Composition for forming charge transport thin films

Abstract

A composition for forming a charge-transporting thin film containing a charge-transporting precursor having a 9-tert-butoxycarbonylcarbazole structure within the molecule and an organic solvent provides a thin film exhibiting good charge-transporting properties even when sintered at low temperatures. Furthermore, the aforementioned charge-transporting precursor can be used to prepare the composition using a low-polarity solvent that causes less damage to substrates and components made of organic compounds compared to highly polar amide solvents.

Description

Technical Field

[0001] This invention relates to compositions for forming charge-transporting thin films. Background Technology

[0002] In electronic components, particularly organic electroluminescent (OLED) devices, charge-transporting thin films composed of organic compounds are used as the light-emitting layer and charge injection layer. In particular, the hole injection layer undertakes the charge transfer between the anode and the hole transport layer or the light-emitting layer, playing an important role in achieving low-voltage driving and high brightness in organic EL devices.

[0003] Methods for forming hole injection layers can be broadly categorized into dry methods, represented by vapor deposition, and wet methods, represented by spin coating. Comparing these methods, wet methods can efficiently fabricate thin films with high flatness over large areas. Therefore, with the current trend towards large-area production of organic EL displays, there is a need for hole injection layers that can be formed using wet methods.

[0004] In view of this reality, the inventors have developed a charge transport material and a compound therein that is highly soluble in organic solvents. This charge transport material can be applied to various wet processes and provides a thin film that can achieve excellent EL element characteristics when applied as a hole injection layer in an organic EL element (see, for example, Patent Documents 1-4).

[0005] Furthermore, in the field of organic EL in recent years, due to the trend of lightweight, thin, and flexible components, substrates and components made of organic compounds are gradually replacing glass substrates. Therefore, there is a need for compositions that can be fired at lower temperatures than existing products, or can be prepared using organic solvents that cause little damage to such substrates and components, while also providing thin films with good charge transport properties.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2008 / 067276

[0009] Patent Document 2: International Publication No. 2008 / 129947

[0010] Patent Document 3: International Publication No. 2006 / 025342

[0011] Patent Document 4: International Publication No. 2010 / 058777

[0012] Patent Document 5: International Publication No. 2006 / 025290

[0013] Patent Document 6: Japanese Patent Application Publication No. 2012-236777

[0014] Non-patent literature

[0015] Non-patent literature 1: Advanced Functional Materials (2013), 23(5), 619-628. Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a composition for forming a charge transport thin film, which exhibits good charge transport properties even when the film is sintered at low temperature, or can be prepared using a low polarity solvent that causes less damage to substrates or components made of organic compounds compared to highly polar amide solvents, and the composition provides a charge transport thin film for organic EL elements that can achieve excellent brightness characteristics when used as a hole injection layer.

[0018] Methods for solving problems

[0019] To achieve the above objectives, the inventors conducted repeated and in-depth research and discovered that: the charge transport precursor having a 9-tert-butoxycarbonylcarbazole structure within the molecule has excellent solubility in low-polarity solvents; the film obtained from the composition for forming a charge transport film containing the charge transport precursor exhibits good charge transport properties even when sintered at low temperatures; and when this film is applied to organic EL devices, excellent device characteristics can be achieved, thus completing the present invention.

[0020] It should be noted that in this invention, "firing at a low temperature" means "firing at a temperature below 200°C".

[0021] Furthermore, for example, Patent Documents 5 and 6 and Non-Patent Document 1 disclose compounds in which the 9-position (N-position) of carbazole is protected with a tert-butoxycarbonyl group as an intermediate, but none of the documents disclose a composition for forming a charge-transporting film containing a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure and an organic solvent.

[0022] That is, the present invention provides:

[0023] 1. A composition for forming a charge-transporting thin film, comprising: a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure, and an organic solvent;

[0024] 2.1 The composition for forming a charge transport thin film, further comprising a dopant substance,

[0025] 3. A charge transport thin film obtained from a composition for forming charge transport thin films of 1 or 2.

[0026] 4. Electronic components that have a 3-layer charge transport thin film.

[0027] 5. Organic electroluminescent elements, which have a 3% charge transport thin film.

[0028] 6.5 Organic electroluminescent element, wherein the charge transport thin film is a hole injection layer or a hole transport layer.

[0029] 7. A method for manufacturing a charge-transporting thin film, characterized in that a charge-transporting thin film forming composition of 1 or 2 is coated on a substrate and fired to detach the 9-tert-butoxycarbonyl group from the charge-transporting precursor.

[0030] The effects of the invention

[0031] The charge-transporting precursor used in this invention, having an intramolecular 9-tert-butoxycarbonylcarbazole structure, can be readily dissolved in low-polarity solvents that cause less damage to substrates and components made of organic compounds compared to highly polar amide solvents, thus facilitating the preparation of charge-transporting thin film compositions. Furthermore, even when dissolved together with dopant in such solvents, this charge-transporting precursor can be readily used to prepare charge-transporting thin film compositions. Moreover, thin films prepared from the charge-transporting thin film compositions of this invention exhibit excellent charge transport properties not only at high temperatures but also when sintered at low temperatures.

[0032] The charge-transporting thin film obtained from the composition for forming such a charge-transporting thin film according to the present invention is suitable for use as a thin film in electronic devices, primarily organic EL devices. In particular, by using the charge-transporting thin film of the present invention as a hole injection layer, organic EL devices with excellent brightness characteristics can be obtained.

[0033] Furthermore, the charge transport thin film forming composition of the present invention can reproduce thin films with excellent charge transport properties with good reproducibility even when using various wet methods such as slot coating and inkjet printing that can form films over large areas, thus fully meeting the developments in the field of organic EL devices in recent years. Detailed Implementation

[0034] The present invention will now be described in more detail.

[0035] The composition for forming charge-transporting thin films of the present invention contains a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure.

[0036] In this invention, charge transport is synonymous with conductivity and hole transport. A charge transport material is a substance that imparts charge transport properties to a solid film obtained using a charge transport thin film forming composition. It may possess charge transport properties on its own or exhibit charge transport properties when used with a charge acceptor material (also called a dopant material). Furthermore, a charge transport material precursor refers to a charge transport material that, during the process of forming a solid film using the charge transport thin film forming composition through external stimulation (e.g., heat), becomes a charge transport material with a different structure (e.g., undergoing a structural change through the removal of intramolecular protecting groups in the precursor), resulting in the manifestation or enhancement of charge transport properties to impart charge transport properties to the solid film. Regarding the charge transport material precursor and the charge transport material obtained therefrom, it may possess charge transport properties on its own or exhibit charge transport properties when used with a charge acceptor material.

[0037] In this invention, by protecting the nitrogen atom at the 9-position of the carbazole structure with a tert-butoxycarbonyl group (hereinafter also referred to as a Boc group), the solubility in low-polarity solvents such as toluene can be improved compared to the case of a carbazole structure without Boc protection and with the NH group exposed. Furthermore, by coating a charge-transporting film forming composition obtained by dissolving a charge-transporting precursor having a carbazole structure with the nitrogen atom at the 9-position protected by a Boc group in the molecule in a solvent onto a substrate and firing it, the Boc group is deactivated and the NH group is exposed, thereby obtaining a film with excellent charge transport properties.

[0038] The charge transport precursors used in this invention are not particularly limited as long as they have a 9-tert-butoxycarbonylcarbazole structure. Typically, examples include charge transport oligomers and charge transport polymers (linear and dendritic) containing a 9-tert-butoxycarbonylcarbazole structure that include repeating units such as aniline, thiophene, pyrrole, carbazole (indophyllocarbazole), or fluorene (including spirofluorene).

[0039] In such charge-transporting oligomers and polymers, the 9-tert-butoxycarbonylcarbazole structure may be present at the end of the molecule, at a position other than the end, or in both. For example, in the case of oligomers or polymers with repeating structures, it may be contained in the main chain, and in the case of side chains, it may be present in the side chains.

[0040] Furthermore, not all 9-tert-butoxycarbonylcarbazole structures are equivalent. For example, some may have substituents in the ring constituting the carbazole structure, while others may not. Additionally, some may share the benzene ring constituting the carbazole structure with other structures, while others may not share the benzene ring constituting the carbazole structure with other structures.

[0041] Furthermore, the 9-tert-butoxycarbonylcarbazole structure can exist randomly in charge-transporting compounds or as a block heterogeneous structure.

[0042] When the charge transport precursor used in this invention has two or more 9-tert-butoxycarbonylcarbazole structures, the two or more of these structures may share the benzene ring in these structures.

[0043] Furthermore, the number of 9-tert-butoxycarbonylcarbazole structures in the charge-transporting precursor used in this invention varies depending on the molecular structure and molecular weight, and therefore cannot be specified uniformly, but is typically 1 to 1,000.

[0044] When the charge-transporting precursor used in this invention is a charge-transporting oligomer compound, its molecular weight is typically 200 to 5,000. From the viewpoint of suppressing sublimation during firing and improving charge transport, it is preferably 300 or more, more preferably 500 or more, further preferably 700 or more, and even more preferably 1,000 or more. From the viewpoint of ensuring good solubility in organic solvents, it is preferably 4,500 or less, more preferably 4,000 or less, further preferably 3,500 or less, and even more preferably 3,000 or less.

[0045] Furthermore, when the charge-transporting precursor used in this invention is a charge-transporting polymer compound, its weight-average molecular weight is typically 6,000 to 200,000. From the viewpoint of improving charge transportability, it is preferably 7,000 or more, more preferably 8,000 or more, further preferably 9,000 or more, and even more preferably 10,000 or more. From the viewpoint of ensuring good solubility in organic solvents, it is preferably 150,000 or less, more preferably 100,000 or less, and even more preferably 75,000 or less.

[0046] It should be noted that the weight-average molecular weight in this invention is the average molecular weight obtained by gel permeation chromatography (GPC) analysis and converted to standard polystyrene.

[0047] In particular, when the charge transport precursor used in this invention is a charge transport oligomer compound containing a portion of the structure shown in formula (M2) described later, from the viewpoint of balancing charge transport, solubility of the precursor in organic solvents, and processability, the number of 9-tert-butoxycarbonylcarbazole structures in the precursor is generally 2 or more and 100 or less, preferably 75 or less, and more preferably 50 or less.

[0048] As a preferred example of a charge-transporting material precursor used in this invention, examples of charge-transporting material precursors comprising a portion of the structure described in the following formula (M1) can be listed, but are not limited thereto.

[0049] [Chemistry 1]

[0050]

[0051] In the formula, G is a monovalent group represented by the following formula (G1). From the viewpoint of improving charge transport and the ease of obtaining the starting material compound, the group represented by formula (G'1-1) or formula (G'1-2) is preferred.

[0052] [Chemistry 2]

[0053]

[0054] In the formula, R 11 ~R 17 The groups can be represented independently as hydrogen atoms, halogen atoms, nitro groups, cyano groups, or groups that can be substituted with halogen atoms, diphenylamino groups, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, or heteroaryl groups with 2 to 20 carbon atoms.

[0055] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with fluorine being the preferred choice.

[0056] Alkyl groups having 1 to 20 carbon atoms can be straight-chain, branched-chain, or cyclic. Examples include straight-chain or branched-chain alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic alkyl groups having 3 to 20 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, dicyclobutyl, dicyclopentyl, dicyclohexyl, dicycloheptyl, dicyclooctyl, dicyclononyl, and dicyclodecyl.

[0057] Specific examples of alkenyl groups having 2 to 20 carbon atoms include vinyl, n-1-propenyl, n-2-propenyl, 1-methylvinyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, and n-1-eicoseneyl.

[0058] Specific examples of alkynyl groups with 2 to 20 carbon atoms include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n-1-hexynyl, n-1-decynyl, n-1-pentadecanynyl, and n-1-eicosynyl.

[0059] Specific examples of aryl groups having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, and 9-phenanthyl.

[0060] Specific examples of heteroaryl groups having 2 to 20 carbon atoms include 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, and 4-pyridyl.

[0061] Specifically, as R 11 ~R 17 Preferably, the atom is hydrogen, fluorine, cyano, alkyl with 1 to 20 carbon atoms that can be substituted by halogen atoms, aryl with 6 to 20 carbon atoms that can be substituted by halogen atoms, and heteroaryl with 2 to 20 carbon atoms that can be substituted by halogen atoms. More preferably, the atom is hydrogen, fluorine, cyano, alkyl with 1 to 10 carbon atoms that can be substituted by halogen atoms, and phenyl with halogen atoms. Further preferably, the atom is hydrogen, fluorine, methyl, and trifluoromethyl. Most preferably, the atom is entirely hydrogen.

[0062] In the formula, L represents a single bond, or a divalent aliphatic hydrocarbon group with 1 to 20 carbon atoms, a divalent aromatic hydrocarbon group with 6 to 20 carbon atoms, or a divalent heteroaromatic hydrocarbon group with 2 to 20 carbon atoms. These groups can be further substituted by substituents.

