge transporting thin film with good transparency are being sought.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: International Publication No. 2008 / 129947

[0014] Patent Document 2: International Publication No. 2015 / 050253

[0015] Patent Document 3: International Publication No. 2017 / 217457

[0016] Patent Document 4: Japanese Patent Application No. 2007-536718

[0017] Patent Document 5: Japanese Patent Application No. 2017-501585

[0018] Patent Document 6: International Publication No. 2013 / 042623 Summary of the invention

[0019] Problems to be solved by the invention

[0020] The present invention has been made in view of such actual conditions, and an object of the present invention is to provide an arylamine compound which has good solubility in an organic solvent and can give a thin film with good optical properties, and which can realize an organic EL element with good properties when the thin film is used as a hole injection layer or the like.

[0021] Means for solving problems

[0022] The present inventors have repeatedly conducted in-depth studies to achieve the above-mentioned purpose, and as a result, have found that a specified arylamine compound having an arylcarbazole skeleton has good solubility in an organic solvent, and a varnish containing the compound gives a thin film with excellent optical properties. When the thin film is applied to a hole injection layer, etc., an organic EL element with good properties is obtained, thereby completing the present invention.

[0023] That is, the present invention provides:

[0024] 1. An arylamine compound characterized by being represented by the following formula (1):

[0025] [Chemistry 1]

[0026]

[0027] (Where R 1Each independently represents an aryl group having 6 to 20 carbon atoms, R 2 Each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, a haloalkyl 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.

[0028] 2.1 an arylamine compound represented by the following formula (1-1),

[0029] [Chemistry 2]

[0030]

[0031] (Where R 1 and R 2 Means the same as above.)

[0032] 3.2 The arylamine compound represented by the following formula (1-1A) or (1-1B),

[0033] [Chemistry 3]

[0034]

[0035] (Where R 1 and R 2 Means the same as above.)

[0036] 4. The arylamine compound according to any one of 1 to 3, wherein R 1 is phenyl, 1-naphthyl or 2-naphthyl,

[0037] 5.4 The arylamine compound, wherein said R 1 All are phenyl,

[0038] 6. The arylamine compound according to any one of 1 to 5, wherein R 2 All hydrogen atoms,

[0039] 7. A charge transporting varnish comprising the arylamine compound according to any one of 1 to 6 and an organic solvent.

[0040] 8.7 The charge transporting varnish comprising a dopant substance,

[0041] 9.8 The charge transport varnish, wherein the dopant substance is an aryl sulfonate compound,

[0042] 10. A charge transporting thin film produced using the charge transporting varnish according to any one of 7 to 9,

[0043] 11. An electronic component comprising the charge transport thin film of 10,

[0044] 12. An organic electroluminescent element comprising the charge transport thin film of 10,

[0045] 13. The organic electroluminescent element of 12, wherein the charge transport thin film is a hole injection layer or a hole transport layer.

[0046] Effects of the Invention

[0047] The arylamine compound of the present invention has good solubility in organic solvents, and by using a charge-transporting varnish containing the arylamine compound, a charge-transporting thin film having high transparency (low k (extinction coefficient)) and a high refractive index (high n) can be obtained.

[0048] The charge transporting thin film can be suitably used as a thin film for electronic devices including organic EL devices. In particular, by applying the charge transporting thin film of the present invention to a hole injection layer of an organic EL device, a device having excellent characteristics can be produced. DETAILED DESCRIPTION

[0049] The present invention is described in more detail below.

[0050] The arylamine compound according to the present invention is characterized by being represented by the following formula (1), and as a preferred embodiment, is represented by formula (1-1).

[0051] [Chemistry 4]

[0052]

[0053] [Chemistry 5]

[0054]

[0055] In formula (1) and (1-1), R 1 Each independently represents an aryl group having 6 to 20 carbon atoms, R 2 Each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, a haloalkyl 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.

[0056] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0057] The alkyl group having 1 to 20 carbon atoms may be a straight-chain, branched or cyclic alkyl group. Examples thereof include a straight-chain or branched alkyl group having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; and a cyclic alkyl group having 3 to 20 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl and bicyclodecyl.

[0058] As for the alkoxy group having 1 to 20 carbon atoms, the alkyl group therein may be a straight chain, branched chain or cyclic alkyl group. Specific examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexoxy, n-octyloxy, n-decyloxy, 2-methylhexyloxy, 2-ethylhexyloxy, 2-n-propylhexyloxy, 2-n-butylhexyloxy, 2-ethyldecyloxy and 3-ethylhexyloxy.

[0059] Specific examples of the aryl group having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, and 9-phenanthrenyl.

[0060] The haloalkyl group having 1 to 20 carbon atoms is a group in which at least one hydrogen atom in the above-mentioned alkyl group having 1 to 20 carbon atoms is substituted with a halogen atom. Specific examples thereof include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a bromodifluoromethyl group, a 2-chloroethyl group, a 2-bromoethyl group, a 1,1-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a 2-chloro-1,1,2-trifluoroethyl group, a pentafluoroethyl group, a 3-bromopropyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,2,3,3,3-hexafluoropropyl group, a 1,1,1,3,3,3-hexafluoropropane-2-yl group, a 3-bromo-2-methylpropyl group, a 4-bromobutyl group, a perfluoropentyl group, and a 2-(perfluorohexyl)ethyl group.

[0061] In particular, if the solubility of the compound in an organic solvent is considered, R 1 An aryl group having 6 to 14 carbon atoms is preferred, and a phenyl group, a 1-naphthyl group, or a 2-naphthyl group is more preferred, and a phenyl group, a 1-naphthyl group, or a 2-naphthyl group is further preferred, and a phenyl group is further preferred.

[0062] If the solubility of the compound in organic solvent is considered, R 2 Preferred are 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. More preferred are a hydrogen atom and an alkyl group having 1 to 10 carbon atoms. Further preferred are all hydrogen atoms.

[0063] In formula (1-1), there is no particular limitation on the binding positions of the three nitrogen atoms of the central carbazole skeleton and the carbazole ring of the aromatic carbazole skeleton. They may be bound at the same position or at different positions. Preferably, they are bound at the 3-position (meta-position) or 4-position (para-position) relative to the nitrogen atom of the aromatic carbazole skeleton, as shown in the following formula (1-1A) or (1-1B), and more preferably at the 3-position.

[0064] [Chemistry 6]

[0065]

[0066] (Where R 1 and R 2 Means the same as above.)

[0067] Preferred arylamine compounds in the present invention include compounds represented by the following formula (2) or (3), but are not limited thereto.

