阅读说明：本技术 电荷传输性清漆 (Charge-transporting varnish ) 是由 牧岛知佳 于 2020-03-23 设计创作，主要内容包括：提供电荷传输性清漆,所述电荷传输性清漆的特征在于,包含电荷传输性物质、用表面处理剂进行了表面改性的含氧化钛粒子、和有机溶剂。(Provided is a charge-transporting varnish characterized by containing a charge-transporting substance, titanium oxide-containing particles surface-modified with a surface treatment agent, and an organic solvent.)

1. A charge-transporting varnish is characterized by comprising a charge-transporting substance, titanium oxide-containing particles surface-modified with a surface-treating agent, and an organic solvent.

2. The charge-transporting varnish according to claim 1, wherein the titanium oxide-containing particles contained in the titanium oxide-containing particles surface-modified with the surface treatment agent are colloidal particles.

3. The charge-transporting varnish according to claim 2, wherein the titanium oxide-containing particles surface-modified with the surface treatment agent are: colloidal particles (D) (surface-modified colloidal particles (D)) wherein the surface of modified titanium oxide-containing colloidal particles (C) (modified colloidal particles (C)) whose surface is coated with metal oxide colloidal particles (B) (coating material (B)) is surface-modified with an amphiphilic surface-treating agent, and wherein the colloidal particles (a) are composed of titanium oxide as a core (core particles (a)).

4. The charge-transporting varnish according to claim 1 or 2, wherein the surface treatment agent is an amphiphilic surface treatment agent.

5. The charge-transporting varnish of claim 3 or 4, wherein the amphiphilic surface treatment agent is an organosilicon compound, a titanate coupling agent, an aluminate coupling agent, or a phosphorous-based surfactant.

6. The charge-transporting varnish according to any one of claims 1 to 5, wherein the charge-transporting substance is a polythiophene derivative having a repeating unit represented by the formula (1) or an amine adduct thereof,

in the formula, R¹And R²Independently represents a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, a fluoroalkoxy group having 1 to 40 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms、-O-[Z-O]_p-R^eOr a sulfonic acid group, or is R¹And R²a-O-Y-O-formed by bonding, wherein Y is a C1-40 alkylene group which may be substituted with a sulfonic acid group and may contain an ether bond, Z is a C1-40 alkylene group which may be substituted with a halogen atom, p is an integer of 1 or more, and R is^eIs a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

7. The charge transporting varnish according to any one of claims 1 to 6, wherein R is¹Is a sulfonic acid group, said R²Is C1-40 alkoxy or-O- [ Z-O]_p-R^eOr is said R¹And R²Bonded to form-O-Y-O-.

8. The charge transporting varnish according to any one of claims 1 to 7, further comprising a heteropoly acid.

9. The charge transporting varnish according to claim 8, wherein the heteropoly acid is phosphotungstic acid.

10. A charge-transporting film obtained from the charge-transporting varnish according to any one of claims 1 to 9.

11. An organic electroluminescent element comprising the charge transporting thin film according to claim 10.

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

13. A method for producing a charge-transporting film, which comprises applying the charge-transporting varnish according to any one of claims 1 to 9 onto a substrate and evaporating the solvent.

14. A method for producing an organic electroluminescent element, wherein the charge transporting thin film according to claim 13 is used.

Technical Field

The present invention relates to a charge-transporting varnish.

Background

In an organic electroluminescence (hereinafter referred to as organic EL) device, a charge-transporting thin film made of an organic compound is used as a light-emitting layer and a charge injection layer. In particular, the hole injection layer plays an important role in transferring charges between the anode and the hole transport layer or the light emitting layer, and in order to realize low-voltage driving and high luminance of the organic EL element.

The methods of forming the hole injection layer are roughly classified into a dry method typified by a vapor deposition method and a wet method typified by a spin coating method, and if these methods are compared, the wet method can efficiently produce a thin film having high flatness over a large area. Therefore, at present, a hole injection layer that can be formed by a wet process is desired for an organic EL display having a large area.

In view of such circumstances, the present inventors have developed a charge transporting material that can be applied to various wet methods and that produces a thin film that can realize excellent EL element characteristics when applied to a hole injection layer of an organic EL element, and a compound used for the charge transporting material that has good solubility in an organic solvent (see, for example, patent documents 1 to 3).

On the other hand, various studies have been made to improve the performance of organic EL devices, and for the purpose of improving light extraction efficiency, for example, studies have been made to adjust the refractive index of a functional film used. Specifically, it has been attempted to increase the efficiency of an element by using a hole injection layer or a hole transport layer having a high or low refractive index, taking into consideration the entire structure of the element and the refractive index of another member adjacent thereto (see, for example, patent documents 4 and 5).

Therefore, the refractive index is an important factor in designing an organic EL element, and the refractive index is also considered as an important physical property value to be considered for a material for an organic EL element.

In addition, in recent years, it has been desired that charge-transporting thin films for organic EL devices have high transmittance and high transparency in the visible region thereof, because of practical circumstances such as a decrease in color purity and color reproducibility of organic EL devices, for coloring of charge-transporting thin films used for organic EL devices (see, for example, patent document 6).

In view of this, the present applicant has found a material for a wet process which suppresses coloring in a visible region and produces a charge-transporting thin film excellent in transparency (see, for example, patent documents 6 and 7).

However, in recent years when the organic EL display has been increased in area, the organic EL display using the wet process has been put to practical use, and development thereof has been intensively carried out, and a material for the wet process which generates a charge-transporting thin film having high transparency has been often required.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2008/129947

Patent document 2: international publication No. 2015/050253

Patent document 3: international publication No. 2017/217457

Patent document 4: japanese Kokai publication No. 2007-536718

Patent document 5: japanese Kohyo publication 2017-501585

Patent document 6: international publication No. 2013/042623

Patent document 7: international publication No. 2008/032616

Disclosure of Invention

Problems to be solved by the invention

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 which can produce a charge-transporting thin film having a high refractive index, transparency, and excellent charge-transporting properties with good reproducibility.

Means for solving the problems

The present inventors have made extensive studies to achieve the above object, and as a result, have found that: a charge-transporting varnish comprising a charge-transporting substance, titanium oxide-containing particles surface-modified with a surface treatment agent, and an organic solvent, whereby a charge-transporting thin film having excellent flatness, high refractive index, transparency, and charge-transporting properties can be obtained with good reproducibility; and when the film was applied to an organic EL element, excellent luminance characteristics could be achieved, and the present invention was completed.

Namely, the present invention provides the following charge-transporting varnish.

1. A charge-transporting varnish characterized by comprising: a charge transporting substance, titanium oxide-containing particles surface-modified with a surface treatment agent, and an organic solvent.

2. The charge-transporting varnish according to claim 1, wherein the titanium oxide-containing particles contained in the titanium oxide-containing particles surface-modified with the surface-treating agent are colloidal particles.

3. The charge-transporting varnish according to claim 2, wherein the titanium oxide-containing particles surface-modified with the surface-treating agent are colloidal particles (D) (surface-modified colloidal particles (D)) surface-modified with an amphiphilic surface-treating agent, the colloidal particles (D)) having a core (core particle (A)) of colloidal particles (A) containing titanium oxide and having a surface thereof coated with metal oxide colloidal particles (B) (coating (B)) and having a surface thereof coated with metal oxide colloidal particles (C) (modified colloidal particles (C)).

4. The charge-transporting varnish according to claim 1 or 2, wherein the surface treatment agent is an amphiphilic surface treatment agent.

5. The charge-transporting varnish according to claim 3 or 4, wherein the amphiphilic surface treatment agent is an organic silicon compound, a titanate coupling agent, an aluminate coupling agent or a phosphorus surfactant.

6. The charge-transporting varnish according to any one of claims 1 to 5, wherein the charge-transporting substance is a polythiophene derivative having a repeating unit represented by formula (1) or an amine adduct thereof.

[ solution 1]

(in the formula, R¹And R²Independently of each other, a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, a fluoroalkoxy group having 1 to 40 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, -O- [ Z-O ]]_p-R^eOr a sulfonic acid group, or is R¹And R²a-O-Y-O-formed by bonding, wherein Y is a C1-40 alkylene group which may be substituted with a sulfonic acid group and may contain an ether bond, Z is a C1-40 alkylene group which may be substituted with a halogen atom, p is an integer of 1 or more, and R is^eIs a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms. )

7. The charge-transporting varnish as claimed in any one of claims 1 to 6, wherein R is¹Is a sulfonic acid group, the above R²Is C1-40 alkoxy or-O- [ Z-O]_p-R^eOr is the above-mentioned R¹And R²Bonded to form-O-Y-O-.

8. The charge transporting varnish according to any one of claims 1 to 7, further comprising a heteropoly acid.

9. The charge-transporting varnish according to claim 8, wherein the heteropoly acid is phosphotungstic acid.

10. A charge-transporting film obtained from the charge-transporting varnish described in any one of 1 to 9.

11. An organic electroluminescent element comprising the charge-transporting thin film of claim 10.

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

13. A method for producing a charge-transporting film, comprising applying the charge-transporting varnish according to any one of claims 1 to 9 onto a substrate and evaporating a solvent.

14. A method for producing an organic electroluminescent element, which comprises using the charge-transporting thin film described in claim 13.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the charge-transporting varnish of the present invention, a charge-transporting thin film having excellent flatness, a high refractive index (high n) and transparency (low extinction coefficient k), and excellent charge-transporting properties can be obtained.

By applying the charge-transporting thin film of the present invention to a hole injection layer or a hole transport layer, preferably a hole injection layer, of an organic EL device, an organic EL device exhibiting excellent luminance characteristics can be realized.

The charge-transporting varnish of the present invention can produce a thin film having excellent charge-transporting properties with good reproducibility even when various wet processes capable of forming a film over a large area, such as a spin coating method and an ink jet method, are used, and therefore can sufficiently cope with the recent progress in the field of organic EL devices.

Detailed Description

The present invention will be described in more detail below.

The charge-transporting varnish of the present invention comprises: a charge transporting material, titanium oxide-containing particles surface-modified with a surface treatment agent (hereinafter, sometimes referred to as surface-modified titanium oxide-containing particles), and an organic solvent.

In the present invention, "solid component" related to the charge-transporting varnish of the present invention means a component other than a solvent contained in the varnish. The charge transport property is synonymous with conductivity and also synonymous with hole transport property. The charge-transporting varnish of the present invention may have charge-transporting properties, or a solid film obtained by using the varnish may have charge-transporting properties.

The charge-transporting substance used in the present invention is not particularly limited, and can be suitably selected from charge-transporting compounds, charge-transporting oligomers, charge-transporting polymers, and the like used in the field of organic EL and the like.

Specific examples thereof include aryl amine derivatives such as oligoaniline derivatives, N '-diarylbenzidine derivatives, and N, N' -tetraarylbenzidine derivatives, thiophene derivatives such as oligothiophene derivatives, thienothiophene derivatives, and thienobenzothiophene derivatives, various charge-transporting compounds such as pyrrole derivatives such as oligopyrroles, charge-transporting oligomers, polythiophene derivatives, polyaniline derivatives, and charge-transporting polymers such as polypyrrole derivatives, and polythiophene derivatives are particularly preferable.

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

[ solution 2]

In the formula, R¹And R²Independently of each other, a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, a fluoroalkoxy group having 1 to 40 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, -O- [ Z-O ]]_p-R^eOr a sulfonic acid group, or is R¹And R²a-O-Y-O-formed by bonding, wherein Y is C1-40 alkylene group which may contain ether bond and may be substituted by sulfonic group, Z is C1-40 alkylene group which may be substituted by halogen atom, p is an integer of 1 or more, R is^eIs a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

Examples of the alkyl group having 1 to 40 carbon atoms include a straight chain, a branched chain and a cyclic group, and examples thereof include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, a n-hexyl group, a n-heptyl group, a n-octyl group, a n-nonyl group, a n-decyl group, a n-undecyl group, a n-dodecyl group, a n-tridecyl group, a n-tetradecyl group, a n-pentadecyl group, a n-hexadecyl group, a n-heptadecyl group, a n-octadecyl group, a n-nonadecyl group, a n-eicosyl group, a docosyl group, a triacontyl group and a forty-alkyl group. In the present invention, the alkyl group having 1 to 18 carbon atoms is preferable, and the alkyl group having 1 to 8 carbon atoms is more preferable.

