Charge-transporting varnish

Abstract

This charge-transporting varnish, which includes: a charge-transporting substance; a dopant substance; metal oxide nanoparticles that are surface-treated with a silane coupling agent having a conductive functional group represented by, for example, formula (S1) below; and a solvent, provides a charge-transporting thin film with excellent transparency and electrical properties. (In the formula, R represents an alkyl group having 1-10 carbon atoms, A1 represents a single bond or an alkylene group having 1-10 carbon atoms, A2 represents a single bond or a divalent linking group other than the alkylene group, and A3 represents a monovalent organic group having a conductive functional group.)

Description

[Technical Field]

[0001] The present invention relates to a charge transporting varnish. [Background technology]

[0002] Organic electroluminescence (hereinafter referred to as organic EL) devices use organic functional films made of organic compounds as the light-emitting layer and charge injection layer. In particular, the hole injection layer is responsible for the exchange of charges between the anode and the hole transport layer or light-emitting layer, and plays an important role in achieving low-voltage operation and high brightness in organic EL devices. Methods for forming hole injection layers are roughly divided into dry processes, typified by vapor deposition, and wet processes, typified by spin coating. Comparing these processes, wet processes can efficiently produce thin films with high flatness over large areas. Therefore, as organic EL displays are currently being made larger, there is a demand for hole injection layers that can be formed by wet processes, and technology related to hole injection materials that can be formed into films by wet processes has been reported (Patent Document 1).

[0003] Furthermore, because coloration of a charge-transporting thin film used in an organic EL element reduces the color purity and color reproducibility of the organic EL element, it is desirable for the charge-transporting thin film for an organic EL element to have high transmittance in the visible region and high transparency. In this regard, the present applicant has already reported that highly transparent charge-transporting thin films can be obtained by adding nanoparticles of metal oxides such as silica and zirconia to a composition for forming a charge-transporting thin film (see Patent Documents 2 and 3).

[0004] However, the charge transport thin films of Patent Documents 2 and 3 contain metal oxide nanoparticles, which are insulating materials. Therefore, if the content of metal oxide nanoparticles is increased or the film is made thicker in order to improve the transparency of the film, the electrical properties of the charge transport thin film will be degraded, and improvements in this regard are needed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2008 / 032616 [Patent Document 2] International Publication No. 2019 / 124413 [Patent Document 3] International Publication No. 2020 / 262418 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a charge transporting varnish that gives a charge transporting thin film excellent in transparency and electrical properties. [Means for solving the problem]

[0007] As a result of extensive research to solve the above problems, the inventors discovered that a charge-transporting thin film with excellent transparency and electrical properties can be obtained by using a charge-transporting varnish containing metal oxide nanoparticles that have been surface-treated with a silane coupling agent having a conductive functional group, and thus completed the present invention.

[0008] That is, the present invention is 1. A charge-transporting varnish comprising a charge-transporting substance, a dopant substance, metal oxide nanoparticles surface-treated with a silane coupling agent having a conductive functional group, and a solvent; 2. The charge transport varnish of 1, wherein the silane coupling agent is a compound represented by the following formula (S1): [ka] (wherein R represents an alkyl group having 1 to 10 carbon atoms, and A 1 represents a single bond or an alkylene group having 1 to 10 carbon atoms, and A 2 represents a single bond or a divalent linking group other than an alkylene group, and A 3represents a monovalent organic group having a conductive functional group. 3. The R represents an alkyl group having 1 to 5 carbon atoms, and A 1 represents an alkylene group having 2 to 5 carbon atoms, and A 2 represents -O-, -S-, -NH-, an amide bond, or a urea bond; A 3 represents an aryl group having a phenylcarbazole structure; 4. The charge-transporting varnish according to 3, wherein the silane coupling agent is a compound represented by the following formula (S1-1): [ka] (wherein R represents an alkyl group having 1 to 5 carbon atoms, and A 1 represents an alkylene group having 2 to 5 carbon atoms, and A 4 represents an arylene group. 5. The charge-transporting varnish according to any one of 1 to 4, wherein the metal oxide nanoparticles are at least one selected from silica and zirconia. 6. The charge-transporting varnish according to any one of 1 to 5, wherein the charge-transporting substance is an arylamine derivative. 7. The charge-transporting varnish according to any one of 1 to 6, wherein the dopant substance is an arylsulfonic acid compound. 8. A charge-transporting thin film obtained from the charge-transporting varnish according to any one of 1 to 7. 9. An electronic device comprising the charge transport thin film of 8. 10. An organic EL device comprising the charge transport thin film of 8. 11. The organic EL device of 10, wherein the charge transporting thin film is a hole injection layer or a hole transport layer. to provide. [Effects of the Invention]

[0009] The charge-transporting varnish of the present invention contains metal oxide nanoparticles that have been surface-treated with a silane coupling agent having a conductive functional group, and therefore not only provides a charge-transporting thin film with excellent transparency and electrical properties, but also provides a charge-transporting thin film that maintains the transparency that is the effect of adding particles and suppresses deterioration in electrical properties, even when the amount of metal oxide nanoparticles added is increased. The charge transporting varnish of the present invention having such properties can be suitably used for producing thin films for electronic devices such as organic EL devices, particularly thin films for organic EL displays. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the average transmittance from 400 to 800 nm of the quartz substrates with 50 nm thin films obtained in Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-2. [Figure 2] FIG. 10 is a diagram showing the average transmittance from 400 to 800 nm of the quartz substrates with 100 nm thin films obtained in Examples 2-3 to 2-4 and Comparative Examples 2-3 to 2-4. [Figure 3] FIG. 10 is a diagram showing the average transmittance from 400 to 800 nm of the quartz substrates with 50 nm thin films obtained in Examples 2-5 to 2-8 and Comparative Examples 2-5 to 2-6. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in more detail below. The charge-transporting varnish according to the present invention is characterized by comprising a charge-transporting substance, a dopant substance, metal oxide nanoparticles (hereinafter sometimes referred to as surface-treated metal oxide nanoparticles) that have been surface-treated with a silane coupling agent having a conductive functional group, and a solvent. In the present invention, the term "charge transportability" is synonymous with "electrical conductivity" and "hole transportability." The charge transporting varnish may itself have charge transportability, or the solid film obtained from the varnish may have charge transportability.

[0012] [1] Surface-treated metal oxide nanoparticles The metal oxide nanoparticles, which are a characteristic component of the charge-transporting varnish of the present invention, are surface-treated with a silane coupling agent having a conductive functional group. The surface of the metal oxide nanoparticles, which are normally insulating materials, is treated with a silane coupling agent having a conductive functional group, making it possible to form a conductive path with the charge-transporting material. Here, nanoparticles refer to fine particles whose primary particles have an average particle size on the order of nanometers (typically 500 nm or less). Metal oxide nanoparticles refer to metal oxides formed into nanoparticles.

[0013] In the present invention, the primary particle size of the metal oxide nanoparticles is not particularly limited as long as it is nano-sized, but is usually 5 nm or more, and from the viewpoint of ensuring good particle dispersibility and ease of production, it is usually 200 nm or less, preferably 100 nm or less, and more preferably 30 nm or less.

[0014] The metals constituting the metal oxide nanoparticles include metals in the usual sense as well as semimetals. Metals in the ordinary sense include, but are not limited to, one or more selected from the group consisting of tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and W (tungsten). On the other hand, a metalloid refers to an element whose chemical and / or physical properties are intermediate between those of a metal and a nonmetal. Although a universal definition of a metalloid has not been established, in the present invention, a total of six elements, namely, boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), are defined as metalloids. These metalloids may be used alone or in combination with two or more of them, or may be used in combination with metals in the usual sense.

[0015] In particular, the metal oxide nanoparticles preferably contain an oxide of one or more metals selected from boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten (W). When two or more metals are used in combination, the metal oxide may be a mixture of oxides of individual metals or a composite oxide containing multiple metals.

[0016] Specific examples of metal oxides include B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, Sb2O3, Sb2O5, TeO2, SnO2, ZrO2, Al2O3, and ZnO, with B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, SnO2, SnO, Sb2O3, TeO2, TiO2, and mixtures thereof being preferred, and SiO2 and ZrO2 being more preferred.

[0017] As the silane coupling agent having a conductive functional group used as a surface treatment agent, for example, a silane coupling agent having an alkoxysilyl group and a conductive functional group can be used. In the present invention, however, a silane coupling agent having a trialkoxysilyl group is preferred, and a compound having a trialkoxysilyl group represented by the following formula (S1) is suitably used.

[0018] [ka]

[0019] In formula (S1), R represents an alkyl group having 1 to 10 carbon atoms, and A 1 represents a single bond or an alkylene group having 1 to 10 carbon atoms, and A 2 represents a single bond or a divalent linking group other than an alkylene group, and A 3 represents a monovalent organic group having a conductive functional group.

[0020] The alkyl group having 1 to 10 carbon atoms represented by R may be linear, branched, or cyclic, and 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 groups. Among these, alkyl groups having 1 to 5 carbon atoms are preferred, alkyl groups having 1 to 3 carbon atoms are more preferred, and methyl and ethyl groups are even more preferred. A 1 The alkylene group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decylene groups. Among these, alkylene groups having 2 to 5 carbon atoms are preferred, alkyl groups having 2 to 4 carbon atoms are more preferred, and ethylene and trimethylene groups are even more preferred.

[0021] A 2 Examples of the divalent linking group include -O-, -S-, and -O-(CH2) k -O-, -S-(CH2) k -S-, -O-(CH2) k -S-, -S-(CH2) k Examples include -O- (in these formulas, k represents an integer of 1 to 5), -NH-, -CO-, -NHCO-, -CONH-, -SONH-, -NHSO-, -NHCONH-, -COO-, -OCO-, and a 2,5-pyrrolidinedione ring represented by the following formula (A2-1). Among these, -O-, -S-, -NH-, an amide bond (-NHCO-, -CONH-), or a urea bond (-NHCONH-) is preferred.

[0022] [ka] (In the formula, an asterisk * represents a bond. The same applies hereinafter.)

[0023] A 3The monovalent organic group having the conductive functional group may be a monovalent group containing a chemical structure conventionally known as a structure that exhibits conductivity, and examples thereof include a monovalent group having an oligoaniline structure, a monovalent group having a triarylamine structure, a monovalent group having an N,N'-diarylbenzidine structure, a monovalent group having an N,N,N',N'-tetraarylbenzidine structure, a monovalent group having a carbazole structure, a monovalent group having an oligothiophene structure, a monovalent group having a thienothiophene structure, a monovalent group having a thienobenzothiophene structure, and a monovalent group having an oligopyrrole structure. However, an aryl group having one or more of these conductive functional groups is preferred, an aryl group having a triarylamine structure or an aryl group having a carbazole structure is more preferred, and an aryl group having a phenylcarbazole structure is even more preferred.

