JP2023143759A - Composition for organic electroluminescent element, organic electroluminescent element, and organic electroluminescent display - Google Patents

Abstract

To provide a composition for an organic electroluminescent element that is for producing the organic electroluminescent element capable of being driven at low voltages and having a long drive life.SOLUTION: A composition for an organic electroluminescent element includes an organic polymer compound having repeating units represented by the following formula (1) and an organic solvent. The absorbance at an optical path length of 10 mm and a wavelength of 500 nm is 0.2 or higher, and the absorbance at an optical path length of 10 mm and a wavelength of 800 nm is 0.05 or higher.SELECTED DRAWING: Figure 1

Description

The present invention relates to a composition for an organic electroluminescent device, an organic electroluminescent device using this composition for an organic electroluminescent device, and an organic EL display equipped with the organic electroluminescent device.

In recent years, as electroluminescence (EL) elements, electroluminescence elements (organic electroluminescence elements) using organic materials instead of inorganic materials such as ZnS have been developed. High luminous efficiency is one of the important factors in organic electroluminescent devices, and the luminous efficiency is determined by the luminescence efficiency, which is composed of a hole transport layer containing an aromatic amine compound and an aluminum complex of 8-hydroxyquinoline. Significant improvements have been made in organic electroluminescent devices provided with layers.

A major issue facing the increasing demand for organic electroluminescent devices is the reduction in driving voltage. For example, display elements for mobile devices are required to be driven at low voltage from batteries, and display elements with low power consumption are also required for general applications other than mobile applications. A reduction in drive voltage is directly linked to a reduction in power consumption. Furthermore, the gradual increase in drive voltage during continuous drive also poses a major problem in maintaining stable display characteristics of the display element.

In order to solve these problems, it has been disclosed that a hole-transporting compound and an electron-accepting compound are reacted to generate a cation radical species that is responsible for charge transport (Patent Documents 1 to 3, Patent Document 1).
Generally, arylamine polymers have hole transport properties and are suitably used as hole transport materials for organic electroluminescent devices. By reacting an arylamine polymer with an electron-accepting compound to generate cation radical species that play a role in charge transport, hole injection from the electrode is promoted, making it possible to lower the voltage of organic electroluminescent devices and increase the length of the device. It is possible to extend the lifespan.
Although it has been possible to lower the driving voltage to some extent using the above-mentioned technology, further reduction of the driving voltage is required in order to further reduce power consumption.

Japanese Patent Application Publication No. 2006-233162 Japanese Patent Application Publication No. 2007-311262 Japanese Patent Application Publication No. 2010-206120

Synthetic Metals, 2017, volume 230, pages 105-112

The present invention provides a composition for an organic electroluminescent device for producing an organic electroluminescent device that can be driven at low voltage and has a long driving life, an organic electroluminescent device using this composition for an organic electroluminescent device, and An object of the present invention is to provide an organic EL display including this organic electroluminescent element.

As a result of extensive studies, the present inventors discovered that by dissolving an arylamine polymer containing a twisted site in its main chain and an electron-accepting compound as a hole-transporting compound in an organic solvent and reacting them, an optical path length of 10 mm could be achieved. , the absorbance at a wavelength of 500 nm is 0.2 or more, and the absorbance at a wavelength of 800 nm with an optical path length of 10 mm is 0.05 or more, and it has been found that the above problems can be solved, and the present invention has been achieved.
That is, the present invention provides a composition for an organic electroluminescent device containing an arylamine polymer having a twisted site in the main chain and an organic solvent, which has an optical path length of 10 mm and an absorbance of 0.2 or more at a wavelength of 500 nm. A composition for an organic electroluminescent device, characterized in that the absorbance at a wavelength of 800 nm is 0.05 or more, and an organic electroluminescent device comprising an organic layer formed using the composition for an organic electroluminescent device. The present invention relates to an organic EL display equipped with this organic electroluminescent element, the gist of which is as follows.

[1] In a composition for an organic electroluminescent device containing an organic polymer compound having a repeating unit represented by the following formula (1) and an organic solvent, the absorbance at an optical path length of 10 mm and a wavelength of 500 nm is 0.2 or more. A composition for an organic electroluminescent device, characterized in that the absorbance at an optical path length of 10 mm and a wavelength of 800 nm is 0.05 or more.

[In formula (1),
Ar ⁵¹ is an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are connected.
Ar ⁵² is at least one selected from the group consisting of a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group. It is a divalent group in which one group is connected to a plurality of groups directly or via a linking group.
Ar ⁵¹ and Ar ⁵² may form a ring via a single bond or a connecting group.
Ar ⁵¹ and Ar ⁵² may have a substituent and/or a crosslinking group.
Ar ⁵² includes a partial structure represented by the following formula (2). ]

[In formula (2), R ⁶⁰¹ and R ⁶²¹ are each independently a hydrogen atom or an alkyl group which may have a substituent and/or a crosslinking group, and at least one of R ⁶⁰¹ and R ⁶²¹ is , an alkyl group which may have a substituent and/or a crosslinking group.
Ring Ar ⁶⁰¹ and ring Ar ⁶²¹ each independently contain a monocyclic or condensed divalent aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group. It is a divalent aromatic heterocyclic group which is a monocyclic or condensed ring which may have one ring, and -* represents a bond with an adjacent atom. ]

[2] The ring Ar ⁶⁰¹ and the ring Ar ⁶²¹ are each independently a 1,4-phenylene group which may have a substituent and/or a crosslinking group, or the ring Ar ⁶⁰¹ and the ring Ar ⁶²¹ One is a 1,4-phenylene group which may have a substituent and/or a crosslinking group, and the other is a 2,7-fluorenyl group which may have a substituent and/or a crosslinking group. The composition for an organic electroluminescent device according to [1], characterized in that:

[3] The organic solvent according to [1] or [2], wherein the organic solvent contains at least one selected from the group consisting of an ether solvent, a ketone solvent, and a hydrocarbon solvent. Composition for organic electroluminescent devices.

[4] The composition for an organic electroluminescent device according to any one of [1] to [3], wherein the absorption at wavelengths of 500 nm and 800 nm is derived from cation radical species.

[5] An organic electroluminescent device comprising a substrate, an anode, an organic layer, and a cathode provided on the substrate, wherein the organic layer is a compound according to any one of [1] to [4]. An organic electroluminescent device comprising an organic layer formed using a composition for an organic electroluminescent device.

[6] The organic electroluminescent device according to [5], wherein the organic layer includes a light emitting layer, and the light emitting layer is formed by a wet film forming method.

[7] The organic electroluminescent device according to [5] or [6], wherein the light-emitting layer contains a light-emitting low-molecular compound.

[8] An organic EL display comprising the organic electroluminescent device according to any one of [5] to [7].

An organic electroluminescent device obtained using the composition for an organic electroluminescent device of the present invention can be driven at a low voltage, can reduce power consumption, and has a long driving life. According to the organic electroluminescent device of the present invention, it is possible to provide an organic EL display that can be driven at a low voltage and has stable display characteristics.

1 is a cross-sectional view schematically showing an example of the structure of an organic electroluminescent device of the present invention.

Embodiments of the organic electroluminescent device composition, organic electroluminescent device, and organic EL display of the present invention will be described in detail below. This is just one example (representative example), and the present invention is not limited to these contents unless it exceeds the gist thereof.

[Composition for organic electroluminescent device]
The composition for an organic electroluminescent device of the present invention (hereinafter sometimes referred to as "composition of the present invention") is a composition for an organic electroluminescent device containing a specific organic polymer compound and an organic solvent. It is characterized in that the absorbance at a wavelength of 500 nm measured by the following method is 0.2 or more, and the absorbance at a wavelength of 800 nm is 0.05 or more.

(Method of measuring absorbance)
The absorbance at a wavelength of 500 nm and the absorbance at a wavelength of 800 nm of the composition for an organic electroluminescent device of the present invention are measured using a spectrophotometer U-3900H (manufactured by Hitachi) under the following measurement conditions.
Measurement condition:
Measurement mode: Wavelength scan Data mode: Abs
Starting wavelength: 1000nm
Ending wavelength: 200nm
Scan speed: 300nm/min
Sampling interval: 0.50nm
Slit: 5nm
Light source switching wavelength: 340nm
Cell length: 10mm
For the reference measurement, the organic solvent contained in each composition for organic electroluminescent elements was used.