The fluoroalkyl group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 40 carbon atoms in which at least 1 hydrogen atom on a carbon atom is substituted with a fluorine atom, and examples thereof include a fluoromethyl group, a difluoromethyl group, a perfluoromethyl group, a 1-fluoroethyl group, a 2-fluoroethyl group, a 1, 2-difluoroethyl group, a 1, 1-difluoroethyl group, a 2, 2-difluoroethyl group, a 1, 1, 2-trifluoroethyl group, a 1, 2, 2-trifluoroethyl group, a 2, 2, 2-trifluoroethyl group, a 1, 1, 2, 2-tetrafluoroethyl group, a perfluoroethyl group, a 1-fluoropropyl group, a 2-fluoropropyl group, a 3-fluoropropyl group, a 1, 1-difluoropropyl group, a 1, 2-difluoropropyl group, a 2, 2-difluoropropyl group, a perfluoroethyl group, a 1-fluoropropyl group, a 2-fluoropropyl group, a 3-fluoropropyl group, 2, 3-difluoropropyl group, 3, 3-difluoropropyl group, 1, 2-trifluoropropyl group, 1, 3-trifluoropropyl group, 1, 2, 3-trifluoropropyl group, 1, 3, 3-trifluoropropyl group, 2, 2, 3-trifluoropropyl group, 2, 3, 3-trifluoropropyl group, 3, 3, 3-trifluoropropyl group, 1, 2, 2-tetrafluoropropyl group, 1, 2, 3-tetrafluoropropyl group, 1, 2, 2, 3-tetrafluoropropyl group, 1, 3, 3, 3-tetrafluoropropyl group, 2, 2, 3, 3-tetrafluoropropyl group, 1, 2, 2, 3-pentafluoropropyl group, 1, 2, 2, 3, 3-pentafluoropropyl group, 1, 3, 3, 3-pentafluoropropyl group, 1, 2, 3, 3, 3-pentafluoropropyl, 2, 3, 3, 3-pentafluoropropyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl, and perfluorooctyl.

Examples of the alkyl group having 1 to 40 carbon atoms include a straight-chain, branched or cyclic alkyl group, and examples thereof include a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a c-propoxy group, a n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a n-pentoxy group, a n-hexoxy group, a n-heptoxy group, a n-octoxy group, a n-nonoxy group, a n-decoxy group, a n-undecoxy group, a n-dodecoxy group, a n-tridecoxy group, a n-tetradecoxy group, a n-pentadecoxy group, a n-hexadecoxy group, a n-heptadecoxy group, a n-octadecanoxy group, a n-nonalkoxy group and a n-eicosoxy group.

The fluoroalkoxy group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkoxy group having 1 to 40 carbon atoms in which at least one hydrogen atom on a carbon atom is replaced with a fluorine atom, and examples thereof include fluoromethoxy, difluoromethoxy, perfluoromethoxy, 1-fluoroethoxy, 2-fluoroethoxy, 1, 2-difluoroethoxy, 1-difluoroethoxy, 2, 2-difluoroethoxy, 1, 2-trifluoroethoxy, 1, 2, 2-trifluoroethoxy, 2, 2, 2-trifluoroethoxy, 1, 2, 2-tetrafluoroethoxy, 1, 2, 2, 2-tetrafluoroethoxy, perfluoroethoxy, 1-fluoropropoxy, 2-fluoropropoxy, 3-fluoropropoxy, 1-difluoropropoxy, 1, 2-difluoropropoxy, etc, 1, 3-difluoropropoxy group, 2, 2-difluoropropoxy group, 2, 3-difluoropropoxy group, 3, 3-difluoropropoxy group, 1, 2-trifluoropropoxy group, 1, 3-trifluoropropoxy group, 1, 2, 3-trifluoropropoxy group, 1, 3, 3-trifluoropropoxy group, 2, 2, 3-trifluoropropoxy group, 2, 3, 3-trifluoropropoxy group, 1, 2, 2-tetrafluoropropoxy group, 1, 2, 3-tetrafluoropropoxy group, 1, 2, 2, 3-tetrafluoropropoxy group, 1, 3, 3, 3-tetrafluoropropoxy group, 2, 2, 3, 3-tetrafluoropropoxy group, 1, 2, 2, 3-pentafluoropropoxy group, 1, 2, 3-pentafluoropropoxy group, 2, 3-fluoropropoxy group, 1, 2, 2, 3, 3-pentafluoropropoxy, 1, 3, 3, 3-pentafluoropropoxy, 1, 2, 3, 3, 3-pentafluoropropoxy, 2, 2, 3, 3, 3-pentafluoropropoxy, and perfluoropropoxy.

Examples of the alkylene group having 1 to 40 carbon atoms include straight-chain, branched-chain and cyclic alkylene groups, and examples thereof include a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, a pentadecylene group, a hexadecylene group, a heptadecylene group, an octadecylene group, a nonadecylene group and an eicosylene group.

Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group, with a phenyl group, a tolyl group, and a naphthyl group being preferred.

Examples of the aryloxy group having 6 to 20 carbon atoms include a phenoxy group, an anthracenoxy group, a naphthoxy group, a phenanthrenoxy group and a fluorenyloxy group.

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

In the above formula (1), R¹And R²Independently of each other, a hydrogen atom, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, -O [ C (R)^aR^b)-C(R^cR^d)-O]_p-R^e、-OR^fOr a sulfonic acid group, or R¹And R²Bonded to form-O-Y-O-.

R^a～R^dIndependently represent a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and specific examples thereof are the same as those listed above.

Wherein R is^a～R^dIndependently of each other, a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a phenyl group is preferable.

R^eIs a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a phenyl group, preferably a hydrogen atom, a methyl group, a propyl group, or a butyl group.

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

R^fIs hydrogen atom, alkyl group having 1 to 40 carbon atoms, fluoroalkyl group having 1 to 40 carbon atoms or aryl group having 6 to 20 carbon atoms, preferably hydrogen atom, alkyl group having 1 to 8 carbon atoms, fluoroalkyl group having 1 to 8 carbon atoms or phenyl group, more preferably-CH₂CF₃。

In the present invention, R¹Preferably a hydrogen atom or a sulfonic acid group, more preferably a sulfonic acid group, and R²Preferably alkoxy group having 1 to 40 carbon atoms or-O- [ Z-O ]]_p-R^eMore preferably-O [ C (R)^aR^b)-C(R^cR^d)-O]_p-R^eOR-OR^fFurther preferred is-O [ C (R)^aR^b)-C(R^cR^d)-O]_p-R^e、-O-CH₂CH₂-O-CH₂CH₂-O-CH₃、-O-CH₂CH₂-O-CH₂CH₂-OH or-O-CH₂CH₂-OH, or is R¹And R²and-O-Y-O-formed by bonding to each other.

For example, a preferred embodiment of the present invention relates to the above polythiophene derivative comprising R¹Is sulfonic acid group, R²Is a repeating unit other than the sulfonic acid group or contains R¹And R²Is bonded toThe repeating unit of the formed-O-Y-O-.

Preferably, the polythiophene derivative contains R¹Is sulfonic acid group, R²Is C1-40 alkoxy or-O- [ Z-O]_p-R^eOr contains a repeating unit of R ¹And R²A repeating unit of-O-Y-O-formed by bonding.

More preferably, the polythiophene derivative described above contains R¹Is sulfonic acid group, R²is-O [ C (R)^aR^b)-C(R^cR^d)-O]_p-R^eOR-OR^fThe repeating unit of (1).

Further preferably, the polythiophene derivative contains R¹Is sulfonic acid group, R²is-O [ C (R)^aR^b)-C(R^cR^d)-O]_p-R^eOr contains a repeating unit of R¹And R²A repeating unit of-O-Y-O-formed by bonding.

Further preferably, the polythiophene derivative contains R¹Is sulfonic acid group, R²is-O-CH₂CH₂-O-CH₂CH₂-O-CH₃、-O-CH₂CH₂-O-CH₂CH₂-OH, or-O-CH₂CH₂-OH, or comprising R¹And R²And repeating units bonded to each other and each of which is a group represented by the following formulae (Y1) and (Y2).

[ solution 3]

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

[ solution 4]

In addition, as the preferred structure of the polythiophene derivative, for example, a polythiophene derivative having a structure represented by the following formula (1a) can be cited. In the following formulae, the units may be bonded randomly or as a block polymer.

[ solution 5]

Wherein a to d represent the molar ratio of each unit, and satisfy 0. ltoreq. a.ltoreq.1, 0. ltoreq. b.ltoreq.1, 0. ltoreq. a + b.ltoreq.1, 0. ltoreq. c.ltoreq.1, 0. ltoreq. d.ltoreq.1, and a + b + c + d.ltoreq.1.

Further, the above polythiophene derivative may be a homopolymer or a copolymer (statistically, including random, gradient and block copolymers). As the polymer containing the monomer A and the monomer B, the block copolymer includes, for example, an A-B diblock copolymer, an A-B-A triblock copolymer, and (AB)_m-a multiblock copolymer. Polythiophenes can also comprise repeating units derived from other types of monomers (e.g., thienothiophenes, selenophenes, pyrroles, furans, tellurothiophenes, anilines, arylamines, and arylenes (e.g., phenylene, phenylenevinylene, fluorene, and the like).

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

In the present invention, the polymer formed may contain repeating units derived from impurities depending on the purity of the initial monomers used in the polymerization. In the present invention, the above-mentioned term "homopolymer" means a polymer comprising a repeating unit derived from 1 monomer, and may comprise a repeating unit derived from impurities. In the present invention, the polythiophene derivative is preferably a polymer in which substantially all of the repeating units are repeating units represented by the formula (1), and more preferably a polymer including at least one of repeating units represented by the formulae (1-1) to (1-5).

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

Examples of the amine compound that can be used for forming the amine adduct include monoalkylamine compounds such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, and n-eicosylamine; primary amine compounds such as monoarylamine compounds including aniline, toluidine, 1-naphthylamine, 2-naphthylamine, 1-anthracenylamine, 2-anthracenylamine, 9-anthracenylamine, 1-phenanthrenylamine, 2-phenanthrenylamine, 3-phenanthrenylamine, 4-phenanthrenylamine, and 9-phenanthrenylamine; n-ethylmethylamine, N-methyl-N-propylamine, N-methylisopropylamine, N-methyl-N-butylamine, N-methyl-sec-butylamine, N-methyl-tert-butylamine, N-methyl-isobutylamine, diethylamine, N-ethyl-N-propylamine, N-ethyl-isopropylamine, N-ethyl-N-butylamine, N-ethyl-tert-butylamine, dipropylamine, N-N-propylisopropylamine, N-N-propyl-N-butylamine, N-N-propylsec-butylamine, diisopropylamine, N-N-butylisopropylamine, N-tert-butylisopropylamine, di (N-butyl) amine, di (sec-butyl) amine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2-dimethylaziridine, azetidine (trimethyleneimine), Dialkylamine compounds such as 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2, 5-dimethylpyrrolidine, piperidine, 2, 6-dimethylpiperidine, 3, 5-dimethylpiperidine, 2, 2, 6, 6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, and octamethyleneimine; diarylamine compounds such as diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1 ' -dinaphthylamine, 2 ' -dinaphthylamine, 1, 2 ' -dinaphthylamine, carbazole, 7H-benzo [ c ] carbazole, 11H-benzo [ a ] carbazole, 7H-dibenzo [ c, g ] carbazole, and 13H-dibenzo [ a, i ] carbazole; secondary amine compounds such as alkylaryl amine compounds including N-methylaniline, N-ethylaniline, N-N-propylaniline, N-isopropylaniline, N-N-butylaniline, N-tert-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, N-N-propyl-1-naphthylamine, indoline, isoindoline, 1, 2, 3, 4-tetrahydroquinoline, and 1, 2, 3, 4-tetrahydroisoquinoline; n, N-dimethylethylamine, N-dimethyl-N-propylamine, N-dimethylisopropylamine, N-dimethyl-N-butylamine, N-dimethyl-sec-butylamine, N-dimethyl-tert-butylamine, N-dimethyl-isobutylamine, N-diethylmethylamine, N-methyldi (N-propyl) amine, N-methyldiisopropylamine, N-methyldi-butylamine, N-methyldi (N-butyl) amine, N-methyldi-isobutylamine, triethylamine, N-diethyl-N-butylamine, N-diisopropylethylamine, N, trialkylamine compounds such as N-di (N-butyl) ethylamine, tri (N-propyl) amine, tri (isopropyl) amine, tri (N-butyl) amine, tri (isobutyl) amine, 1-methylazetidine, 1-methylpyrrolidine, and 1-methylpiperidine; triarylamine compounds such as triphenylamine; alkyl diarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole and 9-ethylcarbazole; tertiary amine compounds such as dialkylarylamine compounds such as N, N-diethylaniline, N-di (N-propyl) aniline, N-di (isopropyl) aniline, and N, N-di (N-butyl) aniline are preferably tertiary amine compounds, more preferably trialkylamine compounds, and still more preferably triethylamine, in consideration of the balance between the solubility of the amine adduct and the charge transporting property of the obtained charge transporting film.

The amine adduct can be obtained by adding the polythiophene derivative to the amine itself or a solution thereof and sufficiently stirring the mixture.