[0068] [Chemistry 7]

[0069]

[0070] As shown in the following scheme, the arylamine compound represented by formula (1) or (1-1) can be produced by reacting a diaminocarbazole compound [Ia] or [Ib] with a halogenated arylcarbazole compound [II] in the presence of a catalyst.

[0071] [Chemistry 8]

[0072]

[0073] (wherein, X represents a halogen atom or a pseudohalogen group, R 1 and R 2 Means the same as above.)

[0074] [Chemistry 9]

[0075]

[0076] (Where X, R 1 and R 2 Means the same as above.)

[0077] Examples of the halogen atom include the same halogen atoms as mentioned above.

[0078] Examples of the pseudohalogen group include (fluoro)alkylsulfonyloxy groups such as a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, and a nonafluorobutanesulfonyloxy group; and aromaticsulfonyloxy groups such as a benzenesulfonyloxy group and a toluenesulfonyloxy group.

[0079] The feed ratio of the diaminocarbazole compound [Ia] or [Ib] to the halogenated arylcarbazole compound [II] may be 5 equivalents or more, preferably about 5 to 5.5 equivalents, based on the amount of all NH groups of the diaminocarbazole compound.

[0080] 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 (tetrakis(triphenylphosphine)palladium), Pd(PPh 3 ) 2 Cl 2 (bis(triphenylphosphine)palladium dichloride), Pd(dba) 2 (bis(dibenzylideneacetone)palladium), Pd 2 (dba) 3 (tris(dibenzylideneacetone)dipalladium), Pd(Pt-Bu 3 ) 2 (Bis(tri(tert-butylphosphine))palladium), Pd(OAc) 2 (palladium acetate) and other palladium catalysts. These catalysts can be used alone or in combination of two or more. In addition, these catalysts can be used together with a known appropriate ligand.

[0081] Examples of such ligands include tertiary phosphines such as triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-tert-butylphosphine, di-tert-butyl(phenyl)phosphine, di-tert-butyl(4-dimethylaminophenyl)phosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, and 1,1'-bis(diphenylphosphino)ferrocene; and triesters of phosphites such as trimethylphosphite, triethylphosphite, and triphenylphosphite. Ildrich, JohnPhos, 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, etc.

[0082] The amount of the catalyst used can be about 0.01 mol to 0.5 mol, preferably about 0.05 to 0.2 mol, based on 1 mol of the halogenated arylcarbazole compound [II].

[0083] When a ligand is used, the amount of the ligand used can be 0.1 to 5 equivalents, preferably 1 to 2 equivalents, based on the metal complex used.

[0084] In addition, a base can be used in the above reaction. Examples of the base include alkali metal simple substances such as lithium, sodium, potassium, lithium hydride, sodium hydride, lithium hydroxide, potassium hydroxide, tert-butoxylithium, tert-butoxysodium, tert-butoxypotassium, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, alkali metal hydrides, alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal bicarbonates; alkaline earth metal carbonates such as calcium carbonate; organic lithiums such as n-butyllithium, sec-butyllithium, tert-butyllithium, lithium diisopropylamine (LDA), 2,2,6,6-tetramethylpiperidinium lithium (LiTMP), and lithium hexamethyldisilazane (LHMDS); and amines such as triethylamine, diisopropylethylamine, tetramethylethylenediamine, triethylenediamine, and pyridine.

[0085] When a base is used, the amount of the base used can be 0.1 to 5 equivalents, preferably 1 to 2 equivalents, based on the halogenated arylcarbazole compound [II] used.

[0086] In the case where all the raw material compounds are solid or from the viewpoint of efficiently obtaining the target arylamine compound, each of the above reactions is carried out in a solvent. When a solvent is used, its type is not particularly limited as long as it does not adversely affect the reaction. As specific examples, aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decahydronaphthalene, etc.), halogenated aliphatic hydrocarbons (chloroform, dichloromethane, dichloroethane, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, etc.), ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane , 1,2-diethoxyethane, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, cyclohexanone, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, etc.), lactams and lactones (N-methylpyrrolidone, γ-butyrolactone, etc.), ureas (N,N-dimethylimidazolidinone, tetramethyl urea, etc.), sulfoxides (dimethyl sulfoxide, cyclopentane, etc.), nitriles (acetonitrile, propionitrile, butyronitrile, etc.), etc. These solvents may be used alone or in combination of two or more.

[0087] The reaction temperature can be appropriately set within the range from the melting point to the boiling point of the solvent used, and is particularly preferably about 0 to 200°C, more preferably 20 to 150°C.

[0088] After the reaction is completed, post-treatment is performed according to a conventional method to obtain the target arylamine compound.

[0089] The above-mentioned arylamine compound of the present invention can be preferably used as a charge transporting substance. In this case, it can be used as a charge transporting varnish comprising the arylamine compound of the present invention and an organic solvent, in which a dopant substance may be included for the purpose of improving its charge transporting ability, etc., depending on the purpose of the obtained film. In addition, the arylamine compound of the present invention can also be used in combination with other previously known charge transporting substances such as aniline derivatives and thiophene derivatives, and the arylamine compound of the present invention is preferably used alone as a charge transporting substance.

[0090] In the present invention, charge transporting property is synonymous with electrical conductivity. The charge transporting varnish may have charge transporting property itself or a solid film obtained therefrom may have charge transporting property.

[0091] The dopant substance is not particularly limited as long as it is soluble in at least one solvent used in the varnish, and both inorganic and organic dopant substances can be used.

[0092] Inorganic and organic dopant substances may be used alone or in combination of two or more.

[0093] Furthermore, the dopant substance may be a substance that, in the process of obtaining a charge transporting thin film as a solid film from a varnish, causes a part of the molecule to be released due to external stimulation such as heating during firing, thereby causing the function of the dopant substance to be initially manifested or enhanced, such as an aromatic sulfonate compound protected with a group from which the sulfonic acid group is easily released.

[0094] In the present invention, heteropolyacids are particularly preferred as inorganic dopant substances.

[0095] The so-called heteropoly acid is a structure in which a heteroatom is located at the center of the molecule, which is typically represented by a Keggin-type chemical structure represented by formula (H1) or a Dawson-type chemical structure represented by formula (H2), and is a polyacid formed by condensation of an isopoly acid of an oxygen-containing acid such as vanadium (V), molybdenum (Mo), tungsten (W), etc. with an oxygen-containing acid of a different element. As such an oxygen-containing acid of a different element, oxygen-containing acids of silicon (Si), phosphorus (P), and arsenic (As) can be mainly listed.

[0096] [Chemistry 10]

[0097]

[0098] As the specific example of heteropolyacid, phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstic molybdic acid etc. can be listed, and these heteropolyacids can be used alone, and two or more combinations can also be used. Furthermore, these heteropolyacids can be obtained as commercially available products, and in addition, known method synthesis can also be adopted.