[0024] Specific examples of the monovalent organic group having the conductive functional group include, but are not limited to, those represented by the following formulae: Among these, groups represented by formulae (A3-9) and (A3-10) are preferred.

[0025] [ka] (wherein the asterisk * and k have the same meanings as above, and A 4 represents an arylene group.

[0026] Particularly preferred are those in which the bonds are at the following positions:

[0027] [ka] (wherein the asterisk *, k and A 4 has the same meaning as above.)

[0028] In each of the above formulas, A 4 represents an arylene group, preferably an arylene group having 6 to 40 carbon atoms. Specific examples of the arylene group include, but are not limited to, those represented by the following formulae:

[0029] [ka] (In the formula, the asterisk * has the same meaning as above.)

[0030] As the arylene group, those in which the bonds are at the following positions are particularly preferred.

[0031] [ka] (In the formula, the asterisk * has the same meaning as above.)

[0032] In particular, as the silane coupling agent used in the present invention, a compound represented by the following formula (S1-1) is preferred, and a compound represented by the following formula (S1-1-1) is more preferred.

[0033] [ka] (wherein R represents an alkyl group having 1 to 5 carbon atoms, and A 1 represents an alkylene group having 2 to 5 carbon atoms, and A 4 represents an arylene group.

[0034] [ka] (wherein R represents an alkyl group having 1 to 5 carbon atoms, and A 1 represents an alkylene group having 2 to 5 carbon atoms, and A 4 represents an arylene group.

[0035] Specific examples of the silane coupling agent include those represented by the following formula, but are not limited to these.

[0036] [ka]

[0037] The silane coupling agent can be obtained by reacting a trialkoxysilane compound having a reactive group such as a halogen atom, NCO, NH2, SH, or 2,5-dioxotetrahydro-3-yl group at the end with an aryl compound having a functional group on the aryl group that reacts with these reactive groups (NH2 group, NCO group, carboxylic acid halide group, sulfonic acid halide group, etc.) using a known method for forming a divalent linking group, such as amidation, urea conversion, or esterification. Alternatively, it can also be obtained by subjecting a trialkoxysilane compound having an SH group at its terminal to a compound having a carbon-carbon double bond and a conductive functional group in a known ene-thiol reaction. Furthermore, it can also be obtained by subjecting a trialkoxysilane compound having an Si—H group to a known hydrosilylation reaction with a compound having a carbon-carbon double bond and a conductive functional group. Alternatively, it can be obtained by reacting a tetraalkoxysilane such as tetraethoxysilane with a compound having a halogen atom such as a chlorine atom or a bromine atom on an aryl group under known conditions.

[0038] Examples of alkoxysilane compounds that can be used in the production of the silane coupling agent of the present invention include 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, glycidoxymethyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl Examples of trialkoxysilanes include butyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyltriethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, trimethoxysilane, and triethoxysilane. These compounds may be commercially available products.

[0039] The primary particle diameter of the surface-treated metal oxide nanoparticles is not particularly limited, but is usually 5 nm or more. From the viewpoint of ensuring good particle dispersibility and ease of production, it is usually 200 nm or less, preferably 100 nm or less, and more preferably 30 nm or less. This particle diameter is the particle diameter at which the cumulative frequency distribution in volume-based particle size distribution measurement by dynamic light scattering becomes 50% (median diameter D 50 )

[0040] In the surface-treated metal oxide nanoparticles used in the present invention, the amount of silane coupling agent modified on the surface of the metal oxide nanoparticles is not particularly limited. However, from the viewpoint of the dispersibility of the metal oxide nanoparticles and the transparency of the resulting thin film, it is preferred that the amount be 0.1 particles / nm or more and 2.0 particles / nm or less. 2 Preferably less than 0.2 to 1.9 particles / nm 2 More preferably, 0.3 to 1.7 particles / nm 2 is even more preferred. The amount of modification X (number of particles / nm 2 ) are the particle size (nm) and specific gravity (g / cm 3 ) is the specific surface area SA (nm 2 / g), the total amount of metal oxide particles M (g), the molecular weight Mw of the silane coupling agent, the amount Y (g) of silane coupling agent, and Avogadro's constant L, and the value is calculated as Y = X * SA * M * Mw / L.

[0041] The amount of metal oxide nanoparticles contained in the charge-transporting varnish of the present invention is not particularly limited, but from the viewpoint of improving the transparency of the obtained thin film and increasing the uniformity of the film, the lower limit of the solid content is usually 20 mass %, preferably 30 mass %, and more preferably 40 mass %, and the upper limit is usually 95 mass %, preferably 90 mass %.

[0042] The surface-treated metal oxide nanoparticles used in the present invention may also be used in the form of a sol dispersed in a dispersion medium. Examples of the dispersion medium include water, methanol, methyl ethyl ketone, methyl isobutyl ketone, N,N-dimethylacetamide, ethylene glycol, isopropanol, methanol, ethylene glycol monopropyl ether, cyclohexanone, ethyl acetate, toluene, and propylene glycol monomethyl ether acetate.

[0043] The solid content concentration of the sol is not particularly limited, but is preferably 5 to 60 mass %, more preferably 10 to 50 mass %, and even more preferably 15 to 30 mass %. The amount of sol used is appropriately determined taking into consideration the concentration so that the amount of surface-treated metal oxide nanoparticles finally contained in the varnish will be the blend amount of the metal oxide nanoparticles described above.

[0044] [2] Charge transporting substance The charge transporting substance is not particularly limited, and can be appropriately selected from charge transporting compounds, charge transporting oligomers, charge transporting polymers, etc. used in the field of organic electroluminescence, for example. Specific examples thereof include various charge transporting compounds such as arylamine derivatives, such as oligoaniline derivatives, N,N'-diarylbenzidine derivatives, and N,N,N',N'-tetraarylbenzidine derivatives; thiophene derivatives, such as oligothiophene derivatives, thienothiophene derivatives, and thienobenzothiophene derivatives; and pyrrole derivatives, such as oligopyrrole; and charge transporting polymers, such as charge transporting oligomers, polythiophene derivatives, polyaniline derivatives, and polypyrrole derivatives. Of these, polythiophene derivatives and arylamine derivatives are preferred.

[0045] Furthermore, from the viewpoint of producing a thin film with high flatness, it is preferable that the charge transport compound (low molecular weight compound) or charge transport oligomer, such as a tertiary arylamine compound represented by formula (A1) or (A2) described below, is monodisperse (i.e., has a molecular weight distribution of 1). In this case, from the viewpoint of preparing a uniform ink that gives a thin film with high flatness, the molecular weight of the charge transport substance is usually about 200 to 9,000, but from the viewpoint of obtaining a thin film with better charge transport properties, it is preferably 300 or more, more preferably 400 or more, and from the viewpoint of preparing a uniform ink that gives a thin film with high flatness with good reproducibility, it is preferably 8,000 or less, more preferably 7,000 or less, even more preferably 6,000 or less, and even more preferably 5,000 or less.

[0046] Examples of the charge transporting substance include those described in JP 2002-151272 A, WO 2004 / 105446 A, WO 2005 / 043962 A, WO 2008 / 032617 A, WO 2008 / 032616 A, WO 2013 / 042623 A, WO 2014 / 141998 A, WO 2014 / 185208 A, Examples of such compounds include those disclosed in International Publication Nos. WO 2015 / 050253, WO 2015 / 137391, WO 2015 / 137395, WO 2015 / 146912, WO 2015 / 146965, WO 2016 / 190326, WO 2016 / 136544, and WO 2016 / 204079.

[0047] A preferred embodiment of the charge transport material is a tertiary arylamine compound having at least one nitrogen atom, all of which have a tertiary arylamine structure. That is, this tertiary arylamine compound has at least one nitrogen atom, all of which have a structure in which three aromatic groups are bonded to each nitrogen atom. The tertiary arylamine compound preferably has two or more nitrogen atoms.

[0048] Suitable examples of the tertiary arylamine compound include compounds represented by the following formula (A1) or (A2).

[0049] [ka]

[0050] In formula (A2), R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a nitro group, or a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom.

[0051] 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 specific examples thereof include linear or branched alkyl groups 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 groups; and cyclic alkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, and bicyclodecyl groups.

[0052] The alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include vinyl, n-1-propenyl, n-2-propenyl, 1-methylvinyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, and n-1-eicosenyl groups.

[0053] The alkynyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n-1-hexynyl, n-1-decynyl, n-1-pentadecinyl, and n-1-eicosynyl groups.

[0054] Examples of the aryl group 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-phenanthryl, and 9-phenanthryl groups. Examples of heteroaryl groups having 2 to 20 carbon atoms include 2-thienyl, 3-thienyl, 2-furanyl, 3-furanyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 2-imidazolyl, 4-imidazolyl, 2-pyridyl, 3-pyridyl, and 4-pyridyl groups.

[0055] Of these, R 1 and R 2 is preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 20 carbon atoms which may be substituted with a halogen atom, an aryl group of 6 to 20 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group of 2 to 20 carbon atoms which may be substituted with a halogen atom, more preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 10 carbon atoms which may be substituted with a halogen atom, or a phenyl group which may be substituted with a halogen atom, still more preferably a hydrogen atom or a fluorine atom, and most preferably a hydrogen atom.

[0056] In formulas (A1) and (A2), Ph 1 is a group represented by formula (P1).

[0057] [ka]

[0058] In formula (P1), the dashed lines represent bonds. 3 ~R 6are each independently a hydrogen atom, a halogen atom, a nitro group, or a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom. Specific examples of these groups include R 1 and R 2 Examples of the above-mentioned methods are the same as those described above.

[0059] In particular, R 3 ~R 6 is preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 20 carbon atoms which may be substituted with a halogen atom, an aryl group of 6 to 20 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group of 2 to 20 carbon atoms which may be substituted with a halogen atom, more preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 10 carbon atoms which may be substituted with a halogen atom, or a phenyl group which may be substituted with a halogen atom, still more preferably a hydrogen atom or a fluorine atom, and most preferably a hydrogen atom.

[0060] Ph 1 Suitable groups for include, but are not limited to, 1,4-phenylene groups.

[0061] In formula (A1), Ar 1 are each independently a group represented by any one of the following formulae (Ar1-1) to (Ar1-11), and are particularly preferably a group represented by any one of the following formulae (Ar1-1') to (Ar1-11').