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

In some of the repeating units constituting the polythiophene derivative or the amine adduct thereof, the chemical structure thereof may be an oxidized structure called "quinoid structure (キノイド structure)". The term "quinoid structure" is used in relation to the term "benzene-type structure (ベンゼノイド structure)", and the former means a structure in which a double bond in an aromatic ring is moved out of the ring (as a result, the aromatic ring disappears) and 2 exocyclic double bonds conjugated to the remaining double bonds remaining in the ring are formed in relation to the latter structure comprising an aromatic ring. The relationship between these two structures can be easily understood by those skilled in the art from the relationship between the structures of benzoquinone and hydroquinone. The quinoid structure of the repeating units for various conjugated polymers is well known to those skilled in the art. As an example, a quinoid structure corresponding to a repeating unit of a polythiophene derivative including a repeating unit represented by the above formula (1) is shown in the following formula (1').

[ solution 6]

(in the formula, R¹And R²As defined in the above formula (1). )

This quinoid structure is produced by a process in which a polythiophene derivative containing a repeating unit represented by the above formula (1) is subjected to an oxidation reaction by a dopant, a so-called doping reaction, and forms a part of structures called a "polaron structure" and a "bipolarin structure" which impart charge transportability to the polythiophene derivative. These structures are well known. In the production of an organic EL element, the introduction of a "polaron structure" and/or a "bipolarin structure" is essential, and in practice, the doping reaction described above is intentionally caused and achieved when a thin film made of a charge-transporting varnish is subjected to a firing treatment in the production of an organic EL element. Consider that: the reason why the polythiophene derivative before the doping reaction has a quinoid structure is that the polythiophene derivative causes an unintentional oxidation reaction in the production process (particularly, in the sulfonation step) equivalent to the doping reaction.

There is a correlation between the amount of the quinoid structure contained in the above polythiophene derivative and the solubility and dispersibility of the polythiophene derivative in an organic solvent, and if the amount of the quinoid structure is increased, the solubility and dispersibility thereof tend to be lowered. Therefore, the introduction of the quinoid structure after forming a thin film from the charge-transporting varnish does not cause a problem, and if the quinoid structure is excessively introduced into the polythiophene derivative by the above-mentioned unintentional oxidation reaction, there is a case where the production of the charge-transporting varnish is hindered. Among polythiophene derivatives, it is known that the solubility and dispersibility in an organic solvent fluctuate, and one of the causes thereof is that the amount of the quinoid structure introduced into polythiophene fluctuates depending on the difference in the production conditions of the respective polythiophene derivatives due to the above-mentioned unintentional oxidation reaction.

Therefore, if the polythiophene derivative is subjected to reduction treatment using a reducing agent, even if the quinoid structure is excessively introduced into the polythiophene derivative, the quinoid structure is reduced by the reduction, and the solubility and dispersibility of the polythiophene derivative in an organic solvent are improved, so that it is possible to stably produce a good charge-transporting varnish that produces a thin film having excellent homogeneity.

The conditions of the reduction treatment are not particularly limited as long as the quinoid structure can be reduced and appropriately converted into a non-oxidized structure, that is, the benzene-type structure (for example, in the polythiophene derivative including the repeating unit represented by the formula (1), the quinoid structure represented by the formula (1') is converted into a structure represented by the formula (1)), and the treatment can be performed by simply contacting the polythiophene derivative or the amine adduct with a reducing agent in the presence or absence of an appropriate solvent, for example.

Such a reducing agent is not particularly limited as long as it is appropriately reduced, and for example, ammonia water, hydrazine, or the like, which is easily available as a commercially available product, is suitable.

The amount of the reducing agent varies depending on the amount of the reducing agent used, and therefore cannot be generally specified, and is usually 0.1 parts by mass or more in view of appropriately performing the reduction, and 10 parts by mass or less in view of not leaving an excessive amount of the reducing agent, based on 100 parts by mass of the polythiophene derivative or the amine adduct to be treated.

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

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

The solubility and dispersibility of the polythiophene derivative or its amine adduct in the solvent change by the reduction treatment, and as a result, the polythiophene derivative or its amine adduct, which is insoluble in the reaction system at the start of the treatment, may be dissolved at the completion of the treatment. In such a case, the polythiophene derivative or its amine adduct can be recovered by a method such as adding the polythiophene derivative or its amine adduct and an incompatible organic solvent (acetone, isopropyl alcohol, or the like in the case of sulfonated polythiophene) to the reaction system, producing a precipitate of the polythiophene derivative or its amine adduct, and filtering.

The weight average molecular weight of the polythiophene derivative containing the repeating unit represented by the formula (1) or the amine adduct thereof is preferably about 1000 to 1000000, more preferably about 5000 to 100000, and further preferably about 10000 to 50000. By setting the weight average molecular weight to be not less than the lower limit, good conductivity is obtained with good reproducibility, and by setting the weight average molecular weight to be not more than the upper limit, solubility in a solvent is improved. The weight average molecular weight is a polystyrene equivalent value obtained by gel permeation chromatography.

The polythiophene derivative or its amine adduct contained in the charge-transporting varnish of the present invention may be 1 type alone or 2 or more types of polythiophene derivatives or its amine adducts containing the repeating unit represented by the formula (1).

Further, as the polythiophene derivative containing the repeating unit represented by the formula (1), a commercially available product may be used, and a product obtained by polymerization by a known method using a thiophene derivative or the like as a starting material may be used, and in any case, a product purified by a method such as reprecipitation or ion exchange is preferably used. By using the purified product, the characteristics of an organic EL element provided with a thin film obtained from the charge-transporting varnish of the present invention can be further improved.

The sulfonation of conjugated polymers and sulfonated conjugated polymers (including sulfonated polythiophenes) are described in U.S. Pat. No. 8017241 to Seshadri et al. Sulfonated polythiophenes are described in international publication No. 2008/073149 and international publication No. 2016/171935.

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

In the present invention, as the charge transporting substance, a polythiophene derivative containing a repeating unit represented by the formula (1) or an amine adduct thereof may be used in combination with a charge transporting substance composed of a charge transporting compound other than the polythiophene derivative containing a repeating unit represented by the formula (1) or an amine adduct thereof.

The content of the charge-transporting substance in the charge-transporting varnish of the present invention is suitably determined in the range of 0.05 to 40 mass%, preferably 0.1 to 35 mass% in the solid content, in general, in consideration of a desired film thickness, viscosity of the varnish, and the like.

The charge-transporting varnish of the present invention contains surface-modified titanium oxide-containing particles. The titanium oxide contained in the particles may have any crystal structure of anatase type, rutile type, anatase-rutile mixed type, and brookite type, and among these, the rutile type is preferably contained in consideration of the refractive index and transparency of the resulting thin film.

In the present invention, the titanium oxide-containing particles contained in the surface-modified titanium oxide-containing particles are preferably colloidal particles, and more preferably: colloidal particles (D) (hereinafter, referred to as surface-modified colloidal particles (D)) in which the surfaces of modified titanium oxide-containing colloidal particles (C) (hereinafter, referred to as modified colloidal particles (C)) having titanium oxide-containing colloidal particles (a) as cores (hereinafter, referred to as core particles (a)) and surfaces of modified titanium oxide-containing colloidal particles (C) (hereinafter, referred to as coating materials (B)) are surface-modified with an amphiphilic surface-treating agent.

The core particle (a) can be produced by a known method such as an ion exchange method, a gel decomposition method, a hydrolysis method, or a reaction method. Examples of the ion exchange method include a method in which an acid salt of Ti is treated with a hydrogen-type ion exchange resin, and a method in which a basic salt thereof is treated with a hydroxyl-type anion exchange resin. Examples of the dispergation method include a method of neutralizing an acid salt of Ti with a base, and a method of washing a gel obtained by neutralizing a basic salt thereof with an acid and dispergating the gel with an acid or a base. Examples of the hydrolysis method include a method of hydrolyzing an alkoxide of Ti, and a method of hydrolyzing a basic salt thereof under heating and then removing an unnecessary acid. An example of the reaction method is a method of reacting a powder of Ti with an acid.

The core particles (a) may contain an oxide of a metal other than Ti within a range not to impair the effects of the present invention. Examples of such metal oxides include oxides of at least 1 metal selected from Al, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, In, Sn, Sb, Ba, Hf, Ta, W, Pb, Bi, and Ce. Among these metal oxides, tin oxide (SnO) is preferable₂)。

The content of the oxide of a metal other than Ti in the core particles (a) (metal oxide equivalent) is preferably 25 mass% or less, and more preferably 20 mass% or less, in the metal oxide, in consideration of the refractive index and transparency of the obtained thin film. The lower limit is not particularly limited, and may be 0 mass%, but is preferably 0.1 mass% or more, more preferably 5 mass% or more, in view of easy availability of the rutile-type titanium oxide.

The core particles (a) can be synthesized, for example, by the method described in international publication No. 2013/081136.

The coating (B) is metal oxide colloidal particles, and does not contain titanium oxide (TiO) as a metal oxide₂) This point of (a) is different from the above-mentioned core particle (a). However, "titanium oxide (TiO) -free" in this case ₂) ", e.g. not negatedIs the presence of titanium oxide that the impurities may contain.

The metal oxide used in the coating (B) is preferably colloidal particles of an oxide of at least 1 metal selected from Si, Al, Sn, Zr, Mo, Sb, and W. The coating (B) may be, for example, SiO as a form of the metal oxide₂、Al₂O₃、SnO₂、ZrO₂、MoO₃、Sb₂O₅、WO₃And the like. These metal oxides may be used alone or in combination. Examples of the method of combining the metal oxides include a method of mixing a plurality of kinds of the metal oxides, a method of compounding the metal oxides, and a method of solid-dissolving the metal oxides at an atomic level.

For example, SnO₂Particles and WO₃SnO wherein particles are chemically bonded to each other at their interface to form a composite₂-WO₃Composite colloidal particles, SnO₂Particles and SiO₂SnO wherein particles are chemically bonded to each other at their interface to form a composite₂-SiO₂Composite colloidal particles, SnO₂Particles and WO₃Particles and SiO₂SnO wherein particles are chemically bonded to each other at their interface to form a composite₂-WO₃-SiO₂Composite colloidal particles, SnO₂Particles and MoO₃Particles and SiO₂SnO wherein particles are chemically bonded to each other at their interface to form a composite₂-MoO₃-SiO₂Composite colloidal particles, Sb₂O₅Particles and SiO ₂Sb having particles chemically bonded to each other at their interface and having a composite structure₂O₅-SiO₂Composite colloidal particles.

When colloidal particles containing a plurality of metal oxides are used as the coating material (B), the ratio (mass ratio) of the metal oxides to be contained is not particularly limited, and for example, SnO₂-SiO₂In the composite colloidal particles, SiO₂/SnO₂The mass ratio of (A) to (B) is preferably 0.1 to 5, in Sb₂O₅-SiO₂In the composite colloidal particles, Sb₂O₅/SiO₂Has excellent mass ratioSelecting 0.1-5.

The coating (B) can be produced by a known method such as an ion exchange method or an oxidation method. Examples of the ion exchange method include a method in which an acid salt of the metal is treated with a hydrogen-type ion exchange resin. As an example of the oxidation method, a method of reacting a powder of the above metal or the above metal oxide with hydrogen peroxide can be cited.

The modified colloidal particles (C) can be obtained by mixing the core particles (a) and the coating material (B) at an appropriate ratio and heating for a predetermined time. The mixing ratio of the core particles (a) to the coating material (B) is preferably 0.05 to 0.5 in terms of a mass ratio (metal oxide equivalent) represented by (B)/(a).

The heating temperature for mixing the core particles (A) and the coating (B) is usually 1 to 100 ℃, preferably 20 to 60 ℃. The heating temperature after mixing is preferably 70 to 350 ℃, and more preferably 70 to 150 ℃. The heating time after the mixing is usually 10 minutes to 5 hours, preferably 30 minutes to 4 hours.

The modified colloidal particles (C) can be usually prepared as an aqueous dispersion by, for example, the methods 1 and 2 described in international publication No. 2017/170275.

The aqueous dispersion of the modified colloidal particles (C) may contain other optional components within a range not impairing the effects of the present invention. In particular, by containing hydroxycarboxylic acids, the dispersibility and other properties of the modified colloidal particles (C) can be further improved. Examples of the hydroxycarboxylic acid include lactic acid, tartaric acid, citric acid, gluconic acid, malic acid, and glycolic acid. The content of the hydroxycarboxylic acid is preferably about 30% by mass or less based on the total metal oxide of the modified colloidal particles (C).