[0099] In particular, when one heteropoly acid is used, the one heteropoly acid is preferably phosphotungstic acid or phosphomolybdic acid, and most preferably phosphotungstic acid. In addition, when two or more heteropoly acids are used, one of the two or more heteropoly acids is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.

[0100] In addition, the heteropolyacid can be used in the present invention as long as it is a commercially available product or a product appropriately synthesized by a known synthesis method even if the number of elements relative to the structure represented by the general formula is large or small in quantitative analysis such as elemental analysis.

[0101] That is, for example, generally, phosphotungstic acid is represented by the chemical formula H 3 (PW 12 O 40 )·nH 2 O represents phosphomolybdic acid with the chemical formula H 3 (PMo 12 O 40 )·nH 2 O represents that, in quantitative analysis, even if the number of P (phosphorus), O (oxygen) or W (tungsten) or Mo (molybdenum) in the formula is more or less, as long as it is a product obtained as a commercial product or a product appropriately synthesized according to a known synthesis method, it can be used in the present invention. In this case, the mass of the heteropolyacid specified in the present invention is not the mass (phosphotungstic acid content) of the pure phosphotungstic acid in the synthetic product or commercial product, but means the total mass in the state of containing hydration water, other impurities, etc. in the form available as a commercial product and the form separable by a known synthesis method.

[0102] The amount of the heteropolyacid used can be about 0.001 to 50.0, preferably about 0.01 to 20.0, and more preferably about 0.1 to 10.0, relative to the charge transporting material 1, expressed as a mass ratio.

[0103] On the other hand, as the organic dopant substance, in particular, a tetracyanoquinodimethane derivative or a benzoquinone derivative can be used.

[0104] Specific examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ) and halogenated tetracyanoquinodimethane represented by the formula (H3).

[0105] Specific examples of benzoquinone derivatives include tetrafluoro-1,4-benzoquinone (F4BQ), tetrachloro-1,4-benzoquinone (tetrachloro-p-benzoquinone), tetrabromo-1,4-benzoquinone, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ).

[0106] [Chemistry 11]

[0107]

[0108] In the formula, R 500 ~R 503 Each independently represents a hydrogen atom or a halogen atom, at least one is a halogen atom, preferably at least two are halogen atoms, more preferably at least three are halogen atoms, and most preferably all are halogen atoms.

[0109] Examples of the halogen atom include the same halogen atoms as mentioned above, and a fluorine atom or a chlorine atom is preferred, and a fluorine atom is more preferred.

[0110] Specific examples of such halogenated tetracyanoquinodimethanes include 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-7,7,8,8-tetracyanoquinodimethane, and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ).

[0111] 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, based on the charge transporting substance.

[0112] In addition, as the organic dopant substance, an electrically neutral onium borate containing a monovalent or divalent anion represented by the following formula (a1) and a counter cation represented by formulae (c1) to (c5) can also be used.

[0113] [Chemistry 12]

[0114]

[0115] (wherein, Ar each 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 + -. )

[0116] [Chemistry 13]

[0117]

[0118] In 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, propylene, tetramethylene, pentamethylene, hexamethylene, etc. Further, the aryl group and heteroaryl group may be the same as those mentioned above.

[0119] Preferred examples of the anion of the above formula (a1) include anions represented by formula (a2), but are not limited thereto.

[0120] [Chemistry 14]

[0121]

[0122] The usage-amount of the onium borate salt is expressed as a mass (molar) ratio, and can be about 0.1 to 10 with respect to the charge transporting substance.

[0123] The onium borate can be synthesized by referring to a known method described in, for example, JP-A-2005-314682.

[0124] In addition, as the organic dopant substance, an arylsulfonic acid compound or an arylsulfonic acid ester compound can also be preferably used.

[0125] Specific examples of the arylsulfonic acid compound include benzenesulfonic acid, toluenesulfonic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2,5-dihexylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, 6,7-dibutyl-2-naphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, 3-dodecyl-2-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 4-hexyl-1-naphthalenesulfonic acid, octylnaphthalenesulfonic acid, 2-octyl-1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, Sulfonic acid, 7-hexyl-1-naphthalenesulfonic acid, 6-hexyl-2-naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, 2,7-dinonyl-4-naphthalenesulfonic acid, dinonylnaphthalene disulfonic acid, 2,7-dinonyl-4,5-naphthalene disulfonic acid, 1,4-benzodioxane disulfonic acid compounds described in International Publication No. 2005 / 000832, arylsulfonic acid compounds described in International Publication No. 2006 / 025342, arylsulfonic acid compounds described in International Publication No. 2009 / 096352, etc.

[0126] Preferred examples of the arylsulfonic acid compound include arylsulfonic acid compounds represented by the formula (H4) or (H5).

[0127] [Chemistry 15]

[0128]

[0129] A 1 represents O or S, preferably O.

[0130] A 2 represents a naphthalene ring or an anthracene ring, preferably a naphthalene ring.

[0131] A 3 represents a 2- to 4-valent perfluorobiphenyl group, and p represents A 1 With A 3 The combination number is an integer satisfying 2≤p≤4, preferably A 3 is perfluorobiphenylene, preferably perfluorobiphenyl-4,4'-diyl, and p is 2.

[0132] q means 2 The number of sulfonic acid groups to be bonded is an integer satisfying 1≤q≤4, and 2 is most preferred.

[0133] A 4 ~A 8 each independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogenated alkenyl group having 2 to 20 carbon atoms, 4 ~A 8 At least three of them are halogen atoms.

[0134] Examples of the halogenated alkyl group having 1 to 20 carbon atoms include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl and 1,1,2,2,3,3,4,4,4-nonafluorobutyl.

[0135] Examples of the haloalkenyl group having 2 to 20 carbon atoms include perfluorovinyl group, perfluoropropenyl group (allyl group), and perfluorobutenyl group.

[0136] Examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms include the same examples as described above, and the halogen atom is preferably a fluorine atom.

[0137] Among these, A is preferred 4 ~A 8 is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms, and A 4 ~A 8At least three of them are fluorine atoms, more preferably hydrogen atoms, fluorine atoms, cyano groups, alkyl groups having 1 to 5 carbon atoms, fluoroalkyl groups having 1 to 5 carbon atoms, or fluoroalkenyl groups having 2 to 5 carbon atoms, and A 4 ~A 8 At least three of them are fluorine atoms, more preferably a hydrogen atom, a fluorine atom, a cyano group, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkenyl group having 1 to 5 carbon atoms, and A 4 , A 5 and A 8 A fluorine atom.

