JP6947180B2 - Varnish for forming charge-transporting thin films - Google Patents

Description

The present invention relates to a varnish for forming a charge-transporting thin film.

In the organic electroluminescence (EL) element, a charge transporting thin film made of an organic compound is used as a light emitting layer and a charge injection layer. The method for forming the charge-transporting thin film is roughly classified into a dry process represented by a vapor deposition method and a wet process represented by a spin coating method. Comparing the dry process and the wet process, the wet process has been found to be superior in efficiently forming a thin film with high flatness over a large area. Practical application of thin film formation by process is being promoted.

In view of this point, the present inventors have developed a varnish for forming a charge-transporting thin film for producing a charge-transporting thin film applicable to various electronic devices by a wet process (for example, Patent Documents). 1).

As for the wet process material for the hole injection layer formed directly above the substrate electrode, it is required to be able to form a film having both high charge transport ability and high flatness. However, in order to obtain a highly flat film, a highly amorphous molecular design with weak intramolecular interaction is effective, while in order to improve the charge transport capacity, a highly crystalline molecular design with strong intramolecular interaction is effective. Since is effective, it has been difficult to achieve both high charge transport capacity and high flatness. Therefore, depending on the molecular skeleton with improved charge transport ability, the solubility in an organic solvent may decrease, or crystallization may occur when the film is dried after coating, resulting in film roughness. Is desired.

Japanese Unexamined Patent Publication No. 2002-151272

The present invention has been made in view of the above circumstances, and makes it possible to promote the solubility of a charge-transporting substance in an organic solvent and to suppress the occurrence of film roughness during film formation as much as possible. It is an object of the present invention to provide a varnish for forming a charge-transporting thin film containing a 2,6,6-tetraalkylpiperidin-N-oxyl derivative.

As a result of diligent studies to achieve the above object, the present inventor has found a varnish containing a specific 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative, a good solvent, and a poor solvent. We have found that the occurrence of film roughness during film formation can be reduced as much as possible, and specifically, the occurrence of film roughness during vacuum drying of a liquid film formed in minute pixels can be suppressed. The present invention has been completed.

（式中、Ｒ^Aは、互いに独立して、炭素数１〜２０のアルキル基を表し、Ｒ^Bは、ヒドロキシ基、オキソ基、又はアセトアミド基を表す。）
２．前記良溶媒が、アミド系溶媒、並びにジエチレングリコール、トリエチレングリコール及びテトラエチレングリコールのグリコール系溶媒からなる群から選ばれる１種以上であり、良溶媒と貧溶媒の比率が質量比で良溶媒：貧溶媒＝１０：９０〜５０：５０である１の電荷輸送性薄膜形成用ワニス、
３．前記貧溶媒が、ジエチレングリコール、トリエチレングリコール及びテトラエチレングリコール以外のグリコール系溶媒、グリコールエーテル系溶媒、並びにグリコールエーテルアセテート系溶媒からなる群から選ばれる１種以上である１又は２の電荷輸送性薄膜形成用ワニス、
４．前記電荷輸送性物質が、分子量２００〜９,５００の電荷輸送性化合物を含む１〜３のいずれかの電荷輸送性薄膜形成用ワニス、
５．前記電荷輸送性物質が、分子量２００〜９,５００のアリールアミン誘導体及びチオフェン誘導体からなる群から選ばれる少なくとも１種を含む１〜４のいずれかの電荷輸送性薄膜形成用ワニス、
６．更にドーパントを含む１〜５のいずれかの電荷輸送性薄膜形成用ワニス、
７．前記ドーパントが、アリールスルホン酸を含む６の電荷輸送性薄膜形成用ワニス、
８．１〜７のいずれかの電荷輸送性薄膜形成用ワニスを用いて製造される電荷輸送性薄膜、
９．８の電荷輸送性薄膜を有する有機エレクトロルミネッセンス素子、
１０．１〜７のいずれかの電荷輸送性薄膜形成用ワニスを用いることを特徴とする、電荷輸送性薄膜の製造方法、
１１．１〜７のいずれかの電荷輸送性薄膜形成用ワニスを用いることを特徴とする、有機エレクトロルミネッセンス素子の製造方法
を提供する。That is, the present invention
1. 1. It contains a 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative represented by the formula (T1), a charge transporting substance, and an organic solvent, and the organic solvent contains a good solvent and a poor solvent. A varnish for forming a charge-transporting thin film, which is characterized by

(Wherein, R ^A is, independently of one another, represent an alkyl group having 1 to 20 carbon atoms, R ^B represents a hydroxy group, an oxo group, or an acetamido group.)
2. The good solvent is at least one selected from the group consisting of an amide solvent and a glycol solvent of diethylene glycol, triethylene glycol and tetraethylene glycol, and the ratio of the good solvent to the poor solvent is a mass ratio of good solvent: poor. Solvent = 10:90 to 50:50, 1 charge-transporting thin film-forming varnish,
3. 3. One or two charge-transporting thin films in which the poor solvent is one or more selected from the group consisting of glycol solvents other than diethylene glycol, triethylene glycol and tetraethylene glycol, glycol ether solvents, and glycol ether acetate solvents. Forming varnish,
4. A varnish for forming a charge-transporting thin film according to any one of 1 to 3, wherein the charge-transporting substance contains a charge-transporting compound having a molecular weight of 200 to 9,500.
5. A varnish for forming a charge-transporting thin film according to any one of 1 to 4, wherein the charge-transporting substance contains at least one selected from the group consisting of arylamine derivatives and thiophene derivatives having a molecular weight of 200 to 9,500.
6. A varnish for forming a charge-transporting thin film according to any one of 1 to 5 containing a dopant.
7. The dopant is a varnish for forming a charge-transporting thin film of 6, which contains aryl sulfonic acid.
A charge-transporting thin film produced by using the charge-transporting thin film-forming varnish according to any one of 8.1 to 7.
An organic electroluminescent device with a 9.8 charge-transporting thin film,
A method for producing a charge-transporting thin film, which comprises using a varnish for forming a charge-transporting thin film according to any one of 10.1 to 7.
Provided is a method for manufacturing an organic electroluminescent device, which comprises using the varnish for forming a charge-transporting thin film according to any one of 11.1 to 7.

By using the varnish for forming a charge-transporting thin film of the present invention, an organic charge-transporting substance having relatively high crystallinity is used as compared with the case where a varnish containing no varnish or a varnish containing another organic oxidizing agent is used. Solubility in a solvent can be improved. Furthermore, it suppresses film roughness during film formation and contributes to improving the flatness of the charge-transporting thin film.
Further, the thin film obtained from the charge transporting thin film forming varnish of the present invention is also expected to be used as an antistatic film, a hole collecting layer of an organic thin film solar cell, and the like.

It is a figure which shows the film profile in a pixel when the varnish of Examples 1 to 3 and Comparative Example 1 was applied | formed on the pixel substrate of the long axis 180 μm.

The charge transporting thin film forming varnish according to the present invention contains a 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative represented by the formula (T1).

Wherein, R ^A independently of one another represent an alkyl group having 1 to 20 carbon atoms. The alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic, and may be, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or s-. A linear or branched group having 1 to 20 carbon atoms such as a butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group. Alkyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, bicyclobutyl group, bicyclopentyl group, bicyclohexyl group, bicycloheptyl group, bicyclooctyl group , Bicyclononyl group, bicyclodecyl group and other cyclic alkyl groups having 3 to 20 carbon atoms.

Among them, as the alkyl group, a linear alkyl group having 1 to 20 carbon atoms is preferable, a linear alkyl group having 1 to 5 carbon atoms is more preferable, a methyl group and an ethyl group are more preferable, and a methyl group is optimal. Is.

From the viewpoint of easiness of synthesis of the derivatives, R ^A are preferably all the same.

R ^B represents a hydroxy group (OH), oxo (= O), or acetamido group (NHCOCH _3).

Specific examples of the 2,2,6,6-tetraalkylpiperidin-N-oxyl derivative represented by the formula (T1) include 4-hydroxy-2,2,6,6-tetramethylpiperidin-N-oxyl (T1). Hydroxy-TEMPO), 4-oxo-2,2,6,6-tetramethylpiperidin-N-oxyl (oxo-TEMPO), 4-acetamide-2,2,6,6-tetramethylpiperidin-N-oxyl ( Acetamide-TEMPO), 4-hydroxy-2,2,6,6-tetraethylpiperidine-N-oxyl, 4-oxo-2,2,6,6-tetraethylpiperidine-N-oxyl, 4-acetamide-2,2 , 6,6-tetraethylpiperidin-N-oxyl and the like. In the present invention, hydroxy-TEMPO, oxo-TEMPO, and acetamide-TEMPO are particularly preferable.

The 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative used in the present invention may be a commercially available product, and can be purchased from, for example, Tokyo Chemical Industry Co., Ltd.

The content of the 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative in the varnish of the present invention is 1 to 1 with respect to the charge-transporting substance (if the dopant is contained, the charge-transporting substance and the dopant). It is about 10% by mass, preferably about 3 to 8% by mass.

As the charge-transporting substance contained in the varnish for forming a charge-transporting thin film according to the present invention, a substance used in the field of organic EL or the like can be used. Specific examples thereof include arylamine derivatives such as oligoaniline derivatives, N, N'-diarylbenzidine derivatives, N, N, N', N'-tetraarylbenzidine derivatives, oligothiophene derivatives, thienothiophene derivatives, and thienobenzothiophene. Examples thereof include various charge-transporting compounds such as thiophene derivatives such as derivatives and pyrrol derivatives such as oligopyrrole. Among them, arylamine derivatives and thiophene derivatives are preferable, and arylamine derivatives are more preferable, because they show excellent dissolution in organic solvents.

The molecular weight of the charge-transporting compound is usually about 200 to 9,500 from the viewpoint of preparing a uniform varnish that gives a thin film having high flatness, but is 300 or more from the viewpoint of obtaining a thin film having more excellent charge-transporting property. Is preferable, 400 or more is more preferable, and from the viewpoint of preparing a uniform varnish that gives a thin film having high flatness with better reproducibility, 8,000 or less is preferable, 7,000 or less is more preferable, and 6,000 or less is more. More preferably, it is more preferably 5,000 or less. From the viewpoint of preventing the charge-transporting substance from separating when the film is thinned, the charge-transporting compound preferably has no molecular weight distribution (dispersity is 1) (that is, has a single molecular weight). ).

Specific examples of the arylamine derivative include those represented by the formula (1).

In formula (1), X ²⁰¹ represents −NY ²⁰¹ −, −O−, −S−, − (CR ^{207 R 208} ) _L − or a single bond, but when m ¹ or m ² is 0. , -NY ²⁰¹ - represents a.

Y ²⁰¹ is an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with a hydrogen atom or Z ^{201 independently of each other.} Represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with Z ^202.

Examples of the alkyl group having 1 to 20 carbon atoms include those similar to those described above.

Specific examples of the alkenyl group having 2 to 20 carbon atoms include an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group and an n-2-butenyl group. n-3-butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, 1-methyl-1-propenyl group, 1-methyl-2-propenyl group, n- Examples thereof include 1-pentenyl group, n-1-decenyl group, n-1-eicosenyl group and the like.

Specific examples of the alkynyl group having 2 to 20 carbon atoms include an ethynyl group, an n-1-propynyl group, an n-2-propynyl group, an n-1-butynyl group, an n-2-butynyl group, and an n-3-butynyl group. Group, 1-methyl-2-propynyl group, n-1-pentynyl group, n-2-pentynyl group, n-3-pentynyl group, n-4-pentynyl group, 1-methyl-n-butynyl group, 2- Methyl-n-butynyl group, 3-methyl-n-butynyl group, 1,1-dimethyl-n-propynyl group, n-1-hexynyl group, n-1-decynyl group, n-1-pentadecynyl group, n- 1-Eicosinyl group and the like can be mentioned.