Note that the measuring instruments used to specify the present invention are not limited to the above-mentioned measuring instruments as long as they can perform measurements equivalent to those described above, and other measuring instruments may be used; It is preferable to use

The composition for an organic electroluminescent device of the present invention has an absorbance (hereinafter sometimes referred to as "absorbance (500)") of 0.2 or more at an optical path length of 10 mm and a wavelength of 500 nm, as determined by the above measurement method. The absorbance at an optical path length of 10 mm and a wavelength of 800 nm (hereinafter sometimes referred to as "absorbance (800)") is 0.05 or more.
It is preferable that the absorbance is greater than or equal to the above value because a charge transport film with high charge transport ability can be obtained and the driving voltage of the resulting device will be reduced. This is because the absorption at wavelengths of 500 nm and 800 nm is derived from cation radical species, and when the absorbance at these wavelengths is high, a sufficient amount of cation radical species are generated and the hole transport property is enhanced.
From such a viewpoint, the absorbance (500) of the composition for an organic electroluminescent device of the present invention is preferably 0.2 or more, more preferably 0.3 or more. Further, the absorbance (800) of the composition for an organic electroluminescent device of the present invention is preferably 0.05 or more, more preferably 0.08 or more.
There is no particular limit to the upper limits of absorbance (500) and absorbance (800), but usually absorbance (500) is 5.0 or less and absorbance (800) is 3.0 or less.

In order to make the absorbance (500) and absorbance (800) of the composition for an organic electroluminescent device of the present invention equal to or higher than the above lower limit, the composition for an organic electroluminescent device of the present invention must contain a specific organic polymer according to the present invention. An example of this method is to use a molecular compound in combination with a suitable organic solvent and an electron-accepting compound to control the component composition so that cation radicals are likely to be generated.

<Composition for forming hole injection/transport layer>
Examples of constituent components when the composition for an organic electroluminescent device of the present invention is a composition for forming a hole injection/transport layer are shown below, but the present invention is not limited thereto.
In addition, when the composition for an organic electroluminescent device of the present invention is a composition for forming a hole injection/transport layer, a hole injection/transport material that is easily oxidized by one electron and an electron accepting compound that is easily oxidized by one electron are used. , the hole injection/transport material, and an organic solvent that dissolves the electron-accepting compound and stably solvates the radical species.

<Hole injection/transport material>
When the composition for an organic electroluminescent device of the present invention is used as a composition for forming a hole injection/transport layer, the organic compound contained is preferably a hole injection/transport material. The hole injection/transport material can be appropriately selected from the materials listed below to form the structure of the present invention.

(Molecular weight of hole injection/transport material)
The hole injection/transport material according to the present invention may be a low-molecular compound or a high-molecular compound, but it is preferable to use a high-molecular compound in terms of heat resistance, charge transport properties, film-forming properties, etc. is preferred.

The low molecular weight compound in the present invention refers to a compound that does not have a distribution of molecular weights but has a single molecular weight. Further, the polymer compound in the present invention refers to a compound having a distribution in molecular weight, for example, a compound having repeating units in its structure.

When the hole injection/transport material is a low molecular weight compound, the molecular weight is usually in the range of 300 or more, preferably 500 or more, and usually 5,000 or less, preferably 2,500 or less. If the molecular weight of the hole-injecting/transporting material is too small, the charge transportability may be reduced, and if it is too large, the solubility may be reduced.

On the other hand, when the hole injection/transport material is a polymer compound, the weight average molecular weight is usually 500 or more, preferably 2,000 or more, more preferably 4,000 or more, and usually 2,000,000 or less, preferably 500, 000 or less, more preferably 200,000 or less. If the weight average molecular weight of the hole injection/transport material is below this lower limit, the film formability of the hole injection/transport material may deteriorate, and the hole injection/transport material glass Heat resistance may be significantly impaired due to lower transition temperature, melting point, and vaporization temperature. If the weight average molecular weight of the hole injection/transport material exceeds this upper limit, purification of the hole injection/transport material may become difficult due to the high molecular weight of impurities.

Note that this weight average molecular weight is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components, and the elution time is longer for lower molecular weight components. However, using a calibration curve calculated from the elution time of polystyrene (standard sample) of known molecular weight, the elution time of the sample can be adjusted to the molecular weight. By converting, the weight average molecular weight is calculated. The number average molecular weight is also calculated in the same way. The same applies to the weight average molecular weight and number average molecular weight of the hole transporting polymer compound, etc., which will be described later.

(Structure of hole injection/transport material)
<<Definition>>
Hereinafter, when explaining in detail the structures of the electron-accepting compound and the charge-transporting polymer compound (polymer) according to the present invention, common partial structures are assumed to be the following structures unless otherwise specified.
In the present invention, "may have a substituent" means that it may have one or more substituents.

<Aromatic hydrocarbon group>
The aromatic hydrocarbon group refers to a monovalent, divalent, or trivalent or more aromatic hydrocarbon ring structure, depending on the bonding state in the structure of the compound to be explained later.
In the structure of the aromatic hydrocarbon ring, the number of carbon atoms is usually not limited, but is preferably 6 or more and 60 or less, and the upper limit of the carbon number is more preferably 48 or less, more preferably The number of carbon atoms is 30 or less. Specifically, the aromatic hydrocarbon group includes a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring. Examples include a 6-membered monocyclic ring or a 2- to 5-fused ring group, such as a ring, or a structure in which a plurality of groups selected from these are connected. When a plurality of aromatic hydrocarbon rings are connected, a structure in which 2 to 10 aromatic hydrocarbon rings are connected is usually used, and a structure in which 2 to 5 aromatic hydrocarbon rings are connected is preferable. When a plurality of aromatic hydrocarbon rings are connected, the same structure may be connected, or different structures may be connected.
Preferred aromatic hydrocarbon ring structures include a benzene ring, a biphenyl ring, that is, a structure in which two benzene rings are connected, a terphenyl ring, that is, a structure in which three benzene rings are connected, a quarterphenylene ring, that is, a structure in which four benzene rings are connected, and a naphthalene ring. , is a fluorene ring.

<Aromatic heterocyclic group>
The aromatic heterocyclic group refers to a monovalent, divalent, or trivalent or more aromatic heterocyclic structure depending on the bonding state in the structure of the compound to be explained below.
In the structure of an aromatic heterocycle, the number of carbon atoms is usually not limited, but is preferably 3 or more and 60 or less, and the upper limit of the carbon number is more preferably 48 or less, more preferably The number of carbon atoms is 30 or less. Specifically, the aromatic heterocyclic group includes a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, Pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, 5- to 6-membered monocyclic or 2- to 4-membered rings such as triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. Examples include a divalent group having a condensed ring or a group in which a plurality of these groups are connected. When a plurality of aromatic heterocycles are connected, the same structure may be connected, or different structures may be connected. When a plurality of aromatic heterocycles are connected, a structure in which 2 to 10 aromatic heterocycles are connected is usually mentioned, and a structure in which 2 to 5 aromatic heterocycles are connected is preferable.
Preferred aromatic heterocyclic structures are a thiophene ring, a benzothiophene ring, a pyrimidine ring, a triazine ring, a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

<Bridging group>
A crosslinking group refers to a group that reacts with another crosslinking group located in the vicinity of the crosslinking group to form a new chemical bond when irradiated with heat and/or active energy rays. In this case, the reactive group may be the same group as the crosslinking group or a different group.
Examples of the crosslinking group include, but are not limited to, a group containing an alkenyl group, a group containing a conjugated diene structure, a group containing an alkynyl group, a group containing an oxirane structure, a group containing an oxetane structure, a group containing an aziridine structure, an azide group, and anhydride group. Examples include a group containing a maleic acid structure, a group containing an alkenyl group bonded to an aromatic ring, and a cyclobutene ring condensed to an aromatic ring. Specific examples of preferred crosslinking groups are preferably represented by any of the following formulas (X1) to (X18) in crosslinking group group T below.

<Bridging group group T>

[In formulas (X1) to (X18), Q represents a direct bond or a connecting group.
"*" represents the bonding position.
R ¹¹⁰ in formula (X4), formula (X5), formula (X6) and formula (formula 10) represents a hydrogen atom or an alkyl group which may have a substituent.
In formulas (X1) to (X4), the benzene ring and naphthalene ring may have a substituent. Furthermore, the substituents may be bonded to each other to form a ring.
In formulas (X1) to (X3), the cyclobutene ring may have a substituent. ]

(Q)
When Q in formulas (X1) to (X18) is a linking group, the linking group is not particularly limited, but is preferably an alkylene group, a divalent oxygen atom, or a divalent group that may have a substituent. is an aromatic hydrocarbon group.
The alkylene group is usually an alkylene group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms.
The divalent aromatic hydrocarbon group usually has 6 or more carbon atoms, and usually has 36 or less carbon atoms, preferably 30 or less, and more preferably 24 or less carbon atoms, and the aromatic hydrocarbon ring has a structure such as benzene. A ring is preferable, and the substituents that it may have can be selected from the substituent group Z described below.