[0062] [ka]

[0063] [ka]

[0064] In formulae (Ar1-1) to (Ar1-11) and formulae (Ar1-1') to (Ar1-11'), the dashed lines represent bonds. 7 ~R 27 , R 30 ~R 51 and R 53 ~R 154 are each independently a hydrogen atom, a halogen atom, a nitro group, or a cyano group, or a diphenylamino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom. 28 and R 29 are each independently Z 1 R is an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 52 is Z 1 and the like. The aryl group has 6 to 20 carbon atoms or the heteroaryl group has 2 to 20 carbon atoms, which may be substituted with one of the following:

[0065] Z 1 is a halogen atom, a nitro group or a cyano group, or Z 2 Z is an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with 2 is a halogen atom, a nitro group or a cyano group, or Z 3 Z is an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 3 is a halogen atom, a nitro group, or a cyano group.

[0066] In particular, R 7 ~R 27 , R 30 ~R 51 and R 53 ~R 154is preferably a hydrogen atom, a fluorine atom, a cyano group, a diphenylamino group which may be substituted with a halogen atom, an alkyl group of 1 to 20 carbon atoms which may be substituted with a halogen atom, an aryl group of 6 to 20 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group of 2 to 20 carbon atoms which may be substituted with a halogen atom, more preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group of 1 to 10 carbon atoms which may be substituted with a halogen atom, or a phenyl group which may be substituted with a halogen atom, still more preferably a hydrogen atom or a fluorine atom, and most preferably a hydrogen atom.

[0067] R 28 and R 29 As the alkyl group, an aryl group having 6 to 14 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group having 2 to 14 carbon atoms which may be substituted with a halogen atom is preferred, a phenyl group which may be substituted with a halogen atom, or a naphthyl group which may be substituted with a halogen atom is more preferred, a phenyl group which may be substituted with a halogen atom is even more preferred, and a phenyl group is even more preferred.

[0068] R 52 As for the hydrogen atom, Z 1 An aryl group having 6 to 20 carbon atoms which may be substituted with a hydrogen atom, Z 1 a phenyl group optionally substituted with, or Z 1 A naphthyl group optionally substituted with Z is more preferred. 1 A phenyl group optionally substituted with is more preferred, and a phenyl group is even more preferred.

[0069] In formulae (Ar1-10), (Ar1-11), (Ar1-10') and (Ar1-11'), Ar 4 are each independently an aryl group having 6 to 20 carbon atoms which may be substituted with a diarylamino group, the aryl group being an aryl group having 6 to 20 carbon atoms. Specific examples of the aryl group having 6 to 20 carbon atoms include the above R 1’ and R 2’Specific examples of the diarylamino group include a diphenylamino group, a 1-naphthylphenylamino group, a di(1-naphthyl)amino group, a 1-naphthyl-2-naphthylamino group, and a di(2-naphthyl)amino group.

[0070] Ar 4 Examples of such an alkyl group include, preferably, phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, p-(diphenylamino)phenyl, p-(1-naphthylphenylamino)phenyl, p-(di(1-naphthyl)amino)phenyl group, p-(1-naphthyl-2-naphthylamino)phenyl, and p-[di(2-naphthyl)amino]phenyl group, with a p-(diphenylamino)phenyl group being more preferred.

[0071] In formula (A1), Ar 2 are each independently a group represented by any one of formulas (Ar2-1) to (Ar2-18), and are particularly preferably a group represented by any one of formulas (Ar2-1'-1) to (Ar2-18'-2). 4 has the same meaning as above, DPA is a diphenylamino group, and the dashed line is a bond.

[0072] [ka]

[0073] [ka]

[0074] In formulae (Ar2-16), (Ar2-16'-1) and (Ar2-16'-2), R 155 is a hydrogen atom, Z 1 an aryl group having 6 to 14 carbon atoms which may be substituted with 1The aryl group and heteroaryl group are heteroaryl groups having 2 to 14 carbon atoms, which may be substituted with R 1’ and R 2’ Among these, R 155 As for the hydrogen atom, Z 1 a phenyl group optionally substituted with Z 1 a 1-naphthyl group optionally substituted with Z 1 a 2-naphthyl group optionally substituted by Z 1 a 2-pyridyl group optionally substituted by Z 1 a 3-pyridyl group optionally substituted by a phenyl group optionally substituted by Z 1 A 4-pyridyl group optionally substituted by Z is preferred. 1 A phenyl group optionally substituted with is even more preferred, and a phenyl group or a (2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl) group is even more preferred.

[0075] In formulae (Ar2-17), (Ar2-17'-1) and (Ar2-17'-2), R 156 and R 157 is Z 1 an aryl group having 6 to 14 carbon atoms which may be substituted by a phenyl group which may be substituted by 1 and heteroaryl groups having 2 to 14 carbon atoms which may be substituted with a phenyl group which may be substituted with R. 1’ and R 2’ Among these, R 156 and R 157 As for Z 1 An aryl group having 6 to 14 carbon atoms which may be substituted by a phenyl group which may be substituted by 1 a phenyl group optionally substituted by a phenyl group optionally substituted by 1 a 1-naphthyl group optionally substituted by a phenyl group optionally substituted by Z 1A 2-naphthyl group optionally substituted with is more preferred.

[0076] In formula (A2), Ar 3 is a group represented by any one of formulas (Ar3-1) to (Ar3-8), and is particularly preferably a group represented by any one of formulas (Ar3-1') to (Ar3-8'). In the following formulae, DPA has the same meaning as above, and the dashed line represents a bond.

[0077] [ka]

[0078] [ka]

[0079] In formula (A1), p is an integer of 1 to 10, and from the viewpoint of increasing the solubility of the compound in organic solvents, it is preferably an integer of 1 to 5, more preferably 1 to 3, still more preferably 1 or 2, and optimally 1. In formula (A2), q is 1 or 2.

[0080] The aniline derivative represented by formula (A1) and the aniline derivative represented by formula (A2) can be produced, for example, according to the method described in WO 2015 / 050253.

[0081] The tertiary arylamine compound is not limited to the above-mentioned compounds, as long as it has at least one nitrogen atom and all of the nitrogen atoms have a tertiary arylamine structure. Other tertiary arylamine compounds that can be used in the present invention include, for example, the arylamine compounds described in International Publication No. 2005 / 094133, the polymerizable compound having a triarylamine partial structure and a polymerizable group described in Japanese Patent No. 5287455, the triarylamine compounds described in Japanese Patent No. 5602191, and the compound described in paragraph

[0054] of Japanese Patent No. 6177771.

[0082] Preferred examples of the tertiary arylamine compound include, but are not limited to, the compounds shown below.

[0083] [ka]

[0084] [3] Dopant materials The dopant substance is not particularly limited as long as it dissolves in at least one solvent used in the charge transport varnish, and both inorganic and organic dopant substances can be used. The inorganic and organic dopant substances may be used alone or in combination of two or more. The amount of the dopant substance cannot be generally defined because it is determined appropriately taking into consideration the type of dopant substance, the desired degree of charge transportability, etc., but is usually within the range of 0.0001 to 100.0 parts by mass per 1 part of the charge transport substance.

[0085] The inorganic dopant substance used in the present invention is preferably a heteropolyacid. Heteropolyacids are polyacids that have a structure in which a heteroatom is located at the center of the molecule, typically represented by a Keggin type chemical structure represented by formula (H1) or a Dawson type chemical structure represented by formula (H2), and are formed by condensing an isopolyacid, which is an oxyacid of vanadium (V), molybdenum (Mo), tungsten (W), etc., with an oxyacid of a different element. Examples of such oxyacids of different elements include oxyacids of silicon (Si), phosphorus (P), and arsenic (As).

[0086] [ka]

[0087] Specific examples of heteropolyacids include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, and phosphotungstomolybdic acid, which may be used alone or in combination of two or more. These heteropolyacids are commercially available or can be synthesized by known methods. In particular, when one type of heteropolyacid is used, the one type of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and most preferably phosphotungstic acid. 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 most preferably phosphotungstic acid. In addition, the heteropolyacid may be used in the present invention regardless of whether it has a large or small number of elements in the structure represented by the general formula in quantitative analysis such as elemental analysis, as long as it is a commercially available product or is appropriately synthesized according to a known synthesis method. For example, phosphotungstic acid generally has the chemical formula H3(PW 12 O 40 )·nH2O, and phosphomolybdic acid has the chemical formula H3(PMo 12 O 40 )·nHO, respectively, but whether the number of P (phosphorus), O (oxygen), W (tungsten), or Mo (molybdenum) in this formula is high or low in quantitative analysis, these compounds can be used in the present invention as long as they are commercially available or appropriately synthesized according to a known synthesis method. In this case, the mass of the heteropolyacid specified in the present invention does not refer to the mass of pure phosphotungstic acid (phosphotungstic acid content) in a synthesized or commercially available product, but rather refers to the total mass, including water of hydration and other impurities, in a commercially available form or in a form that can be isolated by a known synthesis method.

[0088] The amount of heteropolyacid used can be about 0.001 to 50.0 parts by mass, preferably about 0.01 to 20.0 parts, and more preferably about 0.1 to 10.0 parts, per 1 part of charge transporting substance such as polythiophene derivative or arylamine derivative.

[0089] On the other hand, as organic dopant substances, tetracyanoquinodimethane derivatives and benzoquinone derivatives can be used. Specific examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ) and halotetracyanoquinodimethane represented by formula (H3). Specific examples of the benzoquinone derivative include 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetrachloro-1,4-benzoquinone (chloranil), trifluoro-1,4-benzoquinone, tetrafluoro-1,4-benzoquinone, tetrabromo-1,4-benzoquinone, tetracyano-1,4-benzoquinone, etc. Among these, 2,3-dichloro-5,6-dicyano-p-benzoquinone, trifluorobenzoquinone, tetrafluorobenzoquinone, and tetracyanobenzoquinone are preferred, DDQ, chloranil, tetrafluoro-1,4-benzoquinone, and tetracyano-1,4-benzoquinone are more preferred, and DDQ is even more preferred.

[0090] [ka]

[0091] In the formula, R 500 ~R 503 each independently represents a hydrogen atom or a halogen atom, with at least one being a halogen atom, preferably at least two being halogen atoms, more preferably at least three being halogen atoms, and most preferably all being halogen atoms. Examples of the halogen atom include the same as those mentioned above, but a fluorine atom or a chlorine atom is preferred, and a fluorine atom is more preferred.