The dispersion of the modified colloidal particles (C) may contain an alkali component. Examples of the alkali component include alkali metal hydroxides such as Li, Na, K, Rb, and Cs; primary to tertiary alkylamines such as ammonia, ethylamine, isopropylamine, n-propylamine, n-butylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, tripentylamine, tri-n-hexylamine, tri-n-octylamine, dimethylpropylamine, dimethylbutylamine, and dimethylhexylamine; aralkyl amines such as benzylamine and dimethylbenzylamine; alicyclic amines such as piperidine; alkanolamines such as monoethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and the like. These can be used alone in 1, can also be more than 2 combination use. The content of the alkali component is preferably about 30% by mass or less with respect to the total metal oxide of the modified colloidal particles (C). These alkali components can be used in combination with the hydroxycarboxylic acid.

When the concentration of the aqueous dispersion of the modified colloidal particles (C) is further increased, the concentration can be increased to about 65% by mass at the maximum by a conventional method. Examples of the method include an evaporation method and an ultrafiltration method. When the pH of the aqueous dispersion is to be adjusted, the above-mentioned alkali metal hydroxide, amine, quaternary ammonium salt, hydroxycarboxylic acid, or the like may be added.

In the present invention, the total metal oxide concentration of the solvent dispersion of the modified colloidal particles (C) is preferably 10 to 60 mass%, more preferably 20 to 50 mass%.

The aqueous dispersion of the modified colloidal particles (C) is subjected to replacement of the aqueous medium with a hydrophilic organic solvent to obtain an organic solvent dispersion. The substitution can be carried out by a usual method such as distillation or ultrafiltration. Examples of the hydrophilic organic solvent include lower alcohols such as methanol, ethanol, isopropanol and 1-propanol, ethers such as propylene glycol monomethyl ether, linear amides such as dimethylformamide and N, N' -dimethylacetamide, cyclic amides such as N-methyl-2-pyrrolidone, ethyl cellosolve and glycols such as ethylene glycol.

The surface-modified colloidal particles (D) are preferably surface-modified with an amphiphilic surface treatment agent on the surface of the modified colloidal particles (C), more preferably surface-modified with an amphiphilic surface treatment agent having at least 1 selected from polyoxyethylene groups, polyoxypropylene groups, and polyoxybutenyl groups as hydrophilic groups and at least 1 selected from alkylene groups and vinylene groups having 1 to 18 carbon atoms as hydrophobic groups, and still more preferably an amphiphilic silicone compound having at least 1 selected from polyoxyethylene groups, polyoxypropylene groups, and polyoxybutenyl groups as hydrophilic groups and at least 1 selected from alkylene groups and vinylene groups having 1 to 18 carbon atoms as hydrophobic groups is bonded to the surface of the modified colloidal particles (C).

Another preferable embodiment of the surface-modified titanium oxide-containing particles includes colloidal particles in which the surfaces of the core particles (a) are surface-modified with an amphiphilic surface treatment agent.

As the surface treatment agent, an amphiphilic surface treatment agent is preferable if it is considered to improve the dispersibility of the particles in the varnish. In the present invention, as the amphiphilic surface treatment agent, for example, an organic silicon compound, a titanate coupling agent, an aluminate coupling agent, and a phosphorus-based surfactant can be preferably used, and an organic silicon compound is more preferred. Of these, more preferred are amphiphilic surface-treating agents having 1 or more species selected from polyoxyethylene groups, polyoxypropylene groups and polyoxybutenyl groups as hydrophilic groups and 1 or more species selected from alkylene groups or vinylene groups having 1 to 18 carbon atoms as hydrophobic groups.

The hydrophilic group is preferably polyoxyethylene, polyoxypropylene or polyoxybutenyl, and the amphiphilic organosilicon compound 1 contains 3 to 40 moles per molecule.

Examples of the alkylene group having 1 to 18 carbon atoms which may be straight-chain, branched-chain or cyclic include methylene, ethylene, n-propylene, isopropylene, cyclopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, cyclobutylene, 1-methylcyclopropylene, 2-methylcyclopropylene, n-pentylene, 1-methyln-butylene, 2-methyln-butylene, 3-methyln-butylene, 1-dimethyln-propylene, 1, 2-dimethyln-propylene, 2-dimethyln-propylene, 1-ethyln-propylene, cyclopentylene, 1-methylcyclobutylene, 2-methylcyclobutylene, 3-methylcyclobutylene, 1, 2-dimethylcyclopropylene, 2, 3-dimethylcyclopropylene, 1-ethylcyclopropylene, 2-ethylcyclopropylene, n-hexylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-pentylene, 4-methyl-n-pentylene, 1-dimethyln-butylene, 1, 2-dimethyln-butylene, 1, 3-dimethyln-butylene, 2, 2-dimethyln-butylene, 2, 3-dimethyln-butylene, 3-dimethyln-butylene, 1-ethyln-butylene, 2-ethyln-butylene, 1, 2-trimethyln-propylene, 1, 2, 2-trimethyln-propylene, 1-ethyl-1-methyl-n-propylene, 1-ethyl-2-methyl-n-propylene, n-heptylene, n-octylene, N-nonylene, cyclohexylene, 1-methylcyclopentylene, 2-methylcyclopentylene, 3-methylcyclopentylene, 1-ethylcyclobutyl, 2-ethylcyclobutyl, 3-ethylcyclobutyl, 1, 2-dimethylcyclobutyl, 1, 3-dimethylcyclobutyl, 2, 2-dimethylcyclobutyl, 2, 3-dimethylcyclobutyl, 2, 4-dimethylcyclobutyl, 3-dimethylcyclobutyl, 1-n-propylcyclopropylene, 2-n-propylcyclopropylene, 1-isopropylcyclopropylene, 2-isopropylcyclopropylene, 1, 2, 2-trimethylcyclopropylene, 1, 2, 3-trimethylcyclopropylene, 2, 2, 3-trimethylcyclopropylene, 1-ethyl-2-methylcyclopropylene, 2-ethyl-1-methylcyclopropylidene, 2-ethyl-2-methylcyclopropylidene and 2-ethyl-3-methylcyclopropylidene.

Examples of the amphiphilic organosilicon compound include methoxytriethoxypropyltrimethoxysilane, methoxytriethoxyoctyltrimethoxysilane, methoxytriethoxypropyltriethoxysilane, methoxytriethoxypropyltripropoxysilane, methoxytriethoxypropyltriacetoxysilane, methoxytripropoxypropyltrimethoxysilane, methoxytripropoxyoctyltrimethoxysilane, methoxytripropoxypropyltriethoxysilane, methoxytripropoxypropyltripropoxysilane, methoxytripropoxypropyltriethoxysilane, methoxytributoxybutylpropyltrimethoxysilane, methoxytributoxytropyltrimethoxysilane, methoxytributoxybutyloxytrimethoxysilane, methoxytributoxypropyltriethoxysilane, methoxytributoxybutylpropyltrimethoxysilane, methoxytributoxypropyltripropoxysilane, methoxytributoxypropyltrimethoxysilane, methoxytributoxyethyltrimethoxysilane, and the like, Methoxytributoxypropyltriacetoxysilane, methoxytriethylenepropyldimethoxymethylsilane, methoxytripropylenedimethoxymethylsilane, methoxytributoxybutyldimethylmethylsilane, methoxytriethylenepropyldiethoxymethylsilane, methoxytripropylenediethoxymethylsilane, methoxytributoxydiethoxymethylsilane, methoxytriethylenepropyldimethylmethoxysilane, methoxytripropylenepropyldimethylmethoxysilane, methoxytributylpropyldimethylethoxysilane, methoxytripropylenepropyldimethylethoxysilane, methoxytributylpropyldimethylethoxysilane, bis- (methoxytriethylenepropyl) dimethoxysilane, bis- (methoxytripropylenepropyl) dimethoxysilane, methoxytripropylenepropyl-dimethoxysilane, methoxybutylpropyldimethoxysilane, methoxybutylpropylenediethoxysilane, bis- (methoxytriethylenepropyl) dimethoxysilane, methoxybutylpropylenedimethylsilane, bis- (methoxytriethylenepropyl) dimethoxysilane, methoxybutylpropylenedimethylsilane, methoxydimethoxysilane, methoxytriethylenepropyl-dimethoxysilane, methoxysilylsilane, methoxybutylpropylenedimethylsilane, methoxysilane, methoxysilylsilane, and mixtures of, Bis- (methoxytributylpropyl) dimethoxysilane, [ methoxy (polyoxyethylene) n-propyl ] trimethoxysilane, [ methoxy (polyoxyethylene) n-propyl ] triethoxysilane, [ methoxy (polyoxyethylene) n-propyl ] tripropoxysilane, [ methoxy (polyoxyethylene) n-propyl ] triacetoxysilane, [ methoxy (polyoxypropylene) n-propyl ] trimethoxysilane, [ methoxy (polyoxypropylene) n-propyl ] triethoxysilane, [ methoxy (polyoxypropylene) n-propyl ] tripropoxysilane, [ methoxy (polyoxypropylene) n-propyl ] triacetoxysilane, [ methoxy (polyoxy-butylene) n-propyl ] trimethoxysilane, [ methoxy (polyoxy-butylene) n-propyl ] tripropoxysilane, [ methoxy (polyoxy-butylene) n-propyl ] triacetoxysilane, [ methoxy (polyoxyethylene) n-propyl ] dimethoxymethylsilane, [ methoxy (polyoxyethylene) n-propyl ] diethoxymethylsilane, [ methoxy (polyoxyethylene) n-propyl ] dipropoxymethylsilane, [ methoxy (polyoxyethylene) n-propyl ] diacetoxymethylsilane, [ methoxy (polyoxypropylene) n-propyl ] dimethoxymethylsilane, [ methoxy (polyoxypropylene) n-propyl ] diethoxymethylsilane, [ methoxy (polyoxypropylene) n-propyl ] dipropoxymethylsilane, [ methoxy (polyoxypropylene) n-propyl ] diacetoxymethylsilane, [ methoxy (polyoxybutylene) n-propyl ] dimethoxymethylsilane, [ methoxy (polyoxybutylene) n-propyl ] diethoxymethylsilane, [ methoxy (polyoxybutylene) n-propyl ] dipropoxymethylsilane, [ methoxy (polyoxybutylene) n-propyl ] diacetoxymethylsilane.

Specific examples of the amphiphilic titanate coupling agent and the amphiphilic aluminate coupling agent include プレンアクト manufactured by kojisu ファインテクノ (strain), and specific examples of the amphiphilic phosphorus-based surfactant include Disperbyk manufactured by byk chemical and フォスファノール manufactured by tokho chemical industry (strain), but are not limited thereto.

The amount of the amphiphilic surface modifier bonded to the surface of the modified colloidal particles (C) is preferably 0.1 to 30% by mass, more preferably 1 to 15% by mass, and still more preferably 1 to 10% by mass, based on the total metal oxide of the modified colloidal particles (C).

In the present invention, the surface-modified colloidal particles (D) can be obtained, for example, by adding a predetermined amount of an amphiphilic surface modifier having a hydrolyzable group, which is the aforementioned amphiphilic surface modifier, to an aqueous dispersion or a hydrophilic organic solvent dispersion of the modified colloidal particles (C), hydrolyzing the surface modifier with a catalyst such as dilute hydrochloric acid, and bonding the surface modifier to the surfaces of the modified colloidal particles (C).

The aqueous dispersion or hydrophilic organic solvent dispersion of the surface-modified titanium oxide-containing particles of the present invention can be further replaced with a hydrophobic organic solvent. The substitution method can be carried out by a general method such as distillation or ultrafiltration. Examples of the hydrophobic solvent include ketones such as methyl ethyl ketone and methyl isobutyl ketone, cyclic ketones such as cyclopentanone and cyclohexanone, and esters such as ethyl acetate and butyl acetate.

The organic solvent dispersion of surface-modified titanium oxide-containing particles of the present invention may contain other optional components within a range not impairing the effects of the present invention. In particular, by containing phosphoric acid, a phosphoric acid derivative, a phosphoric acid-based surfactant, a hydroxycarboxylic acid, or the like, the dispersibility of the surface-modified titanium oxide-containing particles can be further improved. Examples of the phosphoric acid derivative include phenylphosphonic acid and metal salts thereof. Examples of the phosphate surfactant include Disperbyk (manufactured by beck chemical company), フォスファノール (manufactured by tokyo chemical industries, ltd.), ニッコール (manufactured by solar chemical industries, ltd.), and the like. Examples of the hydroxycarboxylic acid include lactic acid, tartaric acid, citric acid, gluconic acid, malic acid, and glycolic acid. The content of these optional components is preferably about 30% by mass or less based on the total metal oxide of the surface-modified titanium oxide-containing particles.

The total metal oxide concentration of the organic solvent dispersion of the surface-modified titanium oxide-containing particles is preferably 10 to 60% by mass, more preferably 30 to 50% by mass, in view of the dispersion stability of the surface-modified titanium oxide-containing particles.