The alkyl group represented by R ¹¹⁰ has a linear, branched or cyclic structure, and has 1 or more carbon atoms, preferably 24 or less, more preferably 12 or less, and even more preferably 8 or less.

Substitutions that the benzene ring and naphthalene ring in formulas (X1) to (X4), and R ¹¹⁰ in formulas (X4), formula (X5), formula (X6), and formula (X10) may have Preferred groups are an alkyl group, an aromatic hydrocarbon group, an alkyloxy group, and an aralkyl group.
The alkyl group as a substituent has a linear, branched or cyclic structure, and the number of carbon atoms is preferably 24 or less, more preferably 12 or less, still more preferably 8 or less, and preferably 1 or more.
The number of carbon atoms in the aromatic hydrocarbon group as a substituent is preferably 24 or less, more preferably 18 or less, still more preferably 12 or less, and preferably 6 or more. The aromatic hydrocarbon group may further have the above alkyl group as a substituent.
The number of carbon atoms in the alkyloxy group as a substituent is preferably 24 or less, more preferably 12 or less, even more preferably 8 or less, and preferably 1 or more.
The number of carbon atoms in the aralkyl group as a substituent is preferably 30 or less, more preferably 24 or less, even more preferably 14 or less, and preferably 7 or more. The alkylene group contained in the aralkyl group preferably has a linear or branched structure. The aryl group contained in the aralkyl group may further have the above-mentioned alkyl group as a substituent.
Preferred substituents that the cyclobutene rings of formulas (X1) to (X3) may have are alkyl groups. The alkyl group as the substituent has a linear, branched or cyclic structure, and the number of carbon atoms is preferably 24 or less, more preferably 12 or less, still more preferably 8 or less, and preferably 1 or more.

As the crosslinking group, a crosslinking group represented by any one of formulas (X1) to (X3) is preferable because the crosslinking reaction proceeds only with heat, has low polarity, and has little effect on charge transport.

In the crosslinking group represented by formula (X1), a cyclobutene ring is opened by heat, and the opened groups bond to each other to form a crosslinked structure, as shown in the following formula. Note that in the following, the description of the linking group Q in formulas (X1) to (X3), etc. is omitted.

In the crosslinking group represented by the formula (X2), a cyclobutene ring is opened by heat, and the opened groups bond to each other to form a crosslinked structure, as shown in the following formula.

In the crosslinking group represented by formula (X3), a cyclobutene ring is opened by heat, and the opened groups bond to each other to form a crosslinked structure, as shown in the following formula.

In the crosslinking group represented by any of formulas (X1) to (X3), the cyclobutene ring is opened by heat, and the ring-opened group, if there is a double bond in the vicinity, forms a double bond. Reacts to form a crosslinked structure.

An example will be shown below in which a crosslinking group represented by formula (X1) forms a ring-opened group and a crosslinking group represented by formula (X4) having a double bond site forms a crosslinked structure.

In addition to the crosslinking group represented by formula (X4), examples of the group containing a double bond that can react with the crosslinking group represented by any of formulas (X1) to (X3) include formula (X5) , formula (X6), formula (X12), formula (X15), formula (X16), formula (X17), and formula (X18). When a group containing these double bonds is used as a crosslinking group in an electron-accepting compound, the formula (X1 ) to formula (X3) is preferable because it increases the possibility of forming a crosslinked structure.

As the crosslinking group, a radically polymerizable crosslinking group represented by any one of formula (X4), formula (X5), and formula (X6) is preferable because it has low polarity and is unlikely to interfere with charge transport.

As the crosslinking group, a crosslinking group represented by formula (X7) is preferable from the viewpoint of improving electron-accepting properties. Note that when the crosslinking group represented by formula (X7) is used, the following crosslinking reaction proceeds.

A crosslinking group represented by either formula (X8) or (X9) is preferred in terms of high reactivity. Note that when the crosslinking group represented by formula (X8) and the crosslinking group represented by formula (X9) are used, the following crosslinking reaction proceeds.

As the crosslinking group, a cationically polymerizable crosslinking group represented by any one of formula (X10), formula (X11), and formula (X12) is preferred in terms of high reactivity.

<Substituent>
Hereinafter, in the description of the structure of the high molecular compound and low molecular compound in the present invention, unless otherwise specified, the substituent is any group, but is preferably a group selected from the following substituent group Z. . In addition, in the description of the structure of the high molecular compound and low molecular compound in the present invention, the substituent that may be included is selected from the substituent group Z, or the substituent that may be included is selected from the substituent group Z. When it is written that it is preferable that

<Substituent group Z>
Substituent group Z includes an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an arylalkylamino group, an acyl group, a halogen atom, This is a group consisting of a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may have any linear, branched, or cyclic structure.
More specifically, the substituent group Z includes the following structures.

A linear, branched, or cyclic alkyl group having 1 or more carbon atoms, preferably 4 or more, and 24 or less, preferably 12 or less, more preferably 8 or less, and still more preferably 6 or less. Specific examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, and dodecyl group. etc.
A linear, branched, or cyclic alkenyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less; specific examples include vinyl groups.
Straight-chain or branched alkynyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less; specific examples include ethynyl group.
An alkoxy group having 1 or more carbon atoms and 24 or less, preferably 12 or less. Specific examples include methoxy and ethoxy groups.
An aryloxy group or a heteroaryloxy group having 4 or more carbon atoms, preferably 5 or more, and 36 or less, preferably 24 or less. Specific examples include phenoxy, naphthoxy, and pyridyloxy groups.
An alkoxycarbonyl group having 2 or more carbon atoms and 24 or less, preferably 12 or less. Specific examples include methoxycarbonyl group and ethoxycarbonyl group.
A dialkylamino group having 2 or more carbon atoms and 24 or less, preferably 12 or less. Specific examples include dimethylamino group and diethylamino group.
A diarylamino group having carbon atoms of 10 or more, preferably 12 or more, and 36 or less, preferably 24 or less. Specific examples include diphenylamino group, ditolylamino group, N-carbazolyl group, and the like.
An arylalkylamino group having 7 or more carbon atoms and 36 or less, preferably 24 or less. A specific example is a phenylmethylamino group.
An acyl group having 2 or more carbon atoms and 24 or less carbon atoms, preferably 12 or less carbon atoms. Specific examples include acetyl group and benzoyl group.
Halogen atoms such as fluorine atoms and chlorine atoms. Preferably it is a fluorine atom.
A haloalkyl group having 1 or more carbon atoms and 12 or less, preferably 6 or less. Specific examples include trifluoromethyl group and the like.
An alkylthio group having 1 or more carbon atoms, usually 24 or less, preferably 12 or less. Specific examples include methylthio group and ethylthio group.
An arylthio group having carbon atoms of 4 or more, preferably 5 or more, and 36 or less, preferably 24 or less. Specific examples include phenylthio group, naphthylthio group, and pyridylthio group.
A silyl group whose carbon number is usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less. Specific examples include trimethylsilyl group and triphenylsilyl group.
A siloxy group having 2 or more carbon atoms, preferably 3 or more carbon atoms, and usually 36 or less, preferably 24 or less. Specific examples include trimethylsiloxy group, triphenylsiloxy group, and the like.
Cyano group.
An aromatic hydrocarbon group having 6 or more carbon atoms and 36 or less, preferably 24 or less. Specific examples include a phenyl group, a naphthyl group, a group in which a plurality of phenyl groups are linked, and the like.
An aromatic heterocyclic group having carbon atoms of 3 or more, preferably 4 or more, and 36 or less, preferably 24 or less. Specific examples include thienyl group and pyridyl group.

The above substituent may have a linear, branched, or cyclic structure.
When the above substituents are adjacent, the adjacent substituents may bond to each other to form a ring. Preferred ring sizes are a 4-membered ring, a 5-membered ring, and a 6-membered ring, and specific examples include a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.

Among the above substituent group Z, preferred are an alkyl group, an alkoxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group.

Moreover, each substituent in the above substituent group Z may further have a substituent. Examples of these substituents include the same ones as in the above substituent group Z or a crosslinking group. Preferably, there is no further substituent, or an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms. or phenyl group. From the viewpoint of charge transport properties, it is more preferable to have no additional substituents.
When the substituent that each substituent in the substituent group Z may further include is a crosslinking group, the crosslinking group is preferably a crosslinking group selected from the crosslinking group T. A substituent which preferably further has a crosslinking group is an alkyl group or an aromatic hydrocarbon group.