[0092] Specific examples of such halotetracyanoquinodimethanes include 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, and 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane, with F4TCNQ being preferred.

[0093] The amount of the tetracyanoquinodimethane derivative and 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 organic functional material such as a polythiophene derivative or an arylamine derivative.

[0094] Furthermore, an arylsulfonic acid compound can also be used as the organic dopant material. Specific examples of the arylsulfonic acid compound include benzenesulfonic acid, tosylic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2,5-dihexylbenzenesulfonic acid, 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- ... Examples of suitable sulfonic acids include octyl-1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 7-hexyl-1-naphthalenesulfonic acid, 6-hexyl-2-naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, 2,7-dinonyl-4-naphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, the 1,4-benzodioxanedisulfonic acid compounds described in WO 2005 / 000832, the arylsulfonic acid compounds described in WO 2006 / 025342, and the arylsulfonic acid compounds described in WO 2009 / 096352.

[0095] Preferred examples of the arylsulfonic acid compound include arylsulfonic acid compounds represented by formula (H4) or (H5).

[0096] [ka]

[0097] D 1 represents O or S, with O being preferred. D 2 represents a naphthalene ring or an anthracene ring, with a naphthalene ring being preferred. D 3 represents a divalent to tetravalent perfluorobiphenyl group, and s represents D 1 and D 3 It is an integer that satisfies 2≦s≦4, but D 3is a perfluorobiphenyldiyl group, preferably a perfluorobiphenyl-4,4'-diyl group, and s is preferably 2. t is D 2 represents the number of sulfonic acid groups bonded to t, and is an integer satisfying 1≦t≦4, with 2 being optimal.

[0098] D 4 ~D 8 each independently represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogenated alkenyl group having 2 to 20 carbon atoms, and D 4 ~D 8 At least three of the are halogen atoms.

[0099] Examples of halogenated alkyl groups having 1 to 20 carbon atoms include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, and 1,1,2,2,3,3,4,4,4-nonafluorobutyl groups.

[0100] Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include perfluorovinyl, perfluoropropenyl (perfluoroallyl), and perfluorobutenyl groups. Other examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms include those similar to those mentioned above, but the halogen atom is preferably a fluorine atom.

[0101] Among these, D 4 ~D 8 is a hydrogen atom, a halogen atom, a cyano group, a nitro 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 D 4 ~D8 At least three of the groups are preferably fluorine atoms, and are selected from the group consisting of a hydrogen atom, a fluorine atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, and a fluorinated alkenyl group having 2 to 5 carbon atoms, and 4 ~D 8 At least three of them are more preferably fluorine atoms, and are selected from the group consisting of a hydrogen atom, a fluorine atom, a cyano group, a nitro group, a perfluoroalkyl group having 1 to 5 carbon atoms, and a perfluoroalkenyl group having 1 to 5 carbon atoms, and D 4 , D 5 and D 8 It is even more preferred that is a fluorine atom. The perfluoroalkyl group is a group in which all hydrogen atoms of an alkyl group have been substituted with fluorine atoms, and the perfluoroalkenyl group is a group in which all hydrogen atoms of an alkenyl group have been substituted with fluorine atoms.

[0102] u represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1≦u≦4, preferably 2 to 4, and most preferably 2.

[0103] Specific examples of suitable aryl sulfonic acid compounds are listed below, but the present invention is not limited to these.

[0104] [ka]

[0105] The amount of the arylsulfonic acid compound used is preferably about 0.01 to 20.0, more preferably about 0.4 to 5.0, in terms of mole ratio per 1 part of the organic functional material such as a polythiophene derivative or an arylamine derivative. The arylsulfonic acid compound may be a commercially available product, but can also be synthesized by known methods described in WO 2006 / 025342, WO 2009 / 096352, and the like.

[0106] Furthermore, the dopant substance may be a substance whose function as a dopant substance is first exhibited or improved by, for example, a part of its molecule being removed in response to an external stimulus, such as heating during baking, during the process of obtaining a charge-transporting thin film, which is a solid film, from the varnish, for example, an arylsulfonate ester compound protected by a group from which the sulfonic acid group is easily removed.

[0107] The aryl sulfonate compound is not particularly limited as long as it has a sulfonate ester group bonded to an aromatic ring. In a preferred embodiment of the present invention, the molecular weight of the aryl sulfonate compound is preferably 100 or more, more preferably 200 or more, and preferably 5,000 or less, more preferably 4,000 or less, even more preferably 3,000 or less, and even more preferably 2,000 or less. In a preferred embodiment of the present invention, the number of sulfonate ester groups in the aryl sulfonate compound is preferably 2 or more, more preferably 3 or more, and preferably 6 or less, more preferably 5 or less. In a preferred embodiment of the present invention, the aryl sulfonate compound preferably contains an aromatic ring substituted with fluorine.

[0108] Examples of the aryl sulfonate ester compound include the aryl sulfonate ester compounds disclosed in WO 2017 / 217455, the aryl sulfonate ester compounds disclosed in WO 2017 / 217457, and the aryl sulfonate ester compounds described in WO 2019 / 124412. The arylsulfonic acid ester compound is preferably one represented by the following formula (B1) or (B1').

[0109] [ka]

[0110] In formulas (B1) and (B1'), A 01is an m-valent hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings, which may have a substituent, or an m-valent group derived from a compound represented by the following formula (B1a) or (B1b) (i.e., a group obtained by removing m hydrogen atoms on the aromatic rings of a compound represented by the following formula (B1a) or (B1b)).

[0111] [ka] (In the formula, W 1 and W 2 are each independently -O-, -S-, -S(O)-, or -S(O2)-, or -N-, -Si-, -P-, or -P(O)- which may have a substituent.

[0112] An m-valent hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings is a group obtained by removing m hydrogen atoms from a hydrocarbon having 6 to 20 carbon atoms and containing one or more aromatic rings. Examples of the hydrocarbon having one or more aromatic rings include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc. Of these, groups derived from benzene, biphenyl, etc. are preferred as the m-valent hydrocarbon group.

[0113] The hydrocarbon groups may further have some or all of their hydrogen atoms substituted with substituents such as halogen atoms (fluorine, chlorine, bromine, and iodine), nitro, cyano, hydroxy, amino, silanol, thiol, carboxy, sulfonate esters, phosphoric acid, phosphate esters, esters, thioesters, amides, monovalent hydrocarbons, organooxy, organoamino, organosilyl, organothio, acyl, and sulfo groups.

[0114] Here, the monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 10 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, and n-decyl groups; alkenyl groups having 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl, xylyl, tolyl, 1-naphthyl, and 2-naphthyl groups; and aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenylethyl groups.

[0115] Specific examples of the organoxy group include alkoxy, alkenyloxy, aryloxy, etc. The alkyl, alkenyl and aryl groups contained therein are the same as those described above.

[0116] Specific examples of the organoamino group include alkylamino groups having 1 to 12 carbon atoms, such as methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, cyclohexylamino, heptylamino, octylamino, nonylamino, decylamino, and dodecylamino groups; dialkylamino groups in which the alkyl group has 1 to 12 carbon atoms, such as dimethylamino, diethylamino, dipropylamino, dibutylamino, dipentylamino, dihexylamino, dicyclohexylamino, diheptylamino, dioctylamino, dinonylamino, and didecylamino groups; and a morpholino group.

[0117] Specific examples of the organosilyl group include trialkylsilyl groups, each of which is an alkyl group having 1 to 10 carbon atoms, such as trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, pentyldimethylsilyl, hexyldimethylsilyl, octyldimethylsilyl, and decyldimethylsilyl groups. Specific examples of the organothio group include alkylthio groups having 1 to 12 carbon atoms, such as methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio, and dodecylthio groups. Examples of the acyl group include acyl groups having 1 to 10 carbon atoms, such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, and benzoyl groups.

[0118] The monovalent hydrocarbon group, organooxy group, organoamino group, organosilyl group, organothio group and acyl group preferably have 1 to 8 carbon atoms.

[0119] Among these substituents, a fluorine atom, a sulfonic acid group, an alkyl group, an organoxy group, and an organosilyl group are more preferred.

[0120] In formula (B1), A 02 is -O-, -S- or -NH-. Of these, -O- is preferred because it is easy to synthesize.

[0121] In formula (B1), A 03 is an (n+1)-valent aromatic group having 6 to 20 carbon atoms. The (n+1)-valent aromatic group is a group obtained by removing (n+1) hydrogen atoms on the aromatic ring from an aromatic compound having 6 to 20 carbon atoms. In the present invention, the aromatic compound means an aromatic hydrocarbon or an aromatic heterocyclic compound. Examples of the aromatic compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. 3 The aromatic group represented by the formula (I) is preferably a group derived from naphthalene or anthracene.

[0122] In formulas (B1) and (B1′), X 1is an alkylene group having 2 to 5 carbon atoms, and this alkylene group may have -O-, -S- or a carbonyl group between its carbon atoms (carbon-carbon bonds), and some or all of its hydrogen atoms may be further substituted with alkyl groups having 1 to 20 carbon atoms. X 1 Preferred examples of the alkyl group include ethylene, trimethylene, methyleneoxymethylene, and methylenethiomethylene groups, and some or all of the hydrogen atoms in these groups may be further substituted with an alkyl group having 1 to 20 carbon atoms. Examples of the alkyl group 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, n-decyl, n-undecyl, n-dodecyl, and bicyclohexyl groups.

[0123] In formulas (B1) and (B1′), X 2 is a single bond, -O-, -S- or NR-. R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. As this monovalent hydrocarbon group, alkyl groups such as methyl, ethyl and n-propyl groups are preferred. X 2 is preferably a single bond, -O- or -S-, more preferably a single bond or -O-.

[0124] In formulas (B1) and (B1′), X 3is an optionally substituted monovalent hydrocarbon group having 1 to 20 carbon atoms. This monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof 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, n-dodecyl, and bicyclohexyl groups; vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, and 1-butene. Examples of suitable monovalent hydrocarbon groups include alkenyl groups having 2 to 20 carbon atoms, such as phenyl, 2-butenyl, 3-butenyl, and hexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, xylyl, tolyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 2-biphenylyl, 3-biphenylyl, and 4-biphenylyl; and aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenylethyl, and phenylcyclohexyl. Some or all of the hydrogen atoms in the monovalent hydrocarbon groups may be further substituted with a substituent. Examples of such substituents include A 01 The same as those mentioned in the explanation of X 3 is preferably an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.

[0125] In formulas (B1) and (B1′), m is an integer that satisfies 1≦m≦4, and is preferably 2. n is an integer that satisfies 1≦n≦4, and is preferably 2.