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

Specific examples of the heteroaryl group having 2 to 20 carbon atoms include 2-thienyl group, 3-thienyl group, 2-furanyl group, 3-furanyl group, 2-oxazolyl group, 4-oxazolyl group and 5-oxazolyl group. 3-Isooxazolyl group, 4-Isooxazolyl group, 5-Isooxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5-isothiazolyl group, 2-imidazolyl group, Examples thereof include 4-imidazolyl group, 2-pyridyl group, 3-pyridyl group and 4-pyridyl group.

R ²⁰⁷ and R ²⁰⁸ are independently substituted with hydrogen atom, halogen atom, nitro group, cyano group, amino group, aldehyde group, hydroxy group, thiol group, sulfonic acid group, carboxy group and Z ^201. It may be an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or carbon which may be substituted with ^{Z 202.} Heteroaryl groups of number 2 to 20, or -NHY ²⁰² , -NY ²⁰³ Y ²⁰⁴ , -C (O) Y ²⁰⁵ , -OY ^{206 , -SY 207} , -SO ₃ Y ²⁰⁸ , -C (O) OY ²⁰⁹ , Represents -OC (O) Y ²¹⁰ , -C (O) NHY ²¹¹ or -C (O) NY ²¹² Y ²¹³ groups.

Y ^{202 to Y 213} may be independently ^{substituted with Z 201} , an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms. Represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with Z ^202.

Z ²⁰¹ may be substituted with a halogen atom, a nitro group, a cyano group, an amino group, an aldehyde group, a hydroxy group, a thiol group, a sulfonic acid group, a carboxy group, or Z ²⁰³ , an aryl having 6 to 20 carbon atoms. Represents a group or a heteroaryl group having 2 to 20 carbon atoms.

Z ²⁰² is an alkyl having 1 to 20 carbon atoms, which may be substituted with a halogen atom, a nitro group, a cyano group, an amino group, an aldehyde group, a hydroxy group, a thiol group, a sulfonic acid group, a carboxy group, or Z ^203. It represents a group, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms.

Z ²⁰³ represents a halogen atom, a nitro group, a cyano group, an amino group, an aldehyde group, a hydroxy group, a thiol group, a sulfonic acid group, or a carboxy group.

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

Examples of the alkyl group, alkenyl group, alkynyl group, aryl group and heteroaryl group of R ^{207 to} R ²⁰⁸ and Y ^{202 to Y 213 are the same as those described above.}

Among these, R ²⁰⁷ and R ^208, preferably an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom or Z ^201, is a methyl group which may be substituted with a hydrogen atom or Z ²⁰¹ More preferred, both hydrogen atoms are optimal.

L represents the number of divalent groups represented by − (CR ²⁰⁷ R ²⁰⁸ ) −, which is an integer of 1 to 20, preferably 1 to 10, more preferably 1 to 5, and 1 to 2. Even more preferred, 1 is optimal. When L is 2 or more, the plurality of R ^207s may be the same or different from each other, and the plurality of R ^208s may be the same or different from each other.

In particular, as X ²⁰¹ , −NY ²⁰¹ − or a single bond is preferable. As the Y ^201, preferably an alkyl group which may having 1 to 20 carbon atoms substituted with a hydrogen atom or Z ^201, more preferably a methyl group which may be substituted with a hydrogen atom or Z ^201, hydrogen atom Is the best.

R ^{201 to} R ²⁰⁶ are independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, an aldehyde group, a hydroxy group, a thiol group, a sulfonic acid group, a carboxy group and Z ^201. It may be an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or carbon which may be substituted with ^{Z 202.} Heteroaryl groups of number 2 to 20, or -NHY ²⁰² , -NY ²⁰³ Y ²⁰⁴ , -C (O) Y ²⁰⁵ , -OY ^{206 , -SY 207} , -SO ₃ Y ²⁰⁸ , -C (O) OY ²⁰⁹ , It represents −OC (O) Y ²¹⁰ , −C (O) NHY ²¹¹ or −C (O) NY ²¹² Y ²¹³ (Y ^{202 to Y 213} have the same meanings as described above). Examples of these halogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups and heteroaryl groups include those similar to those described above.

In particular, in the formula (1), R ^{201 to} R ²⁰⁴ may be substituted with a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted with ^{Z 201 , or Z 202.} An aryl group having 6 to 14 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms which may be substituted with a hydrogen atom, a fluorine atom, or a fluorine atom is more preferable, and all hydrogen atoms are optimal.

The R ²⁰⁵ and R ²⁰⁶ include a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted with ^{Z 201} , and an aryl having 6 to 14 carbon atoms which may be substituted with ^{Z 202.} A group or a diphenylamino group which may be substituted with ^{Z 202} (a phenyl group in which ^{Y 203} and Y ²⁰⁴ may be substituted with Z ^{202- NY 203} Y ²⁰⁴ group) is preferable, and a hydrogen atom and a fluorine atom are preferable. , Or a diphenylamino group which may be substituted with a fluorine atom is more preferable, and at the same time, a hydrogen atom or a diphenylamino group is even more preferable.

Among these, R ^{201 to} R ²⁰⁴ are substituted with hydrogen atoms, fluorine atoms, and fluorine atoms, and alkyl groups having 1 to 10 carbon atoms may be substituted. R ²⁰⁵ and R ²⁰⁶ are substituted with hydrogen atoms, fluorine atoms, and fluorine atoms. It is preferable that the diphenylamino group, X ²⁰¹ is −NY ²⁰¹ − or a single bond, and Y ²⁰¹ is a hydrogen atom or a methyl group, and R ^{201 to} R ²⁰⁴ are hydrogen atoms, and R ²⁰⁵ and R ²⁰⁶ are. At the same time, a combination of a hydrogen atom or a diphenylamino group and X ²⁰¹ being -NH- or a single bond is more preferable.

In the formula (1), m ¹ and m ² represent integers of 0 or more independently of each other ^{and satisfy 1 ≤ m 1} + m ² ≤ 20, but the charge transport property of the obtained thin film and dissolution of the arylamine derivative are satisfied. Considering the balance with sex, ^{it is preferable to satisfy 2 ≤ m 1} + m ² ≤ 8, more preferably 2 ≤ m ¹ + m ² ≤ 6, and more preferably 2 ≤ m ¹ + m ² ≤ 4. More preferred.

In Y ²⁰¹ to Y ²¹³ and R ²⁰¹ ~R ^208, Z ²⁰¹ is a halogen atom, or an aryl group having 6 to 20 carbon atoms which may be substituted with Z ²⁰³ is substituted preferably, a halogen atom, or Z ²⁰³ Phenyl groups that may be present are more preferred and optimally absent (ie, unsubstituted).

Z ²⁰² is a halogen atom, or preferably an alkyl group having 1 to 20 carbon atoms that may be substituted with Z ^203, a halogen atom, or an alkyl group having 1 to 4 carbon atoms which may optionally be substituted with Z ²⁰³ More preferably, it is best not present (ie, non-substituted).

For Z ²⁰³ , a halogen atom is preferable, fluorine is more preferable, and it is optimal that it is absent (that is, unsubstituted).

In Y ^{201 to Y 213} and R ^{201 to} R ²⁰⁸ , the number of carbon atoms of the alkyl group, the alkenyl group and the alkynyl group is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less. The aryl group and the heteroaryl group preferably have 14 or less carbon atoms, more preferably 10 or less carbon atoms, and even more preferably 6 or less carbon atoms.

The molecular weight of the arylamine derivative represented by the formula (1) is preferably 9,500 or less, more preferably 8,000 or less, and even more preferably 8,000 or less, from the viewpoint of ensuring solubility in an organic solvent. It is 7,000 or less, more preferably 6,000 or less, and even more preferably 5,000 or less. Further, from the viewpoint of enhancing charge transportability, the molecular weight is preferably 300 or more, more preferably 400 or more. From the viewpoint of preventing the charge-transporting substance from separating when the film is thinned, it is preferable that the arylamine derivative represented by the formula (1) has no molecular weight distribution (dispersity is 1) (that is, a single substance). It is preferable that the molecular weight is.

The method for synthesizing the arylamine derivative is not particularly limited, but Bulletin of Chemical Society of Japan, 67, pp. 1749-1752 (1994), Synthetic Metals, 84, pp. 119-120 (1997), Thin Solid. Films, 520 (24), pp. 7157-7163, (2012), International Publication No. 2008/032617, International Publication No. 2008/032616, International Publication No. 2008/1299447, International Publication No. 2013/0864664, etc. The method described is mentioned.

Specific examples of the arylamine derivative represented by the formula (1) include, but are not limited to, those represented by the following formula.

（式中、ＤＰＡは、ジフェニルアミノ基を表す。）

(In the formula, DPA represents a diphenylamino group.)

（式中、Ｐｈは、フェニル基を表し、ＴＰＡは、ｐ−(ジフェニルアミノ)フェニル基を表す。）

(In the formula, Ph represents a phenyl group and TPA represents a p- (diphenylamino) phenyl group.)

Other specific examples of the arylamine derivative include those represented by the formula (2) or (3).

In formula (3), R ¹ and R ² are alkyl groups having 1 to 20 carbon atoms, which may be substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a halogen atom independently of each other. It represents an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms.

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

Examples of the alkyl group having 1 to 20 carbon atoms, the alkenyl group having 2 to 20 carbon atoms, the alkynyl group having 2 to 20 carbon atoms and the aryl group having 6 to 20 carbon atoms include the same as those described above.

Specific examples of the heteroaryl group having 2 to 20 carbon atoms include 2-furanyl group, 3-furanyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 3-isooxazolyl group and 4-isooxazolyl group. Oxygen-containing heteroaryl groups such as 5-isoxazolyl group; 2-thienyl group, 3-thienyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolicyl group, 4-isothiazolyl group, 5-isothiazolyl group. Sulfur-containing heteroaryl groups such as groups; 2-imidazolyl group, 4-imidazolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 3-pyrazyl group, 5-pyrazyl group, 6 −Pyridyl group, 2-pyrimidyl group, 4-pyrimidyl group, 5-pyrimidyl group, 6-pyrimidyl group, 3-pyridadyl group, 4-pyridadyl group, 5-pyridadyl group, 6-pyridadyl group, 1,2,3- Triazine-4-yl group, 1,2,3-triazine-5-yl group, 1,2,4-triazine-3-yl group, 1,2,4-triazine-5-yl group, 1,2, 4-Triazine-6-yl group, 1,3,5-triazine-2-yl group, 1,2,4,5-tetrazine-3-yl group, 1,2,3,4-tetrazine-5-yl group Group, 2-quinolinyl group, 3-quinolinyl group, 4-quinolinyl group, 5-quinolinyl group, 6-quinolinyl group, 7-quinolinyl group, 8-quinolinyl group, 1-isoquinolinyl group, 3-isoquinolinyl group, 4-isoquinolinyl group Group, 5-isoquinolinyl group, 6-isoquinolinyl group, 7-isoquinolinyl group, 8-isoquinolinyl group, 2-quinoxanyl group, 5-quinoxanyl group, 6-quinoxanyl group, 2-quinazolinyl group, 4-quinazolinyl group, 5-quinazolinyl Nitrogen-containing groups such as group, 6-quinazolinyl group, 7-quinazolinyl group, 8-quinazolinyl group, 3-cinnolinyl group, 4-cinnolinyl group, 5-cinnolinyl group, 6-cinnolinyl group, 7-cinnolinyl group, 8-cinnolinyl group. Heteroaryl groups and the like can be mentioned.

Among these, R ¹ and R ² include an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom, a fluorine atom, a cyano group and a halogen atom, and a carbon number which may be substituted with a halogen atom. An aryl group of 6 to 20 or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with a halogen atom is preferable, and a heteroaryl group having 1 carbon atom which may be substituted with a hydrogen atom, a fluorine atom, a cyano group or a halogen atom is preferable. A phenyl group which may be substituted with an alkyl group of 10 to 10 or a halogen atom is more preferable, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group is more preferable, and a hydrogen atom is the most suitable.