[Charge transporting polymer compound]
The composition of the present invention preferably contains a hole transporting polymer compound as the charge transporting polymer compound. The hole-transporting polymer compound is usually used to form a hole-injection layer or a hole-transporting layer, and is included in the charge-transporting film-forming composition described below. In this case, the composition of the present invention can be used to form a hole injection layer or a hole transport layer.

[Organic polymer compound containing arylamine structure as a repeating unit]
In this case, the composition of the present invention is an organic polymer compound containing an arylamine structure represented by the following formula (1) as a repeating unit (hereinafter referred to as "organic polymer compound (1)") as a hole transporting polymer compound. Preferably, this organic polymer compound (1) has a crosslinking group.

[In formula (1),
Ar ⁵¹ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are connected;
Ar ⁵² is at least one selected from the group consisting of a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group. It represents a divalent group in which one group is connected to a plurality of groups directly or via a linking group.
Ar ⁵¹ and Ar ⁵² may form a ring via a single bond or a connecting group.
Ar ⁵¹ and Ar ⁵² may have a substituent and/or a crosslinking group.
Ar ⁵² includes a partial structure represented by formula (2) below. ]

The substituent that Ar ⁵¹ and Ar ⁵² may have is preferably a substituent selected from the above-mentioned substituent group Z.

The crosslinking group that Ar ⁵¹ and Ar ⁵² may have is preferably a crosslinking group selected from the group T of crosslinking groups.

(terminal group)
As used herein, the term "terminal group" refers to a structure at the end of a polymer formed by an end-capping agent used at the end of polymerization of the polymer. In the composition of the present invention, the terminal group of the organic polymer compound (1) is preferably a hydrocarbon group. From the viewpoint of charge transport properties, the hydrocarbon group is preferably a hydrocarbon group having 1 or more and 60 or less carbon atoms, more preferably a hydrocarbon group having 1 or more and 40 or less carbon atoms, and even more preferably a hydrocarbon group having 1 or more and 30 or less carbon atoms. .

As the hydrocarbon group, for example,
Carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc. A straight chain, branched, or cyclic alkyl group whose number is usually 1 or more, preferably 4 or more, and usually 24 or less, preferably 12 or less;
A linear, branched, or cyclic alkenyl group, such as a vinyl group, which usually has 2 or more and 24 or less carbon atoms, preferably 12 or less;
A linear or branched alkynyl group, such as an ethynyl group, which usually has 2 or more and 24 or less carbon atoms, preferably 12 or less;
An aromatic hydrocarbon group, such as a phenyl group or a naphthyl group, whose carbon number is usually 6 or more and 36 or less, preferably 24 or less;
A crosslinking group that is a hydrocarbon group in the crosslinking group group T; preferably a crosslinking group represented by the formula (X1) to the formula (X4);
can be mentioned.

These hydrocarbon groups may further have a substituent, and the optional substituent is preferably an alkyl group or an aromatic hydrocarbon group. When there are a plurality of substituents that may be further included, they may be bonded to each other to form a ring. When these hydrocarbon groups are groups other than crosslinking groups, the substituent may further have a crosslinking group selected from the group T of crosslinking groups as a substituent.

The terminal group is preferably an alkyl group, an aromatic hydrocarbon group, or a crosslinking group that is a hydrocarbon group in the crosslinking group group T, more preferably an aromatic group, from the viewpoint of charge transport properties and durability. It is a hydrocarbon group. When the terminal group is not a crosslinking group, it is also preferable to further have a crosslinking group selected from the group T of crosslinking groups as a substituent.

( ^Ar52 )
Ar ⁵² is at least one selected from the group consisting of a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group. One group represents a divalent group in which a plurality of groups are connected directly or via a linking group, and the aromatic hydrocarbon group and the aromatic heterocyclic group may have a substituent and/or a bridging group.
The substituents that may be included are preferably selected from the substituent group Z described above. The crosslinking group that may be included is preferably a crosslinking group selected from the crosslinking group group T described above.

(Substructure represented by formula (2))
The repeating unit represented by the above formula (1) includes a partial structure represented by the following formula (2) in the main chain structure represented by Ar ⁵² , resulting in a twisted structure of the main chain, which prevents conjugation. inhibit.

<Substructure represented by formula (2)>

[In formula (2),
R ⁶⁰¹ and R ⁶²¹ are each independently a hydrogen atom or an alkyl group which may have a substituent and/or a crosslinking group,
At least one of R ⁶⁰¹ and R ⁶²¹ is an alkyl group that may have a substituent and/or a crosslinking group,
Ring Ar ⁶⁰¹ and ring Ar ⁶²¹ each independently contain a monocyclic or condensed divalent aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group. A monocyclic or fused ring divalent aromatic heterocyclic group that may have
-* represents a bond with an adjacent atom. ]

( ^R601 )
R ⁶⁰¹ and R ⁶²¹ are each independently an alkyl group which may have a substituent or a crosslinking group, and the alkyl group is the same as the alkyl group in the above substituent group Z.

(Ring Ar ⁶⁰¹ , Ring Ar ⁶²¹ )
The aromatic hydrocarbon group and aromatic heterocyclic group as ring Ar ⁶⁰¹ and ring Ar ⁶²¹ are as defined above.

The substituent that these structures may have is preferably a substituent selected from the substituent group Z, and the crosslinking group that these structures may have is preferably a crosslinking group selected from the crosslinking group T.

In the formula (2), ring Ar ⁶⁰¹ and ring Ar ⁶²¹ are preferably each independently a 1,4-phenylene group which may have a substituent and/or a crosslinking group, or ring Ar ⁶⁰¹ and ring Ar ⁶²¹ is a 1,4-phenylene group which may have a substituent and/or a crosslinking group, and the other one is a 1,4-phenylene group which may have a substituent and/or a crosslinking group. This combination is a 7-fluorenyl group. The optional substituent is preferably a substituent selected from the substituent group Z, and the optional crosslinking group is preferably a crosslinking group selected from the crosslinking group T.

( ^Ar51 )
Ar ⁵¹ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are connected; The aromatic heterocyclic group may have a substituent and/or a crosslinking group.
The optional substituent is preferably a substituent selected from the substituent group Z, and the optional crosslinking group is preferably a crosslinking group selected from the crosslinking group T.

(Preferred structure of Ar ⁵¹ having a bridging group)
When Ar ⁵¹ has a crosslinking group, Ar ⁵¹ preferably has a crosslinking group selected from the group T of crosslinking groups at the terminal of a monovalent group in which 2 to 5 benzene rings which may have substituents are connected. A structure having a group is preferred. More preferably, Ar ⁵¹ has a structure having a crosslinking group selected from the group T of crosslinking groups at the end of a monovalent group in which 2 to 5 unsubstituted benzene rings are connected.

<Preferred Ar ⁵¹ >
Ar ⁵¹ is preferably an aromatic hydrocarbon group from the viewpoint of excellent charge transport properties and durability, and among them, a benzene ring (phenyl group), a group in which 2 to 5 benzene rings are connected, or a fluorene ring. A valent group (fluorenyl group) is more preferred, a fluorenyl group is even more preferred, and a 2-fluorenyl group is particularly preferred. These may have substituents and/or crosslinking groups. The substituent is preferably a group selected from the substituent group Z, and the crosslinking group is preferably a crosslinking group selected from the crosslinking group T.

There are no particular limitations on the substituents that the aromatic hydrocarbon group and aromatic heterocyclic group of Ar ⁵¹ may have, as long as they do not significantly reduce the properties of the organic polymer compound (1). The substituent is preferably a group selected from the above substituent group Z, more preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group, and even more preferably an alkyl group.

From the viewpoint of solubility in a solvent, Ar ⁵¹ is preferably a fluorenyl group substituted with an alkyl group having 1 to 24 carbon atoms, and particularly preferably a 2-fluorenyl group substituted with an alkyl group having 4 to 12 carbon atoms. . Furthermore, a 9-alkyl-2-fluorenyl group in which the 9-position of the 2-fluorenyl group is substituted with an alkyl group is preferred, and a 9,9'-dialkyl-2-fluorenyl group in which the 9-position of the 2-fluorenyl group is substituted with an alkyl group is particularly preferred.