[0063] Cy 1This refers to skeletons containing aromatic or heteroaromatic rings, such as those with a benzene skeleton, naphthalene skeleton, anthracene skeleton, pyrene skeleton, thiophene skeleton, furan skeleton, pyrrole skeleton, benzothiophene skeleton, benzofuran skeleton, benzopyrrole skeleton, dibenzothiophene skeleton, dibenzofuran skeleton, carbazole skeleton, fluorene skeleton, spirofluorene skeleton, triarylamine skeleton, diarylamine skeleton, monoarylamine skeleton, thienothiophene skeleton, thienobenzothiophene skeleton, and indolocarbazole skeleton. A -LG group is attached to these skeletons, replacing the hydrogen atoms on the aromatic or heteroaromatic rings or on the amine. Additionally, these skeletons may have substituents other than the -LG group.

[0064] As a more preferred form of the charge-transporting material precursor of the present invention, examples of charge-transporting material precursors that include a partial structure represented by the following formula (M2) can be listed, but are not limited thereto.

[0065] [Chemistry 3]

[0066]

[0067] In the formula, Cy 2 The two Cy groups independently represent the skeletons of aromatic hydrocarbons with 6 to 20 carbon atoms, such as benzene and naphthalene rings. 2 They can combine with each other to form rings. In addition, aromatic hydrocarbon skeletons can have substituents.

[0068] G and L represent the same meanings as above.

[0069] From the viewpoint of charge transport, a charge transport precursor containing a partial structure represented by formula (M2) may further contain at least one of the groups represented by any one of the following formulas (G2) to (G16) within its molecule, in addition to the group represented by formula (G1).

[0070] [Chemistry 4]

[0071]

[0072] [Chemistry 5]

[0073]

[0074] [Chemistry 6]

[0075]

[0076] [Chemistry 7]

[0077]

[0078] From the viewpoint of ease of obtaining the starting material compound and ease of synthesizing the precursor, the group represented by any one of the formulas (G2) to (G16) is preferably represented by any one of the formulas (G'2-1) to (G'16-5).

[0079] [Chemistry 8]

[0080]

[0081] [Chemistry 9]

[0082]

[0083] [Chemistry 10]

[0084]

[0085] [Chemistry 11]

[0086]

[0087] [Chemistry 12]

[0088]

[0089] [Chemistry 13]

[0090]

[0091] [Chemistry 14]

[0092]

[0093] Among them, R 18 ~R 24 R 26 ~R 155 and R 158 ~R 199 Independently representing hydrogen atoms, halogen atoms, nitro groups, cyano groups, or groups that can be substituted with halogen atoms, diphenylamino groups, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, or heteroaryl groups with 2 to 20 carbon atoms, R 156 and R 157 Independently represented by Z 1 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, R 25 Represents a hydrogen atom, which can be Z 4 Substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms, or groups that can be substituted by Z 1 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 1This represents a halogen atom, nitro group, cyano group, or a group that can be oxidized by Z. 2 Substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms, Z 2 This represents a halogen atom, nitro group, cyano group, or a group that can be oxidized by Z. 3 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 3 Z represents a halogen atom, nitro group, or cyano group. 4 Represents halogen atoms, nitro groups, cyano groups, or those that can be Z-type. 5 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 5 Represents halogen atoms, nitro groups, cyano groups, or those that can be Z-type. 3 Specific examples of substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms, as halogen atoms, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and heteroaryl groups having 2 to 20 carbon atoms, can be listed in relation to the above-mentioned R. 11 ~R 17 The same group as the group described in the text.

[0094] Specifically, as R 18 ~R 24 R 26 ~R 155 and R 158 ~R 199 Preferably, the atom is hydrogen, fluorine, cyano, diphenylamino that can be substituted with a halogen atom, alkyl that can be substituted with a halogen atom with 1 to 20 carbon atoms, aryl that can be substituted with a halogen atom with 6 to 20 carbon atoms, or heteroaryl that can be substituted with a halogen atom. More preferably, the atom is hydrogen, fluorine, cyano, alkyl that can be substituted with a halogen atom with 1 to 10 carbon atoms, or phenyl that can be substituted with a halogen atom. Further preferably, the atom is hydrogen, fluorine, methyl, or trifluoromethyl. Most preferably, the atom is hydrogen.

[0095] Additionally, as R 25 Preferred hydrogen atoms, which can be Z 1 The aryl group with 6 to 20 carbon atoms can be substituted by Z 1 Substituted heteroaryl groups with 2 to 20 carbon atoms can be Z-substituted. 4 The substituted alkyl group having 1 to 20 carbon atoms, more preferably a hydrogen atom, can be Z 1 The aryl group with 6 to 14 carbon atoms can be substituted by Z 1 Substituted heteroaryl groups with 2 to 14 carbon atoms can be Z-substituted. 4 The substituted alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom, can be Z 1 The aryl group with 6 to 14 carbon atoms can be substituted by Z 1Substituted nitrogen-containing heteroaryl groups with 2 to 14 carbon atoms can be Z-substituted. 4 The substituted alkyl group having 1 to 10 carbon atoms is preferred, and hydrogen atoms are even more preferred. 1 Substituted phenyl, which can be Z 1 Substituted 1-naphthyl, which can be Z 1 Substituted 2-naphthyl, which can be Z 1 Substituted 2-pyridyl, can be Z 1 Substituted 3-pyridyl, which can be Z 1 Substituted 4-pyridyl, which can be Z 4 Substituted methyl group.

[0096] Moreover, as R 156 and R 157 Z is preferred 1 The aryl group with 6 to 14 carbon atoms can be substituted by Z 1 The substituted heteroaryl group having 2 to 14 carbon atoms is more preferably Z 1 The substituted aryl group having 6 to 14 carbon atoms is further preferably Z 1 Substituted phenyl, which can be Z 1 Substituted 1-naphthyl, which can be Z 1 Substituted 2-naphthyl group.

[0097] Additionally, Ar 13 Each of these terms independently represents an aryl group with 6 to 20 carbon atoms that can be substituted with a di(aryl)amino group (6 to 20 carbon atoms). Specific examples of aryl groups with 6 to 20 carbon atoms include those with R... 11 ~R 17 The same group described herein, as specific examples of di(aryl)amino (with 6 to 20 carbon atoms), can be listed as diphenylamino, 1-naphthylphenylamino, di(1-naphthyl)amino, 1-naphthyl-2-naphthylamino, di(2-naphthyl)amino, etc.

[0098] As Ar 13 Preferred compounds include phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, 9-phenanthyl, p-(diphenylamino)phenyl, p-(1-naphthylphenylamino)phenyl, p-(di(1-naphthyl)amino)phenyl, p-(1-naphthyl-2-naphthylamino)phenyl, and p-(di(2-naphthyl)amino)phenyl, with p-(diphenylamino)phenyl being more preferred.

[0099] Furthermore, in R 25 R 156 and R 157 In the middle, Z 1 Preferred halogen atoms, nitro groups, cyano groups, and those that can be Z 2 Alkyl groups with 1 to 10 carbon atoms that can be substituted, and can be Z2 Alkenes with 2 to 10 carbon atoms that can be substituted can be Z 2 The substituted alkyne group having 2 to 10 carbon atoms is preferred, as is a halogen atom, nitro group, cyano group, or a group that can be substituted by Z. 2 Alkyl groups with 1 to 3 carbon atoms that can be substituted, and can be Z 2 Alkenes with 2 to 3 carbon atoms that are substituted can be Z 2 The substituted 2-3 carbon alkynyl group, preferably with fluorine atom, can be substituted by Z. 2 Alkyl groups with 1 to 3 carbon atoms that can be substituted, and can be Z 2 Alkenes with 2 to 3 carbon atoms that are substituted can be Z 2 The substituted acetylene group has 2 to 3 carbon atoms.

[0100] In R 25 R 156 and R 157 In the middle, Z 4 Preferred halogen atoms, nitro groups, cyano groups, and those that can be Z 5 The substituted aryl group having 6 to 14 carbon atoms is preferred, as is a halogen atom, nitro group, cyano group, or a group that can be substituted by Z. 5 The aryl group with 6 to 10 carbon atoms is substituted, and fluorine atoms are further preferred, which can be substituted by Z. 5 The aryl group with 6 to 10 carbon atoms is substituted, and fluorine atoms are further preferred, which can be substituted by Z. 5 Substituted phenyl groups.

[0101] In R 25 R 156 and R 157 In the middle, Z 2 Preferred halogen atoms, nitro groups, cyano groups, and those that can be Z 3 The substituted aryl group having 6 to 14 carbon atoms is preferred, as is a halogen atom, nitro group, cyano group, or a group that can be substituted by Z. 3 The aryl group with 6 to 10 carbon atoms is substituted, and fluorine atoms are further preferred, which can be substituted by Z. 3 The aryl group with 6 to 10 carbon atoms is substituted, and fluorine atoms are further preferred, which can be substituted by Z. 3 Substituted phenyl groups.

[0102] In R 25 R 156 and R 157 In the middle, Z 5 Preferred halogen atoms, nitro groups, cyano groups, and those that can be Z 3 Alkyl groups with 1 to 10 carbon atoms that can be substituted, and can be Z 3 Alkenes with 2 to 10 carbon atoms that can be substituted can be Z 3 The substituted alkyne group having 2 to 10 carbon atoms is preferred, as is a halogen atom, nitro group, cyano group, or a group that can be substituted by Z. 3 Alkyl groups with 1 to 3 carbon atoms that can be substituted, and can be Z 3 Alkenes with 2 to 3 carbon atoms that are substituted can be Z 3The substituted 2-3 carbon alkynyl group, preferably with fluorine atom, can be substituted by Z. 3 Alkyl groups with 1 to 3 carbon atoms that can be substituted, and can be Z 3 Alkenes with 2 to 3 carbon atoms that are substituted can be Z 3 The substituted acetylene group has 2 to 3 carbon atoms.

[0103] In R 25 R 156 and R 157 In the middle, Z 3 Halogen atoms are preferred, and fluorine atoms are even more preferred.

[0104] In this invention, as R 25 Specific examples of preferred functional groups may be listed below, but are not limited to these.

[0105] [Chemistry 15]

[0106]

[0107] [Chemistry 16]

[0108]

[0109] [Chemistry 17]

[0110]

[0111] [Chemistry 18]

[0112]

[0113] [Chemistry 19]

[0114]

[0115] [Chemistry 20]

[0116]

[0117] While not limited to this, typical examples of preferred precursors for charge-transporting substances include aniline derivatives represented by the following formula (1).

[0118] [Chemistry 21]

[0119]

[0120] Ph in equation (1) above 1 The group represented by formula (P1).

[0121] [Chemistry 22]

[0122]

[0123] R 200 ~R 203 The terms "hydrogen atom," "halogen atom," "nitro group," "cyano group," or "alkyl group with 1 to 20 carbon atoms," "alkenyl group with 2 to 20 carbon atoms," "alkynyl group with 2 to 20 carbon atoms," "aryl group with 6 to 20 carbon atoms," or "heteroaryl group with 2 to 20 carbon atoms" can be used independently to represent specific examples of these halogen atoms, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, and heteroaryl groups with 2 to 20 carbon atoms. Examples of these halogen atoms, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, and heteroaryl groups with 2 to 20 carbon atoms can be listed. 11 ~R 17 The same group as the group described in the text.

[0124] Specifically, as R 200 ~R 203 Preferably, the atom is hydrogen, fluorine, cyano, alkyl with 1 to 20 carbon atoms that can be substituted by halogen atoms, aryl with 6 to 20 carbon atoms that can be substituted by halogen atoms, or heteroaryl with 2 to 20 carbon atoms that can be substituted by halogen atoms. More preferably, the atom is hydrogen, fluorine, cyano, alkyl with 1 to 10 carbon atoms that can be substituted by halogen atoms, or phenyl with halogen atoms. Further preferably, the atom is hydrogen, fluorine, methyl, or trifluoromethyl. Most preferably, the atom is hydrogen.

[0125] On the other hand, Ar in equation (1) 11 and Ar 12 Each of the above formulas (G1) to (G16) represents a group independently, but at least one of them represents a group represented by formula (G1).

[0126] Additionally, preferably, Ar 11 and Ar 12 It represents any one of the above formulas (G'1-1) to (G'16-5), but at least one represents the group represented by the above formula (G'1).

[0127] In formula (1), k is an integer from 1 to 20. From the viewpoint of charge transport, it is preferably 2 or more. From the viewpoint of the solubility of the precursor in organic solvent, it is preferably 10 or less, and more preferably 5 or less.

[0128] In formula (1), from the viewpoint of ease of obtaining the raw material compound and ease of synthesizing the precursor, preferably, all Ar 11 And all of Ar 12 Indicates the same group, or all of Ar 11 Representing the same group and all Ar 12 Indicates the same group.