The primary particle diameters of the core particles (a), the coating material (B), the modified colloidal particles (C), and the surface-modified colloidal particles (D) are preferably in the following ranges in consideration of dispersion stability, refractive index, and transparency of the obtained thin film.

The primary particle diameter of the core particle (A) is preferably 1 to 60nm, preferably 2 to 30nm, and more preferably 2 to 20 nm.

The primary particle diameter of the coating (B) is preferably 5nm or less, more preferably 1 to 5nm, and still more preferably 1 to 4 nm.

The primary particle diameter of the modified colloidal particles (C) is preferably 2 to 100 nm.

The surface-modified colloidal particles (D) preferably have a primary particle diameter of 2 to 100nm, more preferably 5 to 50nm, and still more preferably 5 to 20 nm.

In the present invention, the primary particle diameter can be measured by transmission electron microscope observation.

The surface-modified titanium oxide-containing particles contained in the charge transporting varnish of the present invention are preferably uniformly dispersed in the varnish.

In the charge transporting varnish of the present invention, the content of the surface-modified titanium oxide-containing particles is not particularly limited, but from the viewpoint of suppressing aggregation of particles in the charge transporting material and obtaining a film excellent in flatness with good reproducibility, 30 to 65% by mass, more preferably 40 to 60% by mass, and most preferably 50 to 60% by mass of the solid content is preferable.

The charge transporting varnish of the present invention contains an organic solvent. The organic solvent is not particularly limited as long as components other than the organic solvent used in the charge transporting varnish of the present invention are dispersed or dissolved. Specific examples thereof include aromatic or halogenated aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene and chlorobenzene; aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclohexane; ether solvents such as diethyl ether, tetrahydrofuran, dioxane, and 1, 2-dimethoxyethane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate, n-hexyl acetate, ethyl lactate, γ -butyrolactone, propylene carbonate, and diisopropyl malonate; halogenated hydrocarbon solvents such as dichloromethane, 1, 2-dichloroethane, chloroform and the like; amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1, 3-dimethyl-2-imidazolidinone; alcohol solvents such as methanol, ethanol, isopropanol, n-propanol, cyclohexanol, diacetone alcohol, and 2-phenoxyethanol; glycol ether solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol diglycidyl ether, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate; glycol solvents such as ethylene glycol, propylene glycol, hexylene glycol, 1, 3-octanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1, 3-butanediol, 2, 3-butanediol, and 1, 4-butanediol are suitably selected and used.

These organic solvents can be used alone or in combination of 2 or more.

In the charge-transporting varnish of the present invention, water may be contained as the solvent, and from the viewpoint of obtaining an organic EL device excellent in durability with good reproducibility, the content of water is preferably 10 mass% or less, more preferably 5 mass% or less of the entire solvent, and most preferably a single organic solvent is used as the solvent. The term "organic solvent alone" in this case means that only an organic solvent is used as a solvent, and does not deny the presence of "water" contained in a trace amount in the organic solvent, solid components, and the like used.

When the charge-transporting varnish of the present invention is used as a hole injection layer of an organic EL device, it preferably contains a heteropoly acid from the viewpoint of achieving a low driving voltage. The heteropoly acid is a polyacid having a structure in which a hetero atom is located at the center of a molecule, typically represented by a chemical structure of Keggin type represented by formula (a) or Dawson type represented by formula (B), and which is obtained by condensing an isopoly acid of an oxo acid such as vanadium (V), molybdenum (Mo), tungsten (W), or the like with an oxo acid of a different element. Examples of the oxo acid of such a different element include oxo acids of silicon (Si), phosphorus (P), and arsenic (As).

[ solution 7]

Specific examples of the heteropoly-acid include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, and the like, and these heteropoly-acids may be used alone or in combination of 2 or more kinds. The heteropoly acid used in the present invention can be obtained as a commercially available product, and can be synthesized by a known method.

In particular, in the case where only 1 kind of heteropoly-acid is used, the 1 kind of heteropoly-acid preferably contains tungsten. That is, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, and the like are preferable, and phosphotungstic acid and silicotungstic acid are more preferable.

The heteropoly acid can be used in the present invention even if the number of elements is large or small relative to the structure represented by the general formula in quantitative analysis such as elemental analysis, as long as it is a product obtained as a commercially available product or a product appropriately synthesized according to a known synthesis method.

That is, for example, in general, phosphotungstic acid has the formula H₃(PW₁₂O₄₀)·nH₂O represents, in the quantitative analysis,even if the number of P (phosphorus), O (oxygen) or W (tungsten) in the formula is large or small, it can be used in the present invention as long as it is a product obtained as a commercially available product or a product appropriately synthesized according to a known synthesis method. In this case, the mass of the heteropoly-acid defined in the present invention is not the mass (phosphotungstic acid content) of pure phosphotungstic acid in a synthetic product or a commercially available product, but means the total mass in a state where water of hydration, other impurities and the like are contained in a commercially available product or in a state where they can be separated by a known synthesis method.

When the charge-transporting varnish of the present invention contains a heteropoly acid, the content thereof is about 1.0 to 11.0, preferably about 1.1 to 10.0, more preferably about 1.2 to 9.5, further preferably about 1.3 to 9.0, and further preferably about 1.4 to 8.5 in terms of mass ratio relative to the charge-transporting material 1, whereby a charge-transporting thin film that produces high luminance when used in an organic EL device can be obtained with good reproducibility.

The charge-transporting varnish of the present invention may contain a dopant substance for the purpose of, for example, improving the charge-transporting ability of the resulting thin film depending on the application. The dopant substance is not particularly limited as long as it is dissolved in at least one solvent used in the varnish, and both an inorganic dopant substance and an organic dopant substance can be used.

Examples of the inorganic dopant substance include strong inorganic acids such as hydrogen chloride, sulfuric acid, nitric acid, and phosphoric acid; aluminium (III) chloride (AlCl)₃) Titanium tetrachloride (IV) (TiCl)₄) Boron tribromide (BBr)₃) Boron trifluoride ether complex (BF)₃·OEt₂) Iron (III) chloride (FeCl)₃) Copper (II) chloride (CuCl)₂) Antimony (V) pentachloride (SbCl)₅) Arsenic (V) pentafluoride (AsF)₅) Phosphorus Pentafluoride (PF) ₅) Isometal halides, Cl₂、Br₂、I₂、ICl、ICl₃、IBr、IF₄And the like.

Examples of the organic dopant include tetracyanoquinodimethanes such as 7,7,8, 8-Tetracyanoquinodimethane (TCNQ) and 2, 5-difluoro-7, 7,8, 8-tetracyanoquinodimethane; halogenated tetracyanoquinodimethanes (halogenated TCNQ) such as 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, 2, 5-dichloro-7, 7,8, 8-tetracyanoquinodimethane and the like; benzoquinone derivatives such as tetrachloro-1, 4-benzoquinone (tetrachlorop-benzoquinone) and 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ); benzenesulfonic acid, toluenesulfonic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2, 5-dihexylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, 6, 7-dibutyl-2-naphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, 3-dodecyl-2-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 4-hexyl-1-naphthalenesulfonic acid, octylnaphthalenesulfonic acid, 2-octyl-1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 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, 1, 4-benzodioxan disulfonic acid compounds described in International publication No. 2005/000832, arylsulfonic acid derivatives described in International publication No. 2006/025342, arylsulfonic acid compounds such as dinonylnaphthalenesulfonic acid derivatives described in Japanese patent laid-open No. 2005-108828, and aromatic sulfonic acid compounds such as polystyrenesulfonic acid; non-aromatic sulfonic acid compounds such as 10-camphorsulfonic acid, and the like.

These inorganic and organic dopant substances may be used alone in 1 kind, or 2 or more kinds may be used in combination.

Examples of the arylsulfonic acid compound preferable as the dopant substance in the present invention include arylsulfonic acid compounds represented by the formula (H1) or (H2).

[ solution 8]

A¹Represents O or S, preferably O.

A²Represents a naphthalene ring or an anthracene ringPreferably a naphthalene ring.

A³Represents a 2-4 valent perfluorobiphenyl group, s represents A¹And A³The number of bonds of (A) is an integer satisfying 2. ltoreq. s.ltoreq.4, preferably A³Is perfluorobiphenylene, preferably perfluorobiphenyl-4, 4' -diyl, and s is 2.

q represents the same as A²The number of the bonded sulfonic acid groups is an integer satisfying 1. ltoreq. q.ltoreq.4, and 2 is most preferable.

A⁴～A⁸Independently represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms or a haloalkenyl group having 2 to 20 carbon atoms, A⁴～A⁸At least 3 of which are halogen atoms.

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

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

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

Of these, A is preferred⁴～A⁸Is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or a haloalkenyl group having 2 to 10 carbon atoms, and A⁴～A⁸At least 3 of them are fluorine atoms, more preferably hydrogen atoms, fluorine atoms, cyano groups, C1-5 alkyl groups, C1-5 fluoroalkyl groups, or C2-5 fluoroalkenyl groups, and A⁴～A⁸At least 3 of them are fluorine atoms, more preferably hydrogen atoms, fluorine atoms, cyano groups, perfluoroalkyl groups having 1 to 5 carbon atoms, or perfluoroalkenyl groups having 1 to 5 carbon atoms, and A⁴、A⁵And A⁸Is a fluorine atom.

The perfluoroalkyl group is a group in which all hydrogen atoms of the alkyl group have been substituted with fluorine atoms, and the perfluoroalkenyl group is a group in which all hydrogen atoms of the alkenyl group have been substituted with fluorine atoms.

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

In the case of using an organic compound as the dopant substance, the molecular weight thereof is preferably 3000 or less, more preferably 2500 or less, in view of solubility in an organic solvent.

In particular, the molecular weight of the arylsulfonic acid compound used as the dopant substance is not particularly limited, but is preferably 2000 or less, and more preferably 1500 or less, in view of solubility in an organic solvent.

In the present invention, the following compounds are exemplified as examples of the arylsulfonic acid compound that can be preferably used, but the present invention is not limited thereto.

[ solution 9]

When the charge-transporting varnish of the present invention contains a dopant substance, the content thereof is appropriately set in consideration of the type, amount, and the like of the charge-transporting substance, and is usually about 0.1 to 10 in terms of a mass ratio with respect to the charge-transporting substance 1.

The charge-transporting varnish of the present invention may contain an amine compound for the purpose of improving the dispersibility or solubility of the polythiophene derivative or its amine adduct.

Such an amine compound is not particularly limited as long as it is dissolved in at least one solvent used in the varnish, and may be 1 type alone or 2 or more types.

Specific examples of the primary amine compound include monoalkylamine compounds such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, and n-eicosylamine; monoarylamine compounds such as aniline, toluidine, 1-naphthylamine, 2-naphthylamine, 1-anthracenylamine, 2-anthracenylamine, 9-anthracenylamine, 1-phenanthrenylamine, 2-phenanthrenylamine, 3-phenanthrenylamine, 4-phenanthrenylamine, and 9-phenanthrenylamine.

Specific examples of the secondary amine compound include N-ethylmethylamine, N-methyl-N-propylamine, N-methylisopropylamine, N-methyl-N-butylamine, N-methyl-sec-butylamine, N-methyl-tert-butylamine, N-methyl-isobutylamine, diethylamine, N-ethyl-N-propylamine, N-ethyl-isopropylamine, N-ethyl-N-butylamine, N-ethyl-tert-butylamine, dipropylamine, N-N-propylisopropylamine, N-N-propyl-N-butylamine, N-N-propyl-sec-butylamine, diisopropylamine, N-N-butylisopropylamine, N-tert-butylisopropylamine, di (N-butyl) amine, di (sec-butyl) amine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2-dimethylaziridine, N-tert-butylisopropylamine, di (N-butyl) amine, di (sec-butyl) amine, di (isobutyl amine, aziridine, 2-methylazimine, and mixtures thereof, Dialkylamine compounds such as azetidine (trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2, 5-dimethylpyrrolidine, piperidine, 2, 6-dimethylpiperidine, 3, 5-dimethylpiperidine, 2, 2, 6, 6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, and octamethyleneimine; diarylamine compounds such as diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1 ' -dinaphthylamine, 2 ' -dinaphthylamine, 1, 2 ' -dinaphthylamine, carbazole, 7H-benzo [ c ] carbazole, 11H-benzo [ a ] carbazole, 7H-dibenzo [ c, g ] carbazole, and 13H-dibenzo [ a, i ] carbazole; and alkylaryl amine compounds such as N-methylaniline, N-ethylaniline, N-N-propylaniline, N-isopropylaniline, N-N-butylaniline, N-tert-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, N-N-propyl-1-naphthylamine, indoline, isoindoline, 1, 2, 3, 4-tetrahydroquinoline, and 1, 2, 3, 4-tetrahydroisoquinoline.