When at least one of the 9-position and 9'-position is a fluorenyl group substituted with an alkyl group, the solubility in solvents and the durability of the fluorene ring tend to improve. Furthermore, since both the 9-position and the 9'-position are fluorenyl groups substituted with alkyl groups, the solubility in solvents and the durability of the fluorene ring tend to be further improved.

Further, Ar ⁵¹ is also preferably a spirobifluorenyl group from the viewpoint of solubility in a solvent.

In addition, as the organic polymer compound (1), Ar ⁵¹ in the repeating unit represented by the formula (1) is a group represented by the following formula (51), a group represented by the following formula (52), Alternatively, it is preferable to include a repeating unit that is a group represented by the following formula (53).

<Group represented by formula (51)>

[In formula (51),
* represents a bond with the nitrogen atom in the main chain of formula (1),
Ar ⁵³ and Ar ⁵⁴ each independently represent a divalent aromatic hydrocarbon group which may have a substituent and/or a crosslinking group, an aromatic group which may have a substituent and/or a crosslinking group; A heterocyclic group, an aromatic hydrocarbon group which may have a substituent and/or a crosslinking group, or an aromatic heterocyclic group which may have a substituent and/or a crosslinking group directly or via a linking group. Represents a divalent group connected through a plurality of
Ar ⁵⁵ is an aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, an aromatic heterocyclic group that may have a substituent and/or a crosslinking group, or a substituent and/or a crosslinking group Represents a monovalent group in which a plurality of aromatic hydrocarbon groups or aromatic heterocyclic groups which may have a group are connected directly or via a linking group,
Ar ⁵⁶ represents a hydrogen atom, a substituent or a crosslinking group. ]

Here, each aromatic hydrocarbon group and each aromatic heterocyclic group may have a substituent and/or a crosslinking group. The optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T.

( ^Ar53 )
Ar ⁵³ is preferably a group in which 1 to 6 divalent aromatic hydrocarbon groups are connected, more preferably a group in which 2 to 4 divalent aromatic hydrocarbon groups are connected, and among them, 1 to 4 phenylene groups are connected. A group in which two phenylene groups are connected is more preferable, and a biphenylene group in which two phenylene groups are connected is particularly preferable.

These groups may have substituents and/or crosslinking groups. The optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T. Preferably, Ar ⁵³ is free of substituents and bridging groups.

Furthermore, when a plurality of these divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are connected, the group is preferably bonded so that the plurality of connected divalent aromatic hydrocarbon groups are not conjugated. Specifically, it is preferable to include a 1,3-phenylene group or a group having a substituent and forming a twisted structure due to the steric effect of the substituent, and more preferably a 1,3-phenylene group having no substituent or crosslinking group. , 3-phenylene group, or a group in which a plurality of 1,3-phenylene groups having no substituent or crosslinking group are connected.

In formula (51), it is preferable that Ar ⁵³ be bonded to the 3-position of the carbazole structure to which Ar ⁵³ is bonded, since the hole transport property is enhanced.

( ^Ar54 )
Ar ⁵⁴ is preferably a group in which one or more divalent aromatic hydrocarbon groups, which may be the same or different, are connected, from the viewpoint of excellent charge transport properties and durability; The group hydrocarbon group may have a substituent. When a plurality of aromatic hydrocarbon groups are connected, the number of connected groups is preferably 2 to 10, more preferably 6 or less, and particularly preferably 3 or less from the viewpoint of stability of the formed film. Preferred aromatic hydrocarbon ring structures include benzene rings, naphthalene rings, anthracene rings, and fluorene rings, and more preferred are benzene rings and fluorene rings. The group having multiple connected groups is preferably a group in which 1 to 4 phenylene rings are connected, or a group in which a phenylene ring and a fluorene ring are connected. A biphenylene group in which two phenylene rings are connected is particularly preferred from the viewpoint of broadening the LUMO.

These groups may have substituents and/or crosslinking groups. The optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T. More preferred substituents are phenyl, naphthyl, and fluorenyl. Moreover, it is also preferable that it has no substituent.

( ^Ar55 )
Ar ⁵⁵ is an aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, an aromatic heterocyclic group that may have a substituent and/or a crosslinking group, or a substituent and/or It is a monovalent group in which a plurality of aromatic hydrocarbon groups or aromatic heterocyclic groups which may have a bridging group are connected directly or via a linking group. Preferably, it is a monovalent aromatic hydrocarbon group or a monovalent group in which a plurality of aromatic hydrocarbon groups are connected.

These groups may have substituents and/or crosslinking groups. The optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T.

When a plurality of these groups are connected, it is a monovalent group in which 2 to 10 groups are connected, preferably a monovalent group in which 2 to 5 groups are connected. As the aromatic hydrocarbon group and aromatic heterocyclic group, the same aromatic hydrocarbon group and aromatic heterocyclic group as in Ar ⁵¹ above can be used.

Ar ⁵⁵ preferably has a structure represented by any one of the following formulas (a-1) to (a-7).

In the above formulas (a-1) to (a-7), "-*" represents the bonding position with Ar ⁵⁴ .
These structures may have substituents and/or crosslinking groups. The substituent that these structures may have is preferably a group selected from the substituent group Z, and the crosslinking group that these structures may have is preferably a group selected from the crosslinking group T.

Each of X ^a in (a-2) is independently CH or N, and when CH, H may be substituted with a substituent or a crosslinking group. The substituent is preferably a group selected from the substituent group Z, and the crosslinking group is preferably a group selected from the crosslinking group T. From the viewpoint of stability, the substituent is preferably an aromatic hydrocarbon group, and more preferably a phenyl group. These groups may further have a substituent selected from the substituent group Z or a crosslinking group selected from the crosslinking group T. Preferably (a-2), all X ^a 's are N. More preferred as (a-2) is (a-3).

( ^Ara7 )
Each Ar ^a7 is independently an aromatic hydrocarbon group or an aromatic heterocyclic group. From the viewpoint of stability, Ar ^a7 is preferably an aromatic hydrocarbon group, more preferably a phenyl group. These groups may further have a substituent or a crosslinking group. The optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T.

( ^Ar56 )
Ar ⁵⁶ represents a hydrogen atom, a substituent or a bridging group. When Ar ⁵⁶ is a substituent, it is not particularly limited, but is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, and further a substituent selected from substituent group Z and/or a crosslinking group It may have a crosslinking group selected from T. When Ar ⁵⁶ is a crosslinking group, the crosslinking group is preferably a crosslinking group selected from the group T of crosslinking groups.

When Ar ⁵⁶ is a substituent, it is preferable from the viewpoint of improving durability that it is bonded to the 3-position of the carbazole structure to which Ar ⁵⁶ is bonded in formula (51). Ar ⁵⁶ is preferably a hydrogen atom from the viewpoint of ease of synthesis and charge transport properties. From the viewpoint of improving durability and charge transportability, Ar ⁵⁶ is preferably an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent. , an aromatic hydrocarbon group which may have a substituent is more preferable.

Ar ⁵⁶ is preferably a hydrogen atom from the viewpoint of ease of synthesis and charge transport properties.

(Specific example of group represented by formula (51))
Specific examples of the group represented by formula (51) are listed below, but the group represented by formula (51) is not limited to these.

<Group represented by formula (52)>

[In formula (52),
Ar ⁶¹ and Ar ⁶² each independently represent a divalent aromatic hydrocarbon group which may have a substituent and/or a crosslinking group, a divalent aromatic hydrocarbon group which may have a substituent and/or a crosslinking group; An aromatic heterocyclic group, or an aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, or an aromatic heterocyclic group that may have a substituent or a crosslinking group directly or through a linking group. It is a divalent group in which multiple groups are connected via
Ar ⁶³ to Ar ⁶⁵ each independently represent a hydrogen atom, a substituent, or a crosslinking group.
* represents the bonding position to the nitrogen atom of the main chain in formula (1). ]

The substituents that each aromatic hydrocarbon group may have, the substituents that each aromatic heterocyclic group may have, and Ar ⁶³ to Ar ⁶⁵ when they are substituents are from the substituent group Z. The selected groups are preferred.
A substituent that each aromatic hydrocarbon group may have, a crosslinking group that each aromatic heterocyclic group may have, and Ar ⁶³ to Ar ⁶⁵ in the case of a crosslinking group are from the crosslinking group T. The selected groups are preferred.

(Ar ⁶³ ~ Ar ⁶⁵ )
Ar ⁶³ to Ar ⁶⁵ are each independently the same as Ar ⁵⁶ above.
Ar ⁶³ to Ar ⁶⁴ are preferably hydrogen atoms.