[0138] The perfluoroalkyl group is a group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms, and the perfluoroalkenyl group is a group in which all hydrogen atoms of the alkenyl group are substituted with fluorine atoms.

[0139] r represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1≤r≤4, preferably 2 to 4, and most preferably 2.

[0140] The molecular weight of the arylsulfonic acid compound used as a dopant substance is not particularly limited, but is preferably 2000 or less, more preferably 1500 or less, in consideration of solubility in an organic solvent when used together with the arylamine compound of the present invention.

[0141] Specific examples of preferred arylsulfonic acid compounds are listed below, but the present invention is not limited to these.

[0142] [Chemistry 16]

[0143]

[0144] The amount of the arylsulfonic acid compound used is preferably about 0.01 to 20.0, more preferably about 0.4 to 5.0, relative to the charge transporting substance 1, expressed as a mass (molar) ratio.

[0145] As the arylsulfonic acid compound, a commercially available product may be used, or the arylsulfonic acid compound may be synthesized by a known method described in International Publication No. 2006 / 025342, International Publication No. 2009 / 096352, and the like.

[0146] On the other hand, examples of the aryl sulfonate compound include the aryl sulfonate compounds disclosed in International Publication No. 2017 / 217455, the aryl sulfonate compounds disclosed in International Publication No. 2017 / 217457, and the aryl sulfonate compounds described in Japanese Patent Application No. 2017-243631. Specifically, a compound represented by any one of the following formulas (H6) to (H8) is preferred.

[0147] [Chemistry 17]

[0148]

[0149] (In the formula, m is an integer satisfying 1≤m≤4, preferably 2. n is an integer satisfying 1≤n≤4, preferably 2.)

[0150] In formula (H6), A 11 It is an m-valent group derived from perfluorobiphenyl.

[0151] A 12 It is -O- or -S-, preferably -O-.

[0152] A 13 It is a (n+1)-valent group derived from naphthalene or anthracene, and is preferably a group derived from naphthalene.

[0153] R s1 ~R s4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, s5 It is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

[0154] Specific examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and n-hexyl. An alkyl group having 1 to 3 carbon atoms is preferred.

[0155] The monovalent hydrocarbon group having 2 to 20 carbon atoms may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl; and aryl groups such as phenyl, naphthyl and phenanthryl.

[0156] In particular, in R s1 ~R s4 Among them, R is preferred s1 or R s3 is a straight-chain alkyl group having 1 to 3 carbon atoms, the remainder being hydrogen atoms, or R s1 is a straight-chain alkyl group having 1 to 3 carbon atoms, R s2 ~R s4 In this case, the linear alkyl group having 1 to 3 carbon atoms is preferably a methyl group.

[0157] In addition, as R s5 , preferably a straight-chain alkyl group having 2 to 4 carbon atoms or a phenyl group.

[0158] In formula (H7), A 14 It is an m-valent hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings which may be substituted, and the hydrocarbon group is a group obtained by removing m hydrogen atoms from a hydrocarbon compound having 6 to 20 carbon atoms and containing one or more aromatic rings.

[0159] Examples of such hydrocarbon compounds include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, and phenanthrene.

[0160] Furthermore, with respect to the above-mentioned hydrocarbon group, part or all of its hydrogen atoms may be further substituted by a substituent, and examples of such substituents include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxyl group, an amino group, a silanol group, a thiol group, a carboxyl group, a sulfonate group, phosphoric acid, a phosphate ester, an ester, a thioester, an amide, an organic oxygen group, an organic amino group, an organic silyl group, an organic thio group, an acyl group, a sulfonic group, a monovalent hydrocarbon group, and the like.

[0161] Among these, as A 14 , preferably a group derived from benzene, biphenyl, etc.

[0162] In addition, A 15 It is -O- or -S-, preferably -O-.

[0163] A 16 An (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein the aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from an aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms.

[0164] Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene.

[0165] Among them, as A 16 , preferably a group derived from naphthalene or anthracene, more preferably a group derived from naphthalene.

[0166] R s6 and R s7 are each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group, R s8 is a linear or branched monovalent aliphatic hydrocarbon group. s6 , R s7 and R s8 The total number of carbon atoms in R is 6 or more. s6 , R s7 and R s8 The upper limit of the total number of carbon atoms is not particularly limited, but is preferably 20 or less, and more preferably 10 or less.

[0167] Specific examples of the above-mentioned straight-chain or branched monovalent aliphatic hydrocarbon groups include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, and decyl; and alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl.

[0168] Among these, R s6 Preferably a hydrogen atom, R s7 and R s8 Each independently is preferably an alkyl group having 1 to 6 carbon atoms.

[0169] In formula (H8), R s9 ~R s13 Each is independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or a haloalkenyl group having 2 to 10 carbon atoms.

[0170] The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl and n-decyl.

[0171] The halogenated alkyl 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 above alkyl group having 1 to 10 carbon atoms are substituted with halogen atoms. Specific examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl and 1,1,2,2,3,3,4,4,4-nonafluorobutyl.

[0172] The haloalkenyl group having 2 to 10 carbon atoms is not particularly limited as long as it is a group in which a part or all of the hydrogen atoms of the alkenyl group having 2 to 10 carbon atoms are substituted by halogen atoms. Specific examples thereof include perfluorovinyl, perfluoro-1-propenyl, perfluoro-2-propenyl, perfluoro-1-butenyl, perfluoro-2-butenyl, and perfluoro-3-butenyl.

[0173] Among these, R s9 , preferably nitro, cyano, haloalkyl having 1 to 10 carbon atoms, or haloalkenyl having 2 to 10 carbon atoms, more preferably nitro, cyano, haloalkyl having 1 to 4 carbon atoms, or haloalkenyl having 2 to 4 carbon atoms, further preferably nitro, cyano, trifluoromethyl, or perfluoropropenyl.

[0174] As R s10 ~R s13 , preferably a halogen atom, more preferably a fluorine atom.

[0175] A 17 It is -O-, -S- or -NH-, preferably -O-.

[0176] A 18 An (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, wherein the aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from an aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms.

[0177] Examples of such aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene.

[0178] Among these, as A 18 , preferably a group derived from naphthalene or anthracene, more preferably a group derived from naphthalene.

[0179] R s14 ~R s17 Each independently represents a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms.

[0180] Specific examples of the monovalent aliphatic hydrocarbon group include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl; and alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl. Preferably, the alkyl group has 1 to 20 carbon atoms, more preferably, the alkyl group has 1 to 10 carbon atoms, and still more preferably, the alkyl group has 1 to 8 carbon atoms.