In formulas (2) and (3), Ph ¹ represents a group represented by formula (P1).

In the formula, R ^{3 to} R ⁶ may be substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a halogen atom independently of each other, an alkyl group having 1 to 20 carbon atoms, and 2 carbon atoms. It represents an alkenyl group of ~ 20, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms. Specific examples of these include the same as those described in ^{R 1} and R ^{2 above.}

In particular, R ^{3 to} R ⁶ include an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom, a fluorine atom, a cyano group and a halogen atom, and 6 to 6 carbon atoms which may be substituted with a halogen atom. A heteroaryl group having 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with a halogen atom is preferable, and a heteroaryl group having 1 to 10 carbon atoms which may be substituted with a hydrogen atom, a fluorine atom, a cyano group or a halogen atom is preferable. A phenyl group which may be substituted with an alkyl group or a halogen atom is more preferable, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group is more preferable, and a hydrogen atom is the most suitable.

Hereinafter, ^{specific examples of groups suitable as Ph 1} will be given, but the present invention is not limited thereto.

In the formula (2), Ar ¹ represents a group represented by any of the formulas (B1) to (B11) independently of each other, and in particular, any one of the formulas (B1') to (B11'). The group represented by is preferable.

In the formula, R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a halogen atom. A diphenylamino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms. show. R ²⁸ and R ²⁹ represent an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with ^{Z 1} independently of each other. R ⁵² is a hydrogen atom, may be substituted with Z ^4, substituted alkyl group having 1 to 20 carbon atoms, alkenyl or alkynyl group having 2 to 20 carbon atoms having 2 to 20 carbon atoms, or Z ¹ It represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms.

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

Z ⁴ represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with a halogen atom, a nitro group, a cyano group, or Z ^5. Z ⁵ may be substituted with a halogen atom, a nitro group, a cyano group, or Z ³ , an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms. Represents.

These 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. Specific examples include the same as those described in ^{R 1} and R ^2.

In particular, R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ are substituted with a diphenylamino group or a halogen atom which may be substituted with a hydrogen atom, a fluorine atom, a cyano group or a halogen atom. An alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with a halogen atom may be used. Preferably, an alkyl group having 1 to 10 carbon atoms which may be substituted with a hydrogen atom, a fluorine atom, a cyano group or a halogen atom, or a phenyl group which may be substituted with a halogen atom is more preferable, and a hydrogen atom or a fluorine atom is preferable. , Methyl group, or trifluoromethyl group is even more preferable, and a hydrogen atom is most suitable.

The R ²⁸ and R ^29, an aryl group Z ¹ is carbon atoms and optionally 6-14 replaced by, or heteroaryl group Z ¹ carbon atoms which may be substituted with 2 to 14 preferably, Z ¹ Aryl groups having 6 to 14 carbon atoms which may be ^{substituted with Z 1} are more preferable, and a phenyl group which may be ^{substituted with Z 1} , a 1-naphthyl group which may be substituted with ^{Z 1, or a Z 1 substitution.} 2-naphthyl groups, which may be used, are even more preferred.

As R ^52, a hydrogen atom, an aryl group of Z ¹ is carbon atoms and optionally 6-20 substituted the heteroaryl group which may C2-20 optionally substituted with Z ^1, or Z ⁴ substituent preferably an alkyl group having 1 to 20 carbon atoms that may optionally be a hydrogen atom, Z ¹ in the optionally substituted aryl group having 6 to 14 carbon atoms, Z ¹ carbon atoms, which may be substituted by 2 A heteroaryl group of 14 or an alkyl group having 1 to 10 carbon atoms which may be substituted with ^{Z 4} is more preferable, and a hydrogen atom, an aryl group having 6 to 14 carbon atoms which may be substituted with ^{Z 1, Z.} carbon atoms which may have from 2 to 14 nitrogen-containing heteroaryl group, or Z ⁴ more preferably more even an alkyl group having 1 to 10 carbon atoms substituted with substituted with ^1, hydrogen atom, substituted with Z ¹ which may be a phenyl group, may be substituted with Z ¹ 1-naphthyl group, may be substituted with Z ¹ 2-naphthyl group, it may be substituted with Z ¹ 2-pyridyl group, by Z ¹ may be substituted 3-pyridyl group, may be substituted with Z ¹ 4-pyridyl group, or a methyl group which may be substituted with Z ⁴ is more preferred.

Ar ⁴ represents an aryl group having 6 to 20 carbon atoms, each of which may be substituted with a diarylamino group, which is an aryl group having 6 to 20 carbon atoms, independently of each other. Specific examples of the aryl group having 6 to 20 carbon atoms include the same as ^{those described in R 1} and R ² , and specific examples of the diarylamino group include a diphenylamino group and 1-naphthylphenyl. Examples thereof include an amino group, a di (1-naphthyl) amino group, a 1-naphthyl-2-naphthylamino group, and a di (2-naphthyl) amino group.

Ar ⁴ includes phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4- Phenantryl group, 9-phenanthryl group, p- (diphenylamino) phenyl group, p- (1-naphthylphenylamino) phenyl group, p- (di (1-naphthyl) amino) phenyl group, p- (1-naphthyl-) 2-Phenylamino) phenyl group, p- (di (2-naphthyl) amino) phenyl group and the like are preferable, and p- (diphenylamino) phenyl group is more preferable.

Hereinafter, ^{specific examples of groups suitable as Ar 1} will be given, but the present invention is not limited thereto. In the following formula, DPA and R ⁵² have the same meanings as described above.

In the formula (2), Ar ² represents a group represented by any of the formulas (A1) to (A18) independently of each other, and in particular, the formulas (A1'-1) to (A18'-2). ) Is preferred.

In the formula, R ¹⁵⁵ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with ^{Z 4 , or Z 1} Represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with. R ¹⁵⁶ and R ¹⁵⁷ represent an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with ^{Z 1} independently of each other. DPA, Ar ⁴ , Z ¹ and Z ⁴ have the same meanings as described above. These 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. Specific examples include the same as those described in ^{R 1} and R ^2.

Particularly, as the R ^155, a hydrogen atom, Z ^{1-substituted} having 6 to 20 carbon atoms which may have an aryl group, a heteroaryl group which may C2-20 optionally substituted with Z ^1, or Z ⁴ preferably an alkyl group having 1 to 20 carbon atoms which may be substituted in a hydrogen atom, an optionally substituted aryl group having 6 to 14 carbon atoms in Z ^1, carbon atoms, which may be substituted with Z ¹ A heteroaryl group of 2 to 14 or an alkyl group having 1 to 10 carbon atoms which may be substituted with ^{Z 4} is more preferable, and an aryl group having 6 to 14 carbon atoms which may be substituted with ^{a hydrogen atom or Z 1 is more preferable.} , are carbon atoms and optionally 2 to 14 nitrogen-containing heteroaryl group, or Z ⁴ more preferably more even an alkyl group having 1 to 10 carbon atoms substituted with substituted with Z ^1, hydrogen atom, Z ¹ in an optionally substituted phenyl group, Z ¹ in optionally substituted 1-naphthyl group, Z ¹ in optionally substituted 2-naphthyl group, which may have been or 2-pyridyl substituted with Z ¹ group, may be substituted with Z ¹ 3- pyridyl group and may be substituted with Z ¹ 4-pyridyl group, or a methyl group which may be substituted with Z ⁴ is more preferred.

The R ¹⁵⁶ and R ^157, an aryl group Z ¹ is carbon atoms and optionally 6-14 replaced by, or heteroaryl group Z ¹ carbon atoms which may be substituted with 2 to 14 preferably, Z ¹ Aryl groups having 6 to 14 carbon atoms which may be ^{substituted with Z 1} are more preferable, and a phenyl group which may be ^{substituted with Z 1} , a 1-naphthyl group which may be substituted with ^{Z 1, or a Z 1 substitution.} 2-naphthyl groups, which may be used, are even more preferred.

Hereinafter, ^{specific examples of groups suitable as Ar 2} will be given, but the present invention is not limited thereto. In the following formula, R ¹⁵⁵ and DPA have the same meanings as described above.

In the formula (2), considering the ease of synthesizing the obtained arylamine derivative, ^{it is preferable that Ar 1} is all the same group and Ar ² is all the same group, and Ar ¹ and Ar ² are all the same group. It is more preferable that they are all the same group. That is, as the arylamine derivative represented by the formula (2), the one represented by the formula (2-1) is more preferable.

In formula (2-1), Ph ¹ has the same meaning as described above. x will be described later. Ar ⁵ simultaneously represents a group represented by any of the formulas (D1) to (D13), and in particular, a group represented by any of the formulas (D1') to (D13'). preferable. In the following formula, R ²⁸ , R ²⁹ , R ⁵² , Ar ⁴ and DPA have the same meanings as described above. Specific examples of Ar ⁵ include the same as those described above as specific examples of groups suitable for ^{Ar 1.}

Further, as will be described later, it can be synthesized relatively easily using a relatively inexpensive bis (4-aminophenyl) amine as a raw material compound, and the obtained arylamine derivative has excellent solubility in an organic solvent. The arylamine derivative represented by the formula (2) is preferably represented by the formula (2-2).

In the formula, Ar ⁶ simultaneously represents a group represented by any of the formulas (E1) to (E14). In the following formula, R ⁵² has the same meaning as described above.

In the formula (3), Ar ³ represents a group represented by any of the formulas (C1) to (C8), and a group represented by any of the formulas (C1') to (C8') is particularly preferable. .. In the following formula, DPA has the same meaning as described above.

In the formulas (2) and (2-1), x represents an integer of 1 to 10, but from the viewpoint of increasing the solubility of the compound in an organic solvent, 1 to 5 is preferable, and 1 to 3 is more preferable. 1 or 2 is even more preferred, and 1 is optimal. In formula (3), y represents 1 or 2.

In R ^28, R ^29, R ⁵² and R ¹⁵⁵ ~R ^157, Z ¹ is a halogen atom, a nitro group, a cyano group, an alkyl group having carbon atoms which may be have 1 to 10 substituted by Z ^2, with Z ² An alkenyl group having 2 to 10 carbon atoms which may be substituted, or an alkynyl group having 2 to 10 carbon atoms which may be substituted by ^{Z 2} is preferable, and the alkynyl group is substituted with ^{a halogen atom, a nitro group, a cyano group, or Z 2.} which may be an alkyl group having 1 to 3 carbon atoms, Z ² substituted by carbon atoms and optionally 2-3 alkenyl group, or Z ² may alkynyl group having a carbon number of 2 to 3 may be substituted by the more preferably, a fluorine atom, substituted by Z ² with an optionally substituted alkyl group having 1 to 3 carbon atoms, Z ² substituted by carbon atoms and optionally 2-3 alkenyl group, or Z ² A good alkynyl group having 2 to 3 carbon atoms is even more preferable.