( ^Ar62 )
Ar ⁶² is a divalent aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, a divalent aromatic heterocyclic group that may have a substituent and/or a crosslinking group, or an aromatic hydrocarbon group which may have a substituent and/or a crosslinking group, or a plurality of aromatic heterocyclic groups which may have a substituent and/or a crosslinking group directly or via a linking group. It is a linked divalent group. Preferably, a divalent aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, or a plurality of divalent aromatic hydrocarbon groups that may have a substituent and/or a crosslinking group. It is a linked group. Here, the substituents that the aromatic hydrocarbon group may have and the substituents that the aromatic heterocyclic group may have are preferably the same groups as in the substituent group Z, and further have a bridging group. Good too. As the crosslinking group that the aromatic hydrocarbon group may have and the crosslinking group that the aromatic heterocyclic group may have, groups selected from the group T of crosslinking groups are preferable.

The specific structure of Ar ⁶² is similar to Ar ⁵⁴ .

A specific preferred group for Ar ⁶² is a divalent group such as a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, or a group in which a plurality of these are connected, and more preferably a divalent group in which a benzene ring or a plurality of these are connected. A linked group, particularly preferably a 1,4-phenylene group in which a benzene ring is linked at a divalent position at the 1 and 4 positions, a 2,7-fluorenylene group linked at a divalent position at the 2 and 7 positions of a fluorene ring, Or a group in which a plurality of these are connected, most preferably a group containing "1,4-phenylene group-2,7-fluorenylene group-1,4-phenylene group-".

In these preferred structures of Ar ⁶² , it is preferable that the phenylene group has no substituent or crosslinking group other than at the linking position to avoid twisting of Ar ⁶² due to the steric effect of the substituent. Further, it is preferable that the fluorenylene group has a substituent or a crosslinking group at the 9,9' position from the viewpoint of improving solubility and durability of the fluorene structure. As the substituent, a substituent selected from the above-mentioned substituent group Z is preferable, and an alkyl group is particularly preferable. These substituents may be further substituted with a crosslinking group. The crosslinking group is preferably a crosslinking group selected from the group T of crosslinking groups. Preferably it is a substituent.

( ^Ar61 )
Ar ⁶¹ is the same group as Ar ⁵³ above, and its preferred structure is also the same.

(Specific example of group represented by formula (52))
Specific examples of the group represented by formula (52) are listed below, but the group represented by formula (52) is not limited to the following.

<Group represented by formula (53)>

[In formula (53),
* represents a bond with the nitrogen atom in the main chain of formula (1),
Ar ⁷¹ represents a divalent aromatic hydrocarbon group,
Ar ⁷² and Ar ⁷³ are each independently an aromatic hydrocarbon group, an aromatic heterocyclic group, or two or more groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group directly or through a linking group. represents a monovalent group in which multiple groups are connected, and these groups may have a substituent and/or a crosslinking group,
Ring HA is an aromatic heterocycle containing a nitrogen atom,
X ² and Y ² each independently represent a carbon atom or a nitrogen atom, and when at least one of X ² and Y ² is a carbon atom, the carbon atom has a substituent and/or a crosslinking group. It's okay. ]

The above optional substituent is preferably a group selected from the substituent group Z, and the optional crosslinking group is preferably a group selected from the crosslinking group T.

( ^Ar71 )
Ar ⁷¹ is the same group as Ar ⁵³ above.
As Ar ⁷¹ , a group in which 2 to 6 benzene rings which may have a substituent are connected is particularly preferable, and a quaterphenylene group in which 4 benzene rings which may have a substituent are connected is particularly preferable. Most preferred.
Further, Ar ⁷¹ preferably contains at least one benzene ring connected at the 1 and 3 positions, which are non-conjugated sites, and more preferably contains two or more.

In the case where Ar ⁷¹ is a group in which a plurality of divalent aromatic hydrocarbon groups which may have substituents are connected, it is preferable that all of them are directly bonded and connected from the viewpoint of charge transportability or durability. .
Therefore, as Ar ⁷¹ , preferable structures connecting the nitrogen atom of the main chain of the polymer and the ring HA in the formula (53) are as listed in Scheme 2-1 and Scheme 2-2 below. be. "-*" represents the nitrogen atom of the main chain of formula (1) or the bonding site with ring HA of formula (53). Of the two "-*", either one may be bonded to the nitrogen atom of the main chain of formula (1) or may be bonded to ring HA.

As the substituent that Ar ⁷¹ may have, any one of the above substituent group Z or a combination thereof can be used. The preferred range of the substituents that Ar ⁷¹ may have is the same as the substituents that Ar ⁵³ may have when it is an aromatic hydrocarbon group.

(X ² and Y ² )
X ² and Y ² each independently represent a C (carbon) atom or an N (nitrogen) atom. When at least one of X ² and Y ² is a C atom, it may have a substituent.
From the viewpoint of making it easier to localize LUMO around ring HA, it is preferable that both X ² and Y ² are N atoms.
As the substituent that may be present when at least one of X ² and Y ² is a C atom, any one of the substituent group Z or a combination thereof can be used. From the viewpoint of charge transport properties, it is more preferable that X ² and Y ² have no substituents.

(Ar ⁷² and Ar ⁷³ )
Ar ⁷² and Ar ⁷³ are each independently an aromatic hydrocarbon group, an aromatic heterocyclic group, or two or more groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group directly or through a linking group. It is a monovalent group in which multiple groups are connected. These groups may have a substituent and/or a crosslinking group, and the optional substituent is preferably a group selected from the above substituent group Z, and the optional crosslinking group is A group selected from the above-mentioned crosslinking group T is preferable.

Ar ⁷² and Ar ⁷³ are each independently preferably a phenyl group that may have a substituent or a group in which 2 to 5 benzene rings that may have a substituent are bonded together, and can be easily synthesized and have good stability. From the viewpoint of superiority, it is preferable that the number of benzene rings connected is small, and a phenyl group is particularly preferable. The substituents that these benzene rings may have are selected from the above substituent group Z. Preferably, the structure has no substituents.

(Specific example of group represented by formula (53))
Specific examples of the group represented by formula (53) are listed below, but the group represented by formula (53) is not limited to these.

[Preferred repeating unit represented by formula (1)]
The repeating unit represented by the formula (1) is preferably a repeating unit represented by the following formula (54).

<Repeating unit represented by formula (54)>

[In formula (54),
Ar ⁵¹ is the same as Ar ⁵¹ in the above formula (1),
X is -C(R ²⁰⁷ )(R ²⁰⁸ )-, -N(R ²⁰⁹ )- or -C(R ²¹¹ )(R ²¹² )-C(R ²¹³ )(R ²¹⁴ )-,
R ²⁰¹ , R ²⁰² , R ²²¹ and R ²²² are each independently an alkyl group which may have a substituent and/or a crosslinking group,
R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ each independently have a hydrogen atom, an alkyl group that may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group, an optional aralkyl group, or an aromatic hydrocarbon group optionally having a substituent and/or a crosslinking group,
a and b are each independently an integer of 0 to 4,
c is an integer from 0 to 3,
d is an integer from 0 to 4,
i and j are each independently an integer of 0 to 3. ]

(R ²⁰¹ , R ²⁰² , R ²²¹ , R ²²² )
R ²⁰¹ , R ²⁰² , R ²²¹ and R ²²² in the repeating unit represented by the above formula (54) are each independently an alkyl group which may have a substituent and/or a crosslinking group.
The alkyl group is a straight chain, branched or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but in order to maintain the solubility of the organic polymer compound (1), it is preferably 1 or more, preferably 8 or less, more preferably 6 or less, and even more preferably 3 or less. . More preferably, the alkyl group is a methyl group or an ethyl group.
When there is a plurality of R ^201s , the plurality of R ^201s may be the same or different; when there is a plurality of R ^202s , the plurality of R ^202s may be the same or different. It is preferable that all R ²⁰¹ and R ²⁰² are the same group because the charge can be uniformly distributed around the nitrogen atom and synthesis is also easy.
When there are multiple R ^221s , the multiple R ^221s may be the same or different; when there are multiple R ^222s , the multiple R ^222s may be the same or different. For ease of synthesis, it is preferred that all R ²²¹ and R ²²² are the same group.

(R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ )
R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ each independently have a hydrogen atom, an alkyl group that may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group, It is an optional aralkyl group, or an aromatic hydrocarbon group that optionally has a substituent and/or a crosslinking group.