[0126] The arylsulfonate ester compounds represented by formulas (B1) and (B1') exhibit high solubility in a wide range of solvents, including low-polarity solvents, making it possible to adjust the physical properties of the solution using a wide variety of solvents, resulting in excellent coating properties. Therefore, it is preferable to apply the compound in the form of a sulfonate ester and generate sulfonic acid during drying or baking of the coating film. The temperature at which sulfonic acid is generated from the sulfonate ester is preferably 40 to 260°C, since sulfonic acid is stable at room temperature and preferably below the baking temperature. Furthermore, considering high stability in the varnish and ease of desorption during baking, a temperature of 80 to 230°C is preferred, with 120 to 180°C being more preferred.

[0127] The arylsulfonic acid ester compound represented by formula (B1) is preferably one represented by any one of the following formulae (B1-1) to (B1-3).

[0128] [ka]

[0129] In formula (B1-1), A 11 is an m-valent group derived from perfluorobiphenyl (i.e., a group obtained by removing m fluorine atoms from perfluorobiphenyl). 12 is -O- or -S-, with -O- being preferred. 13 is an (n+1)-valent group derived from naphthalene or anthracene (i.e., a group obtained by removing (n+1) hydrogen atoms from naphthalene or anthracene), with groups derived from naphthalene being preferred.

[0130] In formula (B1-1), R s1 ~R s4 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and R s5 is an optionally substituted monovalent hydrocarbon group having 2 to 20 carbon atoms.

[0131] Specific examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, etc. Among these, alkyl groups having 1 to 3 carbon atoms are preferred.

[0132] The monovalent hydrocarbon group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; and aryl groups such as phenyl, naphthyl, and phenanthryl.

[0133] R s1 ~R s4 Among them, R s1 or R s3 is preferably a linear alkyl group having 1 to 3 carbon atoms, and the remainder is preferably a hydrogen atom. s1 is a linear alkyl group having 1 to 3 carbon atoms, and R s2 ~R s4 is preferably a hydrogen atom. The linear alkyl group having 1 to 3 carbon atoms is preferably a methyl group. s5 As the alkyl group, a linear alkyl group having 2 to 4 carbon atoms or a phenyl group is preferred.

[0134] In formula (B1-1), m is an integer that satisfies 1≦m≦4, and is preferably 2. n is an integer that satisfies 1≦n≦4, and is preferably 2.

[0135] In formula (B1-2), A 14 is an m-valent hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings, which may be substituted. The m-valent hydrocarbon group is a group obtained by removing m hydrogen atoms from a hydrocarbon having 6 to 20 carbon atoms and containing one or more aromatic rings. Examples of the hydrocarbon include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, and phenanthrene.

[0136] In addition, some or all of the hydrogen atoms in the hydrocarbon group may be further substituted with a substituent, and such substituents include halogen atoms (fluorine atom, chlorine atom, bromine atom, iodine atom), nitro, cyano, hydroxy, amino, silanol, thiol, carboxy, sulfonate ester, phosphoric acid, phosphate ester, ester, thioester, amide, monovalent hydrocarbon, organooxy, organoamino, organosilyl, organothio, acyl, and sulfo groups. 14 As the alkyl group, groups derived from benzene, biphenyl, etc. are preferred.

[0137] In formula (B1-2), A 15 is -O- or -S-, with -O- being preferred.

[0138] In formula (B1-2), A 16 is an (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms. The (n+1)-valent aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of this aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc. Among these, A 16 As the alkyl group, a group derived from naphthalene or anthracene is preferred, and a group derived from naphthalene is more preferred.

[0139] In formula (B1-2), R s6 and R s7 are each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group. s8 is a linear or branched monovalent aliphatic hydrocarbon group, provided that R 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.

[0140] Specific examples of the linear or branched 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-hexyl, n-octyl, 2-ethylhexyl, and decyl groups; 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 groups.

[0141] R s6 is preferably a hydrogen atom, and R s7 and R s8 is preferably an alkyl group having 1 to 6 carbon atoms. s7 and R s8 may be the same or different.

[0142] In formula (B1-2), m is an integer that satisfies 1≦m≦4, and is preferably 2. n is an integer that satisfies 1≦n≦4, and is preferably 2.

[0143] In formula (B1-3), R s9 ~R s13 are each independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms.

[0144] 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, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups.

[0145] The halogenated alkyl group having 1 to 10 carbon atoms is not particularly limited as long as it is a group in which some or all of the hydrogen atoms of an alkyl group having 1 to 10 carbon atoms have been substituted with halogen atoms. The halogenated alkyl group may be linear, branched, or cyclic, and 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 groups.

[0146] The halogenated alkenyl group having 2 to 10 carbon atoms is not particularly limited as long as it is a group in which some or all of the hydrogen atoms of an alkenyl group having 2 to 10 carbon atoms have been substituted with halogen atoms. Specific examples thereof include perfluorovinyl, perfluoro-1-propenyl, perfluoro-2-propenyl, perfluoro-1-butenyl, perfluoro-2-butenyl, and perfluoro-3-butenyl groups.

[0147] Of these, R s9 As R, a nitro group, a cyano group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated alkenyl group having 2 to 10 carbon atoms, etc. are preferred, a nitro group, a cyano group, a halogenated alkyl group having 1 to 4 carbon atoms, a halogenated alkenyl group having 2 to 4 carbon atoms, etc. are more preferred, and a nitro group, a cyano group, a trifluoromethyl group, a perfluoropropenyl group, etc. are even more preferred. s10 ~R s13 As the atom, a halogen atom is preferable, and a fluorine atom is more preferable.

[0148] In formula (B1-3), A 17 is —O—, —S— or —NH—, with —O— being preferred.

[0149] In formula (B1-3), A 18is an (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms. The (n+1)-valent aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. Among these, A 18 As the alkyl group, a group derived from naphthalene or anthracene is preferred, and a group derived from naphthalene is more preferred.

[0150] In formula (B1-3), R s14 ~R s17 are each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. The monovalent aliphatic hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof 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. Of these, alkyl groups having 1 to 20 carbon atoms are preferred, alkyl groups having 1 to 10 carbon atoms are more preferred, and alkyl groups having 1 to 8 carbon atoms are even more preferred.

[0151] In formula (B1-3), R s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or OR s19 R s19 is an optionally substituted monovalent hydrocarbon group having 2 to 20 carbon atoms.

[0152] R s18 As the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by s14 ~R s17The same as those mentioned in the explanation of R s18 is a monovalent aliphatic hydrocarbon group, R s18 As the alkyl group, an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable, and an alkyl group having 1 to 8 carbon atoms is even more preferable.

[0153] R s19 Examples of the monovalent hydrocarbon group having 2 to 20 carbon atoms represented by the formula (I) include the above-mentioned monovalent aliphatic hydrocarbon groups other than the methyl group, as well as aryl groups such as a phenyl group, a naphthyl group, and a phenanthryl group. s19 is preferably a linear alkyl group having 2 to 4 carbon atoms or a phenyl group. 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.

[0154] In formula (B1-3), n is an integer that satisfies 1≦n≦4, with 2 being preferred.

[0155] As the arylsulfonic acid ester compound represented by formula (B1-3), those represented by the following formula (B1-3-1) or (B1-3-2) are particularly preferred.

[0156] [ka]

[0157] In formulas (B1-3-1) and (B1-3-2), A 17 , A 18 , R s9 ~R s17 , R s19 and n have the same meaning as above. s20 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and specific examples thereof include R s18 Examples of the above-mentioned methods are the same as those described above.

[0158] In the arylsulfonic acid ester compound represented by formula (B1-3-1), R s14 ~R s17 Among them, R s14 or R s16 is preferably a linear alkyl group having 1 to 3 carbon atoms, and the remainder is preferably a hydrogen atom. s14 is a linear alkyl group having 1 to 3 carbon atoms, and R s15 ~R s17 is preferably a hydrogen atom. As the linear alkyl group having 1 to 3 carbon atoms, a methyl group is preferred. s19 As the alkyl group, a linear alkyl group having 2 to 4 carbon atoms or a phenyl group is preferred.

[0159] In the arylsulfonic acid ester compound represented by formula (B1-3-2), R s14 , R s16 and R s20 The total number of carbon atoms in R is preferably 6 or more. s14 , R s16 and R s20 The upper limit of the total number of carbon atoms in R is preferably 20 or less, more preferably 10 or less. s14 is preferably a hydrogen atom, and R s16 and R s20 is preferably an alkyl group having 1 to 6 carbon atoms. s16 and R s20 may be the same or different from each other.

[0160] The arylsulfonic acid ester compounds represented by formula (B1) may be used singly or in combination of two or more.

[0161] Specific examples of suitable aryl sulfonate compounds include, but are not limited to, those shown below.

[0162] [ka]

[0163] [ka]

[0164] The amount of the arylsulfonic acid ester compound used is preferably about 0.01 to 20.0, more preferably about 0.05 to 15, in terms of mole ratio per 1 part of the organic functional material such as a polythiophene derivative or an arylamine derivative.

[0165] The molecular weight of the organic dopant such as an arylsulfonic acid compound or an arylsulfonic acid ester compound is not particularly limited, but is preferably 4000 or less, more preferably 3000 or less, and even more preferably 2000 or less, taking into consideration the solubility in an organic solvent when used together with a charge transporting substance.

[0166] In the present invention, in consideration of producing 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 a dopant substance, and in consideration of solubility in a solvent, it is more preferable to use an aryl sulfonic acid ester compound.

[0167] [4] Solvent The solvent used in preparing the charge-transporting varnish of the present invention can be a highly polar solvent that can dissolve the charge-transporting material used well. If necessary, a low-polarity solvent may be used because it has better process compatibility than a high-polarity solvent. In the present invention, a low-polarity solvent is defined as one having a dielectric constant of less than 7 at a frequency of 100 kHz, and a high-polarity solvent is defined as one having a dielectric constant of 7 or more at a frequency of 100 kHz.

[0168] Examples of low polarity solvents include: Chlorinated solvents such as chloroform and chlorobenzene; Aromatic hydrocarbon solvents such as toluene, xylene, tetralin, cyclohexylbenzene, and decylbenzene; Aliphatic alcohol solvents such as 1-octanol, 1-nonanol, and 1-decanol; 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; Ester solvents 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, and diethylene glycol monobutyl ether acetate etc.

[0169] Furthermore, examples of highly polar solvents include: Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutyramide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone; Ketone solvents such as ethyl methyl ketone, isophorone, and cyclohexanone; cyano 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; 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; Sulfoxide solvents such as dimethyl sulfoxide etc.