[0129] Furthermore, R in equation (1) 11 ~R 199 and Ar13 The preferred conditions for the groups contained therein are the same as those described above.

[0130] In this invention, the number of carbon atoms in the alkyl, alkenyl, and alkynyl groups is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less.

[0131] Furthermore, the number of carbon atoms in the aforementioned aryl and heteroaryl groups is preferably 14 or less, more preferably 10 or less, and even more preferably 6 or less.

[0132] In this invention, considering the balance between the ease of obtaining the raw materials of the aniline derivative, the solubility of the compound, and the charge transport properties of the resulting charge transport film, an example of a preferred aniline derivative is represented by formula (1').

[0133] [Chemistry 23]

[0134]

[0135] In equation (1'), Ar 21 and Ar 22 Independently composed of hydrogen atoms, groups represented by formula (2) or groups represented by formula (3), 2 Ar atoms 21 and 3 Ar 22 At least one of them is a group represented by formula (3).

[0136] [Chemistry 24]

[0137]

[0138] In equation (2), Ar 1 and Ar 2 Ar groups, representing aryl groups with 6 to 20 carbon atoms, are independent of each other. 3 Ar represents arylene groups with 6 to 20 carbon atoms. 1 ~Ar 3 At least two of them can combine with each other to form a ring with the nitrogen atom.

[0139] Specific examples of aryl groups having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, and 9-phenanthyl.

[0140] Specific examples of arylene groups having 6 to 20 carbon atoms include phenyl-1,2-diyl (o-phenylene), phenyl-1,3-diyl (m-phenylene), phenyl-1,4-diyl (p-phenylene), naphthyl-1,2-diyl, naphthyl-1,3-diyl, naphthyl-1,4-diyl, naphthyl-1,5-diyl, naphthyl-1,6-diyl, naphthyl-1,7-diyl, and naphthyl-1,8-diyl.

[0141] In addition, as Ar 1 ~Ar 3 Any two atoms in the atom can combine with nitrogen atoms to form a ring, such as the carbazole ring.

[0142] Among these, Ar 1 and Ar 2 Phenyl, 1-naphthyl, and 2-naphthyl are preferred, with phenyl being more preferred.

[0143] Additionally, Ar 3 The preferred forms are phenyl-1,2-diyl, phenyl-1,3-diyl, and phenyl-1,4-diyl, with phenyl-1,4-diyl being more preferred.

[0144] Therefore, the group represented by formula (2) is preferably the group represented by formula (2A), and more preferably the group represented by formula (2A-1).

[0145] [Chemistry 25]

[0146]

[0147] As the group represented by the above formula (3), it is preferred to be the group represented by the following formula (3A).

[0148] [Chemistry 26]

[0149]

[0150] From the viewpoint of ease of synthesis, the aniline derivative represented by the above formula (1') preferably has symmetry. Specific examples include all Ar... 21 And all of Ar 22 Examples of the same group (e.g., formula (1'-1)), all Ar 21 All Ar are the same group 22 Examples of the same group (e.g., formulas (1'-2) and (1'-3)).

[0151] [Chemistry 27]

[0152]

[0153] (where G is in the formula) 2 G represents the group represented by the above formula (2A-1). 3 (This refers to the group represented by formula (3A) above.)

[0154] The aniline derivative represented by formula (1) used in this invention can be produced by reacting an amine compound represented by formula (5) with an aryl compound represented by formula (6) in the presence of a catalyst to obtain an amine compound represented by formula (7), and by reacting an amine compound represented by formula (7) with an aryl compound represented by formula (8) in the presence of a catalyst.

[0155] [Chemistry 28]

[0156]

[0157] (In the formula, X represents a halogen atom or a pseudohalogen group, Ar) 11 Ar 12 Ph 1 (and k represent the same meaning as above.)

[0158] As halogen atoms, the same halogen atoms as those mentioned above can be listed.

[0159] Examples of pseudohalogen groups include (fluorinated) alkyl sulfonyl groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy, and nonafluorobutyryloxy; and aromatic sulfonyl groups such as benzenesulfonyloxy and toluenesulfonyloxy.

[0160] Regarding the feed ratio of the amine compound represented by formula (5) to the aryl compound represented by formula (6), the aryl compound can be at least 2 equivalents relative to the amine compound, preferably around 2 to 2.4 equivalents. Furthermore, in this reaction, the amino group (-NH2) represented by formula (5) has low steric hindrance, etc., and Ar... 11 The introduction of the base at both ends is carried out preferentially.

[0161] In addition, regarding the feed ratio of the amine compound represented by formula (7) to the aryl compound represented by formula (8), the aryl compound can be 2 equivalents or more, preferably about 2 to 2.4 equivalents, relative to the amine compound.

[0162] Furthermore, in the manufacture of Ar 11 and Ar 12 In the case of aniline derivatives represented by formula (1) with the same group, the process can be carried out in two stages as described above, such as obtaining an amine compound represented by formula (7) and obtaining an aniline derivative represented by formula (1), or it can be carried out in one stage. In this case, the feed ratio is about 4 to 4.8 equivalents relative to the amine compound represented by formula (5).

[0163] Examples of catalysts used in the above reactions include copper catalysts such as copper chloride, copper bromide, and copper iodide; and palladium catalysts such as Pd(PPh3)4 (tetra(triphenylphosphine)palladium), Pd(PPh3)2Cl2 (bis(triphenylphosphine)palladium dichloride), Pd(dba)2 (bis(dibenzylacetone)palladium), Pd2(dba)3 (tris(dibenzylacetone)dipalladium), Pd(Pt-Bu3)2 (bis(tris(tert-butylphosphine))palladium), and Pd(OAc)2 (palladium acetate). These catalysts can be used individually or in combination of two or more. Furthermore, these catalysts can be used with suitable, known ligands.

[0164] Examples of such ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-tert-butylphosphine, di-tert-butyl(phenyl)phosphine, di-tert-butyl(4-dimethylaminophenyl)phosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, and trimethyl phosphite, triethyl phosphite, triphenyl phosphite, and triphosphite triesters.

[0165] Regarding the amount of catalyst used, it can be set to about 0.2 mol relative to 1 mol of the aryl compound, preferably about 0.15 mol.

[0166] Furthermore, when using a ligand, the amount used can be set to 0.1 to 5 equivalents, preferably 1 to 2 equivalents, relative to the metal complex used.

[0167] When the starting compounds are all solids, or from the viewpoint of efficiently obtaining the target aniline derivative, the above reactions are carried out in a solvent. There are no particular restrictions on the type of solvent used, as long as it does not adversely affect the reaction. Specific examples include aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decahydronaphthalene, etc.), halogenated aliphatic hydrocarbons (chloroform, dichloromethane, dichloroethane, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, etc.), and ethers (diethyl ether, diisopropyl ether, tert-butylmethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, etc.). Solvents such as 1,2-diethoxyethane, ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, cyclohexanone, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, etc.), lactams and lactones (N-methylpyrrolidone, γ-butyrolactone, etc.), ureas (N,N-dimethylimidazolinone, tetramethylurea, etc.), sulfoxides (dimethyl sulfoxide, sulfolane, etc.), and nitriles (acetonitrile, propionitrile, butyronitrile, etc.) can be used individually or in combination.

[0168] Regarding the reaction temperature, it can be appropriately set within the range of the melting point to the boiling point of the solvent used, particularly preferably around 0 to 200°C, and more preferably 20 to 150°C.

[0169] After the reaction is complete, post-processing according to conventional methods can yield the target aniline derivative.

[0170] Furthermore, the aniline derivative represented by formula (1') used in this invention can be manufactured by reacting an amine compound represented by formula (9) with an aryl compound represented by formula (10) in the presence of a catalyst to obtain an amine compound represented by formula (11), and by reacting an amine compound represented by formula (11) with an aryl compound represented by formula (12) in the presence of a catalyst. In this case, the reaction conditions (feed ratio, catalyst, solvent, etc.) can be referred to the above description of formula (1).

[0171] [Chemistry 29]

[0172]

[0173] (where X and Ar are in the formula) 21 and Ar 22 This indicates the same meaning as above.

[0174] Furthermore, the raw materials used in this invention, namely compounds represented by the following formula (G1”), can be obtained by the following known method: reacting the corresponding carbazole with a Bocating agent such as ditert-butyl dicarbonate in the presence of a base such as pyridine or triethylamine.

[0175] [Chemistry 30]

[0176]

[0177] (where X and R are in the formula) 11 ~R 17 This indicates the same meaning as above.

[0178] In addition, the charge-transporting precursors with an intramolecular 9-tert-butoxycarbonylcarbazole structure used in this invention, such as aniline derivatives represented by formula (1) or formula (1'), can also be manufactured by removing other groups from compounds having groups other than the Boc group at the 9 position of the carbazole site, to obtain compounds with a proton at the 9 position of the carbazole site, and introducing a Boc group at the 9 position of the carbazole site in the obtained compounds.

[0179] As for other protecting groups, there are no particular limitations as long as they can be appropriately removed. Typical examples include tert-butyldimethylsilyl and benzyl groups, which can be removed under relatively mild conditions, but these are not the only possibilities. Furthermore, the removal of other protecting groups can be carried out using methods that involve treatment under acidic or basic conditions, or under oxidizing or reducing conditions. For example, refer to GREEN'S PROTECTIVE GROUPS in Organic Synthesis, 4th Edition, and consider the properties of the other protecting groups when using appropriate known methods.

[0180] The introduction of the Boc group can be carried out using the following well-known method: reacting a compound with a proton at the 9-position of the carbazole site with a Bocating agent such as ditert-butyl dicarbonate in the presence of a base such as pyridine or triethylamine.

[0181] The following are specific examples of reactions, but are not limited to these.

[0182] [Chemistry 31]

[0183]

[0184] (where G is in the formula) p G represents a group represented by the following formula (3A-P). H G represents a group represented by the following formula (3A-H). X G represents 4-diphenylaminophenyl. 2 and G 3 This indicates the same meaning as above.

[0185] [Chemistry 32]

[0186]

[0187] (P represents a protecting group other than the Boc group.)

[0188] From the viewpoint of ease of synthesis, the aniline derivative represented by the above formula (1) preferably has symmetry. As a specific example, R can be exemplified. 1 ~R 5 All of which are compounds represented by the groups represented by the above formula (3A) and represented by the following formula (1A), R 1 R 3 and R 5 For hydrogen atoms, R 2 and R 4 Compounds represented by formula (1B) for groups represented by formula (3A) above, R 1 R 3 and R 5 For the group represented by the above formula (2A-1), R 2 and R 4 Compounds represented by formula (1C) for groups represented by formula (3A) above, R 1 R 3 and R 5 The group represented by the above formula (3A) and R 2 and R 4 Compounds represented by the following formula (1D) that are groups represented by the above formula (2A-1) are included, but are not limited to these.

[0189] [Chemistry 33]

[0190]

[0191] The aniline derivative represented by formula (1') used in this invention can be produced by coupling an amine compound represented by formula (1") with a carbazole compound represented by formula (3') in the presence of a catalyst and a base.

[0192] Furthermore, the compound represented by formula (3') can be obtained by the following known method: reacting the corresponding carbazole with a borate reagent such as di-tert-butyl dicarbonate in the presence of a base such as pyridine or triethylamine.

[0193] [Chemistry 34]

[0194]

[0195] (where X and R are in the formula) 21 ~R 22This indicates the same meaning as above.

[0196] The composition for forming a charge-transporting thin film of the present invention comprises: a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure, and an organic solvent. Depending on the intended use of the resulting thin film, it may contain a dopant material for the purpose of improving its charge-transporting capability, etc.

[0197] As a dopant, there are no particular limitations as long as it is soluble in at least one solvent used in the composition; both inorganic and organic dopant substances can be used.

[0198] Furthermore, the dopant material can be a substance whose function as a dopant material is first manifested or enhanced by removing a portion of its molecules during the process of obtaining a charge-transporting thin film as a solid film from the composition, for example by external stimulation such as heating during firing. For example, aryl sulfonate compounds protected by sulfonic acid groups that are easily detached.

[0199] As a dopant material for inorganic systems, heteropoly acids are preferred. Specific examples include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, phosphotungstic acid, and silicomolybdic acid.

[0200] Heteropolyacids are polyacids, typically represented by the Keggin type (D1) or Dawson type (D2) chemical structures, with the heteroatom located at the center of the molecule. They are formed by the condensation of isopolyacids of vanadium (V), molybdenum (Mo), tungsten (W), etc., with oxyacids of dissimilar elements. Examples of such dissimilar oxyacids include those of silicon (Si), phosphorus (P), and arsenic (As).