The alkyl group is not particularly limited, but since it tends to improve the solubility of the organic polymer compound (1), the number of carbon atoms is preferably 1 or more, preferably 24 or less, more preferably 8 or less, and 6 or less. is even more preferable. Further, the alkyl group may have a linear, branched or cyclic structure.
Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group. , n-octyl group, cyclohexyl group, dodecyl group, etc.

The aralkyl group is not particularly limited, but since it tends to improve the solubility of the organic polymer compound (1), the number of carbon atoms is preferably 5 or more, preferably 60 or less, and more preferably 40 or less.
Specifically, the aralkyl group includes a 1,1-dimethyl-1-phenylmethyl group, a 1,1-di(n-butyl)-1-phenylmethyl group, and a 1,1-di(n-hexyl)- 1-phenylmethyl group, 1,1-di(n-octyl)-1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl group , 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1- Examples include n-heptyl group, 8-phenyl-1-n-octyl group, and 4-phenylcyclohexyl group.

The aromatic hydrocarbon group is not particularly limited, but since it tends to improve the solubility of the organic polymer compound (1), the number of carbon atoms is preferably 6 or more, preferably 60 or less, and more preferably 30 or less. preferable.
Specifically, the aromatic hydrocarbon group includes a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring. Examples include monovalent groups such as a 6-membered monocyclic ring or 2 to 5 condensed rings, or a group in which a plurality of these are connected.

From the viewpoint of improving charge transport properties and durability, R ²⁰⁷ and R ²⁰⁸ are preferably a methyl group or an aromatic hydrocarbon group, R ²⁰⁷ and R ²⁰⁸ are more preferably a methyl group, and R ²⁰⁹ is a phenyl group. It is more preferable.

The alkyl group of R ²⁰¹ , R ²⁰² , R ²²¹ , R ²²² , the alkyl group, aralkyl group and aromatic hydrocarbon group of R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ have a substituent and/or a crosslinking group. You can leave it there. Examples of the substituent include the groups listed as preferable groups for the alkyl group, aralkyl group, and aromatic hydrocarbon group in R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ above. Examples of the crosslinking group include crosslinking groups selected from the group T of crosslinking groups.
The alkyl groups of R ²⁰¹ , R ²⁰² , R ²²¹ , and R ²²² , the alkyl groups, aralkyl groups, and aromatic hydrocarbon groups of R ²⁰⁷ to R ²⁰⁹ and R ²¹¹ to R ²¹⁴ are considered substituents from the viewpoint of lowering the voltage. And most preferably, it does not have a crosslinking group.
When a crosslinking group is bonded to the main chain structure of the repeating unit represented by formula (54), the crosslinking group is an alkyl group, an aralkyl group, or an aromatic hydrocarbon group, R ²⁰⁷ to R ²⁰⁹ , R ²¹¹ -R ²¹³ or R ²¹⁴ is preferable.

(a, b, c and d)
In the repeating unit represented by the above formula (54), a and b are each independently an integer of 0 to 4. a+b is preferably 1 or more, furthermore, a and b are each preferably 2 or less, and more preferably both a and b are 1. Here, a is defined when c is 1 or more, and b is defined when d is 1 or more. Moreover, when c is 2 or more, a plurality of a's may be the same or different, and when d is 2 or more, a plurality of b's may be the same or different.
When a+b is 1 or more, the aromatic ring in the main chain is twisted due to steric hindrance, and the solubility of the organic polymer compound (1) in the solvent is excellent, and the coating film formed by the wet film forming method and heat treated is improved. tends to be highly insoluble in solvents. Therefore, when a+b is 1 or more, when forming another organic layer (e.g., a light-emitting layer) on this coating film by a wet film formation method, use a composition for forming another organic layer containing an organic solvent. Elution of the organic polymer compound (1) is suppressed.

In the repeating unit represented by the above formula (54), c is an integer of 0 to 3, and d is an integer of 0 to 4. Each of c and d is preferably 2 or less, more preferably c and d are equal, and particularly preferably both c and d are 1 or both c and d are 2.
When both c and d in the repeating unit represented by the above formula (54) are 1, or both c and d are 2, and both a and b are 2 or 1, R Most preferably, ²⁰¹ and R ²⁰² are bonded to positions symmetrical to each other.
Here, the expression that R ²⁰¹ and R ²⁰² are bonded to positions symmetrical to each other means that the bonding positions of R ²⁰¹ and R ²⁰² are relative to the fluorene ring, carbazole ring, or 9,10-dihydrophenanthrene derivative structure in formula (54). is symmetrical. At this time, 180 degree rotation around the main chain is considered to be the same structure.
When R ²²¹ and R ²²² exist, each independently preferably exists at the 1st, 3rd, 6th, or 8th position with respect to the carbon atom of the benzene ring to which X is bonded. Due to the presence of R ²²¹ and/or R ²²² at this position, the condensed ring to which R ²²¹ and/or R ²²² is bonded and the benzene ring next to it on the main chain are twisted due to steric hindrance. Molecular compound (1) has excellent solubility in solvents, and a coating film formed by a wet film forming method and heat-treated tends to have excellent insolubility in solvents, which is preferable.

(i, j)
In the repeating unit represented by the above formula (54), i and j are each independently an integer of 0 to 3. i and j are each independently preferably an integer of 0 to 2, more preferably 0 or 1. Preferably, i and j are the same integer. i and j are preferably 1 or 2 in order to twist the heavy main chain of the organic polymer compound (1), and R ²²¹ and/or R ²²² are at the 1st and/or 3rd positions of the benzene ring. Preferably, it is bonded to. From the viewpoint of ease of synthesis, it is preferable that i and j are 0. In addition, the bonding position of the benzene ring is the carbon atom next to the carbon atom to which X is bonded, and the carbon atom to which R ²²¹ or R ²²² can be bonded is the 1st position, and is bonded to the adjacent structure as the main chain. The carbon atom is at the 2nd position.

(X)
X in the above formula (54) is preferably -C(R ²⁰⁷ )(R ²⁰⁸ )- or -N(R ²⁰⁹ )-, and -C(R ²⁰⁷ )(R ²⁰⁸ )- is more preferable.

[Electron accepting compound]
When the composition for an organic electroluminescent device of the present invention is a composition for forming a hole injection/transport layer, it preferably contains an electron-accepting compound.
As the electron-accepting compound, a compound having oxidizing power and the ability to accept one electron from the above-mentioned hole injection/transport material is preferable. Specifically, a compound having an electron affinity of 4 eV or more is preferable, and a compound having an electron affinity of 5 eV or more is more preferable.

Examples of electron-accepting compounds include onium salts substituted with organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, iron(III) chloride (JP-A-11-251067) Publications), high valence inorganic compounds such as ammonium peroxodisulfate, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris(pentafluorophenyl)borane (JP 2003-31365), fullerene derivatives, iodine etc.
Among the above-mentioned compounds, onium salts substituted with organic groups, high-valent inorganic compounds, and the like are preferable because they have strong oxidizing power. Moreover, onium salts substituted with organic groups, cyano compounds, aromatic boron compounds, etc. are preferable because they have high solubility in various solvents and are applicable to forming films by wet film forming methods.

Specific examples of organic group-substituted onium salts, cyano compounds, and aromatic boron compounds suitable as electron-accepting compounds include those described in International Publication No. 2005/089024 pamphlet, and preferred examples thereof are also the same. be. Examples include, but are not limited to, compounds represented by the following structural formulas.

In addition, one type of electron-accepting compound may be used alone, or two or more types may be used in any combination and ratio.

[Cation radical species]
As the cation radical species, an ionic compound consisting of a cation radical, which is a chemical species from which one electron has been removed from the hole injection/transport material, and a counter anion is preferable. However, when the cation radical is derived from a polymer compound with hole transport ability, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.
The cation radical is preferably a chemical species obtained by removing one electron from the organic polymer compound (1) as a hole injection/transport material. It is preferable that the cation radical is a chemical species obtained by removing one electron from the organic polymer compound (1) in terms of amorphousness, visible light transmittance, heat resistance, solubility, and the like.
Here, the cation radical species can be generated by mixing the organic polymer compound (1) and the above-mentioned electron-accepting compound. That is, by mixing the organic polymer compound (1) and the electron-accepting compound, electron transfer occurs from the organic polymer compound (1) to the electron-accepting compound, and the cation radicals of the hole injection/transport material A cationic ionic compound consisting of a counter anion is generated.

[Organic solvent]
The type of organic solvent is not limited as long as it can satisfactorily dissolve each component in the composition for an organic electroluminescent device and does not cause undesirable chemical reactions with these components. A solvent that does not contain a substance that can deactivate radical species or a substance that generates such a substance is preferred.
In view of the above, preferred examples of solvents include at least one selected from the group consisting of ether solvents, ester solvents, ketone solvents, and hydrocarbon solvents.