[0170] [5] Silane compounds When the resulting thin film is used as a hole injection layer of an organic EL device, the charge transport varnish may contain an organosilane compound for the purpose of improving injection into the hole transport layer, improving the life characteristics of the device, etc. The content of the organosilane compound is usually about 1 to 30% by mass based on the total mass of the charge transport substance and the dopant substance.

[0171] [6] Charge-transporting varnish and charge-transporting thin film The viscosity of the charge-transporting varnish is determined appropriately 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 refers to the components other than the solvent contained in the charge-transporting varnish. The solids concentration of the charge-transporting varnish is determined appropriately taking into consideration the viscosity and surface tension of the varnish, the thickness of the thin film to be produced, and the like, but is typically about 0.1 to 10.0 mass %, and in consideration of improving the coatability of the varnish, it is preferably about 0.5 to 5.0 mass %, and more preferably about 1.0 to 3.0 mass %.

[0172] The method for preparing the charge-transporting varnish is not particularly limited, but examples include a method in which a charge-transporting substance and a dopant substance are dissolved in a high-polarity solvent, and then a low-polarity solvent and surface-treated metal oxide nanoparticles are added thereto, and a method in which a high-polarity solvent and a low-polarity solvent are mixed, and then a charge-transporting substance and a dopant substance are dissolved therein, and then surface-treated metal oxide nanoparticles are added thereto.

[0173] In particular, when preparing a charge-transporting varnish, from the viewpoint of obtaining a thin film with higher flatness with good reproducibility, it is desirable to use a varnish obtained by dissolving a charge-transporting substance, a dopant substance, etc. in an organic solvent and then filtering the solution using a filter on the order of submicrometers.

[0174] The charge transporting varnish described above can be used to easily produce a charge transporting thin film, and is therefore suitable for use in producing electronic devices, particularly organic EL devices. In this case, the charge transporting thin film can be formed by applying the above-mentioned charge transporting varnish onto a substrate and baking it. The method for applying the varnish is not particularly limited, and examples thereof include dipping, spin coating, transfer printing, roll coating, brush coating, inkjet coating, spraying, and slit coating. It is preferable to adjust the viscosity and surface tension of the varnish depending on the application method.

[0175] Furthermore, the atmosphere in which the charge-transporting varnish is baked after application is not particularly limited, and a thin film with a uniform film surface and high charge transport properties can be obtained not only in an air atmosphere but also in an inert gas such as nitrogen or in a vacuum. However, depending on the type of dopant substance used, a thin film with charge transport properties can sometimes be reproducibly obtained by baking the varnish in an air atmosphere.

[0176] The baking temperature is appropriately determined within a range of about 100 to 260°C, taking into consideration the use of the resulting thin film, the degree of charge transport property to be imparted to the resulting thin film, the type and boiling point of the solvent, etc. For example, when the resulting thin film is used as a hole injection layer of an organic EL device, a baking temperature of about 140 to 250°C is preferred, and about 145 to 240°C is more preferred. However, when the above-mentioned arylamine compound is used as the charge transport material, a thin film with good charge transport property can be obtained even at a low baking temperature of 200°C or less. During firing, the temperature may be changed in two or more stages in order to achieve a more uniform film formation or to promote the reaction on the substrate, and heating may be carried out using an appropriate device such as a hot plate or an oven.

[0177] The thickness of the charge transport thin film is not particularly limited, but is preferably 5 to 300 nm when used as a functional layer provided between the anode and the light-emitting layer of an organic EL device, such as a hole injection layer, a hole transport layer, or a hole injection transport layer. Methods for changing the film thickness include changing the solid concentration in the varnish or changing the amount of solution on the substrate during application.

[0178] The charge-transporting thin film of the present invention described above exhibits an average transmittance of 90% or more in a wavelength region of 400 to 800 nm at a film thickness of 50 nm, and in some embodiments exhibits an average transmittance of 92% or more, and in other embodiments exhibits an average transmittance of 95% or more.

[0179] [7] Organic electroluminescence (EL) elements When the charge transporting thin film is applied to an organic EL device, the organic EL device can be configured to include the charge transporting thin film between a pair of electrodes. Representative configurations of organic EL devices include, but are not limited to, the following (a) to (f). In the following configurations, an electron blocking layer or the like can be provided between the light-emitting layer and the anode, and a hole blocking layer or the like can be provided between the light-emitting layer and the cathode, as necessary. Furthermore, the hole injection layer, the hole transport layer, or the hole injection transport layer may also function as an electron blocking layer or the like, and the electron injection layer, the electron transport layer, or the electron injection transport layer may also function as a hole blocking layer or the like. Furthermore, an arbitrary functional layer can be provided between each layer as necessary. (a) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (b) Anode / hole injection layer / hole transport layer / light-emitting layer / electron injection transport layer / cathode (c) Anode / hole injection transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (d) Anode / hole injection transport layer / light-emitting layer / electron injection transport layer / cathode (e) Anode / hole injection layer / hole transport layer / light-emitting layer / cathode (f) Anode / hole injection transport layer / light-emitting layer / cathode

[0180] The terms "hole injection layer," "hole transport layer," and "hole injection transport layer" refer to layers formed between the light-emitting layer and the anode, which have the function of transporting holes from the anode to the light-emitting layer. When only one layer of a hole-transporting material is provided between the light-emitting layer and the anode, it is the "hole injection transport layer." When two or more layers of a hole-transporting material are provided between the light-emitting layer and the anode, the layer closest to the anode is the "hole injection layer," and the remaining layers are "hole transport layers." In particular, the hole injection (transport) layer is a thin film that is excellent not only in accepting holes from the anode but also in injecting holes into the hole transport (light-emitting) layer. The terms "electron injection layer," "electron transport layer," and "electron injection transport layer" refer to layers formed between the light-emitting layer and the cathode, which have the function of transporting electrons from the cathode to the light-emitting layer. When only one layer of an electron-transporting material is provided between the light-emitting layer and the cathode, it is the "electron injection transport layer." When two or more layers of electron-transporting materials are provided between the light-emitting layer and the cathode, the layer closest to the cathode is the "electron injection layer," and the other layers are "electron transport layers." The "light-emitting layer" is an organic layer that has a light-emitting function, and when a doping system is used, it contains a host material and a dopant material. In this case, the host material mainly functions to promote the recombination of electrons and holes and confine excitons within the light-emitting layer, while the dopant material functions to efficiently emit light from the excitons obtained by the recombination. In the case of a phosphorescent element, the host material mainly functions to confine excitons generated by the dopant within the light-emitting layer.

[0181] The charge-transporting thin film of the present invention can be used as a functional layer provided between an anode and an emitting layer in an organic EL device, and is suitable as a hole-injection layer, a hole-transport layer, or 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.

[0182] When an EL device is produced using the charge transporting varnish of the present invention, the materials to be used and the production method thereof are as follows, but are not limited thereto. An example of a method for producing 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 to previously perform surface treatment on the electrodes, such as washing with alcohol or pure water, or UV ozone treatment or oxygen plasma treatment, within a range that does not adversely affect the electrodes. A hole injection layer made of the charge transport thin film of the present invention is formed on an anode substrate by the above-described method. This is then introduced into a vacuum deposition apparatus, 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 deposited. Alternatively, instead of forming the hole transport layer and the light-emitting layer by deposition in this method, these layers are formed by a wet process using a hole transport layer-forming composition containing a hole transport polymer and a light-emitting layer-forming composition containing a light-emitting polymer. If necessary, an electron blocking layer may be provided between the light-emitting layer and the hole transport layer.

[0183] Anode materials include transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), and metal anodes made of metals such as aluminum or their alloys, preferably planarized. Polythiophene derivatives and polyaniline derivatives with high charge transport properties can also be used. Other metals that may be used to form the metal anode include, but are not limited to, gold, silver, copper, indium, and alloys thereof.

[0184] Examples of materials for forming the hole transport layer include triarylamines such as (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spiro dimer, N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD), 4,4',4"-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), and 4,4',4"-tris[1-naphthyl(phenyl)amino]triphenylamine (1-TNATA), and oligothiophenes such as 5,5"-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2"-terthiophene (BMA-3T).

[0185] Materials for forming the light-emitting layer include, but are not limited to, low-molecular-weight light-emitting materials such as metal complexes such as aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and silole derivatives; and systems in which a light-emitting material and an electron transfer material are mixed with a polymer compound such as poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), or polyvinylcarbazole. Furthermore, when forming a light-emitting layer by vapor deposition, it may be co-deposited with a light-emitting dopant. Examples of the light-emitting dopant include, but are not limited to, metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(ppy)), naphthacene derivatives such as rubrene, quinacridone derivatives, and fused polycyclic aromatic rings such as perylene.

[0186] Examples of materials for forming the electron transport layer / hole blocking layer include, but are not limited to, oxydiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, and pyrimidine derivatives.

[0187] Materials for forming the electron injection layer include, but are not limited to, metal oxides such as lithium oxide (Li2O), magnesium oxide (MgO), and alumina (Al2O3), and metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF). Cathode materials include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, and the like. Examples of materials for forming the electron blocking layer include, but are not limited to, tris(phenylpyrazole)iridium.

[0188] Hole-transporting polymers include poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine]-endcapped with Examples thereof include polysilcisquinoxane and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)].