[0181] R s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or OR s19 . R s19 It is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

[0182] As R s18 Examples of the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms include the same groups as described above.

[0183] In R s18 When it is a monovalent aliphatic hydrocarbon group, R s18 An alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 10 carbon atoms is more preferred, and an alkyl group having 1 to 8 carbon atoms is further preferred.

[0184] As R s19 The monovalent hydrocarbon group having 2 to 20 carbon atoms includes, in addition to the groups other than the methyl group among the above-mentioned monovalent aliphatic hydrocarbon groups, aryl groups such as phenyl, naphthyl, and phenanthryl.

[0185] Among these, R s19 A linear alkyl group having 2 to 4 carbon atoms or a phenyl group is preferred.

[0186] 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.

[0187] Specific examples of preferred arylsulfonate compounds include the following, but are not limited to these.

[0188] [Chemistry 18]

[0189]

[0190] The amount of the arylsulfonic acid ester compound used is preferably about 0.01 to 20, more preferably about 0.05 to 10, relative to 1 of the charge transporting substance, expressed as a mass (molar) ratio.

[0191] In the present invention, if the production of a charge transporting film with excellent transparency and a high refractive index is considered, an aryl sulfonic acid compound or an aryl sulfonic ester compound is preferably used as a dopant substance. If the solubility in a solvent and a film with a smaller extinction coefficient are considered, an aryl sulfonic ester compound is more preferably used.

[0192] Furthermore, when the obtained thin film is used as a hole injection layer of an organic EL element, the charge transport varnish may contain an organic silane compound for the purpose of improving the injectability into the hole transport layer and improving the life characteristics of the element. The content thereof is generally about 1 to 30% by mass relative to the total mass of the charge transport substance and the dopant substance.

[0193] As the organic solvent used in preparing the charge transport varnish of the present invention, a high polarity solvent that can dissolve the arylamine compound of the present invention well can be used. The arylamine compound of the present invention can be dissolved in the solvent regardless of the polarity of the solvent. In addition, as required, compared with the high polarity solvent, a low polarity solvent can be used in terms of excellent process suitability. In the present invention, the so-called low polarity solvent is defined as a solvent having a relative dielectric constant of less than 7 at a frequency of 100kHz, and the so-called high polarity solvent is defined as a solvent having a relative dielectric constant of 7 or more at a frequency of 100kHz.

[0194] Examples of low polarity solvents include

[0195] Chlorinated solvents such as chloroform and chlorobenzene;

[0196] Aromatic hydrocarbon solvents such as toluene, xylene, tetralin, cyclohexylbenzene, decylbenzene, etc.

[0197] Aliphatic alcohol solvents such as 1-octanol, 1-nonanol, and 1-decanol;

[0198] Ether 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, and triethylene glycol butyl methyl ether;

[0199] Ester solvents such as methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, di(2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate.

[0200] In addition, examples of highly polar solvents include

[0201] Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutylamide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone;

[0202] Ketone solvents such as methyl ethyl ketone, isophorone, and cyclohexanone;

[0203] Cyano-based solvents such as acetonitrile and 3-methoxypropionitrile;

[0204] Polyol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butylene glycol, and 2,3-butylene glycol;

[0205] Monohydric alcohol solvents 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;

[0206] Sulfoxide solvents such as dimethyl sulfoxide, etc.

[0207] The viscosity of the charge transport varnish is appropriately determined depending on the thickness of the film to be produced and the solid content concentration, and is usually 1 to 50 mPa·s at 25° C. In the present invention, the solid content refers to components other than the solvent contained in the charge transport varnish.

[0208] In addition, 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 film to be produced, etc., and is usually about 0.1 to 10.0 mass %. If considering improving the coating properties of the varnish, it is preferably about 0.5 to 5.0 mass %, and more preferably about 1.0 to 3.0 mass %.

[0209] There is no particular limitation on the method for preparing the charge transport varnish, and examples thereof include a method of dissolving a solid component of a charge transport material including the aromatic amine compound of the present invention in a high polarity solvent and adding a low polarity solvent thereto; a method of mixing a high polarity solvent and a low polarity solvent and dissolving the charge transport material therein, etc.

[0210] In particular, when preparing a charge transport varnish, it is preferred to dissolve the charge transport substance, dopant substance, etc. in an organic solvent and then filter using a submicron filter or the like from the viewpoint of obtaining a thin film with higher flatness with good reproducibility.

[0211] The charge-transporting varnish described above can be used to easily produce a charge-transporting thin film, and thus can be suitably used in the production of electronic devices, particularly organic EL devices.

[0212] 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.

[0213] The coating method of the varnish is not particularly limited, and examples thereof include dipping, spin coating, transfer printing, roller coating, brush coating, inkjet, spray coating, and slit coating. The viscosity and surface tension of the varnish are preferably adjusted according to the coating method.

[0214] In addition, there is no particular restriction on the firing atmosphere of the charge transport varnish after coating. Not only in the air atmosphere, but even in an inert gas such as nitrogen or a vacuum, a thin film with a uniform film-forming surface and high charge transport properties can be obtained. Depending on the type of dopant substance used, by firing the varnish in the air atmosphere, a thin film with charge transport properties can sometimes be obtained with good reproducibility.

[0215] The calcining temperature is appropriately set within the range of about 100 to 260°C, taking into account the purpose of the obtained film, the degree of charge transport properties imparted to the obtained film, the type of solvent, the boiling point, etc. For example, when the obtained film is used as a hole injection layer of an organic EL element, the calcining temperature is preferably about 140 to 250°C, and more preferably about 145 to 240°C. When the above-mentioned aromatic amine compound represented by formula (1) is used as a charge transport material, a film having good charge transport properties can be obtained even at a low temperature of less than 200°C.

[0216] During firing, in order to develop a more uniform film-forming property and to advance the reaction on the substrate, two or more temperature changes may be applied, and heating may be performed using appropriate equipment such as a hot plate or an oven.

[0217] The film thickness of the charge transport thin film is not particularly limited. When used as a functional layer provided between the anode and the light-emitting layer such as a hole injection layer, a hole transport layer, or a hole injection transport layer of an organic EL element, the film thickness is preferably 5 to 300 nm. As a method for changing the film thickness, there are methods such as changing the solid content concentration in the varnish and changing the amount of solution on the substrate during coating.

[0218] The charge transport film of the present invention described above is represented by an average value in the wavelength region of 400 to 800 nm, and generally shows a refractive index (n) greater than 1.50 and an extinction coefficient (k) less than 0.10. In one embodiment, it shows a refractive index (n) greater than 1.60, and in another embodiment, it shows a refractive index (n) greater than 1.70. In addition, in one embodiment, it shows an extinction coefficient (k) less than 0.07, and in another embodiment, it shows an extinction coefficient (k) less than 0.02.