In R ²⁸ , R ²⁹ , R ⁵² and R ^{155 to} R ¹⁵⁷ , Z ⁴ is preferably an aryl group having 6 to 14 carbon atoms which may be substituted with a halogen atom, a nitro group, a cyano group or Z ^5. An aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, a nitro group, a cyano group, or Z ⁵ is more preferable, and an aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom or Z ^{5 is preferable.} Aryl groups are even more preferred, with fluorine atoms or phenyl groups optionally substituted with ^{Z 5 being even more preferred.}

In R ²⁸ , R ²⁹ , R ⁵² and R ^{155 to} R ¹⁵⁷ , Z ² is preferably an aryl group having 6 to 14 carbon atoms which may be substituted with a halogen atom, a nitro group, a cyano group or Z ^3. An aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, a nitro group, a cyano group, or Z ³ is more preferable, and an aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom or Z ^{3 is more preferable.} Aryl groups are even more preferred, and phenyl groups, which may be substituted with ^{a fluorine atom or Z 3, are even more preferred.}

In R ^28, R ^29, R ⁵² and R ¹⁵⁵ ~R ^157, Z ⁵ is a halogen atom, a nitro group, a cyano group, Z ³ optionally substituted by an alkyl group having 1 to 10 carbon atoms, with Z ³ An alkenyl group having 2 to 10 carbon atoms which may be substituted, or an alkynyl group having 2 to 10 carbon atoms which may be substituted by ^{Z 3} is preferable, and the alkynyl group is substituted with ^{a halogen atom, a nitro group, a cyano group, or Z 3.} which may be an alkyl group having 1 to 3 carbon atoms, Z ^{3-substituted} carbon atoms and optionally 2-3 alkenyl group, or Z ³ an alkynyl group having a carbon number of 2 to 3 may be substituted by the more preferably, a fluorine atom, substituted by Z ³ in the optionally substituted alkyl group having 1 to 3 carbon atoms, Z ^{3-substituted} carbon atoms and optionally 2-3 alkenyl group, or Z ³ A good alkynyl group having 2 to 3 carbon atoms is even more preferable.

In R ²⁸ , R ²⁹ , R ⁵² and R ^{155 to} R ¹⁵⁷ , Z ³ is preferably a halogen atom, more preferably a fluorine atom.

In R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ , Z ¹ is a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms which may be substituted with ^{Z 2.} Z ² in which may be substituted an alkenyl group having a carbon number of 2-3, or an alkynyl group having a carbon number of 2-3 is preferable optionally substituted by Z ^2, optionally substituted with a halogen atom, or Z ² Alkyl groups having 1 to 3 carbon atoms are more preferable, and methyl groups which may be substituted with ^{a fluorine atom or Z 2 are even more preferable.}

In R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ , Z ⁴ is a halogen atom, a nitro group, a cyano group, or an aryl group having 6 to 10 carbon atoms which may be substituted with ^{Z 5.} Is preferable, an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom or Z ⁵ is more preferable, and a phenyl group which may be substituted with ^{a fluorine atom or Z 5 is even more preferable.}

In R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ , Z ² is a halogen atom, a nitro group, a cyano group, or an aryl group having 6 to 10 carbon atoms which may be substituted with ^{Z 3.} Is preferable, an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom or Z ³ is more preferable, and a phenyl group which may be substituted with ^{a fluorine atom or Z 3 is even more preferable.}

In R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ , Z ⁵ is a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms which may be substituted with ^{Z 3.} Z ³ optionally substituted by an alkenyl group having a carbon number of 2-3, or an alkynyl group having a carbon number of 2-3 is preferable optionally substituted by Z ^3, substituted with a halogen atom, or Z ³ Alkyl groups having 1 to 3 carbon atoms are more preferable, and methyl groups which may be substituted with ^{a fluorine atom or Z 3 are even more preferable.}

In R ^{7 to} R ²⁷ , R ^{30 to} R ⁵¹ and R ^{53 to} R ¹⁵⁴ , Z ³ is preferably a halogen atom, more preferably a fluorine atom.

^{Specific examples of groups suitable as R 52} and R ¹⁵⁵ in the present invention include, but are not limited to, those shown below.

In the present invention, the alkyl group, alkenyl group and alkynyl group have preferably 10 or less carbon atoms, more preferably 6 or less carbon atoms, and even more preferably 4 or less carbon atoms. The aryl group and the heteroaryl group have preferably 14 or less carbon atoms, more preferably 10 or less carbon atoms, and even more preferably 6 or less carbon atoms.

The molecular weight of the arylamine derivative represented by the formula (2) and the arylamine derivative represented by the formula (3) is usually about 200 to 9,500 from the viewpoint of preparing a uniform varnish that gives a thin film with high flatness. However, from the viewpoint of preparing a uniform varnish that gives a thin film with high flatness with better reproducibility, 8,000 or less is preferable, 7,000 or less is more preferable, and 6,000 or less is even more preferable. It is more preferably 000 or less, more preferably 300 or more, and even more preferably 400 or more, from the viewpoint of obtaining a thin film having more excellent charge transportability. From the viewpoint of preventing the charge-transporting substance from separating when the film is thinned, it is preferable that the charge-transporting compound has no molecular weight distribution (dispersity is 1) (that is, it has a single molecular weight). Is preferable).

The arylamine derivative represented by the formula (2) and the arylamine derivative represented by the formula (3) can be produced according to the method described in International Publication No. 2015/050253.

Hereinafter, specific examples of the arylamine derivative represented by the formula (2) or (3) will be given, but the present invention is not limited thereto. In the formulas, "Me" represents a methyl group, "Et" represents an ethyl group, a "Pr ^n" is n- propyl group, "Pr ^i" is i- propyl group, "Bu ^n" is n- Butyl group, "Bu ⁱ " is i-butyl group, "Bu ^s " is s-butyl group, "Bu ^t " is t-butyl group, "DPA" is diphenylamino group, "SBF" is Represents each of the 9,9'-spirobi [9H-butyl] -2-yl groups.

The content of the charge-transporting substance in the varnish of the present invention is appropriately set in consideration of the viscosity and surface tension of the varnish, the thickness of the thin film to be produced, and the like. It is about 0% by mass, preferably about 0.5 to 5.0% by mass, and more preferably about 1.0 to 3.0% by mass, considering that the coatability of the varnish is improved. In the present invention, the charge transporting substance preferably has at least one amino group (NH) in its molecule in consideration of its solubility in the organic solvent.

The varnish for forming a charge-transporting thin film of the present invention may contain a dopant from the viewpoint of further improving the charge-transporting property of the obtained thin film. The dopant is not particularly limited, but aryl sulfonic acid is preferable. An example thereof is an aryl sulfonic acid represented by the formula (4) or (5).

In the formula (4), A ¹ represents −O− or −S−, but −O− is preferable. A ² represents a naphthalene ring or an anthracene ring, but a naphthalene ring is preferable. A ³ represents a 2- to tetravalent perfluorobiphenyl group, j ¹ represents the number of bonds between A ¹ and A ^{3, and is an integer satisfying 2 ≤ j 1} ≤ 4, but A ³ is a divalent par. It is preferably a fluorobiphenyl group and j ^{1 is 2.} j ² represents the number of sulfonic acid groups bonded to A ^{2 , and is an integer satisfying 1 ≦ j 2} ≦ 4, but 2 is preferable.

In formula (5), A ^{4 to} A ⁸ are independent of each other, a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkyl halide group having 1 to 20 carbon atoms, or 2 carbon atoms. Represents a halogenated alkenyl group of ~ 20, but at least 3 of ^{A 4} ~ A ^{8 are halogen atoms.} k represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1 ≦ k ≦ 4, but 2 to 4 is preferable, and 2 is more preferable.

As the alkyl halide group having 1 to 20 carbon atoms, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, 3,3,3- Trifluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,2,2,3,3,3-heptafluoropropyl group, 4,4,4-trifluorobutyl group, 3,3,4,4,4-pentafluorobutyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 1,1,2,2,3,3,4,4, Examples thereof include 4-nonafluorobutyl group. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include a perfluorovinyl group, a 1-perfluoropropenyl group, a perfluoroallyl group, a perfluorobutenyl group and the like.

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

Among these, A ^{4 to} A ⁸ are a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkyl halide group having 1 to 10 carbon atoms, or an alkenyl halide group having 2 to 10 carbon atoms. In addition, ^{at least three of A 4 to} A ⁸ are preferably fluorine atoms, which are a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 5 carbon atoms, and an alkyl fluoride having 1 to 5 carbon atoms. It is more preferably a group or a fluorinated alkenyl group having 2 to 5 carbon atoms, and ^{at least 3 of A 4 to} A ⁸ are fluorine atoms, and a hydrogen atom, a fluorine atom, a cyano group, and 1 to 5 carbon atoms. It is even more preferable that the perfluoroalkyl group or the perfluoroalkenyl group having 1 to 5 carbon ^{atoms is a fluorine atom, and A 4} , A ⁵ and A ^{8 are fluorine atoms.}

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

Specific examples of the above-mentioned aryl sulfonic acid will be given, but the present invention is not limited thereto.

The content of the dopant in the varnish of the present invention is appropriately set in consideration of the type and amount of the charge-transporting substance, but is usually about 0.5 to 10 in terms of mass ratio with respect to the charge-transporting substance. Is.

In the present invention, at least one good solvent and at least one poor solvent are used as the organic solvent used when preparing the varnish for forming a charge-transporting thin film. Here, the good solvent means a solvent having a high dissolving ability of a charge transporting substance. A poor solvent is a solvent used for the purpose of improving wettability to a substrate, adjusting the surface tension of the solvent, adjusting the polarity, adjusting the boiling point, etc., although it is inferior in terms of solubility in a charge-transporting substance. means.

Good solvents include N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, 1,3. -Amid solvents such as dimethyl-2-imidazolidinone and N-cyclohexyl-2-pyrrolidinone, glycol solvents such as diethylene glycol, triethylene glycol and tetraethylene glycol (referred to as good glycol solvents), and sulfoxide solvents such as dimethyl sulfoxide. Can be mentioned. In the present invention, amide-based solvents and glycol-based solvents are preferable. These good solvents may be used individually or in combination of two or more.

Examples of the poor solvent include glycol-based solvents other than the glycol-based solvent, glycol ether-based solvents, and glycol ether acetate-based solvents.

As a specific example of a glycol-based solvent as a poor solvent (referred to as a glycol-based poor solvent),
Ethylene glycol, dipropylene glycol, 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, Examples thereof include 1,4-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol (hexylene glycol), 1,3-octylene glycol, 3,6-octylene glycol and the like.

Specific examples of glycol ether solvents include
Ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, propylene glycol Alkylene glycol mono such as propylene glycol monoalkyl ethers such as monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl ether and propylene glycol monohexyl ether. Alkyl ethers;
Ethylene glycol monoaryl ethers such as ethylene glycol monophenyl ether, alkylene glycol monoaryl ethers such as propylene glycol monoaryl ethers such as propylene glycol monophenyl ether;
Ethylene glycol monoaralkyl ethers such as ethylene glycol monobenzyl ether, alkylene glycol monoaralkyl ethers such as propylene glycol monoaralkyl ethers such as propylene glycol monobenzyl ether;
Ethylene glycol alkoxyalkyl ethers such as ethylene glycol butoxyethyl ether, alkylene glycol alkoxyalkyl ethers such as propylene glycol alkoxyalkyl ethers such as propylene glycol butoxyethyl ether;
Ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol diisopropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol diisopropyl Alkylene glycol dialkyl ethers such as propylene glycol dialkyl ethers such as ethers and propylene glycol dibutyl ethers;
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monoalkyl ethers of diethylene glycol monohexyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl Dialkylene glycol mono such as dipropylene glycol monoalkyl ethers such as ether, dipropylene glycol monopropyl ether, dipropylene glycol monoisopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monoisobutyl ether, dipropylene glycol monohexyl ether, etc. Alkyl ethers;
Diethylene glycol monoaryl ethers such as diethylene glycol monophenyl ether, dialkylene glycol monoaryl ethers such as dipropylene glycol monoaryl ethers such as dipropylene glycol monophenyl ether;
Diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol diisopropyl ether, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dipropyl ether, dipropylene glycol diisopropyl ether, Dipropylene glycol dialkyl ethers such as dipropylene glycol dibutyl ethers Dialkylene glycol dialkyl ethers such as dipropylene glycol dialkyl ethers;
Triethylene glycol monoalkyl ethers such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether, trialkylene glycol monoalkyl ethers such as tripropylene glycol monoalkyl ethers such as tripropylene glycol monomethyl ether and tripropylene glycol monoethyl ether. Ethers;
Examples thereof include triethylene glycol dialkyl ethers such as triethylene glycol dimethyl ether and triethylene glycol diethyl ether, and trialkylene glycol dialkyl ethers such as tripropylene glycol dialkyl ethers such as tripropylene glycol dimethyl ether and tripropylene glycol diethyl ether.