[0189] Examples of light-emitting polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylenevinylene derivatives such as poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

[0190] As described above, the charge-transporting varnish of the present invention is suitably used for forming functional layers provided between the anode and light-emitting layer of an organic EL device, such as a hole injection layer, a hole transport layer, or a hole injection transport layer. However, it can also be used for forming charge-transporting thin films in electronic devices such as organic photoelectric conversion devices, organic thin-film solar cells, organic perovskite photoelectric conversion devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic optical inspectors, organic photoreceptors, organic field quenching devices, light-emitting electrochemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasmon light-emitting devices. [Example]

[0191] The present invention will be described in more detail below with reference to Production Examples, Preparation Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. The apparatuses used are as follows. (1) Substrate cleaning: Substrate cleaning equipment (low-pressure plasma method) manufactured by Choshu Sangyo Co., Ltd. (2) Varnish application: Mikasa Co., Ltd. Spin Coater MS-A100 (3) Film thickness measurement: Kosaka Laboratory Co., Ltd. Micro-profile measuring instrument Surfcorder ET-4000 (4) Fabrication of hole-only devices: Multi-function deposition system C-E2L1G1-N manufactured by Choshu Sangyo Co., Ltd. (5) Measurement of current density of hole-only element: Multi-channel IVL measurement device manufactured by EHC Corporation (6) Measurement of transmittance: Shimadzu Science Co., Ltd. UV-3600 ultraviolet-visible near-infrared spectrophotometer

[0192] [1] Production of silane coupling agents with conductive functional groups [Production Example 1] Production of silane coupling agent (Si1) [ka]

[0193] Brominated compound 1 (7.71 g, 15.00 mmol, manufactured by YURUI (SHANGHAI) CHEMICAL CO., LTD.), Pd(dba) (863.0 mg, 5 mol%, manufactured by Tokyo Chemical Industry Co., Ltd.), (tBuP)HBF (435.0 mg, 5 mol%, manufactured by Kanto Chemical Co., Inc.), toluene (120 mL), and 1 M toluene solution of LiN(SiMe) (33 mL, 33 mmol, manufactured by Aldrich) were placed in a 300 mL flask and stirred at room temperature for 20 h. The mixture was then cooled to 0 °C, and 1 M aqueous HCl (66 mL, 66 mmol, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added and stirred for 1.5 h. 1 N NaOH aqueous solution was added until the reaction solution pH was greater than 7. The mixture was then separated, the aqueous layer was removed, and the organic layer was washed with saturated brine. Toluene was removed from the organic layer under reduced pressure, and the solid was dissolved in 30 mL of toluene, followed by the addition of 200 mL of hexane. The solid was filtered and dried to give 4.86 g (72% yield) of amine 2.

[0194] [ka]

[0195] A 300 mL flask was charged with amine 2 (2.80 g, 6.23 mmol), THF (130 mL), and silane compound 3 (6.66 g, 26.91 mmol), and the mixture was stirred at 60 °C for 19 hours. The mixture was cooled to room temperature, and the THF was removed under reduced pressure. The resulting solid was purified by silica gel chromatography (solvent: toluene:ethyl acetate = 4 / 1 → 2 / 1 (v / v)), yielding 2.81 g (65% yield) of the desired silane coupling agent (Si1).

[0196] [Production Example 2] Production of silane coupling agent (Si2) [ka]

[0197] The same method as in Production Example 1 was repeated except that bromo-form 4 (11.95 g, 30.00 mmol) was used instead of bromo-form 1, to obtain 5.52 g of the desired amine-form 5 (yield 99%).

[0198] [ka]

[0199] The same method as in Production Example 1 was repeated except that amine 5 (9.00 g, 26.91 mmol) was used instead of amine 2, to obtain 7.84 g (yield 50%) of the target silane coupling agent (Si2).

[0200] [2] Preparation of metal oxide nanoparticles (sol) (comparison particles) [Preparation Example 1] 250 g of MEK-dispersed silica sol (Nissan Chemical Industries, Ltd., MEK-ST, particle size 10-15 nm, SiO2 30% by mass) and 170 g of triethylene glycol butyl methyl ether were placed in a 500 ml recovery flask and placed in a rotary evaporator. The mixture was concentrated under reduced pressure to a mass of 250 g, yielding a triethylene glycol butyl methyl ether-dispersed silica sol containing SiO2 30% by mass.

[0201] [Preparation Example 2] 12 g of a PGMEA dispersion of zirconia particles (PixClear manufactured by Pixelligent Technologies, average particle size 7-10 nm, zirconia concentration: 50% by mass) and 24 g of triethylene glycol butyl methyl ether were placed in a 300 ml recovery flask and placed in a rotary evaporator. The mixture was concentrated under reduced pressure to a mass of 30 g, yielding a triethylene glycol butyl methyl ether-dispersed zirconia sol containing 20% ​​by mass of ZrO2.

[0202] [3] Preparation of surface-treated metal oxide nanoparticles (sols) The "calculated modification amount" in each preparation example was determined by the following method. The radius of the particle is r, and the surface area of ​​each particle is 4πr 2The volume per particle is calculated as 4πr 3 Calculated from / 3. The weight per particle was calculated using the calculated particle volume and the specific gravity of SiO2 or ZrO2. The specific surface area per particle was calculated from the calculated weight per particle and the surface area per particle. And the modification amount X (pieces / nm 2 ) and the specific surface area SA (nm 2 / g), the total amount of metal oxide particles M (g), the molecular weight Mw of the silane coupling agent, the amount Y (g) of the silane coupling agent, and Avogadro's constant L, were used to calculate the coefficient of friction coefficient Y according to the formula Y=X*SA*M*Mw / L. The specific gravity of SiO2 is 2.2 g / cm 3 The specific gravity of ZrO2 is 6.0 g / cm 3 The particles used in Preparation Examples 3 and 4 and Comparative Preparation Example 1 had a radius r of 12 nm, and the particles used in Preparation Examples 5 and 6 had a radius r of 7 nm.

[0203] [Preparation Example 3] A 50 ml eggplant flask was filled with methanol-dispersed silica sol (Nissan Chemical Industries, Ltd., MT-ST, particle size 10-15 nm, SiO2 30 mass%, specific gravity 2.2 g / cm3). 3 5.0 g of silica sol, 10.0 g of triethylene glycol butyl methyl ether, and 0.2 g of silica were added, and the mixture was heated under reflux at 60°C for 4 hours to modify the silica sol surface with silica (calculated modification amount: 0.5 particles / nm 2 After the reaction, the methanol was removed under reduced pressure using a rotary evaporator to obtain a triethylene glycol butyl methyl ether-dispersed Si1-modified silica sol (Sil-ST) containing 15.9% by mass of SiO2.

[0204] [Preparation Example 4] A 50 ml eggplant flask was filled with methanol-dispersed silica sol (Nissan Chemical Industries, Ltd., MT-ST, particle size 10-15 nm, SiO2 30 mass%, specific gravity 2.2 g / cm3). 35.0 g of HCl, 10.0 g of triethylene glycol butyl methyl ether, and 0.32 g of Si were added, and the mixture was heated under reflux at 60°C for 4 hours to modify the silica sol surface with Si (calculated modification amount: 1.0 particles / nm 2 After the reaction, the methanol was removed under reduced pressure using a rotary evaporator to obtain a triethylene glycol butyl methyl ether-dispersed Si2-modified silica sol (Si2-ST) containing 16.4% by mass of SiO2.

[0205] [Comparative Preparation Example 1] A 50 ml eggplant flask was filled with methanol-dispersed silica sol (Nissan Chemical Industries, Ltd., MT-ST, particle size 10-15 nm, SiO2 30 mass%, specific gravity 2.2 g / cm3). 3 5.0 g of silica sol, 10.0 g of triethylene glycol butyl methyl ether, and 0.66 g of silicon dioxide were added, and the mixture was heated under reflux at 60°C for 4 hours to modify the surface of the silica sol with silicon dioxide (calculated modification amount: 2.0 particles / nm 2 However, the particles settled within a few hours of reaction, and a modified silica sol could not be obtained.

[0206] [Preparation Example 5] A 50 ml recovery flask was filled with a PGMEA dispersion of zirconia particles (PixClear manufactured by Pixelligent Technologies, average particle size 7-10 nm, zirconia concentration: 50 mass%, specific gravity 6.0 g / cm). 3 2 g of silica, 5.67 g of triethylene glycol butyl methyl ether, and 0.09 g of silica were added, and the mixture was heated under reflux at 60°C for 4 hours to modify the zirconia surface with silica (calculated modification amount: 0.5 silica / nm 2 After the reaction, PGMEA was removed under reduced pressure using a rotary evaporator to obtain 15.8% by mass of SiO2 triethylene glycol butyl methyl ether-dispersed Si1-modified zirconia sol (Si1-ZrO2).

[0207] [Preparation Example 6] A 50 ml recovery flask was filled with a PGMEA dispersion of zirconia particles (PixClear manufactured by Pixelligent Technologies, average particle size 7-10 nm, zirconia concentration: 50 mass%, specific gravity 6.0 g / cm). 3 2 g of zirconia, 5.67 g of triethylene glycol butyl methyl ether, and 0.15 g of Si1 were added, and the mixture was heated under reflux at 60°C for 4 hours to modify the zirconia surface with Si2 (calculated modification amount: 1 / nm 2 After the reaction, PGMEA was removed under reduced pressure using a rotary evaporator to obtain 17.1% by mass of SiO2 triethylene glycol butyl methyl ether-dispersed Si2-modified zirconia sol (Si2-ZrO2).

[0208] [4] Preparation of charge-transporting varnish [Example 1-1] Under a nitrogen atmosphere, 0.034 g of the following arylamine compound (A1) synthesized according to the method described in WO 2015 / 050253 and 0.091 g of the following arylsulfonate ester (D1) synthesized according to the method described in WO 2017 / 217455 were dissolved in a mixed solvent of 1.71 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.79 g of Si1-ST obtained in Preparation Example 3 was added and stirred to obtain a charge-transporting varnish.

[0209] [ka]

[0210] [Example 1-2] Under a nitrogen atmosphere, 0.034 g of the arylamine compound (A1) and 0.091 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.67 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.83 g of Si2-ST obtained in Preparation Example 4 was added and stirred to obtain a charge-transporting varnish.

[0211] [Examples 1-3] Under a nitrogen atmosphere, 0.068 g of the arylamine compound (A1) and 0.18 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 0.93 g of triethylene glycol butyl methyl ether, 1.35 g of butyl benzoate, and 0.90 g of dimethyl phthalate. 1.57 g of Si1-ST obtained in Preparation Example 3 was added and stirred to obtain a charge-transporting varnish.

[0212] [Examples 1-4] Under a nitrogen atmosphere, 0.068 g of the arylamine compound (A1) and 0.18 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 0.83 g of triethylene glycol butyl methyl ether, 1.35 g of butyl benzoate, and 0.90 g of dimethyl phthalate. 1.67 g of Si2-ST obtained in Preparation Example 4 was added and stirred to obtain a charge-transporting varnish.

[0213] [Comparative Example 1-1] Under a nitrogen atmosphere, 0.041 g of arylamine compound (A1) and 0.109 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.81 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.67 g of the triethylene glycol butyl methyl ether-dispersed silica sol obtained in Preparation Example 1 was added and stirred to obtain a charge-transporting varnish.

[0214] [Comparative Example 1-2] Under a nitrogen atmosphere, 0.034 g of the arylamine compound (A1) and 0.091 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.67 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.83 g of the triethylene glycol butyl methyl ether-dispersed silica sol obtained in Preparation Example 1 was added and stirred to obtain a charge-transporting varnish.