[0219] When the charge transporting thin film is applied to an organic EL element, the charge transporting thin film may be provided between a pair of electrodes constituting the organic EL element.

[0220] As a representative structure of an organic EL element, the following (a) to (f) can be listed, but it is not limited to these. It should be noted that in the following structure, as needed, an electron blocking layer can be provided between the light-emitting layer and the anode, and a hole blocking layer can be provided between the light-emitting layer and the cathode. In addition, the hole injection layer, the hole transport layer or the hole injection transport layer can also have the function of an electron blocking layer, and the electron injection layer, the electron transport layer or the electron injection transport layer can also have the function of a hole blocking layer. Furthermore, as needed, any functional layer can also be provided between the layers.

[0221] (a) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode

[0222] (b) Anode / hole injection layer / hole transport layer / light-emitting layer / electron injection transport layer / cathode

[0223] (c) Anode / HIT / Emission layer / Electron transport layer / Electron injection layer / Cathode

[0224] (d) Anode / hole injection and transport layer / light-emitting layer / electron injection and transport layer / cathode

[0225] (e) Anode / HOL injection layer / HOL transport layer / Emission layer / Cathode

[0226] (f) Anode / HIT Injection and Transport Layer / Light Emitting Layer / Cathode

[0227] "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. When only one layer of hole transport material is provided between the light-emitting layer and the anode, it is a "hole injection transport layer". When two or more layers of hole transport material are provided between the light-emitting layer and the anode, the layer close to the anode is a "hole injection layer" and the other layers are "hole transport layers". In particular, the hole injection (transport) layer uses a thin film that is excellent not only in hole acceptance from the anode but also in hole injection into the hole transport (light-emitting) layer.

[0228] “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. When only one layer of electron transport material is provided between the light-emitting layer and the cathode, it is an “electron injection transport layer”; 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”, and the layers other than the cathode are “electron transport layers”.

[0229] The "light-emitting layer" is an organic layer having a light-emitting function, and in the case of a doping system, it includes a host material and a dopant material. In this case, the host material mainly has the function of promoting the recombination of electrons and holes and confining excitons in the light-emitting layer, and the dopant material has the function of making the excitons obtained by the recombination emit light efficiently. In the case of a phosphorescent element, the host material mainly has the function of confining the excitons generated by the dopant in the light-emitting layer.

[0230] The charge transporting 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 element, preferably as a hole injection layer, a hole transport layer, or a hole injection transport layer, more preferably as a hole injection layer or a hole transport layer, and further preferably as a hole injection layer.

[0231] As materials used and production methods when producing an EL element using the charge transporting varnish of the present invention, the following materials used and production methods can be cited, but they are not limited to these.

[0232] An example of a method for producing an OLED element having a hole injection layer composed of a thin film obtained from the charge transport varnish of the present invention is as follows. In addition, as for the electrode, it is preferred to perform a cleaning with alcohol, pure water, etc. in advance within a range that does not adversely affect the electrode; and a surface treatment with UV ozone treatment, oxygen-plasma treatment, etc.

[0233] On the anode substrate, the above method is used to form a hole injection layer composed of a charge transport film of the present invention. It is introduced into a vacuum evaporation device, and a hole transport layer, a light-emitting layer, an electron transport layer, an electron transport layer / hole blocking layer, and a cathode metal are sequentially evaporated. Alternatively, in this method, instead of using evaporation to form a hole transport layer and a light-emitting layer, a hole transport layer forming composition containing a hole transport polymer and a light-emitting layer forming composition containing a light-emitting polymer are used to form these layers by a wet method. Furthermore, as needed, an electron blocking layer can be provided between the light-emitting layer and the hole transport layer.

[0234] As anode materials, transparent electrodes represented by indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes composed of metals represented by aluminum, and alloys thereof, etc. are listed, preferably anode materials that have been flattened. Polythiophene derivatives and polyaniline derivatives with high charge transport properties can also be used.

[0235] In addition, examples of other metals constituting the metal anode include gold, silver, copper, indium, and alloys thereof, but are not limited to these.

[0236] As materials for forming the hole transport layer, there can be listed (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spirodimer, N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD), 4,4',4"-tri[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), 4,4',4"-tri[1-naphthyl(phenyl)amino]triphenylamine (1-TNATA) and other triarylamines, 5,5"-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2"-terthiophene (BMA-3T) and other oligothiophenes, etc.

[0237] As materials for forming the light-emitting layer, there can be listed low molecular light-emitting materials such as metal complexes such as aluminum complex of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bisphenylene benzene derivatives, bisphenylene arylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and silole derivatives; and systems in which light-emitting materials and electron transfer materials are mixed in polymer compounds such as poly(p-phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly(3-alkylthiophene), and polyvinylcarbazole, but the present invention is not limited to these.

[0238] When the light-emitting layer is formed by vapor deposition, it may be co-deposited with a light-emitting dopant. Examples of the light-emitting dopant include tris(2-phenylpyridine)iridium(III) (Ir(ppy) 3), tetracene derivatives such as rubrene, quinacridone derivatives, condensed polycyclic aromatic rings such as perylene, etc., but are not limited to these.

[0239] Examples of the material for forming the electron transport layer / hole blocking layer include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, and pyrimidine derivatives, but are not limited thereto.

[0240] Examples of materials for forming the electron injection layer include lithium oxide (Li 2 O), magnesium oxide (MgO), aluminum oxide (Al 2 O 3 ) and other metal oxides, lithium fluoride (LiF), and metal fluorides of sodium fluoride (NaF), but are not limited to these.

[0241] Examples of the cathode material include aluminum, magnesium-silver alloys, and aluminum-lithium alloys, but are not limited thereto.

[0242] Examples of the material for forming the electron blocking layer include tris(phenylpyrazole)iridium, but the material is not limited to these.

[0243] Examples of hole transport polymers include poly[(9,9-dihexylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4-diamine)], poly[(9,9-bis{1'-pentene [(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], poly[(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] terminated with polysilsesquioxane, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], etc.

[0244] Examples of the light-emitting polymer include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylenevinylene derivatives such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

[0245] As described above, the charge transport varnish of the present invention is preferably used for the formation of functional layers provided between the anode and the light-emitting layer, such as the hole injection layer, the hole transport layer, and the hole injection transport layer of the organic EL element. In addition, it can also be used in the formation of charge transport thin films in electronic elements such as organic photoelectric conversion elements, organic thin-film solar cells, organic perovskite photoelectric conversion elements, organic integrated circuits, organic electric field effect transistors, organic thin-film transistors, organic light-emitting transistors, organic optical detectors, organic light receivers, organic electroluminescent extinction elements, light-emitting electronic chemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasmon light-emitting elements.