Specific examples of the glycol ether acetate solvent include
Ethylene glycol monomethyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol Alkylene glycol monoalkyl ether acetates such as propylene glycol monoalkyl ether acetates such as monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol monobutyl ether acetate;
Ethylene glycol monoacetates such as ethylene glycol monoacetate, alkylene glycol monoacetates such as propylene glycol monoacetate such as propylene glycol monoacetate;
Ethylene glycol diacetates such as ethylene glycol diacetate, alkylene glycol diacetates such as propylene glycol diacetate such as propylene glycol diacetate;
Diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoisopropyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoisobutyl ether acetate, diethylene glycol monoalkyl ether acetate diethylene glycol monoalkyl ether acetates, dipropylene glycol Monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monopropyl ether acetate, dipropylene glycol monoisopropyl ether acetate, dipropylene glycol monobutyl ether acetate, dipropylene glycol monoisobutyl ether acetate, dipropylene glycol monohexyl ether acetate Dipropylene glycol monoalkyl ether acetates and the like Dialkylene glycol monoalkyl ether acetates and the like can be mentioned.

In the present invention, as a preferable combination of the good solvent and the poor solvent, a glycol-based good solvent is used as the good solvent, and triethylene glycol dialkyl ethers are combined as the poor solvent, or an amide solvent is used as the good solvent. Examples thereof include a case where a glycol-based poor solvent and dialkylene glycol monoalkyl ethers are combined as the solvent.

The ratio of the good solvent to the poor solvent in the varnish is preferably good solvent: poor solvent = 10: 90 to 50:50, more preferably 20:80 to 50:50 in terms of mass ratio.

In the present invention, two or more types selected from the above-mentioned good solvent and poor solvent are used in combination, but the combination is not limited, and when a specific TEMPO derivative is used, a charge transporting substance is dissolved to form a varnish. Can be prepared.

Appropriate use of an organic solvent for the 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative promotes the dissolution of the charge transporting substance in the organic solvent, and further during film formation. The occurrence of film roughness can be suppressed as much as possible. This enables reliable film formation and contributes to the improvement of productivity of electronic devices.

The viscosity of the varnish of the present invention is appropriately set according to the thickness of the thin film to be produced and the solid content concentration, but is usually 1 to 50 mPa · s at 25 ° C., and its surface tension is usually 20 to 50 mN. / M.

The method for preparing the varnish for forming a charge-transporting thin film is not particularly limited, but for example, the dopant is first dissolved in a solvent, and the charge-transporting substance 2,2,6,6-tetraalkylpiperidine-N- Examples thereof include a method of sequentially adding an oxyl derivative and a method of dissolving a mixture of a charge-transporting substance, a dopant, and a 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative in a solvent.

When there are a plurality of organic solvents, the charge transporting substance, the dopant, and the 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative are dissolved sequentially or simultaneously in a mixed solvent of the plurality of organic solvents. It is preferable to let it.

In the present invention, the varnish for forming a charge-transporting thin film uses a sub-micro-order filter or the like after dissolving a charge-transporting substance, a dopant, or the like in an organic solvent from the viewpoint of obtaining a highly flat thin film with good reproducibility. It is desirable to filter.

By applying the varnish for forming a charge transport thin film of the present invention on a substrate, drying it, and then firing it, a thin film exhibiting a charge transport function can be formed on the substrate.

Examples of the varnish coating method include, but are not limited to, a dip method, a spin coating method, a transfer printing method, a roll coating method, a brush coating method, an inkjet method, a spray method, and a slit coating method. The coating method is preferably an inkjet method, a spray method, a slit coating method, or a roll coating method in consideration of film formation on a large substrate. It is preferable to adjust the viscosity and surface tension of the varnish according to the coating method.

The firing temperature is appropriately set within the range of approximately 100 to 260 ° C. in consideration of the intended use of the obtained thin film, the degree of charge transportability applied to the obtained thin film, and the like, and the hole injection layer of the organic EL element. When used as, it is preferably about 140 to 250 ° C, more preferably about 150 to 230 ° C. Further, heating may be performed using an appropriate device such as a hot plate or an oven.

The film thickness of the charge transporting thin film is not particularly limited, but when used as a hole injection layer of an organic EL element, it is preferably 5 to 500 nm, more preferably 10 to 300 nm. As a method of changing the film thickness, there are a method of changing the concentration of a charge-transporting substance or the like in the varnish, a method of changing the amount of the solution on the substrate at the time of coating, and the like.

The surface roughness Ra of the obtained charge-transporting thin film is preferably 10 nm or less, more preferably 8 nm or less, still more preferably 6 nm or less. When the surface roughness Ra is not more than the upper limit, the occurrence of a short circuit when the organic EL element is driven is effectively reduced.

The charge transporting thin film of the present invention can be suitably used as a hole injection layer in an organic EL device, but can also be used as a charge transport functional layer such as a hole injection transport layer.

The organic EL device of the present invention has a pair of electrodes and has the above-mentioned charge transporting thin film of the present invention between these electrodes.

Typical configurations of the organic EL element include, but are not limited to, the following (a) to (f). In the following configuration, if necessary, an electron block layer or the like may be provided between the light emitting layer and the anode, and a hole block layer or the like may be provided between the light emitting layer and the cathode. Further, the hole injection layer, the hole transport layer or the hole injection transport layer may also have a function as an electron block layer or the like, and the electron injection layer, the electron transport layer or the electron injection transport layer is a hole (hole). It may also have a function as a block layer or the like.
(A) Antenna / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (b) anode / hole injection layer / hole transport layer / light emitting layer / electron injection transport layer / Cathode (c) Electron / hole injection transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (d) anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (e) anode / positive Hole injection layer / hole transport layer / light emitting layer / cathode (f) anode / hole injection transport layer / light emitting layer / cathode

The "hole injection layer", "hole transport layer" and "hole injection transport layer" are layers formed between the light emitting layer and the anode, and transport holes from the anode to the light emitting layer. It has a function. When only one layer of hole transporting material is provided between the light emitting layer and the anode, it is a "hole injection transport layer", and a layer of hole transporting material between the light emitting layer and the anode. When two or more layers are provided, the layer close to the anode is the "hole injection layer", and the other layers are the "hole transport layers". In particular, as the hole injection layer and the hole injection transport layer, thin films having excellent hole acceptability from the anode as well as hole injection into the hole transport layer and the light emitting layer, respectively, are used.

The "electron injection layer", "electron transport layer" and "electron transport layer" are layers formed between the light emitting layer and the cathode and have a function of transporting electrons from the cathode to the light emitting layer. Is. When only one layer of electron transporting material is provided between the light emitting layer and the cathode, it is an "electron injection transporting layer", and two layers of electron transporting material are provided between the light emitting layer and the cathode. When the above is provided, the layer close to the cathode is the "electron injection layer", and the other layers are the "electron transport layer".

The "light emitting layer" is an organic layer having a light emitting function, and includes a host material and a dopant material when a doping system is adopted. At this time, the host material mainly has a function of promoting recombination of electrons and holes and confining excitons in the light emitting layer, and the dopant material efficiently emits excitons obtained by recombination. Has a function. In the case of a phosphorescent device, the host material mainly has a function of confining excitons generated by the dopant in the light emitting layer.

Examples of materials and manufacturing methods used when manufacturing an organic EL device using the varnish for forming a charge-transporting thin film of the present invention include, but are not limited to, the following.

It is preferable that the electrode substrate to be used is purified by performing liquid cleaning with detergent, alcohol, pure water or the like in advance.

An example of the method for producing the organic EL element of the present invention when the thin film obtained from the charge transporting thin film forming varnish of the present invention is a hole injection layer is as follows.

By the above-mentioned method, the varnish for forming a charge-transporting thin film of the present invention is applied onto an anode substrate and fired to prepare a hole injection layer on an electrode. A hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are provided on the hole injection layer in this order. The hole transport layer, the light emitting layer, the electron transport layer and the electron injection layer may be formed by either a vapor deposition method or a coating method (wet process) depending on the characteristics of the material to be used and the like.

Examples of the anode material include transparent electrodes typified by indium tin oxide (ITO) and indium zinc oxide (IZO), and metal anodes composed of metals typified by aluminum and alloys thereof, which are flat. Those that have undergone chemical treatment are preferable. Polythiophene derivatives and polyaniline derivatives having high charge transport properties can also be used.

Other metals that make up the metal anode include scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, thulium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, and cadmium. , Indium, scandium, lantern, cerium, placeodium, neodym, promethium, samarium, europium, gadrinium, terbium, dysprosium, holmium, erbium, thulium, itterbium, hafnium, tarium, tungsten, renium, osmium, iridium, platinum, gold, titanium , Lead, bismuth and alloys thereof, but are not limited thereto.

Materials for forming the hole transport layer include (triphenylamine) dimer derivative, [(triphenylamine) dimer] spirodimer, N, N'-bis (naphthalen-1-yl) -N, N'-bis. (Phenyl) -benzidine (α-NPD), N, N'-bis (naphthalen-2-yl) -N, N'-bis (phenyl) -benzidine, N, N'-bis (3-methylphenyl)- N, N'-bis (phenyl) -benzidine, N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) -9,9-spirobifluorene, N, N'-bis ( Naphthalene-1-yl) -N, N'-bis (phenyl) -9,9-spirobifluorene, N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) -9, 9-Dimethyl-fluorene, N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -9,9-dimethyl-fluorene, N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) -9,9-diphenyl-fluorene, N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -9,9-diphenyl-fluorene , N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine, 2,2', 7,7'-tetrakis (N, N-diphenyl) Amino) -9,9-spirobifluorene, 9,9-bis [4- (N, N-bis-biphenyl-4-yl-amino) phenyl] -9H-fluorene, 9,9-bis [4- ( N, N-bis-naphthalen-2-yl-amino) phenyl] -9H-fluorene, 9,9-bis [4- (N-naphthalen-1-yl-N-phenylamino) -phenyl] -9H-fluorene 2,2', 7,7'-tetrakis [N-naphthalenyl (phenyl) -amino] -9,9-spirobifluorene, N, N'-bis (phenanthrene-9-yl) -N, N'- Bis (phenyl) -benzidine, 2,2'-bis [N, N-bis (biphenyl-4-yl) amino] -9,9-spirobifluorene, 2,2'-bis (N, N-diphenylamino) ) -9,9-Spirobifluorene, di- [4- (N, N-di (p-tolyl) amino) -phenyl] cyclohexane, 2,2', 7,7'-tetra (N, N-di) (p-tolyl) amino) -9,9-spirobifluorene, N, N, N', N'-tetra-naphthalen-2-yl-benzidine, N , N, N', N'-tetra- (3-methylphenyl) -3,3'-dimethylbenzidine, N, N'-di (naphthalenyl) -N, N'-di (naphthalen-2-yl)- Benzidine, N, N, N', N'-tetra (naphthalenyl) -benzidine, N, N'-di (naphthalen-2-yl) -N, N'-diphenylbenzidine-1,4-diamine, N ¹ , N ⁴ -diphenyl-N ¹ , N ⁴ -di (m-tolyl) benzene-1,4-diamine, N ² , N ² , N ⁶ , N ⁶ -tetraphenylnaphthalene-2,6-diamine, tris (4) -(Kinoline-8-yl) phenyl) amine, 2,2'-bis (3- (N, N-di (p-tolyl) amino) phenyl) biphenyl, 4,4', 4''-tris [3 Triarylamines such as −methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4', 4''-tris [1-naphthyl (phenyl) amino] triphenylamine (1-TNATA) 5,5''-bis- {4- [bis (4-methylphenyl) amino] phenyl} -2,2': 5', 2''-oligothiophenes such as turthiophene (BMA-3T), etc. Hole-transporting low-molecular-weight materials and the like can be mentioned.