Specific examples of the tertiary amine compound include N, N-dimethylethylamine, N-dimethyl-N-propylamine, N-dimethylisopropylamine, N-dimethyl-N-butylamine, N-dimethyl-sec-butylamine, N-dimethyl-tert-butylamine, N-dimethyl-isobutylamine, N-diethylmethylamine, N-methyldi (N-propyl) amine, N-methyldiisopropylamine, N-methyldi (N-butyl) amine, N-methyldi-isobutylamine, triethylamine, N-diethyln-butylamine, N-diisopropylethylamine, N-di (N-butyl) ethylamine, tri (N-propyl) amine, tri (isopropyl) amine, tri (N-butyl) amine, tri (isobutyl) amine, 1-methylazetidine, N-diisopropylethylamine, N-di (N-butyl) amine, tri (N-propyl) amine, tri (isopropyl) amine, tri (N-butyl) amine, tri (isobutyl) amine, 1-methylazetidine, N-methyl-isopropylamine, N-N-isopropylamine, N-isopropylamine, and N-isopropylamine, N-N-isopropylamine, or a-N-isopropylamine, or a, Trialkylamine compounds such as 1-methylpyrrolidine and 1-methylpiperidine; triarylamine compounds such as triphenylamine; alkyl diarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole and 9-ethylcarbazole; and dialkylarylamine compounds such as N, N-diethylaniline, N-di (N-propyl) aniline, N-di (isopropyl) aniline, and N, N-di (N-butyl) aniline.

In particular, when the charge-transporting varnish of the present invention contains an amine compound, the amine compound preferably contains a primary amine compound, particularly a monoalkylamine having 2 to 20 carbon atoms, because of its excellent ability to improve the dispersibility and solubility of the polythiophene derivative or its amine adduct used in the present invention.

When the charge-transporting varnish of the present invention contains an amine compound, the content thereof is usually 200 mass% or less relative to the polythiophene derivative or its amine adduct used in the present invention, and preferably 50 mass% or more in order to obtain the above-described effects by the amine compound.

The charge-transporting varnish of the present invention may contain a known organosilane compound. When the charge-transporting varnish contains such an organic silane compound, the charge-transporting thin film obtained from the varnish can be used as a hole injection layer of an organic EL device, and thus the hole injection property into the hole transport layer provided in contact therewith can be improved.

As the organosilane compound, an alkoxysilane is preferable, and trialkoxysilanes and tetraalkoxysilanes are more preferable. Examples of the alkoxysilane include tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, 3, 3, 3-trifluoropropyltrimethoxysilane, dimethyldiethoxysilane, and dimethyldimethoxysilane. In the present invention, TEOS (tetraethoxysilane), tetramethoxysilane, tetraisopropoxysilane can be preferably used among these. These organosilane compounds can be used alone in 1 kind or more than 2 kinds in combination.

When the charge-transporting varnish of the present invention contains an organic silane compound, the content thereof is usually about 0.1 to 50% by mass in the solid content, but is preferably about 0.5 to 40% by mass, more preferably about 0.8 to 30% by mass, and still more preferably about 1 to 20% by mass, in consideration of the balance between improvement of the flatness of the obtained film and suppression of reduction in charge-transporting property.

The viscosity of the charge-transporting varnish of the present invention is usually 1 to 50 mPas at 25 ℃ and the surface tension is usually 20 to 50mN/m at 25 ℃. The viscosity and surface tension of the charge transporting varnish of the present invention can be adjusted by changing the type of the organic solvent used, the ratio thereof, the solid content concentration, and the like, in consideration of various factors such as the coating method used and the desired film thickness.

The solid content concentration of the charge-transporting varnish in the present invention is appropriately set in consideration of viscosity, surface tension, and the like of the varnish, the thickness of the produced film, and the like, and is usually about 0.1 to 15% by mass, and is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass or less from the viewpoint of suppressing aggregation of the charge-transporting substance and the surface-modified titanium oxide-containing particles in the varnish.

The charge-transporting varnish of the present invention can be produced by mixing the charge-transporting substance, the surface-modified titanium oxide-containing particles, the organic solvent, and other components used as needed. The mixing order is not particularly limited, and examples of a method by which the charge-transporting varnish of the present invention can be produced easily and with good reproducibility include: a method in which a charge transporting substance is dissolved in an organic solvent, and other components or a solution thereof prepared in advance and an aqueous dispersion or an organic solvent dispersion of surface-modified titanium oxide-containing particles are added to the solution; a method of adding a solution of a charge-transporting substance prepared in advance and other components or solutions thereof to an aqueous dispersion or an organic solvent dispersion of surface-modified titanium oxide-containing particles. In this case, if necessary, an organic solvent may be further added at the end, or a part of the components relatively easily soluble in the solvent may be added to the mixture without being contained therein, and from the viewpoint of suppressing aggregation and separation of the constituent components and producing a charge-transporting varnish excellent in uniformity with good reproducibility, it is preferable to prepare a well-dispersed aqueous dispersion or organic solvent dispersion of the surface-modified titanium oxide-containing particles and a mixture containing the other components, respectively, mix them, and then sufficiently stir them. Note that, in the case of the charge transporting substance and the surface-modified titanium oxide-containing particles, depending on the kind and amount of the solvents to be mixed together, it is noted that aggregation or precipitation may occur during mixing. In addition, when a varnish is prepared by using the surface-modified colloidal particles (D), it is necessary to determine the concentration of the surface-modified colloidal particles (D) and the amount of the surface-modified colloidal particles (D) to be used so that the metal oxide in the finally obtained varnish becomes a desired amount.

In the preparation of the varnish, the varnish may be appropriately heated in a range where the components are not decomposed and not deteriorated.

In the present invention, the charge-transporting varnish may be filtered by a submicron filter or the like at an intermediate stage of the production of the varnish or after mixing all the components in order to obtain a film having a higher flatness with good reproducibility.

The charge-transporting varnish described above is applied to a substrate and baked, whereby a charge-transporting thin film can be formed on the substrate.

The method of applying the varnish is not particularly limited, and examples thereof include a dipping method, a spin coating method, a transfer printing method, a roll coating method, a brush coating method, an ink jet method, a spray coating method, and a slit coating method.

In addition, when the charge-transporting varnish of the present invention is used, the firing atmosphere is not particularly limited, and a thin film having a uniform film formation surface and high charge-transporting property can be obtained not only in the atmospheric atmosphere but also in an inert gas such as nitrogen or in a vacuum. The firing temperature is appropriately set in the range of about 100 to 260 ℃ in consideration of the application of the obtained film, the degree of charge transport property imparted to the obtained film, the kind of solvent, the boiling point, and the like, and when the obtained film is used as a hole injection layer of an organic EL element, it is preferably about 140 to 250 ℃, and more preferably about 145 to 240 ℃. In order to develop a more uniform film-forming property during firing, the reaction may be allowed to proceed on the substrate by applying a temperature change of 2 stages or more, and heating may be performed using an appropriate device such as a hot plate or an oven.

The thickness of the charge-transporting thin film is not particularly limited, and is preferably 5 to 300nm when the charge-transporting thin film is used as a hole injection layer, a hole transport layer, or a hole injection transport layer of an organic EL device. As a method of changing the film thickness, there are methods of changing the concentration of solid components in the varnish, changing the amount of solution on the substrate at the time of coating, and the like.

The charge transport thin film of the present invention described above generally exhibits a refractive index (n) of 1.50 or more and an extinction coefficient (k) of 0.500 or less, as represented by an average value of a wavelength region of 400 to 800nm, and in one embodiment exhibits a refractive index (n) of 1.60 or more, in another embodiment exhibits a refractive index (n) of 1.70 or more, in yet another embodiment exhibits a refractive index (n) of 1.75 or more, in one embodiment exhibits an extinction coefficient (k) of 0.100 or less, in yet another embodiment exhibits an extinction coefficient (k) of 0.070 or less, and in yet another embodiment exhibits an extinction coefficient (k) of 0.050 or less.

The organic EL device of the present invention has a pair of electrodes, and a charge transport layer composed of the charge transport thin film of the present invention described above is provided between the electrodes.

Typical configurations of the organic EL element include the following (a) to (f), but are not limited thereto. In the following configuration, an electron blocking layer or the like may be provided between the light-emitting layer and the anode, and a hole (hole) blocking layer or the like may be provided between the light-emitting layer and the cathode, as necessary. The hole injection layer, the hole transport layer, or the hole injection transport layer may have a 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 have a function as a hole (hole) blocking layer or the like. Further, an arbitrary functional layer may be provided between the layers 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/luminescent layer/electron transport layer/electron injection layer/cathode

(d) Anode/hole injection transport layer/light emitting layer/electron injection transport layer/cathode

(e) Anode/hole injection layer/hole transport layer/light emitting layer/cathode

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

The "hole injection layer", "hole transport layer" and "hole injection transport layer" are layers formed between the light-emitting layer and the anode, and have a function of transporting holes from the anode to the light-emitting layer, and are "hole injection transport layer" when only 1 layer of a hole-transporting material is provided between the light-emitting layer and the anode, and are "hole injection layer" when 2 or more layers of a hole-transporting material are provided between the light-emitting layer and the anode, the layer close to the anode is the "hole injection layer", and the other layers are the "hole transport layers". In particular, a thin film excellent in hole accepting property from the anode and hole injecting property into the hole transporting (light emitting) layer is used as the hole injecting (transporting) layer.

The "electron injection layer", "electron transport layer" and "electron injection transport layer" are layers formed between the light-emitting layer and the cathode, and have a function of transporting electrons from the cathode to the light-emitting layer, and are the "electron injection transport layer" when only 1 layer of an electron-transporting material is provided between the light-emitting layer and the cathode, and are the "electron injection layer" when 2 or more layers of an electron-transporting material are provided between the light-emitting layer and the cathode, the layer close to the cathode is the "electron injection layer", and the other layers are the "electron transport layers".

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

The charge-transporting thin film produced from the charge-transporting varnish of the present invention is preferably used as a hole injection layer, a hole transport layer, or a hole injection transport layer, more preferably used as a hole injection layer or a hole transport layer, and still more preferably used as a hole injection layer, as a functional layer formed between an anode and a light-emitting layer in an organic EL device.

Examples of the materials and methods for producing an EL element using the charge-transporting varnish of the present invention include, but are not limited to, the following materials and methods.

An example of a method for producing an OLED element having a hole injection layer made of a thin film (the thin film is obtained from the charge-transporting varnish of the present invention) is as follows. In the electrode, it is preferable to perform cleaning with alcohol, pure water, or the like in advance in a range where adverse effects are not exerted on the electrode; surface treatment such as UV ozone treatment, oxygen-plasma treatment, or the like is employed.

The charge-transporting varnish described above is used to form a hole injection layer on the anode substrate by the above-described method. The organic electroluminescent material is introduced into a vacuum evaporation device, and a hole transport layer, a luminescent layer, an electron transport layer/hole blocking layer, an electron injection layer and cathode metal are evaporated in sequence. Alternatively, in this method, instead of forming the hole transport layer and the light-emitting layer by vapor deposition, a composition for forming a hole transport layer containing a hole transport polymer and a composition for forming a light-emitting layer containing a light-emitting polymer are used, and these layers are formed by a wet process. If necessary, an electron blocking layer may be provided between the light-emitting layer and the hole transport layer.

Examples of the anode material include a transparent electrode typified by Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO), a metal anode typified by aluminum, an alloy thereof, and the like, and a flattened anode material is preferable. Polythiophene derivatives and polyaniline derivatives having high charge transport properties can also be used.

Examples of the other metal constituting the metal anode include gold, silver, copper, indium, and alloys thereof, but are not limited thereto.

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

Examples of the material for forming the light-emitting layer include low-molecular-weight light-emitting materials such as metal complexes of 8-hydroxyquinoline and the like, metal complexes of 10-hydroxybenzo [ h ] quinoline, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl) benzothiazole, silole derivatives and the like; and a system in which a light-emitting material and an electron-transporting material are mixed in a polymer compound such as poly (p-phenylene vinylene), poly [ 2-methoxy-5- (2-ethylhexyloxy) -1, 4-phenylene vinylene ], poly (3-alkylthiophene) or polyvinylcarbazole, but the present invention is not limited thereto.

In the case where the light-emitting layer is formed by vapor deposition, the light-emitting layer may be co-deposited with a light-emitting dopant, and examples of the light-emitting dopant include tris (2-phenylpyridine) iridium (III) (ir (ppy)₃) Isometal complex, red fluorescenceAnd tetracene derivatives such as alkenes, quinacridone derivatives, fused polycyclic aromatic rings such as perylenes, and the like, but the present invention is not limited thereto.