[0246] Example

[0247] The present invention is described in more detail below by giving examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that the apparatus used is as follows.

[0248] (1) MALDI-TOF-MS: manufactured by Bruker, autoflex III smartbeam

[0249] (2) 1 H-NMR: JNM-ECP300 FT NMR SYSTEM manufactured by JEOL Ltd.

[0250] (3) Substrate cleaning: Substrate cleaning equipment manufactured by Choshu Industry Co., Ltd. (reduced pressure plasma method)

[0251] (4) Varnish coating: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.

[0252] (5) Film thickness measurement: SURFCORDER ET-4000 micro-profile measuring instrument manufactured by Kosaka Laboratory Co., Ltd.

[0253] (6) Component production: Multifunctional evaporation equipment system C-E2L1G1-N manufactured by Choshu Industry Co., Ltd.

[0254] (7) Measurement of current density and brightness of the device: Multi-channel IVL measurement equipment manufactured by EHC Co., Ltd.

[0255] (8) EL element life measurement (brightness half-life measurement): Organic EL brightness life evaluation system PEL-105S manufactured by EHC Co., Ltd.

[0256] (9) Determination of refractive index (n) and extinction coefficient (k): Multi-incident angle spectroscopic ellipsometer VASE manufactured by JA Woollam Japan

[0257] [1] Production of arylamine compounds

[0258] [Example 1-1] Synthesis of Arylamine Compound A

[0259] [Chemistry 19]

[0260]

[0261] 0.3 g of 3,6-diaminocarbazole, 2.570 g of 2-bromophenylcarbazole, and Pd 2 (dba) 2 0.086g, [(tBu) 3 PH]BF 4 0.087 g, 1.05 g of tBuONa, and 10 g of toluene were stirred at 80°C for 3 hours. Then, the mixture was returned to room temperature and filtered through Celite. Toluene and saturated brine were added to the filtrate for separation, and the aqueous layer was removed. An appropriate amount of MgSO 4 , and let stand at room temperature for 10 minutes. 4 The filtrate was concentrated by filtration through silica gel. The obtained concentrate was dropped into a mixed solvent of ethyl acetate and methanol, stirred at room temperature for 30 minutes, and the precipitated solid was separated by filtration. The obtained solid was dried to obtain 0.82 g of arylamine compound A (yield 38%).

[0262] 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).

[0263] [Example 1-2] Synthesis of Arylamine Compound B

[0264] [Chemistry 20]

[0265]

[0266] 0.502 g of 3,6-diaminocarbazole, 4.441 g of 3-bromophenylcarbazole, and Pd 2 (dba) 2 0.037g, [(tBu) 3 PH]BF 40.037g, tBuONa1.346g, and toluene 15g were stirred at 80°C for 5.5 hours. After the reaction was completed, Celite filtration was performed and the target part was concentrated by silica gel chromatography. The active body was added to the concentrate, stirred at room temperature for 1 hour, and then the activated carbon was removed by Celite filtration. The obtained filtrate was dropped into a mixed solvent of ethyl acetate and methanol and stirred at room temperature for 1 hour. The precipitated solid was separated by filtration and the obtained solid was dried to obtain 3.50g of arylamine compound B (yield 98%).

[0267] 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).

[0268] [2] Preparation of charge transport varnish

[0269] [Example 2-1]

[0270] The arylamine compound A (0.027 g) obtained in Example 1-1 and the aryl sulfonate A (0.024 g) represented by the following formula synthesized according to the method described in International Publication No. 2017 / 217455 were added to chloroform (10 g), stirred at room temperature to dissolve, and the obtained solution was filtered with a syringe filter having a pore size of 0.2 μm to obtain a charge transport varnish A1.

[0271] [Chemistry 21]

[0272]

[0273] [Example 2-2]

[0274] 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.

[0275] [Example 2-3]

[0276] 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.

[0277] [Examples 2-4]

[0278] 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.

[0279] [3] Thin film production and film property evaluation

[0280] [Example 3-1 and Example 3-2]

[0281] The varnishes obtained in Examples 2-1 and 2-2 were applied to a quartz substrate using a spin coater, dried at 120°C for 1 minute in an atmospheric firing, and then fired at 200°C for 15 minutes in an atmospheric atmosphere to form a 50 nm uniform thin film on the quartz substrate.

[0282] The obtained quartz substrate with a film was used to measure the average refractive index n in the visible region and the average extinction coefficient k in the visible region at a wavelength of 400 to 800 nm.

[0283] [Table 1]

[0284] Average refractive index in the visible region n Average extinction coefficient k in the visible region Example 3-1 1.71 0.014 Example 3-2 1.66 0.062

[0285] As shown in Table 1, it is understood that the thin film obtained from the charge transporting varnish of the present invention has a high refractive index and a low extinction coefficient.

[0286] [4] Fabrication and Characteristic Evaluation of Hole-Only Device (HOD) 1

[0287] [Preparation of Solution for Forming Hole Injection Layer]

[0288] 0.137 g of an aniline derivative represented by formula (T) synthesized according to the method described in International Publication No. 2013 / 084664 and 0.271 g of an arylsulfonic acid represented by formula (N) synthesized according to the method described in International Publication No. 2006 / 025342 were dissolved in 6.7 g of 1,3-dimethyl-2-imidazolidinone under a nitrogen atmosphere. 10 g of cyclohexanol and 3.3 g of propylene glycol were added to the obtained solution in sequence, and stirred to prepare a solution for forming a hole injection layer.

[0289] [Chemistry 22]

[0290]

[0291] [Example 4-1]

[0292] As the ITO substrate, a glass substrate of 25 mm×25 mm×0.7 mm on which indium tin oxide (ITO) was patterned with a film thickness of 150 nm was used. 2The plasma cleaning device (150W, 30 seconds) removed impurities on the surface. Then, the hole injection layer formation solution prepared above was applied to the ITO substrate by spin coating, heated to 80°C on a hot plate in the atmosphere, dried for 1 minute, and then heated and calcined at 230°C for 15 minutes to form a hole injection layer (film thickness: 30nm).

[0293] Next, the charge transport varnish A2 obtained in Example 2-3 was applied onto the hole injection layer using a spinner, and then baked at 130° C. for 10 minutes in an air atmosphere to form a 40 nm hole transport layer thin film.