Materials forming the light emitting layer include tris (8-quinolinolate) aluminum (III) (Alq ₃ ), bis (8-quinolinolate) zinc (II) (Znq ₂ ), and bis (2-methyl-8-quinolinolate)-. 4- (p-phenylphenolate) aluminum (III) (BAlq), 4,4'-bis (2,2-diphenylvinyl) biphenyl, 9,10-di (naphthalen-2-yl) anthracene, 2-t -Butyl-9,10-di (naphthalen-2-yl) anthracene, 2,7-bis [9,9-di (4-methylphenyl) -fluorene-2-yl] -9,9-di (4-yl) Methylphenyl) fluorene, 2-methyl-9,10-bis (naphthalen-2-yl) anthracene, 2- (9,9-spirobifluorene-2-yl) -9,9-spirobifluorene, 2,7 -Bis (9,9-spirobifluoren-2-yl) -9,9-spirobifluorene, 2- [9,9-di (4-methylphenyl) -fluorene-2-yl] -9,9- Di (4-methylphenyl) fluorene, 2,2'-dipyrenyl-9,9-spirobifluorene, 1,3,5-tris (pyrene-1-yl) benzene, 9,9-bis [4- (pyrenyl) ) Phenyl] -9H-fluorene, 2,2'-bi (9,10-diphenylanthracene), 2,7-dipyrenyl-9,9-spirobifluorene, 1,4-di (pyrene-1-yl) benzene 1,3-di (pyrene-1-yl) benzene, 6,13-di (biphenyl-4-yl) pentacene, 3,9-di (naphthalen-2-yl) perylene, 3,10-di (naphthalene) -2-Il) Fluorene, Tris [4- (pyrenyl) -phenyl] amine, 10,10'-di (biphenyl-4-yl) -9,9'-biantracene, N, N'-di (naphthalene-) 1-yl) -N, N'-diphenyl- [1,1': 4', 1'': 4'', 1'''-quarterphenyl] -4,4'''-diamine, 4,4 '-Di [10- (naphthalene-1-yl) anthracene-9-yl] biphenyl, dibenzo {[f, f']-4,4', 7,7'-tetraphenyl} diindeno [1,2,3 -Cd: 1', 2', 3'-lm] perylene, 1- (7- (9,9'-biantrasen-10-yl) -9,9-dimethyl-9H-fluorene-2-yl) pyrene , 1- (7- (9,9'-biantrasen-10-yl) -9,9-dihexyl-9H- Fluoren-2-yl) pyrene, 1,3-bis (carbazole-9-yl) benzene, 1,3,5-tris (carbazole-9-yl) benzene, 4,4', 4''-tris (carbazole) -9-yl) triphenylamine, 4,4'-bis (carbazole-9-yl) biphenyl (CBP), 4,4'-bis (carbazole-9-yl) -2,2'-dimethylbiphenyl, 2 , 7-bis (carbazole-9-yl) -9,9-dimethylfluorene, 2,2', 7,7'-tetrakis (carbazole-9-yl) -9,9-spirobifluorene, 2,7- Bis (carbazole-9-yl) -9,9-di (p-tolyl) fluorene, 9,9-bis [4- (carbazole-9-yl) -phenyl] fluorene, 2,7-bis (carbazole-9) -Il) -9,9-spirobifluorene, 1,4-bis (triphenylsilyl) benzene, 1,3-bis (triphenylsilyl) benzene, bis (4-N, N-diethylamino-2-methylphenyl) ) -4-Methylphenylmethane, 2,7-bis (carbazole-9-yl) -9,9-dioctylfluorene, 4,4''-di (triphenylsilyl) -p-terphenyl, 4,4' -Di (triphenylsilyl) biphenyl, 9- (4-t-butylphenyl) -3,6-bis (triphenylsilyl) -9H-carbazole, 9- (4-t-butylphenyl) -3,6- Ditrityl-9H-carbazole, 9- (4-t-butylphenyl) -3,6-bis (9- (4-methoxyphenyl) -9H-fluoren-9-yl) -9H-carbazole, 2,6-bis (3- (9H-carbazole-9-yl) phenyl) pyridine, triphenyl (4- (9-phenyl-9H-fluoren-9-yl) phenyl) silane, 9,9-dimethyl-N, N-diphenyl- 7- (4- (1-phenyl-1H-benzo [d] imidazol-2-yl) phenyl) -9H-fluoren-2-amine, 3,5-bis (3- (9H-carbazole-9-yl)) Phenyl) pyridine, 9,9-spirobifluorene-2-yl-diphenyl-phosphine oxide, 9,9'-(5- (triphenylsilyl) -1,3-phenylene) bis (9H-carbazole), 3- (2,7-bis (diphenylphosphoryl) -9-phenyl-9H-fluoren-9-yl) -9-phenyl-9H-carbazole 4,4,8,8,12 , 12-Hexa (p-tolyl) -4H-8H-12H-12C-azadibenzo [cd, mn] pyrene, 4,7-di (9H-carbazole-9-yl) -1,10-phenanthrolin, 2,2 '-Bis (4- (carbazole-9-yl) phenyl) biphenyl, 2,8-bis (diphenylphosphoryl) dibenzo [b, d] thiophene, bis (2-methylphenyl) diphenylsilane, bis [3,5- Di (9H-carbazole-9-yl) phenyl] diphenylsilane, 3,6-bis (carbazole-9-yl) -9- (2-ethyl-hexyl) -9H-carbazole, 3- (diphenylphosphoryl) -9 -(4- (Diphenylphosphoryl) phenyl) -9H-carbazole, 3,6-bis [(3,5-diphenyl) phenyl] -9-phenylcarbazole and the like can be mentioned. A light emitting layer may be formed by co-depositing these materials with a light emitting dopant.

Luminescent dopants include 3- (2-benzothiazolyl) -7- (diethylamino) coumarin, 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H, 11H-10- (2-Benzothiazolyl) quinolidino [9,9a, 1gh] coumarin, quinacridone, N, N'-dimethyl-quinacridone, tris (2-phenylpyridine) iridium (III) (Ir (ppy) ₃ ), bis (2-phenyl) Ppyridine) (acetylacetonate) iridium (III) (Ir (ppy) ₂ (acac)), tris [2- (p-tolyl) pyridine] iridium (III) (Ir (mppy) ₃ ), 9,10-bis [N, N-di (p-tolyl) amino] anthracene, 9,10-bis [phenyl (m-tolyl) amino] anthracene, bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (II), N ¹⁰ , N ¹⁰ , N ¹⁰ , N ¹⁰ -Tetra (p-trill) -9,9'-Biantracene-10,10'-Diamine, N ¹⁰ , N ¹⁰ , N ¹⁰ , N ¹⁰ -Tetraphenyl-9,9 '-Biantracene-10,10'-diamine, N ¹⁰ , N ¹⁰ -diphenyl-N ¹⁰ , N ¹⁰ -dinaphthalenyl-9,9'-biantrasen-10,10'-diamine, 4,4'-bis ( 9-Ethyl-3-carbazobinylene) -1,1'-biphenyl, perylene, 2,5,8,11-tetra-t-butylperylene, 1,4-bis [2- (3-N-ethylcarbazolyl) ) Vinyl] benzene, 4,4'-bis [4- (di-p-tolylamino) styryl] biphenyl, 4- (di-p-tolylamino) -4'-[(di-p-tolylamino) styryl] styryl, Bis [3,5-difluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl)] iridium (III), 4,4'-bis [4- (diphenylamino) styryl] biphenyl, bis (2, 4-Difluorophenylpyridinato) tetrakis (1-pyrazolyl) borate iridium (III), N, N'-bis (naphthalen-2-yl) -N, N'-bis (phenyl) -tris (9,9-) Dimethylfluorenylene), 2,7-bis {2- [phenyl (m-tolyl) amino] -9,9-dimethyl-fluoren-7-yl} -9,9-dimethyl-fluorene, N- (4- (4-4-" ((E) -2- (6 ((E) -4-( Diphenylamino) styryl) naphthalene-2-yl) vinyl) phenyl) -N-phenylbenzeneamine, fac-iridium (III) tris (1-phenyl-3-methylbenzimidazolin-2-iriden-C, C ² ), mer-Iridium (III) Tris (1-phenyl-3-methylbenzimidazolin-2-iriden-C, C ² ), 2,7-bis [4- (diphenylamino) styryl] -9,9-spirobifluorene , 6-Methyl-2- (4- (9- (4- (6-methylbenzo [d] thiazole-2-yl) phenyl) anthracene-10-yl) phenyl) benzo [d] thiazole, 1,4-di [4- (N, N-diphenyl) amino] styrylbenzene, 1,4-bis (4- (9H-carbazole-9-yl) styryl) benzene, (E) -6- (4- (diphenylamino) styryl) ) -N, N-diphenylnaphthalene-2-amine, bis (2,4-difluorophenylpyridinato) (5- (pyridin-2-yl) -1H-tetrazolate) iridium (III), bis (3-tri Fluoromethyl-5- (2-pyridyl) pyrazole) ((2,4-difluorobenzyl) diphenylphosphinate) Iridium (III), bis (3-trifluoromethyl-5- (2-pyridyl) pyrazolate) (benzyldiphenyl) Phenylate) iridium (III), bis (1- (2,4-difluorobenzyl) -3-methylbenzimidazolium) (3- (trifluoromethyl) -5- (2-pyridyl) -1,2,4 -Triazolate) iridium (III), bis (3-trifluoromethyl-5- (2-pyridyl) pyrazolate) (4', 6'-difluorophenylpyridinate) iridium (III), bis (4', 6' -Difluorophenylpyridinato) (3,5-bis (trifluoromethyl) -2- (2'-pyridyl) pyrolate) iridium (III), bis (4', 6'-difluorophenylpyridinato) (3) -(Trifluoromethyl) -5- (2-pyridyl) -1,2,4-triazolate) iridium (III), (Z) -6-mesityl-N- (6-mesytylquinolin-2 (1H)- Iliden) Kinolin-2-amine-BF ₂ , (E) -2- (2- (4- (dimethylamino) styryl) -6-methyl-4H-pyran-4-iriden) malononitrile, 4- (dicyanomethylene) -2- Methyl-6-juloridyl-9-enyl-4H-pyran, 4- (dicyanomethylene) -2-methyl-6- (1,1,7,7-tetramethyldurolidyl-9-enyl) -4H-pyran , 4- (Dicyanomethylene) -2-t-butyl-6- (1,1,7,7-tetramethyldurolysin-4-yl-vinyl) -4H-pyran, tris (dibenzoylmethane) phenylquinoline europium ( III) 5,6,11,12-tetraphenylnaphthacene, bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonate) iridium (III), tris (1-phenylisoquinolin) iridium (III), bis (1-phenylisoquinoline) (acetylacetonate) iridium (III), bis [1- (9,9-dimethyl-9H-fluoren-2-yl) -isoquinoline] (acetylacetonate) iridium (III) III), bis [2- (9,9-dimethyl-9H-fluoren-2-yl) quinoline] (acetylacetonate) iridium (III), tris [4,4'-di-t-butyl- (2, 2')-bipyridine] ruthenium (III) bis (hexafluorophosphate), tris (2-phenylquinoline) iridium (III), bis (2-phenylquinoline) (acetylacetonate) iridium (III), 2,8 -Di-t-butyl-5,11-bis (4-t-butylphenyl) -6,12-diphenyltetracene, bis (2-phenylbenzothiazolato) (acetylacetonate) iridium (III), 5, 10,15,20-Tetraphenyltetrabenzoporphyrin platinum, osmium (II) bis (3-trifluoromethyl-5- (2-pyridine) -pyrazolate) dimethylphenylphosphine, osmium (II) bis (3- (trifluoro) Methyl) -5- (4-t-butylpyridyl) -1,2,4-triazolate) diphenylmethylphosphine, osmium (II) bis (3- (trifluoromethyl) -5- (2-pyridyl) -1, 2,4-Triazole) dimethylphenylphosphine, osmium (II) bis (3- (trifluoromethyl) -5- (4-t-butylpyridyl) -1,2,4-triazolate) dimethylphenylphosphine, bis [2 -(4-n-Hexylphenyl) quinoline] (acetylacetonate) iridium (III), tris [2- (4-n-he) Xylphenyl) quinoline] iridium (III), tris [2-phenyl-4-methylquinoline] iridium (III), bis (2-phenylquinoline) (2- (3-methylphenyl) pyridinate) iridium (III), bis (2- (9,9-diethyl-fluoren-2-yl) -1-phenyl-1H-benzo [d] imidazolato) (acetylacetonate) iridium (III), bis (2-phenylpyridine) (3-( Pyridin-2-yl) -2H-chromen-2-onate) iridium (III), bis (2-phenylquinoline) (2,2,6,6-tetramethylheptane-3,5-geonate) iridium (III) , Bis (Phenylisoquinoline) (2,2,6,6-Tetramethylheptane-3,5-Zionate) Iridium (III), Iridium (III) Bis (4-Phenylthieno [3,2-c] Pyridinato-N , C ² ) Acetylacetonate, (E) -2- (2-t-butyl-6- (2- (2,6,6-trimethyl-2,4,5,6-tetrahydro-1H-pyrolo] , 2,1-ij] quinoline-8-yl) vinyl) -4H-pyran-4-ylidene) malononitrile, bis (3-trifluoromethyl-5- (1-isoquinolyl) pyrazolate) (methyldiphenylphosphine) ruthenium, Bis [(4-n-hexylphenyl) isoquinoline] (acetylacetonate) iridium (III), platinum (II) octaethylporphine, bis (2-methyldibenzo [f, h] quinoxalin) (acetylacetonate) iridium ( III), Tris [(4-n-hexylphenyl) xoquinolin] iridium (III) and the like can be mentioned.