[0215] [Comparative Example 1-3] Under a nitrogen atmosphere, 0.082 g of the arylamine compound (A1) and 0.218 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.12 g of triethylene glycol butyl methyl ether, 1.35 g of butyl benzoate, and 0.90 g of dimethyl phthalate. To this was added 1.33 g of the triethylene glycol butyl methyl ether-dispersed silica sol obtained in Preparation Example 1, and the mixture was stirred to obtain a charge-transporting varnish.

[0216] [Comparative Example 1-4] Under a nitrogen atmosphere, 0.068 g of arylamine compound (A1) and 0.182 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 0.83 g of triethylene glycol butyl methyl ether, 1.35 g of butyl benzoate, and 0.90 g of dimethyl phthalate. To this was added 1.67 g of the triethylene glycol butyl methyl ether-dispersed silica sol obtained in Preparation Example 1, and the mixture was stirred to obtain a charge-transporting varnish.

[0217] [Examples 1-5] Under a nitrogen atmosphere, 0.048 g of arylamine compound (A1) and 0.127 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.98 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.47 g of the Si1-ZrO2 obtained in Preparation Example 5 was added and stirred to obtain a charge-transporting varnish.

[0218] [Examples 1-6] Under a nitrogen atmosphere, 0.041 g of arylamine compound (A1) and 0.11 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.84 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. To this solution, 0.63 g of the Si1-ZrO2 obtained in Preparation Example 5 was added and stirred to obtain a charge-transporting varnish.

[0219] [Examples 1-7] Under a nitrogen atmosphere, 0.048 g of arylamine compound (A1) and 0.13 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 2.01 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.44 g of Si2-ZrO2 obtained in Preparation Example 6 was added and stirred to obtain a charge-transporting varnish.

[0220] [Examples 1-8] Under a nitrogen atmosphere, 0.041 g of arylamine compound (A1) and 0.11 g of arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.89 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.58 g of Si2-ZrO2 obtained in Preparation Example 6 was added and stirred to obtain a charge-transporting varnish.

[0221] [Comparative Example 1-5] Under a nitrogen atmosphere, 0.048 g of the arylamine compound (A1) and 0.13 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 2.08 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.37 g of the triethylene glycol butyl methyl ether-dispersed zirconia sol obtained in Preparation Example 2 was added and stirred to obtain a charge-transporting varnish.

[0222] [Comparative Examples 1-6] Under a nitrogen atmosphere, 0.041 g of the arylamine compound (A1) and 0.11 g of the arylsulfonic acid ester (D1) were dissolved in a mixed solvent of 1.98 g of triethylene glycol butyl methyl ether, 1.43 g of butyl benzoate, and 0.95 g of dimethyl phthalate. 0.49 g of the triethylene glycol butyl methyl ether-dispersed zirconia sol obtained in Preparation Example 2 was added thereto and stirred to obtain a charge-transporting varnish.

[0223] [5] Preparation of charge transport thin films and evaluation of transmittance [Example 2-1] The varnish obtained in Example 1-1 was applied to a quartz substrate using a spin coater and then dried in air at 120°C for 1 minute. The dried quartz substrate was then baked in air at 230°C for 15 minutes to form a uniform thin film of 50 nm on the quartz substrate.

[0224] [Example 2-2, Comparative Example 2-1 and Comparative Example 2-2] Thin films were formed in the same manner as in Example 2-1, except that the varnishes obtained in Example 1-2, Comparative Example 1-1 and Comparative Example 1-2 were used instead of the varnish obtained in Example 1-1.

[0225] [Example 2-3] The varnish obtained in Example 1-3 was applied to a quartz substrate using a spin coater and then dried in air at 120°C for 1 minute. The dried quartz substrate was then baked in air at 230°C for 15 minutes to form a uniform thin film of 100 nm on the quartz substrate.

[0226] [Examples 2-4, Comparative Examples 2-3 and 2-4] Thin films were formed in the same manner as in Example 2-1, except that the varnishes obtained in Example 1-4, Comparative Example 1-3 and Comparative Example 1-4 were used instead of the varnish obtained in Example 1-3.

[0227] [Examples 2-5 to 2-8 and Comparative Examples 2-5 to 2-6] Thin films were formed in the same manner as in Example 2-1, except that the varnishes obtained in Examples 1-5 to 1-8, Comparative Example 1-5, and Comparative Example 1-6 were used instead of the varnish obtained in Example 1-1.

[0228] The quartz substrates with thin films obtained in the above examples and comparative examples were used to measure light transmittance using a spectrophotometer. The results are shown in Figures 1 to 3 and Tables 1 and 2.

[0229] [Table 1]

[0230] [Table 2]

[0231] As shown in Figures 1 and 2 and Table 1, even when organosilica sol modified with silane coupling agents Si1 and Si2 (Si1-ST, Si2-ST) was added, the average light transmittance in the visible region was about the same as when triethylene glycol butyl methyl ether dispersed silica sol was added. That is, it was shown that the charge transporting thin film of the present invention containing silica particles modified with a silane coupling agent can maintain excellent transmittance in the visible region.

[0232] On the other hand, as shown in Figure 3 and Table 2, even when zirconia sol modified with silane coupling agents Si1 and Si2 (Si1-ZrO2, ZrO2) was added, the average light transmittance in the visible region was found to be about the same as when triethylene glycol butyl methyl ether dispersed zirconia sol was added. That is, it was shown that the charge transporting thin film of the present invention containing zirconia particles modified with a silane coupling agent can maintain excellent transmittance in the visible region.

[0233] [6] Fabrication and characterization of hole-only devices (HODs) [Example 3-1] The varnish obtained in Example 1-1 was applied to an ITO substrate using a spin coater and then dried in air at 120°C for 1 minute. The dried ITO substrate was then baked in air at 230°C for 15 minutes to form a uniform 50 nm thin film on the ITO substrate. A 25 mm x 25 mm x 0.7 mm glass substrate with a patterned 150 nm thick indium tin oxide (ITO) film formed on its surface was used as the ITO substrate. Surface impurities were removed using an O2 plasma cleaning device (150 W, 30 seconds) before use. Next, the ITO substrate on which the thin film was formed was subjected to a deposition apparatus (vacuum degree 1.0 × 10 -5A 30-nm thick film of α-NPD (N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine) was formed at 0.2 nm / sec using a GaN film (AlP) and then an 80-nm thick film of aluminum was formed at 0.2 nm / sec to fabricate a hole-only device. To prevent deterioration of characteristics due to the influence of oxygen, water, etc. in the air, the device was sealed with a sealing substrate before its characteristics were evaluated. Sealing was performed as follows: In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, the device was placed between sealing substrates, and the sealing substrates were bonded together with an adhesive (Moresco Moisture Cut WB90US(P) manufactured by MORESCO Corporation). At this time, a moisture scavenger (HD-071010W-40 manufactured by DYNIC Corporation) was placed inside the sealing substrate together with the device. The bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation dose: 6,000 mJ / cm). 2 ), and then annealed at 80°C for 1 hour to cure the adhesive.

[0234] [Example 3-2, Comparative Example 3-1 and Comparative Example 3-2] HOD was obtained in the same manner as in Example 3-1, except that the varnish obtained in Example 1-2, Comparative Example 1-1, and Comparative Example 1-2 were used instead of the varnish obtained in Example 1-1.

[0235] [Example 3-3] HOD was obtained in the same manner as in Example 3-1, except that the varnish obtained in Example 1-3 was used instead of the varnish obtained in Example 1-1, and the film thickness was set to 100 nm.

[0236] [Examples 3-4, Comparative Examples 3-3 and 3-4] HOD was obtained in the same manner as in Example 3-3, except that the varnish obtained in Example 1-4, Comparative Example 1-3, and Comparative Examples 1 to 4 were used instead of the varnish obtained in Example 1-1.

[0237] [Examples 3-5 to 3-8 and Comparative Examples 3-5 to 3-6] HOD was obtained in the same manner as in Example 3-1, except that the varnish obtained in Examples 1-5 to 1-8 and Comparative Examples 1-5 to 1-6 were used instead of the varnish obtained in Example 1-1.

[0238] The current density of the obtained HOD was measured when it was driven at 5 V. The results are shown in Tables 3 and 4.

[0239] [Table 3]

[0240] [Table 4]

[0241] As shown in Table 3, it can be seen that the thin film prepared from the charge transport varnish of the present invention, which uses silica modified with a silane coupling agent having a conductive functional group, exhibits better charge transport properties than the thin film of the comparative example. On the other hand, as shown in Table 4, it can be seen that the thin film prepared from the charge transporting varnish of the present invention, which uses zirconia modified with a silane coupling agent having a specific conductive functional group, exhibits better charge transport properties than the thin film of the comparative example.

Claims

1. A charge transporting material, a dopant material, metal oxide nanoparticles that have been surface-treated with a silane coupling agent having a conductive functional group, and a solvent, A charge-transporting varnish characterized in that the silane coupling agent is a compound represented by the following formula (S1): 【Chemistry 1】 (wherein R represents an alkyl group having 1 to 5 carbon atoms, A 1 represents an alkylene group having 2 to 5 carbon atoms; A 2 represents —O—, —S—, —NH—, an amide bond, a urea bond, or a combination thereof; A 3 represents an aryl group having a phenylcarbazole structure.

2. The above A 3 2. The charge-transporting varnish according to claim 1, wherein is at least one selected from the group consisting of formula (A3-1), formula (A3-4), and formula (A3-9). 【Chemistry 2】 (wherein the asterisk * represents a bond, A 4 represents an arylene group.

3. 2. The charge-transporting varnish according to claim 1, wherein the silane coupling agent is a compound represented by the following formula (S1-1): 【Transformation 3】 (wherein R represents an alkyl group having 1 to 5 carbon atoms, A 1 represents an alkylene group having 2 to 5 carbon atoms; A 4 represents an arylene group.

4. 4. The charge-transporting varnish according to claim 1, wherein the metal oxide nanoparticles are at least one selected from the group consisting of silica and zirconia.

5. 5. The charge-transporting varnish according to claim 1, wherein the charge-transporting substance is an arylamine derivative.

6. 6. The charge transporting varnish according to claim 1, wherein the dopant substance is an arylsulfonic acid compound.

7. A charge-transporting thin film obtained from the charge-transporting varnish according to any one of claims 1 to 6.

8. An electronic device comprising the charge transporting thin film according to claim 7.

9. An organic electroluminescence device comprising the charge transporting thin film according to claim 7.

10. 10. The organic electroluminescence device according to claim 9, wherein the charge transporting thin film is a hole injection layer or a hole transport layer.

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