[0294] On it, a vapor deposition device (vacuum degree 1.0×10 -5 Pa), and an aluminum thin film of 80 nm was formed at 0.2 nm / sec to obtain a hole-only device (HOD).

[0295] [Example 4-2]

[0296] 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.

[0297] The current density of the HOD produced above was measured at a driving voltage of 4 V. Table 2 shows the results.

[0298] [Table 2]

[0299] <![CDATA[Current density (mA / cm 2 )]]> Example 4-1 201 Example 4-2 282

[0300] As shown in Table 2, it is found that the thin film produced from the charge transporting varnish of the present invention exhibits excellent charge transporting properties as a hole transporting layer.

[0301] [5] Fabrication of single-layer devices (SLD)

[0302] [Example 5-1]

[0303] The charge transport varnish A1 obtained in Example 2-1 was applied to the same ITO substrate as Example 4-1 using a spin coater, dried at 120°C for 1 minute under atmospheric firing, and then fired at 200°C for 15 minutes under atmospheric atmosphere to form a hole injection layer (film thickness: 50 nm).

[0304] On it, a vapor deposition device (vacuum degree 1.0×10 -5 Pa), and an aluminum thin film of 80 nm was formed at 0.2 nm / sec to obtain a single-layer device (SLD).

[0305] [Example 5-2]

[0306] An SLD was produced by the same method 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.

[0307] The current density of the SLD produced as described above was measured at a driving voltage of 4 V. Table 3 shows the results.

[0308] [Table 3]

[0309] <![CDATA[Current density (mA / cm 2 )]]> Example 5-1 3110 Example 5-2 4590

[0310] As shown in Table 3, it is found that the thin film produced from the charge transporting varnish of the present invention exhibits good charge transporting properties.

[0311] [6] Production of HOD2

[0312] [Example 6-1]

[0313] The charge transport varnish A1 obtained in Example 2-1 was applied to the same ITO substrate as in Example 4-1 using a spin coater, dried at 120°C for 1 minute in the atmosphere, and then fired at 200°C for 15 minutes to form a hole injection layer (film thickness: 50 nm).

[0314] On it, a vapor deposition device (vacuum degree 2.0×10 -5 HOD was obtained by sequentially stacking thin films of α-NPD and aluminum on a substrate of 100 nm (Pa). The deposition rate was 0.2 nm / sec. The thicknesses of the thin films of α-NPD and aluminum were 30 nm and 80 nm, respectively.

[0315] [Example 6-2]

[0316] 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.

[0317] The current density of the HOD produced as described above was measured at a driving voltage of 4 V. Table 4 shows the results.

[0318] [Table 4]

[0319] <![CDATA[Current density (mA / cm 2 )]]> Example 6-1 171 Example 6-2 360

[0320] As shown in Table 4, it can be seen that the thin film produced from the charge transporting varnish of the present invention exhibits good hole injecting properties into the hole transporting layer as the hole injecting layer.

[0321] [7] Fabrication and characteristic evaluation of organic EL elements

[0322] [Example 7-1]

[0323] The charge transport varnish A1 obtained in Example 2-1 was applied to the same ITO substrate as in Example 4-1 using a spinner, dried at 120° C. for 1 minute in air, and then baked at 200° C. for 15 minutes to form a 50 nm thin film.

[0324] Next, the ITO substrate with the thin film formed thereon was subjected to a vacuum deposition apparatus (vacuum degree 1.0×10 -5 Pa), and a 30nm α-NPD film was formed at 0.2nm / sec. Next, a 10nm film of the electron blocking material HTEB-01 manufactured by Kanto Chemical Co., Ltd. was formed. Next, the luminescent layer main material NS60 and the luminescent layer dopant material Ir(ppy) manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. were added. 3 Co-evaporation. For co-evaporation, Ir(ppy) 3 The evaporation rate was controlled so that the concentration of Alq 3 , lithium fluoride and aluminum thin films are stacked to obtain an organic EL element. At this time, in terms of the evaporation rate, for Alq 3 The deposition rate was 0.2 nm / sec for aluminum and 0.02 nm / sec for lithium fluoride, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.

[0325] It should be noted that in order to prevent the degradation of characteristics due to the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate, and its characteristics were evaluated. The sealing was performed according to the following steps. The organic EL element was placed between the sealing substrates in a nitrogen atmosphere with an oxygen concentration of less than 2 ppm and a dew point of less than -76°C, and the sealing substrates were pasted with an adhesive (MORESCO MOISTURE CUT WB90US(P)). At this time, a water scavenger (HD-071010W-40 manufactured by DYNIC CO., LTD.) was placed in the sealing substrate together with the organic EL element. The pasted sealing substrate was irradiated with UV light (wavelength: 365 nm, irradiation amount: 6000 mJ / cm 2 ) and then annealed at 80°C for 1 hour to cure the adhesive.

[0326] [Example 7-2]

[0327] 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.

[0328] The obtained organic EL device was measured at 5000 cd / m 2The driving voltage, current density, current efficiency, luminous efficiency, external luminous quantum yield (EQE) and LT85 (initial brightness 5000cd / m 2 The results are shown in Table 5.

[0329] [Table 5]

[0330]

[0331] As shown in Table 5, it can be seen that the organic EL elements of the present invention all exhibit high current efficiency and high EQE, and also exhibit good life characteristics.

Claims

1. An arylamine compound, characterized in that It is represented by the following formula (1): [Chemistry 1] In the formula, R 1 Each independently represents an aryl group having 6 to 20 carbon atoms, R 2 All are hydrogen atoms.

2. The arylamine compound according to claim 1, which is represented by the following formula (1-1): [Chemistry 2] In the formula, R 1 and R 2 Means the same as above.

3. The arylamine compound according to claim 2, which is represented by the following formula (1-1A) or (1-1B): [Chemistry 3] In the formula, R 1 and R 2 Means the same as above.

4. The arylamine compound according to any one of claims 1 to 3, wherein The R 1 is phenyl, 1-naphthyl or 2-naphthyl.

5. The arylamine compound according to claim 4, wherein The R 1 All are phenyl groups. 6 . A charge-transporting varnish comprising the arylamine compound according to claim 1 and an organic solvent.

7. The charge-transporting varnish according to claim 6, which contains a dopant substance.

8. The charge transporting varnish according to claim 7, wherein The dopant substance is an aryl sulfonate compound. 9 . A charge-transporting thin film produced using the charge-transporting varnish according to claim 6 . 10 . An electronic component comprising the charge transport thin film according to claim 9 .

11. An organic electroluminescent element comprising the charge transport thin film according to claim 9.

12. The organic electroluminescent element according to claim 11, wherein The charge transporting thin film is a hole injection layer or a hole transporting layer.

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