Examples of the material forming the electron transport layer include 8-hydroxyquinolinolate-lithium, 2,2', 2''-(1,3,5-benzintril) -tris (1-phenyl-1-H-benz). Imidazole), 2- (4-biphenyl) 5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolin, 4 , 7-Diphenyl-1,10-phenanthroline, bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum, 1,3-bis [2- (2,2'-bipyridine-6-yl) ) -1,3,4-Oxaziazo-5-yl] benzene, 6,6'-bis [5- (biphenyl-4-yl) -1,3,4-oxadiazo-2-yl] -2,2' -Bipyridine, 3- (4-biphenyl) -4-phenyl-5-t-butylphenyl-1,2,4-triazole, 4- (naphthalen-1-yl) -3,5-diphenyl-4H-1, 2,4-Triazole, 2,9-bis (naphthalen-2-yl) -4,7-diphenyl-1,10-phenanthrolin, 2,7-bis [2- (2,2'-bipyridine-6-yl) ) -1,3,4-oxadiazo-5-yl] -9,9-dimethylfluorene, 1,3-bis [2- (4-t-butylphenyl) -1,3,4-oxadiazo-5-yl] ] Benzene, tris (2,4,6-trimethyl-3- (pyridine-3-yl) phenyl) borane, 1-methyl-2- (4- (naphthalen-2-yl) phenyl) -1H-imidazo [4 , 5f] [1,10] phenanthroline, 2- (naphthalen-2-yl) -4,7-diphenyl-1,10-phenanthroline, phenyl-dipyrenylphosphine oxide, 3,3', 5,5'- Tetra [(m-pyridyl) -phen-3-yl] biphenyl, 1,3,5-tris [(3-pyridyl) -phen-3-yl] benzene, 4,4'-bis (4,6-diphenyl) -1,3,5-triazin-2-yl) biphenyl, 1,3-bis [3,5-di (pyridine-3-yl) phenyl] benzene, bis (10-hydroxybenzo [h] quinolinato) berylium, Examples thereof include diphenylbis (4- (pyridine-3-yl) phenyl) silane, 3,5-di (pyrene-1-yl) pyridine and the like.

Materials that form the electron injection layer include lithium oxide (Li ₂ O), magnesium oxide (MgO), alumina (Al ₂ O ₃ ), lithium fluoride (LiF), sodium fluoride (NaF), and magnesium fluoride (NaF). MgF ₂ ), cesium fluoride (CsF), strontium fluoride (SrF ₂ ), molybdenum trioxide (MoO ₃ ), aluminum, lithium acetylacetonate (Li (acac)), lithium acetate, lithium benzoate, etc. ..

Examples of the cathode material include aluminum, magnesium-silver alloy, aluminum-lithium alloy, lithium, sodium, potassium, cesium and the like.

Further, another example of the method for producing the organic EL element of the present invention when the thin film obtained from the charge transporting thin film forming varnish of the present invention is a hole injection layer is as follows.

In the method for manufacturing an organic EL element described above, instead of performing the vacuum deposition operation of the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer, the charge of the present invention is formed by sequentially forming the hole transport layer and the light emitting layer. An organic EL element having a charge transporting thin film formed by a transportable thin film forming varnish can be manufactured. Specifically, the varnish for forming a charge-transporting thin film of the present invention is applied onto an anode substrate to prepare a hole injection layer by the above method, and a hole transport layer and a light emitting layer are sequentially formed on the hole injection layer. Further, a cathode material is vapor-deposited to obtain an organic EL element.

As the cathode and anode materials to be used, the same materials as those described above can be used, and the same cleaning treatment and surface treatment can be performed.

As a method for forming the hole transport layer and the light emitting layer, a solvent is added to the hole transport polymer material or the light emitting polymer material, or a material to which a dopant is added to these, and the solvent is dissolved or uniformly dispersed, respectively. Examples thereof include a method of forming a film by applying it on a hole injection layer or a hole transport layer and then firing it.

Examples of the hole-transporting polymer material include poly [(9,9-dihexylfluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,4-diamino). Phenylene)], poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,1'-biphenylene-4,4- Diamine)], poly [(9,9-bis {1'-penten-5'-yl} fluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1, 4-Diaminophenylene)], poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) -benzidine] -endcapped with polysilsesquioxane, poly [(9, 9, 9-didioctylfluorenyl-2,7-diyl) -co- (4,4'-(N- (p-butylphenyl)) diphenylamine)] and the like can be mentioned.

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

Examples of the solvent include toluene, xylene, chloroform and the like. Examples of the dissolution or uniform dispersion method include methods such as stirring, heating stirring, and ultrasonic dispersion.

The coating method is not particularly limited, and examples thereof include an inkjet method, a spray method, a dip method, a spin coating method, a transfer printing method, a roll coating method, and brush coating. The coating is preferably carried out under an inert gas such as nitrogen or argon.

Examples of the firing method include a method of heating under an inert gas or in a vacuum in an oven or a hot plate.

An example of the method for producing the organic EL element of the present invention when the thin film obtained from the charge transporting thin film forming varnish of the present invention is a hole injection transport layer is as follows.

A hole injection transport layer is formed on the anode substrate, and a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are provided in this order on the hole injection transport layer. Examples of methods and specific examples for forming the light emitting layer, the electron transport layer, and the electron injection layer are the same as those described above.

Examples of the anode material, the light emitting layer, the light emitting dopant, the material forming the electron transport layer and the electron block layer, and the cathode material include the same materials as described above.

If necessary, a hole block layer, an electron block layer, or the like may be provided between the electrode and each of the layers. For example, as a material for forming an electron block layer, tris (phenylpyrazole) iridium and the like can be mentioned.

The materials forming the anode and cathode and the layer formed between them differ depending on whether the element having the bottom emission structure or the top emission structure is manufactured. Therefore, the material is appropriately selected in consideration of this point. ..

Normally, in an element having a bottom emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side, whereas in an element having a top emission structure, a reflective anode made of metal is used and the direction is opposite to that of the substrate. Light is extracted from a certain transparent electrode (cathode) side. Therefore, for example, regarding the anode material, a transparent anode such as ITO is used when manufacturing an element having a bottom emission structure, and a reflective anode such as Al / Nd is used when manufacturing an element having a top emission structure.

The organic EL device of the present invention may be sealed together with a water catching agent or the like, if necessary, in accordance with a conventional method in order to prevent deterioration of characteristics.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The devices used are as follows.
(1) Application of varnish during film roughness evaluation: Cluster Technology Co., Ltd., inkjet system (2) Vacuum drying device: Major Jig Co., Ltd., micro vacuum chamber MJ-8S
(3) Vacuum drying pump: ULVAC, Inc., turbo molecular pump UTM-50 / T9
(4) Film thickness measurement and film surface evaluation: Microshape measuring machine Surfcoder ET-4000 manufactured by Kosaka Laboratory Co., Ltd.
(5) Application of varnish during device evaluation: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.
(6) Fabrication of organic EL element: Multi-function vapor deposition equipment system C-E2L1G1-N manufactured by Choshu Industry Co., Ltd.
(7) Measurement of brightness, etc. of organic EL element: IVL measurement system manufactured by EHC Co., Ltd. (8) Life measurement of organic EL element (LT95: Measurement of time when brightness decreases by 5% from initial brightness) :( Organic EL brightness life evaluation system PEL-105S manufactured by EHC Co., Ltd.

[1] Preparation of charge-transporting varnish and evaluation of solubility [Example 1-1]
After dissolving 0.431 g of the aryl sulfonic acid represented by the formula (b-1) in a mixed solvent composed of diethylene glycol (8.0 g) and triethylene glycol dimethyl ether (12.0 g), the aryl represented by the formula (f) 0.188 g of an amine derivative and 0.050 g of oxo-TEMPO (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added, and the mixture was stirred at 50 ° C., 400 rpm for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish A. The arylamine derivative was synthesized according to the method described in International Publication No. 2015/050253, and the aryl sulfonic acid was synthesized according to the method described in International Publication No. 2006/025432.

[Example 1-2]
Instead oxo -TEMPO used in Examples 1-1, except that R ^B is used hydroxy -TEMPO (manufactured by Tokyo Kasei Kogyo (Co.)) 0.050 g is a hydroxy group is, similarly to Example 1-1 The varnish was prepared according to the above method and stirred at 50 ° C., 400 rpm for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish B was obtained.

[Example 1-3]
Instead oxo -TEMPO used in Examples 1-1, except that R ^B is used acetamide -TEMPO (Tokyo Kasei Kogyo Co., Ltd.) 0.050 g acetamide group, similarly to Example 1-1 The varnish was prepared according to the above method and stirred at 50 ° C., 400 rpm for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish C was obtained.

[Example 1-4]
Instead of the mixed solvent used in Example 1-1, 1,3-dimethyl-2-imidazolidinone (6.6 g), 2,3-butanediol (8 g) and dipropylene glycol monomethyl ether (5.4 g). ) Was used, but the varnish was prepared in the same manner as in Example 1-1, and the mixture was stirred at 50 ° C., 400 rpm, and 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish D was obtained.

[Example 1-5]
A varnish was prepared in the same manner as in Example 1-4 except that 0.050 g of hydroxy-TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the oxo-TEMPO used in Examples 1-4. , 50 ° C., 400 rpm, and stirred for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish E was obtained.

[Example 1-6]
A varnish was prepared in the same manner as in Example 1-4 except that 0.050 g of acetamide-TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the oxo-TEMPO used in Examples 1-4. , 50 ° C., 400 rpm, and stirred for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish F was obtained.

[Comparative Example 1-1]
The varnish was prepared in the same manner as in Example 1-1 except that oxo-TEMPO was not added in Example 1-1, but the arylamine derivative was dissolved even after stirring at 70 ° C., 400 rpm and 30 minutes. I couldn't finish it.