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

As a material for forming the electron injection layer, lithium oxide (Li) can be mentioned₂O), magnesium oxide (MgO), aluminum oxide (Al)₂O₃) And metal oxides such as lithium fluoride (LiF), and metal fluorides such as sodium fluoride (NaF), but the metal oxides are not limited to these.

Examples of the cathode material include, but are not limited to, aluminum, magnesium-silver alloy, and aluminum-lithium alloy.

Examples of the material for forming the electron blocking layer include, but are not limited to, tris (phenylpyrazole) iridium.

Examples of the hole-transporting polymer include poly [ (9, 9-dihexylfluorene-2, 7-diyl) -co- (N, N '-bis { p-butylphenyl } -1, 4-diaminophenylene) ], poly [ (9, 9-dioctylfluorene-2, 7-diyl) -co- (N, N' -bis { p-butylphenyl } -1,1 '-biphenylene-4, 4-diamine) ], poly [ (9, 9-bis { 1' -penten-5 '-yl } fluorene-2, 7-diyl) -co- (N, N' -bis { p-butylphenyl } -1, 4-diaminophenylene) ], poly [ N ] terminated with polysilsesquioxane, n ' -bis (4-butylphenyl) -N, N ' -bis (phenyl) -benzidine ], poly [ (9, 9-dioctylfluorene-2, 7-diyl) -co- (4,4 ' - (N- (p-butylphenyl)) diphenylamine) ], and the like.

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

The material constituting the anode and the cathode and the layer formed therebetween is different depending on which element is to be manufactured which element has a bottom emission structure or a top emission structure, and is appropriately selected in consideration of this point.

In general, in the case of an element having a bottom emission structure, a transparent anode is used on the substrate side, and light is extracted from the substrate side, whereas in the case of an element having a top emission structure, a reflective anode made of metal is used, and light is extracted from the transparent electrode (cathode) side located in the opposite direction to the substrate side.

The organic EL element of the present invention can be sealed with a water-capturing agent or the like as needed in accordance with a conventional method in order to prevent deterioration of the characteristics.

The charge-transporting varnish of the present invention is preferably used for forming a functional layer formed between an anode and a light-emitting layer of an organic EL element, as described above, and can also be used for forming a charge-transporting thin film in an electronic element such as an organic photoelectric conversion element, an organic thin-film solar cell, an organic perovskite photoelectric conversion element, an organic integrated circuit, an organic field-effect transistor, an organic thin-film transistor, an organic light-emitting transistor, an organic optical detector, an organic light receiver, an organic electro-extinction element, a light-emitting electrochemical cell, a quantum dot light-emitting diode, a quantum laser, an organic laser diode, or an organic plasmon light-emitting element.

Examples

The present invention will be described more specifically below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The method for measuring physical properties and the apparatus used therefor are as follows.

[ measurement of physical Properties of surface-modified titanium oxide-containing particles ]

(1) Water content: determined by Karl Fischer titration.

(2) Primary particle size: the dispersion was dried on a copper mesh, observed with a transmission electron microscope, and the particle diameters of 100 particles were measured, and the average value thereof was determined as the primary particle diameter.

(3) Specific gravity: the temperature was determined by the following method (50 ℃).

(4) Viscosity: the temperature was measured by an Ostwald viscometer (50 ℃).

(5) Particle size by dynamic light scattering: determined by measurement using a Zetasizer Nano manufactured by Malvern.

(6) Solid content concentration: determined from the solid matter remaining after firing at 600 ℃.

(7) Bonding amount of organosilane compound: the amount of the organic silane compound bonded to the modified metal oxide colloidal particles was determined by elemental analysis.

The device comprises the following steps: series II CHNS/O Analyzer 2400 manufactured by PerkinElmer

[ preparation and evaluation of Charge-transporting varnish ]

(1) Cleaning a substrate: apparatus for cleaning substrate (vacuum plasma method) manufactured by Changzhou industry

(2) Coating of varnish: ミカサ Kabushiki Kaisha spin coater MS-A100

(3) Measurement of film thickness: SURFCORDER ET-4000, a Fine Profile measuring machine manufactured by Okawa Katsuba research

(4) Determination of the optical properties of the films: high-speed spectroscopic ellipsometer M-2000UI manufactured by J.A.Woollam corporation and having multiple incident angle rotation compensation

(5) Production of EL element: multifunctional vapor deposition device system C-E2L1G1-N manufactured by Changzhou industry

(6) Measurement of luminance and the like of EL element: (there are systems for I-V-L measurement, manufactured by テック & ワールド)

[1] Production of surface-modified titanium oxide-containing colloidal particles

Production example 1-1 production of Nuclear particle (A)

126.2g of pure water was charged into a 1 liter vessel, and 17.8g of metastannic acid (as SnO)₂In terms of conversion, it contained 15g of titanium tetraisopropoxide (produced by Showa Kagaku Co., Ltd.) and 284g of titanium tetraisopropoxide (produced as TiO)₂The contents of 80g, A-1 manufactured by Nippon Caoda corporation, 98g, oxalic acid dihydrate (70 g, manufactured by Uyu Kagaku corporation, calculated as oxalic acid), and 438g, a 35 mass% tetraethylammonium hydroxide aqueous solution (manufactured by セイケムジャパン) were calculated. The resulting mixed solution had an oxalic acid/titanium atom molar ratio of 0.78 and hydrogenThe molar ratio tetraethylammonium oxide/titanium atoms was 1.04. 950g of this mixed solution was held at 80 ℃ for 2 hours, and further, was held at 580Torr under reduced pressure for 2 hours to prepare a titanium mixed solution. The pH of the prepared titanium mixed solution was 4.7, the conductivity was 27.2mS/cm, and the metal oxide concentration was 10.0 mass%. 950g of the titanium mixed solution and 950g of pure water were put into a 3-liter glass-lined autoclave vessel, and hydrothermal treatment was carried out at 140 ℃ for 5 hours. After cooling to room temperature, the solution after the hydrothermal treatment was taken out as a light milky-white aqueous dispersion containing colloidal titanium oxide particles. The resulting dispersion had a pH of 3.9, a conductivity of 19.7mS/cm, TiO ₂The concentration was 4.2 mass%, the tetraethylammonium hydroxide concentration was 8.0 mass%, the oxalic acid concentration was 3.7 mass%, the particle size by dynamic light scattering method was 16nm, and in transmission electron microscope observation, elliptical particles having a primary particle size of 5 to 15nm were observed. The powder obtained by drying the obtained dispersion at 110 ℃ was analyzed by X-ray diffraction and confirmed to be a rutile crystal. The obtained colloidal particles containing titanium oxide were used as core particles (a).

Production examples 1-2 production of coating (B)

Mixing sodium silicate aqueous solution (sodium silicate No. JIS3, SiO₂27.9g of sodium stannate 3 hydrate (SnO) (manufactured by Fuji chemical Co., Ltd.) was diluted with 27.9g of pure water and added thereto, wherein the content was 34 mass%₂55 mass% in Showa chemical Co., Ltd.) in an amount of 8.6g was dissolved under stirring to obtain an aqueous silicic acid-sodium stannate solution. 64.4g of the obtained silicic acid-sodium stannate aqueous solution was diluted with 411g of pure water, and passed through a column packed with a hydrogen-type cation exchange resin (アンバーライト (registered trademark) IR-120B) to obtain an aqueous dispersion of silica-tin dioxide composite oxide colloidal particles (pH2.7, SnO) (SnO: SnO 2.7)₂Contains 0.83 mass% in terms of SiO₂Contains 1.67 mass% of SiO ₂/SnO₂Mass ratio 2.0)570 g.

Subsequently, 2.9g of diisopropylamine was added to the obtained aqueous dispersion of silica-tin dioxide composite oxide colloidal particles. The obtained dispersion was an aqueous dispersion of basic silica-tin dioxide composite oxide colloidal particles, which were colloidal particles having a primary particle diameter of 5nm or less and a pH of 8.2. The obtained basic silica-tin dioxide composite oxide colloidal particles were used as a coating (B).

Production examples 1 to 3 production of modified colloidal particles (C)

The above-mentioned coating material (B)570g was added to 1900g of the aqueous dispersion of the core particles (A) under stirring at 25 ℃ and then the mixture was held at 95 ℃ for 3 hours to obtain an aqueous dispersion of modified colloidal particles (C). Then, the resulting aqueous dispersion was passed through a column packed with a hydrogen type cation exchange resin (アンバーライト IR-120B), whereby 2730g of an aqueous dispersion of acidic modified titanium oxide composite colloidal particles was obtained. The obtained dispersion had a pH of 2.7, a total metal oxide concentration of 4.0 mass%, and a mass ratio (metal oxide equivalent) represented by (B)/(A) of 0.15. To the resulting dispersion, 2.2g of diisobutylamine was added. The pH of the resulting dispersion was 4.5. Then, this dispersion was concentrated in an evaporator equipped with an eggplant-shaped flask, and water was distilled off at 600Torr while adding methanol to obtain 533g of a methanol dispersion of modified colloidal particles (C). The resulting methanol dispersion was: a specific gravity of 0.949, a viscosity of 1.2 mPas, a pH of 4.8 (diluted with water having the same mass as that of the dispersion), a total metal oxide concentration of 20.5 mass%, and a water content of 3.1 mass%.

Production examples 1 to 4 production of surface-modified colloidal particles (D)

5.5g of polyether-modified silane (trade name: X-12-641), which was prepared by adding 533g of the modified colloidal particle (C) obtained in production examples 1 to 3 to methanol dispersion, was heated under reflux at 70 ℃ for 5 hours to obtain methanol dispersion of modified colloidal particles (C) having a polyether group bonded to the surface. Then, by using an evaporator, methanol was distilled off while adding propylene glycol monomethyl ether at 80Torr to replace methanol with propylene glycol monomethyl ether, thereby obtaining 270g of a propylene glycol monomethyl ether dispersion (hereinafter referred to as dispersion X) of surface-modified colloidal particles (D) having polyether-modified silane bonded to the surface thereof. The obtained dispersion liquid X had a specific gravity of 1.353, a viscosity of 7.0 mPas, a total metal oxide concentration of 40.3% by mass, a primary particle diameter of 5 to 10nm as observed with a transmission electron microscope, and a particle diameter of 9nm by a dynamic light scattering method. In the obtained surface-modified colloidal particles (D), the polyether-modified silane bonded to the surface of the modified colloidal particles (C) was 4.0 mass% with respect to the total metal oxide of the modified colloidal particles (C).

[2] Synthesis of Compounds

Production example 2-1

500g of an aqueous dispersion (solid content concentration: 0.6% by mass) of a polythiophene derivative as a polymer comprising a repeating unit represented by the formula (1a) as a repeating unit was mixed with 0.9g of triethylamine, and the resulting mixture was dried by rotary evaporation. Then, the obtained dried product was further dried overnight in a vacuum oven at 50 ℃ to obtain 4g of a polythiophene derivative a in which an amine was added to a sulfonic acid group.

Production example 2-2

Polythiophene derivative a2.00g was dissolved in 100mL of 28% aqueous ammonia (manufactured by genuine chemical corporation), and the resulting solution was stirred at room temperature overnight. The resulting reaction mixture was reprecipitated with 1500mL of acetone, and the precipitate was collected by filtration. The resulting precipitate was dissolved again in 20mL of water and 7.59g of triethylamine (manufactured by Tokyo chemical industry Co., Ltd.), and stirred at 60 ℃ for 1 hour. The obtained reaction mixture was cooled, and then reprecipitation treatment was performed using a mixed solvent of 1000mL of isopropyl alcohol and 500mL of acetone, and precipitates were collected by filtration. The resulting precipitate was vacuum-dried at 50 ℃ for 1 hour under reduced pressure to obtain 1.30g of an amine-treated polythiophene derivative amine adduct.

Production examples 2 to 3

An arylsulfonic acid compound B represented by the formula (B-1) was synthesized according to the method described in International publication No. 2006/025342.

[ solution 10]

[3] Preparation of composition for preparation of varnish

[ preparation examples 1-1]

A dipropylene glycol solution containing 10 mass% of the arylsulfonic acid compound B was prepared. The above solution was prepared by stirring at 400rpm at 50 ℃ for 1 hour using a thermal stirrer.

[ preparation examples 1-2]

A propylene carbonate solution containing 10 mass% of phosphotungstic acid (PWA, manufactured by japan new metals corporation) was prepared. The above solution was prepared by stirring at 400rpm for 10 minutes at room temperature using a stirrer.

[ preparation examples 1 to 3]

A 1, 3-dimethyl-2-imidazolidinone solution containing 10 mass% of the arylsulfonic acid compound B was prepared. The above solution was prepared by stirring at 400rpm at 50 ℃ for 1 hour using a thermal stirrer.