[0201] [Chemistry 35]

[0202]

[0203] Specific examples of heteropoly acids include phosphomolybdic acid, silimolybdic acid, phosphotungstic acid, silimolybdic acid, and phosphotungmolybdic acid, which can be used alone or in combination of two or more. Furthermore, the heteropoly acids used in this invention are commercially available, and can also be synthesized using known methods.

[0204] In particular, when using one heteropolyacid, phosphotungstic acid or phosphomolybdic acid is preferred, and phosphotungstic acid is most preferred. Furthermore, when using two or more heteropolyacids, phosphotungstic acid or phosphomolybdic acid is preferred, and phosphotungstic acid is more preferred.

[0205] It should be noted that heteropolyacids can be used in this invention, even if the number of elements is greater or less than that of the structure represented by the general formula, as long as they are products obtained as commercial products or products appropriately synthesized according to known synthetic methods.

[0206] That is, for example, generally, phosphotungstic acid is represented by the chemical formula H3(PW) 12 O 40 Phosphomolybdic acid is represented by the chemical formula H3(PMo)·nH2O. 12 O 40 The expression ·nH2O indicates that, in quantitative analysis, regardless of the quantity of P (phosphorus), O (oxygen), W (tungsten), or Mo (molybdenum) in the formula, as long as it is a commercially available product or a product appropriately synthesized according to a known synthetic method, it can be used in this invention. In this case, the mass of the heteropolyacid specified in this invention is not the mass of pure phosphotungstic acid in the synthesized product or commercially available product (phosphotungstic acid content), but rather means the total mass in the form available as a commercial product and in the form separable by a known synthetic method, including hydrated water, other impurities, etc.

[0207] Regarding the heteropolyacid contained in the composition for forming charge-transporting thin films of the present invention, expressed as a mass ratio, it can be set to about 0.01 to 50 relative to the charge-transporting substance 1, preferably about 0.1 to 10, and more preferably about 1.0 to 5.0.

[0208] In addition, examples of organic dopants include aryl sulfonic acids, aryl sulfonates, ionic compounds consisting of a defined anion and its countercation, tetracyanoquinone dimethane derivatives, and benzoquinone derivatives.

[0209] Examples of tetracyanoquinone dimethane derivatives include 7,7,8,8-tetracyanoquinone dimethane (TCNQ), 2-fluoro-7,7,8,8-tetracyanoquinone dimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinone dimethane, tetrafluoro-7,7,8,8-tetracyanoquinone dimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinone dimethane, 2-fluoro-7,7,8,8-tetracyanoquinone dimethane, 2-chloro-7,7,8,8-tetracyanoquinone dimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinone dimethane, and 2,5-dichloro-7,7,8,8-tetracyanoquinone dimethane.

[0210] Examples of benzoquinone derivatives include tetrachloro-1,4-benzoquinone (tetrachloro-p-benzoquinone) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ).

[0211] In particular, compounds represented by the following formula (4) or (5) are preferred as aryl sulfonic acids.

[0212] [Chemistry 36]

[0213]

[0214] In equation (4), D 1 Indicates -O- or -S-, with -O- preferred. D 2 Indicates a naphthalene ring or anthracene ring, preferably a naphthalene ring. D 3 This refers to perfluorobiphenyl with valences of 2 to 4. 1 D represents 1 With D 3 The associativity of is such that 2 ≤ j 1 For integers ≤4, D is preferred. 3 It is a divalent perfluorobiphenyl, and j 1 It is 2. j 2 Indicates D 2 The number of sulfonic acid groups bound satisfies 1 ≤ j 2 Integers ≤ 4, preferably 2.

[0215] In equation (5), D 4 ~D 8 Independently representing hydrogen atoms, halogen atoms, cyano groups, alkyl groups with 1 to 20 carbon atoms, haloalkyl groups with 1 to 20 carbon atoms, or haloalkenyl groups with 2 to 20 carbon atoms, D 4 ~D 8 At least three of them are halogen atoms. i represents the number of sulfonic acid groups bonded to the naphthalene ring, which is an integer satisfying 1≤i≤4, preferably 2 to 4, and more preferably 2.

[0216] Alkyl groups having 1 to 20 carbon atoms can be straight-chain, branched-chain, or cyclic. Examples include straight-chain or branched-chain alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic alkyl groups having 3 to 20 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, dicyclobutyl, dicyclopentyl, dicyclohexyl, dicycloheptyl, dicyclooctyl, dicyclononyl, and dicyclodecyl.

[0217] Examples of alkyl halogens having 1 to 20 carbon atoms include trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, perfluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, and perfluorobutyl. Examples of alkenyl halogens having 2 to 20 carbon atoms include perfluorovinyl, 1-perfluoropropenyl, perfluoroallyl, and perfluorobutenyl.

[0218] Examples of halogen atoms include the same halogen atoms as those mentioned above, with fluorine atoms being preferred.

[0219] Of these, D 4 ~D 8 Preferably, it is 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 D 4 ~D 8 At least three of them are fluorine atoms, more preferably hydrogen atoms, fluorine atoms, cyano groups, alkyl groups having 1 to 5 carbon atoms, fluoroalkyl groups having 1 to 5 carbon atoms, or fluoroalkenyl groups having 2 to 5 carbon atoms, and D 4 ~D 8 At least three 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 D 4 D 5 and D 8 It is a fluorine atom.

[0220] It should be noted that perfluoroalkyl is a group in which all the hydrogen atoms of an alkyl group are replaced by fluorine atoms, and perfluoroalkenyl is a group in which all the hydrogen atoms of an alkenyl group are replaced by fluorine atoms.

[0221] Specific examples of preferred aryl sulfonic acids include those shown below, but are not limited to these.

[0222] [Chemistry 37]

[0223]

[0224] In particular, from the viewpoint of the preservation stability of the composition, aryl sulfonate compounds are preferred, for example, aryl sulfonate compounds represented by the following formula (6) or (6') are preferred.

[0225] [Chemistry 38]

[0226]

[0227] In equations (6) and (6'), A 1 It is a hydrocarbon group with a carbon number of 6 to 20 that may have substituents and contains one or more aromatic rings, or a group with an m-valence derived from a compound represented by formula (7) or (8) below.

[0228] [Chemistry 39]

[0229]

[0230] (where W) 2 and W 3They can be independently -O-, -S-, -S(O)-, or -S(O2)-, or may have substituents such as -N-, -Si-, -P-, or -P(O)-.

[0231] The aforementioned hydrocarbon group with a carbon number of 6 to 20 and an m-valence comprising one or more aromatic rings is a group obtained by removing m hydrogen atoms from a hydrocarbon comprising one or more aromatic rings comprising 6 to 20 carbon atoms. Examples of hydrocarbons comprising one or more aromatic rings include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. Among these, groups derived from benzene, biphenyl, etc., are preferred as the aforementioned hydrocarbon group.

[0232] Regarding the aforementioned hydrocarbon group, some or all of its hydrogen atoms may be further replaced by substituents. These substituents may be fluorine, chlorine, bromine, iodine, nitro, cyano, hydroxyl, amino, silanol, thiol, carboxyl, sulfonate, phosphate, phosphate ester, ester, thioester, amide, monovalent hydrocarbon, organooxy, organoamino, organosilicon, organosulfur, acyl, sulfonyl, etc.

[0233] Among them, the monovalent hydrocarbon groups mentioned above can be alkyl groups with 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; alkenyl groups with 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl, xylyl, tolyl, 1-naphthyl, and 2-naphthyl; and aralkyl groups with 7 to 20 carbon atoms, such as benzyl and phenylethyl.

[0234] Examples of the aforementioned organic oxygen groups include alkoxy, alkenoxy, and aryloxy groups. Examples of the alkyl, alkenyl, and aryl groups contained therein include groups identical to those described above.

[0235] Examples of the aforementioned organic amino groups include alkylamino groups with 1 to 12 carbon atoms, such as methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, cyclohexylamino, heptylamino, octylamino, nonylamino, decylamino, and dodecylamino; dialkylamino groups with each alkyl group having 1 to 12 carbon atoms, such as dimethylamino, diethylamino, dipropylamino, dibutylamino, dipentylamino, dihexylamino, dicyclohexylamino, diheptylamino, dioctylamino, dinonylamino, and didecylamino; and morpholinoyl groups, etc.

[0236] Examples of the aforementioned organosilicon alkyl groups include trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, pentyldimethylsilyl, hexyldimethylsilyl, octyldimethylsilyl, and decyldimethylsilyl, where each alkyl group has 1 to 10 carbon atoms.

[0237] Examples of the aforementioned organothio groups include alkylthio groups with 1 to 12 carbon atoms, such as methylthio, ethylthio, propanethio, butanethio, pentanethio, hexanethio, heptanethio, octanethio, nonanethio, decanethio, and dodecanethio.

[0238] Examples of acyl groups with 1 to 10 carbon atoms include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, and benzoyl.

[0239] Furthermore, the number of carbon atoms in the aforementioned monovalent hydrocarbon group, organic oxygen group, organic amino group, organic silyl group, organic sulfur group, and acyl group is preferably 1 to 8.

[0240] Among these substituents, fluorine atoms, sulfonic acid groups, alkyl groups, organooxy groups, and organosilicon alkyl groups are preferred.

[0241] In equation (6), A 2 The form can be -O-, -S-, or -NH-. Among these, -O- is preferred for ease of synthesis.

[0242] In equation (6), A 3 An aromatic group is an aromatic group with a carbon number of 6 to 20 and a valence of (n+1). The aforementioned aromatic group is obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic compound with a carbon number of 6 to 20. Furthermore, in this invention, aromatic compound refers to aromatic hydrocarbons and aromatic heterocyclic compounds. Examples of such aromatic compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc., among which, as an aromatic compound derived from A... 3 The aromatic group indicated is preferably a group derived from naphthalene or anthracene.

[0243] In equations (6) and (6'), X 1 It is an alkylene group having 2 to 5 carbon atoms. Furthermore, the aforementioned alkylene group may have -O-, -S-, or carbonyl groups between its carbon atoms, and some or all of its hydrogen atoms may be further substituted by alkyl groups having 1 to 20 carbon atoms. As X 1Preferably, ethylene, trimethylene, methyleneoxymethylene, methylenethiomethylene, etc., and some or all of the hydrogen atoms in these groups may be further replaced by alkyl groups having 1 to 20 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dicyclohexyl, etc.

[0244] In equations (6) and (6'), X 2 For single bonds, -O-, -S-, or -NR a -. R a It is a monovalent hydrocarbon group consisting of a hydrogen atom or 1 to 10 carbon atoms. Alkyl groups such as methyl, ethyl, and n-propyl are preferred as the monovalent hydrocarbon group. As X 2 Preferred is a single bond, -O- or -S-, more preferably a single bond or -O-.

[0245] In equations (6) and (6'), X 3 This refers to a monovalent hydrocarbon group having 1 to 20 carbon atoms that can be substituted. Examples of such monovalent hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dicyclohexyl, and other alkyl groups having 1 to 20 carbon atoms; vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2... -Butenyl, 3-butenyl, hexenyl, and other alkenyl groups with 2 to 20 carbon atoms; phenyl, xylyl, tolyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, 9-phenanthyl, 2-biphenyl, 3-biphenyl, 4-biphenyl, and other aryl groups with 6 to 20 carbon atoms; benzyl, phenylethyl, phenylcyclohexyl, and other aralkyl groups with 7 to 20 carbon atoms. Furthermore, some or all of the hydrogen atoms of the above-mentioned monovalent hydrocarbon groups may be further substituted with substituents. Examples of substituents include those related to A... 1 The same substituents as described in the specification. As X 3 Preferably, it is an alkyl group with 1 to 20 carbon atoms, or an aryl group with 6 to 20 carbon atoms.

[0246] In equations (6) and (6'), m is an integer satisfying 1≤m≤4, preferably 2. n is an integer satisfying 1≤n≤4, preferably 2.

[0247] Aryl sulfonate compounds represented by formula (6) or (6') exhibit high solubility in a wide range of solvents containing low polarity, thus allowing for the use of a variety of solvents to adjust the physical properties of the solution and resulting in excellent coating characteristics. Therefore, coating in the sulfonate state is preferred, with sulfonic acid generated during the drying or firing of the coating film. The temperature at which sulfonic acid is generated from the sulfonate is preferably stable at room temperature and below the firing temperature, thus it can be 40–260°C. Furthermore, considering the high stability within the composition and ease of detachment during firing, 80–230°C is preferred, and 120–180°C is more preferred.

[0248] As an aryl sulfonate compound represented by formula (6), it is preferred to be a compound represented by any one of the following formulas (6-1) to (6-3).

[0249] [Chemistry 40]

[0250]

[0251] (In the formula, m and n are the same as above.)

[0252] In equation (6-1), A 11 A is an m-valent group derived from perfluorobiphenyl. 12 It can be -O- or -S-, with -O- preferred. A 13 It is a (n+1) valence group derived from naphthalene or anthracene, preferably a group derived from naphthalene.