[Comparative Example 1-2]
The varnish was prepared in the same manner as in Example 1-4 except that oxo-TEMPO was not added in Example 1-4, but the arylamine derivative was dissolved even after stirring at 70 ° C., 400 rpm, and 30 minutes. I couldn't finish it.

[Comparative Example 1-3]
A varnish was prepared in the same manner as in Example 1-1 except that 0.050 g of TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the oxo-TEMPO used in Example 1-1. The mixture was stirred at ° C., 400 rpm for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish G was obtained.

[Comparative Example 1-4]
A varnish was prepared in the same manner as in Example 1-4 except that 0.050 g of TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the oxo-TEMPO used in Examples 1-4. The mixture was stirred at ° C., 400 rpm for 10 minutes. As a result, the arylamine derivative was completely dissolved in the solvent, and after filtering through a filter, a charge-transporting varnish H was obtained.

[Comparative Example 1-5]
Instead of the oxo-TEMPO used in Example 1-1, 0.050 g of 2-azaadamantane-N-oxyl (hereinafter referred to as AZADO), which is a similarly general-purpose organic oxidizing agent, was used. The varnish was prepared in the same manner as in Example 1-1, but the arylamine derivative was not completely dissolved even after stirring at 70 ° C., 400 rpm, and 30 minutes. For AZADO, refer to International Publication No. 2010/123115 and International Publication No. 2006/001387, as well as J. Am. Chem. Soc., 2006, 128 (26), pp. 8412-8413 and their supporting information. Synthesized.

[Comparative Example 1-6]
A varnish was prepared in the same manner as in Example 1-4 except that 0.050 g of AZADO was used instead of the oxo-TEMPO used in Example 1-4, but after stirring at 70 ° C., 400 rpm and 30 minutes. However, the arylamine derivative was not completely dissolved.

[Comparative Example 1-7]
Instead oxo -TEMPO used in Examples 1-1, except that R ^B is used an amino -TEMPO (manufactured by Tokyo Kasei Kogyo (Co.)) 0.050 g is an amino group, as in Example 1-1 The varnish was prepared according to the above method, but the arylamine derivative was not completely dissolved even after stirring at 70 ° C., 400 rpm, and 30 minutes.

[Comparative Example 1-8]
A varnish was prepared in the same manner as in Example 1-4 except that 0.050 g of amino-TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the oxo-TEMPO used in Examples 1-4. However, the arylamine derivative was not completely dissolved even after stirring at 70 ° C., 400 rpm, and 30 minutes.

The evaluation results of solubility are summarized in Table 19. In Table 19 below, regarding the evaluation of solubility, the case where the arylamine derivative was completely dissolved was indicated by ◯, and the case where the arylamine derivative was not completely dissolved was indicated by ×. As a result, it was confirmed that the arylamine derivative was completely dissolved in the mixed solvent when TEMPO, oxo-TEMPO, hydroxy-TEMPO or acetamide-TEMPO was added regardless of the composition of the solvent. On the other hand, when AZADO or amino-TEMPO was added, it was confirmed that the arylamine derivative was not completely dissolved. From these results, it can be seen that TEMPO and a specific TEMPO derivative contribute to the promotion of solubility.

[2] In-pixel flatness evaluation [Example 2-1]
Using an ITO substrate having a liquid-repellent structure having a pixel width (between structures) of 90 × 180 μm and a height of 1.5 μm and the charge-transporting varnish A prepared in Example 1-1, a liquid was introduced into the pixels by an inkjet method. A film was formed and the solvent was volatilized in a vacuum drying device to prepare a dried film having a film thickness of about 200 nm. Then, the surface roughness (Ra) in the long axis direction in the pixel was measured with the fine shape measuring machine Surfcoder ET-4000. The results are also shown in Table 20. Further, the film profile in the long axis direction in the pixel is shown in FIG.

[Example 2-2]
The surface roughness of the dry film was evaluated in the same manner as in Example 2-1 except that the charge transporting varnish B prepared in Example 1-2 was used. The results are shown in Table 20 and FIG.

[Example 2-3]
The surface roughness of the dry film was evaluated in the same manner as in Example 2-1 except that the charge transporting varnish C prepared in Example 1-3 was used. The results are shown in Table 20 and FIG.

[Comparative Example 2-1]
The surface roughness of the dried film was evaluated in the same manner as in Example 2-1 except that the charge-transporting varnish G prepared in Comparative Example 1-3 was used. The results are shown in Table 20 and FIG.

From Table 20 and FIG. 1, it can be seen that when a specific TEMPO derivative is used, the roughness of the dry film in the pixel is suppressed as compared with the case where TEMPO is used. This is because TEMPO, which is highly volatile, causes crystallization of the arylamine derivative during the drying process of the liquid film, whereas TEMPO derivative, which is less volatile (that is, has a high boiling point) than TEMPO, is arylamine. It is considered that this is because the crystallization of the derivative is suppressed.

[3] Fabrication and Characteristic Evaluation of Hole-Only Element (HOD) In the following Examples and Comparative Examples, the ITO substrate is a 25 mm × 25 mm × 0.7 t glass substrate in which ITO is patterned on the surface with a film thickness of 150 nm. Was used, _{and impurities on the surface were removed by an O 2} plasma cleaning device (150 W, 30 seconds) before use.

[Example 3-1]
After applying the charge-transporting varnish A to the ITO substrate using a spin coater, it is tentatively fired at 120 ° C. for 1 minute in the atmosphere, and then main fired at 230 ° C. for 15 minutes, and then fired on the ITO substrate at 50 nm. A thin film was formed.
On top of this, a thin film of α-NPD and aluminum was sequentially laminated using a vapor deposition apparatus (vacuum degree 2.0 × 10 ^{-5 Pa) to obtain HOD.} The vapor deposition was carried out under the condition of a vapor deposition rate of 0.2 nm / sec. The film thicknesses of the α-NPD and aluminum thin films were 30 nm and 80 nm, respectively.
In order to prevent deterioration of characteristics due to the influence of oxygen, water, etc. in the air, HOD was sealed with a sealing substrate and then its characteristics were evaluated. Sealing was performed by the following procedure.
In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -85 ° C or less, HOD is placed between the sealing substrates, and the sealing substrates are bonded with an adhesive (MORESCO Co., Ltd. Moresco Moisture Cut WB90US (P)). rice field. At this time, a water catching agent (HD-071010W-40 manufactured by DYNIC CORPORATION) was housed in the sealing substrate together with the HOD. The bonded substrate was irradiated with UV light (wavelength 365 nm, irradiation amount 6,000 mJ / cm ² ), and then annealed at 80 ° C. for 1 hour to cure the adhesive.

[Example 3-2]
HOD was prepared in the same manner as in Example 3-1 except that the charge-transporting varnish B was used instead of the charge-transporting varnish A.

[Example 3-3]
HOD was prepared in the same manner as in Example 3-1 except that the charge-transporting varnish C was used instead of the charge-transporting varnish A.

[Comparative Example 3-1]
HOD was prepared in the same manner as in Example 3-1 except that the charge-transporting varnish G was used instead of the charge-transporting varnish A.

The current density at a drive voltage of 3 V was measured for each HOD produced in the above Examples and Comparative Examples. The results are shown in Table 21.

As shown in Table 21, the charge-transporting thin film containing the specific TEMPO derivative used in the present invention showed equal or better hole-transporting property than the charge-transporting thin film containing TEMPO.

[4] Manufacture of Organic EL Element and Evaluation of Characteristics In the following Examples and Comparative Examples, a 25 mm × 25 mm × 0.7 t glass substrate in which ITO is patterned on the surface with a film thickness of 150 nm was used. Before use, an O ₂ plasma cleaning device (150 W, 30 seconds) was used to remove impurities on the surface.

[Example 4-1]
The charge-transporting varnish A is applied to an ITO substrate using a spin coater, dried at 120 ° C. for 1 minute, and further fired at 230 ° C. for 15 minutes in an atmospheric atmosphere to form a uniform thin film having a thickness of 50 nm on the ITO substrate. Was formed.
Next, α-NPD was formed on the ITO substrate on which the thin film was formed at 0.2 nm / sec using a ^{vapor deposition apparatus (vacuum degree 1.0 × 10 -5 Pa) at 30 nm.} Next, CBP and Ir (PPy) ₃ were co-deposited. For co-evaporation, the vapor deposition rate was controlled so that the concentration of Ir (PPy) _{3 was 6%, and 40 nm was laminated.} Next, _{a thin film of Alq 3} , lithium fluoride, and aluminum was sequentially laminated to prepare an organic EL device. At this time, the vapor deposition rate was _{0.2 nm / sec for Alq 3} and aluminum, and 0.02 nm / sec for lithium fluoride, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.
In order to prevent the deterioration of the characteristics due to the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate and then the characteristics were evaluated. The sealing was carried out in the same manner as described above.

[Example 4-2]
An organic EL device was produced in the same manner as in Example 4-1 except that the charge-transporting varnish B was used instead of the charge-transporting varnish A.

[Comparative Example 4-1]
An organic EL device was produced in the same manner as in Example 4-1 except that the charge-transporting varnish G was used instead of the charge-transporting varnish A.

These elements, the voltage at the luminance 1,000 cd / m ^2, current efficiency, LT95 (initial luminance 1,000 cd / m ²⁾ was measured. The results are shown in Table 22. The area of the light emitting surface size of each element was 2 mm × 2 mm.

As shown in Table 22, the charge-transporting thin film containing the specific TEMPO derivative used in the present invention exhibited the same organic EL characteristics as the charge-transporting thin film containing TEMPO.

Claims (11)

And 2,2,6,6-tetraalkyl piperidine -N- oxyl derivative of formula (T1), a charge transport material comprises an organic solvent, charge the organic solvent comprises a good solvent and a poor solvent A varnish for forming a transportable thin film,
The charge transporting material comprises at least one selected from the group consisting of arylamine derivatives and thiophene derivatives having a single molecular weight in the range of 200-9,500.
The good solvent is at least one selected from the group consisting of an amide solvent and a glycol solvent of diethylene glycol, triethylene glycol and tetraethylene glycol, and the poor solvent is other than diethylene glycol, triethylene glycol and tetraethylene glycol. A varnish for forming a charge-transporting thin film, which is one or more selected from the group consisting of a glycol-based solvent and a glycol ether-based solvent.

(Wherein, R ^A is, independently of one another, represent an alkyl group having 1 to 20 carbon atoms, R ^B represents a hydroxy group, an oxo group, or an acetamido group.) Before KiRyo solvent and yo the ratio is the mass ratio of the poor solvent solvent: antisolvent = 10: 90-50: 50 a charge transporting thin film-forming varnish according to claim 1, wherein. The good solvents are N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, 1,3. For forming a charge-transporting thin film according to claim 1 or 2, which is at least one selected from the group consisting of -dimethyl-2-imidazolidinone, N-cyclohexyl-2-pyrrolidinone, diethylene glycol, triethylene glycol and tetraethylene glycol. varnish. The one according to any one of claims 1 to 3, wherein the content of the 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative is 1 to 10.0% by mass with respect to the charge transporting substance. Varnish for forming a charge-transporting thin film. The varnish for forming a charge-transporting thin film according to any one of claims 1 to 4, wherein the content of the charge-transporting substance is 0.1 to 10.0% by mass in the varnish. The varnish for forming a charge-transporting thin film according to any one of claims 1 to 5, further comprising a dopant. The varnish for forming a charge-transporting thin film according to claim 6, wherein the dopant contains an aryl sulfonic acid. Charge transporting thin film obtained et al is from the charge-transporting thin film-forming varnish according to any one of claims 1-7. The organic electroluminescence device having the charge transporting thin film according to claim 8. A method for producing a charge-transporting thin film, which comprises using the varnish for forming a charge-transporting thin film according to any one of claims 1 to 7. A method for producing an organic electroluminescent device, which comprises using the varnish for forming a charge-transporting thin film according to any one of claims 1 to 7.

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