[ preparation examples 1 to 4]

A propylene glycol solution containing 10 mass% of the arylsulfonic acid compound B was prepared. The above solution was prepared by stirring at 400rpm at 50 ℃ for 1 hour using a thermal stirrer.

[4] Preparation of Charge-transporting varnish

[ example 1-1]

0.050g of amine-treated polythiophene derivative amine adduct was added to 0.49g of dipropylene glycol (manufactured by genuine chemical corporation) and 0.080g of 2-ethylhexylamine (manufactured by tokyo chemical industries, ltd.), and stirred at 80 ℃ for 3 hours using a thermal stirrer. To the obtained mixture were added 1.88g of tripropylene glycol (manufactured by Tokyo chemical industry Co., Ltd.), 0.51g of propylene carbonate (manufactured by Tokyo chemical industry Co., Ltd.), 1.88g of triethylene glycol monobutyl ether (manufactured by Tokyo chemical industry Co., Ltd.), and 2.83g of diisopropyl malonate (manufactured by Tokyo chemical industry Co., Ltd.), and the mixture was stirred at 400rpm and room temperature for 10 minutes using a stirrer. Next, 0.50g of a 10 mass% dipropylene glycol solution of an arylsulfonic acid compound B, 1.25g of a 10 mass% propylene carbonate solution of phosphotungstic acid, 0.50g of the dispersion liquid obtained in production examples 1 to 4, and 0.025g of 3, 3, 3-trifluoropropyltrimethoxysilane (KBM-7103, manufactured by shin-Etsu chemical Co., Ltd.) were added to the obtained mixture, followed by stirring. Finally, the resulting mixture was filtered with a PP pin filter having a pore diameter of 0.2 μm to obtain a charge-transporting varnish.

[ examples 1-2]

0.050g of amine-treated polythiophene derivative amine adduct was added to 0.49g of dipropylene glycol (manufactured by genuine chemical corporation) and 0.080g of 2-ethylhexylamine (manufactured by tokyo chemical industries, ltd.), and stirred at 80 ℃ for 3 hours using a thermal stirrer. To the obtained mixture were added 1.88g of tripropylene glycol (manufactured by Tokyo chemical industry Co., Ltd.), 0.92g of propylene carbonate (manufactured by Tokyo chemical industry Co., Ltd.), 1.88g of triethylene glycol monobutyl ether (manufactured by Tokyo chemical industry Co., Ltd.), and 2.83g of diisopropyl malonate (manufactured by Tokyo chemical industry Co., Ltd.), and the mixture was stirred at 400rpm and room temperature for 10 minutes using a stirrer. Next, 0.50g of a 10 mass% dipropylene glycol solution of an arylsulfonic acid compound B, 0.75g of a 10 mass% propylene carbonate solution of phosphotungstic acid, 0.59g of the dispersion liquid obtained in production examples 1 to 4, and 0.025g of 3, 3, 3-trifluoropropyltrimethoxysilane (KBM-7103, manufactured by shin-Etsu chemical Co., Ltd.) were added to the obtained mixture, followed by stirring. The resulting mixture was filtered with a PP pin filter having a pore size of 0.2 μm to obtain a charge-transporting varnish.

[ examples 1 to 3]

0.050g of amine-treated polythiophene derivative amine adduct was added to 0.83g of 1, 3-dimethyl-2-imidazolidinone (manufactured by Kanto chemical Co., Ltd.), 1.28g of dipropylene glycol (manufactured by Kanto chemical Co., Ltd.), and 0.080g of 2-ethylhexylamine (manufactured by Tokyo chemical industry Co., Ltd.), and the mixture was stirred at 80 ℃ for 3 hours using a thermal stirrer. To the obtained mixture was added 1.89g of dipropylene glycol monomethyl ether (manufactured by Kanto chemical Co., Ltd.), and the mixture was stirred at 400rpm for 10 minutes at room temperature using a stirrer. Next, 0.63g of a 10 mass% solution of 1, 3-dimethyl-2-imidazolidinone of an arylsulfonic acid compound B, 0.25g of the dispersion obtained in production examples 1 to 4, and 0.013g of 3, 3, 3-trifluoropropyltrimethoxysilane (KBM-7103, manufactured by shin-Etsu chemical Co., Ltd.) were added to the obtained mixture, and the mixture was stirred. The resulting mixture was filtered using a PP pin filter having a pore size of 0.2 μm to obtain a charge-transporting varnish.

[ examples 1 to 4]

0.050g of amine-treated polythiophene derivative amine adduct was added to 0.49g of propylene glycol (manufactured by genuine chemical corporation) and 0.080g of 2-ethylhexylamine (manufactured by tokyo chemical industries, ltd.), and stirred at 80 ℃ for 3 hours using a thermal stirrer. To the obtained mixture were added 2.83g of tripropylene glycol (manufactured by Tokyo chemical industry Co., Ltd.), 2.46g of propylene carbonate (manufactured by Tokyo chemical industry Co., Ltd.), 0.94g of triethylene glycol monobutyl ether (manufactured by Tokyo chemical industry Co., Ltd.), and 1.88g of diisopropyl malonate (manufactured by Tokyo chemical industry Co., Ltd.), and the mixture was stirred at 400rpm and room temperature for 10 minutes by using a stirrer. Next, 0.50g of a 10 mass% propylene glycol solution of an arylsulfonic acid compound B, 0.74g of the dispersion obtained in preparation examples 1 to 4, and 0.025g of 3, 3, 3-trifluoropropyltrimethoxysilane (KBM-7103, manufactured by shin-Etsu chemical Co., Ltd.) were added to the obtained mixture, followed by stirring. The resulting mixture was filtered using a PP pin filter having a pore size of 0.2 μm to obtain a charge-transporting varnish.

Comparative examples 1 to 1

0.050g of amine-treated polythiophene derivative amine adduct was added to 0.66g of propylene glycol (manufactured by genuine chemical corporation) and 0.080g of 2-ethylhexylamine (manufactured by tokyo chemical industries, ltd.), and stirred at 80 ℃ for 3 hours using a thermal stirrer. To the obtained mixture were added 1.26g of tripropylene glycol (manufactured by Tokyo chemical industry Co., Ltd.), 2.83g of propylene carbonate (manufactured by Tokyo chemical industry Co., Ltd.), 0.27g of dipropylene glycol monobutyl ether (manufactured by Kanto chemical industry Co., Ltd.), and 1.88g of diisopropyl malonate (manufactured by Tokyo chemical industry Co., Ltd.), and the mixture was stirred at 400rpm and room temperature for 10 minutes using a stirrer. Then, 0.33g of a 10 mass% propylene glycol solution of the arylsulfonic acid compound B and 0.75g of a 10 mass% dipropylene glycol monobutyl ether solution of phosphotungstic acid were added to the obtained mixture, and the mixture was stirred. Next, when 3.0g of the modified colloidal particles (C) obtained in production examples 1 to 3 were added to a 10 mass% tripropylene glycol dispersion, the solution became cloudy, and a sufficiently uniform charge-transporting varnish that could be used for forming a charge-transporting film was not obtained.

[5] Evaluation of film physical Properties

The varnishes obtained in examples 1-1 and 1-2 were applied to a quartz substrate using a spin coater, and then fired at 120 ℃ for 1 minute. Next, the resultant was fired at 230 ℃ for 15 minutes to form a thin film having a thickness of 35nm on the substrate.

The refractive index n and the extinction coefficient k were measured using the obtained quartz substrate with the thin film by using a multi-incident-angle rotation compensation type high-speed spectroscopic ellipsometer. The results are shown in table 1. The average values of n and k values measured at wavelengths of 400 to 800nm are shown in Table 1.

[ Table 1]

	Refractive index n	Extinction coefficient k
			Examples 1 to 1	1.83	0.035
Examples 1 to 2	1.80	0.038

From the results of table 1, it was confirmed: the film obtained from the charge-transporting varnish of the present invention has a high refractive index and transparency.

[6] Device fabrication and characteristic evaluation

In the following examples, as the ITO substrate, a glass substrate of 25mm × 25mm × 0.7t having ITO patterned on the surface thereof with a film thickness of 50nm was used, and O was used before use₂The plasma cleaning apparatus (150W, 30 seconds) was used to remove impurities on the surface.

[6-1] production and characteristic evaluation of a Single hole device (HOD)

[ example 2-1]

The varnish obtained in example 1-1 was coated on an ITO substrate using a spin coater, and then baked at 120 ℃ for 1 minute. Next, the resultant was fired at 230 ℃ for 15 minutes to form a 35nm thin film on the substrate. An evaporation apparatus (degree of vacuum of 1.0X 10) was used for the ITO substrate on which the thin film was formed ^-5Pa), an α -NPD film of 30nm was formed at 0.2 nm/sec. On the surface, a deposition apparatus (degree of vacuum 4.0X 10) was used^-5Pa) to form an aluminum thin film, yielding an HOD. The evaporation was carried out at an evaporation rate of 0.2 nm/sec. The thickness of the aluminum thin film was set to 80 nm. In order to prevent deterioration of characteristics due to the influence of oxygen, water, and the like in the air, the HOD was sealed with a sealing substrate, and then the characteristics thereof were evaluated. The sealing was performed as follows. The HOD was put between the sealing substrates in a nitrogen atmosphere having an oxygen concentration of 2ppm or less and a dew point of-76 ℃ or less, and the sealing substrates were bonded with an adhesive (MORCO MOISTURE CUT WB90US (P) manufactured by MORCO CORPORATION). At this time, the water-capturing agent (HD-071010W-40, manufactured by ダイニック Co.) was contained in the sealing substrate together with the organic EL element. The pasted sealing substrate was irradiated with UV light (wavelength: 365nm, dose: 6000 mJ/cm)²) Thereafter, the adhesive was cured by annealing at 80 ℃ for 1 hour.

Examples 2-2 and 2-4

An HOD was produced in the same manner as in example 2-1, except that the varnishes obtained in examples 1-2 and 1-4 were used instead of the varnish obtained in example 1-1.

[ examples 2 to 3]

An HOD was produced in the same manner as in example 2-1, except that the varnish obtained in example 1-3 was used in place of the varnish obtained in example 1-1, and the baking was carried out at 200 ℃ for 1 minute.

The current density when the obtained HOD was driven at 5V was measured. The results are shown in table 2.

[ Table 2]

	Charge-transporting varnish	Current Density (mA/cm)2)
			Example 2-1	Examples 1 to 1	545.2
Examples 2 to 2	Examples 1 to 2	484.3
			Examples 2 to 3	Examples 1 to 3	170.8
Examples 2 to 4	Examples 1 to 4	55.5

As shown in table 2, the charge-transporting thin film obtained from the charge-transporting varnish of the present invention exhibited good hole injection properties for a film made of α -NPD equivalent to the hole-transporting layer.

[6-2] production of organic EL element and evaluation of characteristics

[ example 3-1]

The varnish obtained in example 1-1 was applied to an ITO substrate using a spin coater, and then baked at 120 ℃ for 1 minute. Next, the resultant was fired at 230 ℃ for 15 minutes to form a 35nm thin film on the substrate. Next, an evaporation apparatus (degree of vacuum 1.0X 10) was used for the ITO substrate on which the thin film was formed^-5Pa) of0.2 nm/sec formed a 30nm α -NPD film. Next, a film of an electron-blocking material HTEB-01 (manufactured by Kanto chemical Co., Ltd.) was formed at 10 nm. Next, a light-emitting layer host material NS60 and a light-emitting layer dopant material Ir (PPy) manufactured by Nissian iron-on-gold chemical Co., Ltd₃And (4) co-evaporation. For co-evaporation, the evaporation rate is controlled so that Ir (PPy) ₃The concentration of (2) was 6%, and 40nm was stacked. Secondly, adding Alq₃The organic EL element was obtained by sequentially laminating thin films of lithium fluoride and aluminum. At this time, the deposition rate is set to Alq₃And aluminum at 0.2 nm/sec, and lithium fluoride at 0.02 nm/sec, to give films of 20nm, 0.5nm and 80nm, respectively. After sealing the element by the same method as in example 2-1, the characteristics were evaluated.

[ examples 3-2]

An organic EL device was produced in the same manner as in example 3-1, except that the varnish obtained in example 1-2 was used in place of the varnish obtained in example 1-1.

Examples 3 to 3 and 3 to 4

An organic EL device was produced in the same manner as in example 3-1, except that the varnishes obtained in examples 1-3 and 1-4 were used instead of the varnish obtained in example 1-1, and were fired at 200 ℃ for 1 minute instead of firing at 120 ℃.

The obtained organic EL element was measured to have a luminance of 10000cd/m²Driving voltage, current density and current efficiency during driving. The results are shown in table 3.

[ Table 3]

As shown in table 3, the organic EL element including the charge-transporting thin film obtained from the charge-transporting varnish of the present invention was driven well.