[0253] In equation (6-1), R s1 ~R s4 Independently composed of hydrogen atoms, or alkyl groups having 1 to 6 carbon atoms in a straight or branched form, R s5 It is a monovalent hydrocarbon group with 2 to 20 carbon atoms that can be substituted.

[0254] The linear or branched alkyl group described above is not particularly limited, and examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and n-hexyl. Among these, alkyl groups having 1 to 3 carbon atoms are preferred.

[0255] Examples of monovalent hydrocarbon groups with 2 to 20 carbon atoms include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, as well as aryl groups such as phenyl, naphthyl, and phenanthrene.

[0256] R s1 ~R s4 Among them, R is preferred. s1 or R s3 It is a straight-chain alkyl group with 1 to 3 carbon atoms, and the remainder is hydrogen atoms, or R s1 R is a straight-chain alkyl group having 1 to 3 carbon atoms. s2 ~R s4It is a hydrogen atom. As a straight-chain alkyl group having 1 to 3 carbon atoms, methyl is preferred. Additionally, as R... s5 Preferably, it is a straight-chain alkyl or phenyl group with 2 to 4 carbon atoms.

[0257] In equation (6-2), A 14 This refers to a substituted hydrocarbon group containing one or more aromatic rings with 6 to 20 carbon atoms and an m-valent group. The aforementioned hydrocarbon group is obtained by removing m hydrogen atoms from a hydrocarbon containing one or more aromatic rings with 6 to 20 carbon atoms. Examples of such hydrocarbons include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, and phenanthrene. Furthermore, with respect to the aforementioned hydrocarbon group, some or all of its hydrogen atoms may be further substituted with substituents. Examples of such substituents include those related to A... 1 The same substituents as described in the specification. As A 14 Preferably, examples related to A can be listed. 1 The preferred example illustrates the same group as the group.

[0258] In equation (6-2), A 15 It can be either -O- or -S-, with -O- being preferred.

[0259] In equation (6-2), A 16 An aromatic group is an aromatic group with a valence of (n+1) carbon atoms, having a carbon number of 6 to 20. These aromatic groups are obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic compound having a carbon number of 6 to 20. Examples of such aromatic compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. Among these, A... 16 Preferably, the group is derived from naphthalene or anthracene, and more preferably from naphthalene.

[0260] In equation (6-2), R s6 and R s7 Each group consists independently of a hydrogen atom, or a straight-chain or branched monovalent aliphatic hydrocarbon group. R s8 It is a straight-chain or branched monovalent aliphatic hydrocarbon group. However, R s6 R s7 and R s8 The total number of carbons is 6 or more. For R s6 R s7 and R s8 There is no particular limit to the total number of carbon atoms, but it is preferred to be 20 or less, and more preferably 10 or less.

[0261] There are no particular limitations on the aforementioned straight-chain or branched monovalent aliphatic hydrocarbon groups, and examples include alkyl groups with 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, and decyl; and alkenyl groups with 2 to 20 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl.

[0262] As R s6 Hydrogen atoms are preferred as R s7 and R s8 Preferably, it is an alkyl group having 1 to 6 carbon atoms. In this case, R s7 and R s8 They can be the same or different.

[0263] In equation (6-2), m is an integer satisfying 1≤m≤4, preferably 2. n is an integer satisfying 1≤n≤4, preferably 2.

[0264] In equation (6-3), R s9 ~R s13 They are independently composed of hydrogen atoms, nitro groups, cyano groups, halogen atoms, alkyl groups with 1 to 10 carbon atoms, haloalkyl groups with 1 to 10 carbon atoms, or haloalkenyl groups with 2 to 10 carbon atoms.

[0265] Regarding the alkyl groups having 1 to 10 carbon atoms, they can be linear, branched, or cyclic. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0266] For the aforementioned alkyl halogens having 1 to 10 carbon atoms, there is no particular limitation as long as some or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are replaced by halogen atoms. The aforementioned alkyl halogens can be linear, branched, or cyclic. Specific examples include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, and 1,1,2,2,3,3,4,4,4-nonafluorobutyl.

[0267] As for the aforementioned halogenated alkenyl groups with 2 to 10 carbon atoms, there is no particular limitation as long as some or all of the hydrogen atoms of the alkenyl group with 2 to 10 carbon atoms are replaced by halogen atoms. Specific examples include perfluorovinyl, perfluoro-1-propenyl, perfluoro-2-propenyl, perfluoro-1-butenyl, perfluoro-2-butenyl, and perfluoro-3-butenyl.

[0268] Among these, as R s9 Preferably, nitro, cyano, halogenated alkyl groups having 1 to 10 carbon atoms, or halogenated alkenyl groups having 2 to 10 carbon atoms are used; more preferably, nitro, cyano, halogenated alkyl groups having 1 to 4 carbon atoms, or halogenated alkenyl groups having 2 to 4 carbon atoms are used; even more preferably, nitro, cyano, trifluoromethyl, or perfluoropropylene are used. Additionally, as R... s10 ~R s13 Halogen atoms are preferred, and fluorine atoms are even more preferred.

[0269] In equation (6-3), A 17 It can be -O-, -S-, or -NH-, with -O- being preferred.

[0270] In equation (6-3), A 18 An aromatic group is an aromatic group with a valence of (n+1) carbon atoms, having a carbon number of 6 to 20. These aromatic groups are obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic compound having a carbon number of 6 to 20. Examples of such aromatic compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, and pyrene. Among these, A... 18 Preferably, the group is derived from naphthalene or anthracene, and more preferably from naphthalene.

[0271] In equation (6-3), R s14 ~R s17 A monovalent aliphatic hydrocarbon group consisting of 1 to 20 carbon atoms, which are either hydrogen atoms or in a straight or branched form.

[0272] Examples of monovalent aliphatic hydrocarbon groups include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl; and alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl. Among these, alkyl groups with 1 to 20 carbon atoms are preferred, alkyl groups with 1 to 10 carbon atoms are more preferred, and alkyl groups with 1 to 8 carbon atoms are even more preferred.

[0273] In equation (6-3), R s18 It is a straight-chain or branched monovalent aliphatic hydrocarbon group with 1 to 20 carbon atoms, or OR s19 R s19It is a monovalent hydrocarbon group with 2 to 20 carbon atoms that can be substituted.

[0274] As a result of R s18 The expression refers to a straight-chain or branched monovalent aliphatic hydrocarbon group with 1 to 20 carbon atoms; other groups identical to those listed above can be included. In R s18 When the group is a monovalent aliphatic hydrocarbon group, as R s18 Preferably, it is an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably an alkyl group having 1 to 8 carbon atoms.

[0275] As a result of R s19 The monovalent hydrocarbon groups representing 2 to 20 carbon atoms, besides the methyl group mentioned above in the monovalent aliphatic hydrocarbon groups, can also include aryl groups such as phenyl, naphthyl, and phenanthrene. Among these, as R... s19 Preferably, it is a straight-chain alkyl or phenyl group having 2 to 4 carbon atoms. Other substituents that may be present in the above-mentioned monovalent hydrocarbon group include fluorinated groups, alkoxy groups having 1 to 4 carbon atoms, nitro groups, cyano groups, etc.

[0276] In equation (6-3), n is an integer that satisfies 1≤n≤4, preferably 2.

[0277] As an aryl sulfonate compound represented by formula (6-3), it is particularly preferred to be represented by the following formula (6-3-1) or (6-3-2).

[0278] [Chemistry 41]

[0279]

[0280] In the formula, A 17 A 18 R s9 ~R s17 R s19 And n is the same as above. R s20 It is a straight-chain or branched monovalent aliphatic hydrocarbon group with 1 to 20 carbon atoms. Specific examples include those related to R. s18 The same group as the group described in the description.

[0281] In aryl sulfonate compounds represented by formula (6-3-1), it is preferred that R s14 ~R s17 Chinese R s14 or R s16 It is a straight-chain alkyl group with 1 to 3 carbon atoms, and the remainder is hydrogen atoms, or R s14 R is a straight-chain alkyl group having 1 to 3 carbon atoms. s15 ~R s17 It is a hydrogen atom. As a straight-chain alkyl group having 1 to 3 carbon atoms, methyl is preferred. Additionally, as R... s19 Preferably, it is a straight-chain alkyl or phenyl group with 2 to 4 carbon atoms.

[0282] In the aryl sulfonate compounds represented by formula (6-3-2), R s14 R s16 and R s20 The total number of carbon atoms is preferably 6 or more. s14 R s16 and R s20 The upper limit for the total number of carbons is preferably 20 or less, more preferably 10 or less. In this case, as R s14 Hydrogen atoms are preferred as R s16 and R s20 Preferably, it is an alkyl group having 1 to 6 carbon atoms. Additionally, R s16 and R s20 They can be the same or different.

[0283] The aryl sulfonate compounds represented by formulas (6) and (6') can be used alone or in combination of two or more.

[0284] Furthermore, examples of preferred aryl sulfonates may be shown below, but are not limited thereto.

[0285] [Chemistry 42]

[0286]

[0287] In the case of organic dopant materials, from the viewpoint of solubility in organic solvents, the molecular weight is preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less.

[0288] Furthermore, when the composition for forming a charge transport thin film according to the present invention contains an organic dopant, its content, expressed as a molar ratio, is typically about 0.01 to 20 relative to 1 charge transport substance.

[0289] Furthermore, when the obtained thin film is used as a hole injection layer for an organic EL element, the charge transport thin film forming composition of the present invention may contain an organosilane compound, the content of which is typically about 1 to 30% by mass relative to the charge transport material, with the aim of improving the injectability of the hole injection layer and the lifetime characteristics of the element.

[0290] As the organic solvent used in preparing the charge-transporting thin film forming composition of the present invention, a highly soluble solvent that can readily dissolve the charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure can be used. To dissolve the charge-transporting precursor having an intramolecular carbazole structure without substituents on the nitrogen atom of the carbazole group, at least one highly polar solvent is required. However, the charge-transporting precursor used in the present invention, having an intramolecular 9-tert-butoxycarbonylcarbazole structure, has a tert-butoxycarbonyl group on the nitrogen atom of the carbazole group, and therefore can be dissolved in the solvent regardless of its polarity. Furthermore, a low-polarity solvent can be used where, if it offers superior process suitability compared to a highly polar solvent, it is desirable. In the present invention, a low-polarity solvent is defined as a solvent with a relative permittivity of less than 7 at a frequency of 100 kHz, and a highly polar solvent is defined as a solvent with a relative permittivity of 7 or higher at a frequency of 100 kHz.

[0291] Examples of low-polarity solvents include:

[0292] Chloroform, chlorobenzene, and other chlorinated solvents;

[0293] Toluene, xylene, tetrahydronaphthalene, cyclohexylbenzene, decylbenzene and other alkylbenzene and other aromatic hydrocarbon solvents;

[0294] Aliphatic alcohol solvents such as 1-octanol, 1-nonanol, and 1-decanol;

[0295] Ether solvents such as tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, and triethylene glycol butyl methyl ether.

[0296] Ester solvents such as methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, di(2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate.

[0297] In addition, examples of highly polar solvents include:

[0298] Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutyramide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolinone;

[0299] Ketone solvents such as ethyl methyl ketone, isophorone, and cyclohexanone;

[0300] Acetonitrile, 3-methoxypropionitrile and other cyano-based solvents;

[0301] Polyol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butanediol, and 2,3-butanediol;

[0302] Solvents consisting of monohydric alcohols other than aliphatic alcohols, such as diethylene glycol monomethyl ether, diethylene glycol monophenyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3-phenoxybenzyl alcohol, and tetrahydrofurfuryl alcohol.

[0303] Sulfoxide solvents such as dimethyl sulfone.

[0304] The viscosity of the composition for forming charge transport thin films of the present invention is typically 1 to 50 mPa·s at 25°C, and the surface tension is typically 20 to 50 mN / m at 25°C.

[0305] Regarding the viscosity and surface tension of the composition for forming charge transport thin films according to the present invention, various factors such as the coating method used and the desired film thickness can be considered, and adjustments can be made by changing the type of organic solvent used, their ratio, the concentration of solid components, etc.

[0306] The charge transport thin film forming composition of the present invention can be manufactured by mixing the components described above.

[0307] When preparing the composition, it is appropriate to heat it within a range that does not decompose or deteriorate the components.

[0308] In this invention, for the composition for forming charge transport thin films, in order to obtain a thin film with better reproducibility and higher flatness, filtration can be performed using a submicron-sized filter or the like during the manufacturing process of the composition, or after all the components have been mixed.

[0309] By coating the charge-transporting film forming composition described above onto a substrate and firing it, a charge-transporting film can be formed on the substrate. In this invention, during firing, the 9-tert-butoxycarbonyl group is desorbed from the charge-transporting precursor while the organic solvent evaporates, thereby obtaining a film with excellent charge-transporting properties.

[0310] There are no particular limitations on the coating method of the composition, and examples include dip coating, spin coating, transfer printing, roller coating, brush coating, inkjet coating, and spray coating. It is preferable to adjust the viscosity and surface tension of the composition according to the coating method.

[0311] Furthermore, when using the composition of the present invention, there are no particular limitations on the firing atmosphere. Not only in an atmospheric atmosphere, but also in an inactive gas such as nitrogen or in a vacuum, a thin film with a uniform film-forming surface and high charge transport can be obtained.

[0312] Regarding the firing temperature, considering the intended use of the resulting film, the degree of charge transport properties imparted to the film, the type of solvent, boiling point, etc., it is appropriately set within the range of approximately 100 to 260°C. When the resulting film is used as a hole injection layer for an organic EL element, approximately 140 to 250°C is preferred, and approximately 145 to 240°C is more preferred. In particular, since the composition of the present invention has the characteristic of being able to be fired at low temperatures below 200°C, a film with excellent charge transport properties can be achieved even when fired at relatively low temperatures.

[0313] Furthermore, during firing, in order to achieve higher uniformity of film formation and to allow the reaction to proceed on the substrate, temperature changes of two or more stages can be applied. Heating can be performed using appropriate equipment such as hot plates or ovens.

[0314] There is no particular limitation on the thickness of the charge transport thin film, but when used as a hole injection layer in an organic EL element, 5 to 200 nm is preferred. Methods for varying the film thickness include changing the concentration of solid components in the composition and changing the amount of solution on the substrate during coating.

[0315] The organic EL element of the present invention has a pair of electrodes, between which is the charge transport thin film of the present invention described above.

[0316] Representative configurations of organic EL devices include (a) to (f) below, but are not limited to these. It should be noted that, in the following configurations, an electron blocking layer may be provided between the light-emitting layer and the anode, and a hole blocking layer may be provided between the light-emitting layer and the cathode, as needed. Furthermore, a hole injection layer, a hole transport layer, or a hole injection transport layer may also function as an electron blocking layer, and an electron injection layer, an electron transport layer, or an electron injection transport layer may also function as a hole blocking layer. Moreover, arbitrary functional layers may be provided between the layers as needed.

[0317] (a) Anode / Hole Injection Layer / Hole Transport Layer / Emitting Layer / Electron Injection Layer / Electron Transport Layer / Cathode

[0318] (b) Anode / Hole Injection Layer / Hole Transport Layer / Light Emitting Layer / Electron Injection Transport Layer / Cathode

[0319] (c) Anode / Hole Injection Transport Layer / Light Emitting Layer / Electron Injection Layer / Electron Transport Layer / Cathode

[0320] (d) Anode / Hole Injection Transport Layer / Light Emitting Layer / Electron Injection Transport Layer / Cathode

[0321] (e) Anode / Hole Injection Layer / Hole Transport Layer / Light Emitting Layer / Cathode

[0322] (f) Anode / hole injection transport layer / light-emitting layer / cathode

[0323] "Hole injection layer," "hole transport layer," and "hole injection transport layer" are layers formed between the light-emitting layer and the anode, which function to transport holes from the anode to the light-emitting layer. When only one layer of hole-transporting material is disposed between the light-emitting layer and the anode, it is called a "hole injection transport layer." When two or more layers of hole-transporting material are disposed between the light-emitting layer and the anode, the layer closest to the anode is the "hole injection layer," and the layers outside are "hole transport layers." In particular, the hole injection (transport) layer uses a thin film that exhibits excellent hole acceptance not only from the anode but also excellent hole injection properties into the hole transport (light-emitting) layer.

[0324] "Electron injection layer", "electron transport layer" and "electron injection transport layer" are layers formed between the light-emitting layer and the cathode, which have the function of transporting electrons from the cathode to the light-emitting layer. When only one layer of electron transport material is set between the light-emitting layer and the cathode, it is called "electron injection transport layer". When two or more layers of electron transport material are set between the light-emitting layer and the cathode, the layer closest to the cathode is the "electron injection layer" and the layers outside it are "electron transport layers".

[0325] The "light-emitting layer" is an organic layer with light-emitting function. In the case of a doped system, it comprises a host material and a dopant material. In this case, the host material primarily functions to promote electron-hole recombination and confine excitons within the light-emitting layer, while the dopant material enables the excitons generated through recombination to emit light efficiently. In the case of phosphorescent devices, the host material primarily functions to confine the excitons generated by the dopant within the light-emitting layer.

[0326] The charge transport thin film of the present invention can be used as a hole injection layer, a hole transport layer, or a hole injection transport layer in organic EL devices, and is preferably used as a hole injection layer.

[0327] The following are examples of materials and manufacturing methods used when fabricating EL elements using the charge transport thin film forming composition of the present invention, but are not limited to these.

[0328] An example of a method for fabricating an OLED element having a hole injection layer composed of a thin film obtained from the charge transport thin film forming composition of the present invention is described below. Furthermore, regarding the electrodes, it is preferable to pre-treat them with cleaning using alcohol, pure water, etc., within a range that does not adversely affect the electrodes; and to perform surface treatments such as UV ozone treatment or oxygen-plasma treatment.

[0329] On the anode substrate, a hole injection layer composed of the charge transport thin film of the present invention is formed using the method described above. This layer is then introduced into a vacuum evaporation apparatus, where a hole transport layer, a light-emitting layer, an electron transport layer, an electron transport layer / hole blocking layer, and a cathode metal are sequentially deposited by evaporation. Alternatively, instead of forming the hole transport layer and the light-emitting layer by evaporation, a hole transport layer forming composition containing a hole transport polymer and a light-emitting layer forming composition containing a light-emitting polymer are used to form these layers by a wet process. Furthermore, if necessary, an electron blocking layer may be provided between the light-emitting layer and the hole transport layer.

[0330] Examples of anode materials include transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes composed of metals such as aluminum, and their alloys, with anode materials that have undergone planarization treatment being preferred. Polythiophene derivatives and polyaniline derivatives, which have high charge transport properties, can also be used.

[0331] Furthermore, other metals that can constitute a metal anode include gold, silver, copper, indium, and their alloys, but are not limited to these.

[0332] Materials that can form hole transport layers include triarylamine derivatives, [(triphenylamine)dimer]spirodimers, N,N'-bis(naphthyl-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD), 4,4',4”-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), 4,4',4”-tris[1-naphthyl(phenyl)amino]triphenylamine (1-TNATA), and oligothiophenes such as 5,5”-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2”-terthiophene (BMA-3T).

[0333] Materials that form the luminescent layer include, but are not limited to, metal complexes such as aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bis(styrene)benzene derivatives, bis(styrene)arylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, thiophene derivatives, and other low-molecular-weight luminescent materials; systems in which luminescent materials and electron-mobilizing materials are mixed in polymers such as poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), and polyvinylcarbazole.

[0334] In addition, when the light-emitting layer is formed by vapor deposition, it can be co-deposited with a light-emitting dopant. Examples of light-emitting dopant include metal complexes such as tris(2-phenylpyridine)iridium(III)(Ir(ppy)3), tetraphenyl derivatives such as rubrene, quinacridone derivatives, perylene and other fused polycyclic aromatic rings, but it is not limited to these.

[0335] Materials that can form electron transport layers / hole blocking layers include, but are not limited to, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, and pyrimidine derivatives.

[0336] Materials that can form the electron injection layer include metal oxides such as lithium oxide (Li2O), magnesium oxide (MgO), and aluminum oxide (Al2O3), as well as metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF), but are not limited to these.

[0337] Examples of cathode materials include aluminum, magnesium-silver alloys, and aluminum-lithium alloys, but these are not the only ones that can be used.

[0338] Materials that can form an electron blocking layer include tri(phenylpyrazole)iridium, but are not limited to these.

[0339] Examples of hole-transporting polymers include poly[(9,9-dihexylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenyl-4,4-diamine)], and poly[(9,9-bis{1'-pentene]]. -5'-yl}fluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], etc., are all end-capped with polysilsesquioxane.

[0340] Examples of luminescent polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylene vinylidene derivatives such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

[0341] The charge-transport thin film forming composition of the present invention, as described above, is preferably used for the formation of hole injection layer or hole transport layer in organic EL devices. In addition, it can also be used in the formation of charge-transport thin films in electronic devices such as organic photoelectric conversion devices, organic thin-film solar cells, organic perovskite photoelectric conversion devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic optical detectors, organic photoreceptors, organic electroluminescent elements, light-emitting electrochemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasmon light-emitting elements.

[0342] Example

[0343] The present invention is illustrated in more detail below with examples and comparative examples, but the present invention is not limited to the examples described below. It should be noted that the apparatus used is as described below.

[0344] (1) 1 H-NMR: AVANCE III HD 500MHz nuclear magnetic resonance spectrometer manufactured by Bruker Biospin Co., Ltd.

[0345] (2) Substrate cleaning: Substrate cleaning equipment (depressurized plasma method) manufactured by Choshu Sangyo Co., Ltd.

[0346] (3) Coating of the composition: Mikasa Co., Ltd. manufactures MS-A100 spin coaters.

[0347] (4) Film thickness measurement: SURFCORDER ET-4000 micro-shape measuring instrument manufactured by Kosaka Research Institute Co., Ltd.

[0348] (5) Fabrication of EL components: Choshu Sangyo Co., Ltd. manufactures a multi-functional vapor deposition system C-E2L1G1-N

[0349] (6) Measurement of current density, etc. of EL elements: EHC Corporation manufactures multi-channel IVL measurement devices.

[0350] [1] Synthesis of compounds

[0351] [Synthetic Example 1] Synthesis of Aryl Sulfonate

[0352] The aryl sulfonate S, represented by the following formula, was synthesized according to International Publication No. 2017 / 217455.

[0353] [Chemistry 43]

[0354]

[0355] [Synthetic Example 2] Synthesis of aniline derivatives A, B and C

[0356] The following aniline derivatives A and B were synthesized according to the methods described in Manufacturing Examples 11 and 9 of International Publication No. 2015 / 050253, respectively.

[0357] [Chemistry 44]

[0358]

[0359] Aniline derivative C was synthesized using the following method.

[0360] Di-tert-butyl dicarbonate (982 mg, 4.5 mmol) and 4-dimethylaminopyridine (367 mg, 3 mmol) were added to a THF (tetrahydrofuran) suspension (25 mL) of aniline derivative B (1.18 g, 1 mmol), and the resulting mixture was stirred at room temperature for 3 hours.

[0361] Then, the reaction solution was added dropwise to methanol (125 mL), the precipitated solid was filtered off, and the filter was dried to obtain aniline derivative C (1.46 g). The following shows... 1 Results of H-NMR measurements.

[0362] 1 H-NMR (500MHz, THF-d8) δ [ppm]: 1.78 (s, 27H), 6.95-7.01 (m, 8H), 7.05-7.09 (m, 20H), 7.22-7.25 (m, 8H), 7.29-7.32 (m, 6H) ),7.45(dd,J=7.5,8.5Hz,3H),7.89(d,J=2.0Hz,3H),7.98(d,J=7.5Hz,3H),8.25(d,J=9.0Hz,3H),8.34(d,J=8.5Hz,3H).

[0363] [Chemistry 45]

[0364]

[0365] [Synthetic Example 3] Synthesis of aniline derivatives D and E

[0366] (1) Synthesis of Compound 1

[0367] [Chemistry 46]

[0368]

[0369] In a THF suspension (150 mL) of 60% sodium hydride (4.8 g, 120 mmol), a THF solution (200 mL) of 2-bromocarbazole (24.6 g, 100 mmol) was added dropwise under ice-cold conditions, and the mixture was stirred at room temperature for 30 minutes. Then, a THF solution (40 mL) of tert-butyldimethylchlorosilane (18.1 g, 120 mmol) was added dropwise under ice-cold conditions, and the mixture was stirred at room temperature for 2 hours. Water (66 mL) was added, and the mixture was extracted three times with ethyl acetate (50 mL), dried over magnesium sulfate, filtered, and the solvent was distilled off to give a light brown solid. Hexane (150 mL) was added, and the mixture was filtered. Methanol (333 mL) was added to the filtrate, and the mixture was refluxed for 30 minutes, cooled to room temperature, and filtered to give compound 1 as a white solid (27.1 g, yield: 75%). The following is shown... 1 Results of H-NMR measurements.

[0370] 1 H-NMR (500MHz, CDCL3) δ [ppm]: 0.75 (s, 6H), 1.04 (s, 9H), 7.24 (t, J = 7.5Hz, 1H), 7.34 (d, J = 8.0Hz, 1H), 7.38(t,J=7.5Hz,1H),7.59(d,J=8.5Hz,1H),7.73(s,1H),7.90(d,J=8.5Hz,1H),8.02(d,J=7.5Hz,1H).

[0371] (2) Synthesis of compound 2

[0372] [Chemistry 47]

[0373]

[0374] In a toluene solution (60 mL) of 4,4'-diaminodiphenylamine (3 g, 15 mmol) and compound 1 (11.1 g, 30.75 mmol), Pd(dba)₂ (173 mg, 0.3 mmol), [(t-Bu)₃PH]BF₄ (174 mg, 0.6 mmol), and t-BuONa (3.17 g, 33 mmol) were added, and the mixture was heated and stirred at 80 °C for 2 hours. After washing with saturated brine (60 mL), the mixture was dried over sodium sulfate, filtered, and the solvent was distilled off. The solution was purified by column chromatography to give compound 2 as a white solid (3.6 g, yield: 32%). The following is shown... 1 Results of H-NMR measurements.

[0375] 1H-NMR (500MHz, DMSO-d6) δ [ppm]: 0.67 (s, 12H), 0.96 (s, 18H), 6.85 (d, J = 8.5Hz, 2H), 7.02 (d, J = 8.5Hz, 4H), 7.08 (d, J = 8.5Hz, 4H), 7.11 (t,J=7.5Hz,2H),7.18-7.22(m,4H),7.53(d,J=8.0Hz,2H),7.76(brs,1H),7.87(d,J=8.5Hz,2H),7.90(d,J=7.5Hz,2H),7.96(brs,2H).

[0376] (3) Synthesis of compound 3

[0377] [Chemistry 48]

[0378]

[0379] Pd(dba)₂ (155 mg, 0.27 mmol), [(t-Bu)₃PH]BF₄ (160 mg, 0.55 mmol), and t-BuONa (1.84 g, 19.15 mmol) were added to a toluene solution (35 mL) of compound 2 (3.45 g, 4.56 mmol) and 2-bromo-9-phenylcarbazole (4.63 g, 14.36 mmol), and the mixture was heated and stirred at 90 °C for 2 hours. The solution was washed with saturated brine (35 mL), passed through silica gel (90 g), and then further bleed toluene (520 mL) into the silica gel. The resulting solution was concentrated to 140 g, and a mixture of ethyl acetate (260 mL) / methanol (780 mL) was added dropwise. The mixture was stirred at room temperature for 2 hours. Compound 3 was obtained by filtering the precipitated solid as a yellow solid (5.35 g, yield: 79%). The following is shown... 1 Results of H-NMR measurements.

[0380] 1 H-NMR (500MHz, THF-d8) δ [ppm]: 0.50 (s, 12H), 0.86 (s, 18H), 7.03-7.08 (m, 15H), 7.11-7.21 (m, 8H), 7. 26-7.34(m,10H),7.42-7.58(m,15H),7.88(d,J=8.5Hz,2H),7.92(d,J=7.5Hz,2H),8.00-8.06(m,6H).

[0381] (4) Synthesis of aniline derivative D

[0382] [Chemistry 49]

[0383]

[0384] In a 25 mL solution of compound 3 (5.28 g, 3.56 mmol) in THF, a 1 mol / L tetrabutylammonium chloride / THF solution (10.7 mL, 10.7 mmol) was added dropwise under ice-cold conditions, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was then added dropwise to methanol (90 mL), and the precipitated solid was filtered to give aniline derivative D as a yellow solid (4.16 g, yield: 93%). The following is shown... 1 Results of H-NMR and MALDI-TOF-MS measurements.

[0385] 1 H-NMR(500MHz,THF-d8)δ[ppm]: 6.96-7.12(m,17H),7.17-7.35(m,18H),7.41-7.60(m,13H),7.89-7.94(m,4H),7.99-8.05(m,6H),10.00(brs,2H).

[0386] MALDI-TOF-MS m / Z measurement: 1253.52 ([M+H]) + Calculated value: 1253.49

[0387] (5) Synthesis of aniline derivative E

[0388] [Transformation 50]

[0389]

[0390] Di-tert-butyl dicarbonate (655 mg, 3 mmol) and 4-dimethylaminopyridine (244 mg, 2 mmol) were added to a THF suspension (25 mL) of aniline derivative D (1.25 g, 1 mmol), and the resulting mixture was stirred at room temperature for 3 hours.

[0391] Then, the reaction solution was added dropwise to methanol (125 mL), the precipitated solid was filtered off, and the filter was dried to obtain aniline derivative E (1.38 g, yield: 95%). The following is shown... 1 Results of H-NMR measurements.

[0392] 1H-NMR (500MHz, THF-d8) δ [ppm]: 1.41 (s, 18H), 7.06-7.13 (m, 12H), 7.19-7.35 (m, 19H), 7.43-7.6 1(m,13H),7.84(d,J=8.5Hz,2H),7.90(d,J=7.5Hz,2H),8.02-8.07(m,8H),8.30(d,J=8.5Hz,2H).

[0393] [2] Preparation of compositions for forming charge transport thin films (selection of solvent for composition preparation)

[0394] [Example 1-1]

[0395] Aniline derivative C (0.526 g) was added to cyclohexylbenzene (10 g) in an aromatic hydrocarbon solvent, heated and stirred, and completely dissolved to obtain composition C1.

[0396] [Examples 1-2]

[0397] Aniline derivative C (0.526 g) was added to a mixed solvent consisting of butyl benzoate (7 g) and 3-phenoxytoluene (3 g), which are low-polarity solvents containing polar groups. The mixture was heated and stirred until it was completely dissolved, yielding composition C2.

[0398] [Examples 1-3]

[0399] Aniline derivative C (0.526 g) was added to a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g), and dipropylene glycol monomethyl ether (1 g), which are highly polar solvents containing polar groups. The mixture was heated and stirred until it was completely dissolved, yielding composition C3.

[0400] [Examples 1-4]

[0401] Aniline derivative E (0.526 g) was added to cyclohexylbenzene (10 g), heated and stirred, and completely dissolved to obtain composition E1.

[0402] [Examples 1-5]

[0403] Aniline derivative E (0.526 g) was added to a mixed solvent consisting of butyl benzoate (7 g) and 3-phenoxytoluene (3 g), and the mixture was heated and stirred until it dissolved completely, yielding composition E2.

[0404] [Examples 1-6]

[0405] Aniline derivative E (0.526 g) was added to a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition E3.

[0406] [Comparative Example 1-1]

[0407] Aniline derivative A (0.526 g) was added to cyclohexylbenzene (10 g) in an aromatic hydrocarbon solvent, heated and stirred, and completely dissolved to obtain composition A1.

[0408] [Comparative Examples 1-2]

[0409] Aniline derivative A (0.526 g) was added to a mixed solvent consisting of butyl benzoate (7 g) and 3-phenoxytoluene (3 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition A2.

[0410] [Comparative Examples 1-3]

[0411] Aniline derivative A (0.526 g) was added to a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition A3.

[0412] [Comparative Examples 1-4]

[0413] Aniline derivative B (0.526 g) was added to cyclohexylbenzene (10 g) in an aromatic hydrocarbon solvent and heated and stirred, but it did not completely dissolve.

[0414] [Comparative Examples 1-5]

[0415] Aniline derivative B (0.526 g) was added to a mixed solvent consisting of butyl benzoate (7 g) and 3-phenoxytoluene (3 g), and the mixture was heated and stirred. The mixture did not completely dissolve.

[0416] [Comparative Examples 1-6]

[0417] Aniline derivative B (0.526 g) was added to a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition B3.

[0418] [Comparative Examples 1-7]

[0419] Aniline derivative D (0.526 g) was added to cyclohexylbenzene (10 g) in an aromatic hydrocarbon solvent and heated and stirred, but it did not completely dissolve.

[0420] [Comparative Examples 1-8]

[0421] Aniline derivative D (0.526 g) was added to a mixed solvent consisting of butyl benzoate (7 g) and 3-phenoxytoluene (3 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition D2.

[0422] [Comparative Examples 1-9]

[0423] Aniline derivative D (0.526 g) was added to a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and the mixture was heated and stirred until it was completely dissolved, yielding composition D3.

[0424] The results of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-9 are summarized in Table 1. These results confirmed the following:

[0425] The aniline derivatives C and E used in the examples showed good solubility in both highly polar and low-polarity solvents. The aniline derivative A used in the comparative examples also showed good solubility in both highly polar and low-polarity solvents.

[0426] On the other hand, the aniline derivative B used in the comparative example dissolved in a highly polar solvent, but did not completely dissolve in a low-polarity solvent. Additionally, the aniline derivative D used in the comparative example dissolved in both highly polar solvents and low-polarity solvents containing polar groups, but did not completely dissolve in low-polarity solvents without polar groups.

[0427] [Table 1]

[0428] Composition Aniline derivatives Instructions for using solvents Solubility Example 1-1 C1 Aniline derivative C Low polarity without polar groups ○ Examples 1-2 C2 Aniline derivative C Low polarity with polar groups ○ Examples 1-3 C3 Aniline derivative C High polarity ○ Examples 1-4 E1 Aniline derivative E Low polarity without polar groups ○ Examples 1-5 E2 Aniline derivative E Low polarity with polar groups ○ Examples 1-6 E3 Aniline derivative E High polarity ○ Comparative Example 1-1 A1 Aniline derivative A Low polarity without polar groups ○ Comparative Examples 1-2 A2 Aniline derivative A Low polarity with polar groups ○ Comparative Examples 1-3 A3 Aniline derivative A High polarity ○ Comparative Examples 1-4 - Aniline derivative B Low polarity without polar groups × Comparative Examples 1-5 - Aniline derivative B Low polarity with polar groups × Comparative Examples 1-6 B3 Aniline derivative B High polarity ○ Comparative Examples 1-7 - Aniline derivative D Low polarity without polar groups × Comparative Examples 1-8 D2 Aniline derivative D Low polarity with polar groups ○ Comparative Examples 1-9 D3 Aniline derivative D High polarity ○

[0429] [3] Preparation of compositions for forming charge transport thin films

[0430] [Example 2-1]

[0431] A aniline derivative C (0.155 g) and an aryl sulfonate S (0.261 g) were added to a mixed solvent consisting of 3-phenoxytoluene (3 g) and butyl benzoate (7 g), and the mixture was heated and stirred to prepare a charge transport thin film forming composition C4.

[0432] [Example 2-2]

[0433] Aryl sulfonate S (0.261 g) was dissolved in a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and then aniline derivative C (0.155 g) was added. The mixture was heated and stirred to prepare composition C5 for charge transport thin film formation.

[0434] [Examples 2-3]

[0435] Aryl sulfonate S (0.263 g) was dissolved in a mixed solvent consisting of 3-phenoxytoluene (3 g) and butyl benzoate (7 g), and then aniline derivative E (0.153 g) was added. The mixture was heated and stirred to prepare composition E4 for charge transport thin film formation.

[0436] [Examples 2-4]

[0437] Aryl sulfonate S (0.263 g) was dissolved in a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and then aniline derivative E (0.153 g) was added. The mixture was heated and stirred to prepare composition E5 for charge transport thin film formation.

[0438] [Comparative Example 2-1]

[0439] A charge-transporting film forming composition A4 was prepared by adding aniline derivative A (0.151 g) and aryl sulfonate S (0.266 g) represented by the following formula to a mixed solvent consisting of 3-phenoxytoluene (3 g) and butyl benzoate (7 g), and heating and stirring.

[0440] [Comparative Example 2-2]

[0441] Aryl sulfonate S (0.266 g) was dissolved in a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and then aniline derivative A (0.151 g) was added. The mixture was heated and stirred to prepare composition A5 for charge transport thin film formation.

[0442] [Comparative Examples 2-3]

[0443] Aniline derivative B (0.134 g) and aryl sulfonate S (0.283 g) were added to a mixed solvent consisting of 3-phenoxytoluene (3 g) and butyl benzoate (7 g), and stirred to attempt the preparation of composition B4 for charge transport film formation, but it did not completely dissolve and no composition usable in film formation was obtained.

[0444] [Comparative Examples 2-4]

[0445] Aryl sulfonate S (0.283 g) was dissolved in a mixed solvent consisting of 1,3-dimethyl-2-imidazolinone (7 g), 2,3-butanediol (2 g) and dipropylene glycol monomethyl ether (1 g), and then aniline derivative B (0.134 g) was added. The mixture was heated and stirred to prepare composition B5 for charge transport thin film formation.

[0446] The compositions for forming charge-transporting thin films prepared in the above examples and comparative examples are summarized in Table 2. The results shown in Table 2 confirm the following:

[0447] In Examples 2-1 to 2-4, it was confirmed that the aniline derivative used exhibited good solubility in both highly polar and low-polarity solvents, resulting in a composition for forming a uniform charge-transporting thin film.

[0448] Comparative Examples 2-1 and 2-2 (which used aniline derivatives with a phenyl group on the nitrogen atom of the carbazole group) similarly confirmed, as in the examples above, that the aniline derivatives exhibited good solubility in both highly polar and low-polarity solvents, resulting in a composition for forming a uniform charge-transfer thin film.

[0449] On the other hand, for Comparative Examples 2-3 and 2-4 (where aniline derivatives without substituents on the nitrogen atom of the carbazolium group were used), it was confirmed that although the aniline derivatives used were soluble in highly polar solvents, they were not completely soluble in low-polar solvents, and the applicable organic solvents were limited.

[0450] [Table 2]

[0451] Composition Aniline derivatives Solvent type of composition Solubility Example 2-1 C4 Aniline derivative C low polarity ○ Example 2-2 C5 Aniline derivative C High polarity ○ Example 2-3 E4 Aniline derivative E low polarity ○ Examples 2-4 E5 Aniline derivative E High polarity ○ Comparative Example 2-1 A4 Aniline derivative A low polarity ○ Comparative Example 2-2 A5 Aniline derivative A High polarity ○ Comparative Examples 2-3 B4 Aniline derivative B low polarity × Comparative Examples 2-4 B5 Aniline derivative B High polarity ○

[0452] [4] Fabrication and Characterization of Single-Layer Components (SLDs)

[0453] In the following examples and comparative examples, the following product was used as the ITO substrate: a 25mm×25mm×0.7t glass substrate with ITO patterned on the surface at a film thickness of 150nm was used, and impurities on the surface were removed by an O2 plasma cleaning device (150W, 30 seconds) before use.

[0454] [Example 3-1]

[0455] After the charge transport thin film forming composition C4 obtained in Example 2-1 was coated on an ITO substrate using a spin coater, a temporary firing was performed at 120°C for 1 minute under atmospheric conditions, followed by a main firing at 200°C for 15 minutes, forming a 50 nm thin film on the ITO substrate.

[0456] On it, a vapor deposition apparatus (vacuum degree 4.0 × 10⁻⁶) is used. -5An aluminum thin film was formed by vapor deposition (Pa), resulting in a SLD. The deposition was performed at a rate of 0.2 nm / s. The thickness of the aluminum thin film was set to 80 nm.

[0457] Furthermore, to prevent performance degradation caused by the influence of oxygen and water in the air, the SLD was sealed with a sealing substrate, and its performance was evaluated. The sealing was performed according to the following procedure.

[0458] The SLD was placed between sealing substrates in a nitrogen atmosphere with an oxygen concentration below 2 ppm and a dew point below -85°C, and the sealing substrates were bonded together using an adhesive material (MORESCO MOISTURE CUT WB90US(P) manufactured by MORESCO Co., Ltd.). At this time, a water-absorbing agent (Dynick Co., Ltd. HD-071010W-40) was placed inside the sealing substrates along with the SLD. The bonded sealing substrates were then irradiated with UV light (wavelength 365 nm, irradiation dose 6,000 mJ / cm²). 2 After that, anneal at 80°C for 1 hour to cure the adhesive material.

[0459] [Examples 3-2 to 3-4, Comparative Examples 3-1 to 3-3]

[0460] The SLD was prepared using the same method as in Example 3-1, except that instead of the charge transport thin film forming composition C4 obtained in Example 2-1, the charge transport thin film forming compositions C2, E1, E2, A1, A2 or B2 obtained in Examples 2-2 to 2-4, Comparative Examples 2-1, 2-2 or 2-4 were used.

[0461] For each SLD fabricated in the above embodiments and comparative examples, the current density at a driving voltage of 3V was measured. The results are shown in Table 3.

[0462] [Table 3]

[0463] Composition <![CDATA[Current density (mA / cm 2 )]]> Example 3-1 C4 4,550 Example 3-2 C5 4,490 Comparative Example 3-1 A4 4,130 Comparative Example 3-2 A5 3,700 Comparative Example 3-3 B5 4,200 Example 3-3 E4 1,790 Examples 3-4 E5 2,080

[0464] As shown in Table 3, films obtained from compositions containing a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure exhibit higher hole transport properties compared to films obtained from compositions containing a charge-transporting substance having a carbazole structure having, for example, a hydrogen atom at its N-position instead of a 9-tert-butoxycarbonyl group.

[0465] [5] Fabrication and performance evaluation of single hole elements (HODs)

[0466] In the following embodiments and comparative examples, the same ITO substrate as described above was used as the ITO substrate.

[0467] [Example 4-1]

[0468] After the charge transport thin film forming composition C4 obtained in Example 2-1 was coated onto an ITO substrate using a spin coater, a temporary firing was performed at 120°C for 1 minute under atmospheric conditions, followed by a main firing at 200°C for 15 minutes, forming a 50 nm thin film on the ITO substrate.

[0469] On it, a vapor deposition apparatus (vacuum degree 2.0 × 10⁻⁶) is used. -5 HOD was obtained by sequentially stacking α-NPD and aluminum films. Evaporation was performed at a rate of 0.2 nm / s. The film thicknesses of the α-NPD and aluminum films were 30 nm and 80 nm, respectively.

[0470] It should be noted that, in order to prevent performance degradation caused by the influence of oxygen, water, etc. in the air, the characteristics of the HOD were evaluated after it was sealed with a sealing substrate. The sealing was performed according to the following procedure.

[0471] In a nitrogen atmosphere with an oxygen concentration below 10 ppm and a dew point below -75°C, HOD was introduced between sealing substrates, and the substrates were bonded together using an adhesive material (MORESCO MOISTURE CUT WB90US(P) manufactured by MORESCO Co., Ltd.). At this time, a water-absorbing agent (Dynitsuku Co., Ltd. HD-071010W-40) was introduced into the sealing substrates along with the HOD. The bonded sealing substrates were then irradiated with UV light (wavelength 365 nm, irradiation dose 6,000 mJ / cm²). 2 After that, annealing is performed at 80℃ for 1 hour to cure the adhesive material.

[0472] [Examples 4-2 to 4-4, Comparative Examples 4-1 to 4-2]

[0473] HODs were prepared using the same method as in Example 3-1, except that the charge transport thin film forming compositions C5, E4, E5, A4, A5, or B5 obtained in Examples 2-2 to 2-4, Comparative Examples 2-1 or 2-4 were used instead of the charge transport thin film forming composition C4.

[0474] For each HOD fabricated in the above embodiments and comparative examples, the current density at a driving voltage of 3V was measured. The results are shown in Table 4.

[0475] [Table 4]

[0476] Composition <![CDATA[Current density (mA / cm 2 )]]> Example 4-1 C4 1,300 Example 4-2 C5 1,410 Comparative Example 4-1 A4 850 Comparative Example 4-2 A5 870 Example 4-3 E4 542 Example 4-4 E5 464

[0477] As shown in Table 4, films obtained from compositions containing charge-transporting precursors having an intramolecular 9-tert-butoxycarbonylcarbazole structure exhibit superior hole injection properties for α-NPDs, which are frequently used as hole transport layers, compared to films obtained from compositions containing charge-transporting substances that do not have such a 9-tert-butoxycarbonylcarbazole structure but have a carbazole structure with, for example, a hydrogen atom at their N-position instead of a 9-tert-butoxycarbonyl group.

[0478] [Example 5-1]

[0479] The hole injection layer forming composition obtained by the method described later was applied by spin coating, heated to 80°C on a hot plate in the atmosphere, dried for 1 minute, and then further heated and sintered at 230°C for 15 minutes to form a charge transport thin film (film thickness: 30 nm) as the hole injection layer.

[0480] Next, the charge transport thin film forming composition C1 obtained in Example 1-1 was coated on the hole injection layer using a spin coater, and then fired at 200°C for 15 minutes in an atmospheric atmosphere to form a 40 nm charge transport thin film as a hole transport layer.

[0481] A vapor deposition apparatus (vacuum degree 1.0 × 10⁻⁶) was used on it. -5 A single-hole device (HOD) was obtained by forming an 80 nm aluminum thin film at a speed of 0.2 nm / s.

[0482] It should be noted that the composition for forming a hole injection layer is prepared by the following steps. 0.137 g of an aniline derivative represented by formula (3), synthesized according to the method described in International Publication No. 2013 / 084664, and 0.271 g of an arylsulfonic acid represented by formula (4), synthesized according to the method described in International Publication No. 2006 / 025342, are dissolved in 6.7 g of 1,3-dimethyl-2-imidazolinone under a nitrogen atmosphere. 10 g of cyclohexanol and 3.3 g of propylene glycol are added sequentially to the resulting solution, and the mixture is stirred to obtain the composition for forming a hole injection layer (hereinafter the same).

[0483] [Chemistry 51]

[0484]

[0485] [Example 5-2, Comparative Examples 5-1 to 5-2]

[0486] Except for replacing charge transport thin film forming composition C1 with charge transport thin film forming compositions E1, A1, or D2 obtained in Examples 1-4, Comparative Examples 1-1, or 1-8, HODs were prepared using the same method as in Example 5-1. Furthermore, when charge transport thin film forming compositions A3, B3, C3, D3, or E3 containing highly polar solvents were used, the underlying hole injection layer was damaged, and HODs suitable for evaluating electrical properties were not produced.

[0487] For each HOD fabricated in the above embodiments and comparative examples, the current density at a driving voltage of 4V was measured. The results are shown in Table 5.

[0488] [Table 5]

[0489] Composition <![CDATA[Current density (mA / cm 2 )]]> Example 5-1 C1 2,820 Example 5-2 E1 1,140 Comparative Example 5-1 A1 995 Comparative Example 5-2 D2 446

[0490] The results in Table 5 confirm that films obtained from compositions containing a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure also function well as hole transport layers compared to films obtained from compositions containing a charge-transporting substance having a carbazole structure with, for example, a hydrogen atom at its N-position, instead of a 9-tert-butoxycarbonyl group.

Claims

1. A composition for forming a charge-transporting thin film, comprising: a charge-transporting precursor having an intramolecular 9-tert-butoxycarbonylcarbazole structure, and an organic solvent. in, The charge-transporting precursor is an aniline derivative represented by the following formula (1). In the above equation (1), k is 2, Ph 1 The group represented by formula (P1), Ar 11 and Ar 12 Each group can be represented independently by any one of the following formulas (G1) to (G3), but at least one of them must represent a group represented by formula (G1). R 200 ~R 203 The groups can be independently represented by hydrogen atoms, halogen atoms, nitro groups, cyano groups, or alkyl groups with 1 to 20 carbon atoms that can be substituted with halogen atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, or heteroaryl groups with 2 to 20 carbon atoms. R 11 ~R 17 The groups can be independently represented by hydrogen atoms, halogen atoms, nitro groups, cyano groups, or groups that can be substituted with halogen atoms, diphenylamino groups, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, or heteroaryl groups with 2 to 20 carbon atoms. R 18 ~R 24 R 26 ~R 39 Independently representing hydrogen atoms, halogen atoms, nitro groups, cyano groups, or groups that can be substituted with halogen atoms, diphenylamino groups, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, alkynyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, or heteroaryl groups with 2 to 20 carbon atoms, R 25 Represents a hydrogen atom, which can be Z 4 Substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms, or groups that can be substituted by Z 1 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 1 This represents a halogen atom, nitro group, cyano group, or a group that can be oxidized by Z. 2 Substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms, Z 2 This represents a halogen atom, nitro group, cyano group, or a group that can be oxidized by Z. 3 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 3 Z represents a halogen atom, nitro group, or cyano group. 4 Represents halogen atoms, nitro groups, cyano groups, or those that can be Z-type. 5 Substituted aryl groups with 6 to 20 carbon atoms or heteroaryl groups with 2 to 20 carbon atoms, Z 5 Represents halogen atoms, nitro groups, cyano groups, or those that can be Z-type. 3 Substituted alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, or alkynyl groups having 2 to 20 carbon atoms. The molecular weight of the charge-transporting precursor is 200–5000. The organic solvents include chlorinated solvents, aromatic hydrocarbon solvents, aliphatic alcohol solvents, ether solvents, ester solvents, amide solvents, ketone solvents, cyano solvents, polyol solvents, monohydric alcohol solvents (excluding aliphatic alcohols), and sulfoxide solvents.

2. The composition for forming charge-transporting thin films according to claim 1, further comprising a dopant substance.

3. A charge transport thin film obtained from the composition for forming a charge transport thin film according to claim 1 or 2.

4. An electronic component having the charge-transporting thin film according to claim 3.

5. An organic electroluminescent element having the charge-transporting thin film according to claim 3.

6. The organic electroluminescent element according to claim 5, wherein, The charge transport thin film is a hole injection layer or a hole transport layer.

7. A method for manufacturing a charge-transporting thin film, characterized in that, The composition for forming a charge-transporting thin film according to claim 1 or 2 is coated on a substrate and fired to detach the 9-tert-butoxycarbonyl group from the charge-transporting precursor.

Images