Specific examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, and phenetol. , 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and other aromatic ethers. Any one of these ether solvents may be used alone, or two or more may be used in any combination and ratio.

Specific examples of ester solvents include aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and benzoate. Examples include aromatic esters such as n-butyl acid. Any one of these ester solvents may be used alone, or two or more may be used in any combination and ratio.

Examples of the ketone solvent include aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone, and alicyclic ketone solvents such as cyclohexanone, cyclooctanone and fenchone. Any one of these ketone solvents may be used alone, or two or more thereof may be used in any combination and ratio.

Examples of hydrocarbon solvents include toluene, xylene, mesitylene, cyclohexylbenzene (phenylcyclohexane), tetralin, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, methylnaphthalene, etc. Aromatic hydrocarbon solvents include alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane. Any one of these hydrocarbon solvents may be used alone, or two or more thereof may be used in any combination and ratio.

Furthermore, one or more ether solvents and one or more ester solvents may be used in combination in any ratio. Furthermore, one or more ether solvents and one or more ketone solvents may be used in combination in any ratio. Furthermore, one or more ester solvents and one or more ketone solvents may be used in combination in any ratio.

In addition, solvents that can be used in addition to the above-mentioned ether solvents, ester solvents, ketone solvents, and hydrocarbon solvents include, for example, amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; Examples include dimethyl sulfoxide. Any one of these may be used alone, or two or more may be used in any combination and ratio. Furthermore, one or more of these solvents may be used in combination with one or more of the above-mentioned ether solvents, ester solvents, ketone solvents, and hydrocarbon solvents. In particular, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve oxidizing agents and polymers, so they are preferably used in combination with ether solvents and ester solvents.
Ether solvents and hydrocarbon solvents are preferable, and hydrocarbon solvents are more preferable because they have a small effect of solvating electron-accepting compounds and generate cation radical species more easily than organic polymer compounds and electron-accepting compounds. .

[Content of each component]
The content of the organic solvent in the composition of the present invention is usually 1% by mass or more, preferably 70% by mass or more, and usually 99.999% by mass or less, preferably 99% by mass or less.
If the content of the organic solvent is at least the above-mentioned lower limit, the viscosity tends to be low and film-forming workability tends to be excellent, and when it is below the above-mentioned upper limit, the film-forming efficiency is excellent.

The content of the organic polymer compound (1) in the composition of the present invention is usually 0.001% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and usually 50% by mass or more. % or less, preferably 20% by mass or less, more preferably 15% by mass or less.
If the content of the organic polymer compound (1) is at least the above-mentioned lower limit, it is easy to form a uniform flat film, and when it is below the above-mentioned upper limit, the film has low viscosity and excellent film-forming workability.

The content of the electron-accepting compound in the composition of the present invention is usually 0.00001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 50% by mass or less, A desirable range is usually 5% by mass or less, more preferably 1% by mass or less.

In particular, by mixing the organic polymer compound (1) of the present invention and an electron-accepting compound, a sufficient amount of cation radicals can be efficiently generated. The proportion is preferably 1% by mass or more, more preferably 3% by mass or more, particularly preferably 5% by mass or more, preferably 50% by mass or less, further preferably 40% by mass or less, and particularly preferably 30% by mass or less.

<Other ingredients>
Furthermore, the composition of the present invention may contain other components other than those mentioned above. Examples of other components include leveling agents, antifoaming agents, and the like.
Examples of leveling agents include silicone surfactants, fluorine surfactants, and the like. Any one type of leveling agent may be used alone, or two or more types may be used in combination in any combination and ratio.
When the composition of the present invention contains a leveling agent, its content is usually 0.0001% by mass or more, preferably 0.001% by mass or more, and usually 1% by mass or less, preferably 0.1% by mass. The range is as follows. Too little content of the leveling agent may result in poor leveling, and too much content may impair the electrical properties of the film.
Examples of antifoaming agents include silicone oil, fatty acid esters, phosphoric acid esters, and the like. Any one type of antifoaming agent may be used alone, or two or more types may be used in combination in any combination and ratio.
When the composition of the present invention contains an antifoaming agent, its content is usually 0.0001% by mass or more, preferably 0.001% by mass or more, and usually 1% by mass or less, preferably 0.1% by mass. % or less. If the content of the antifoaming agent is too small, the antifoaming effect may be lost, and if the content is too large, the electrical properties of the membrane may be impaired.

<Reason why it is effective>
The charge transporting polymer compound according to this embodiment has a twist in its main chain. Since conjugation is inhibited by twisting, the charge transporting polymer compound of this embodiment has a deep ionization potential, making it difficult to generate cation radicals in a solution.
In this embodiment, it is thought that by using an organic solvent with low polarity, the affinity between the organic solvent and the electron-accepting compound becomes low, and the electron-accepting compound gathers near the charge-transporting polymer compound. Therefore, doping progresses even in the solution, and cation radicals are sufficiently generated, which is preferable.

[Organic electroluminescent device]
The organic electroluminescent device of the present invention is an organic electroluminescent device comprising a substrate, an anode, an organic layer, and a cathode provided on the substrate, wherein the organic layer is formed using the composition of the present invention. It contains an organic layer formed by
The layer structure of the organic electroluminescent device of the present invention, its formation method, etc. will be explained below with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device 10 of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, and 5 6 represents a light emitting layer, 6 represents a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.

<Substrate>
The substrate serves as a support for the organic electroluminescent device, and is usually a quartz or glass plate, a metal plate, a metal foil, or a synthetic resin, ie, a plastic film or sheet. Among these, glass plates and transparent synthetic resin films such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. The substrate 1 is preferably made of a material with high gas barrier properties since the organic electroluminescent element is unlikely to be deteriorated by outside air. In particular, when using a material with low gas barrier properties such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate 1 to improve the gas barrier properties.

<Anode>
The anode 2 has a function of injecting holes into the layer on the light emitting layer side. The anode 2 is usually made of metal such as aluminum, gold, silver, nickel, palladium, or platinum; metal oxide such as indium and/or tin oxide; metal halide such as copper iodide; carbon black or poly(3); -Methylthiophene), polypyrrole, polyaniline, and other conductive polymers.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum evaporation method. When forming the anode 2 using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., disperse them in a suitable binder resin solution. It can also be formed by coating it on the substrate 1. In the case of a conductive polymer, the anode 2 can be formed by directly forming a thin film on the substrate by electrolytic polymerization, or by coating the conductive polymer on the substrate (Appl. Phys. Lett., 60, p. 2711, 1992).

The thickness of the anode 2 may be determined depending on the required transparency, material, etc. When particularly high transparency is required, the thickness is preferably such that the visible light transmittance is 60% or more, and more preferably 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
If transparency is not required, the thickness of the anode 2 may be set to any desired thickness depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate 1.

After forming the anode 2, if the next layer is to be formed on its surface, impurities on the anode are removed by treatment with ultraviolet rays + ozone, oxygen plasma, argon plasma, etc. before film formation. At the same time, it is preferable to adjust the ionization potential to improve the hole injection property.

<Hole injection layer 3>
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer, and is usually formed on the anode 2.
It is particularly preferable that the hole injection layer according to the present invention is formed by a wet film forming method using the composition for an organic electroluminescent device according to the present invention.

In this specification, the wet film forming method refers to a film forming method, that is, a coating method such as a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, We adopt wet film forming methods such as capillary coating method, inkjet method, nozzle printing method, screen printing method, gravure printing method, flexographic printing method, etc., and dry the film formed by these methods to form a film. The method of doing this.

The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

<Hole transport layer 4>
The hole transport layer 4 is a layer that has the function of transporting holes from the anode 2 side to the light emitting layer 5 side. Although the hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, it is preferably provided from the viewpoint of strengthening the function of transporting holes from the anode 2 to the light emitting layer 5. When providing the hole transport layer 4, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. When the hole injection layer 3 is present, the hole transport layer 4 is formed between the hole injection layer 3 and the light emitting layer 5.

The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The hole transport layer 4 may be formed by a vacuum evaporation method or a wet film formation method. From the viewpoint of excellent film-forming properties, it is preferable to form the film by a wet film-forming method.

The hole transport layer 4 usually contains a hole transport compound that becomes the hole transport layer 4. In particular, the hole transporting compound contained in the hole transporting layer 4 includes two or more tertiary compounds represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl. Aromatic diamine containing an amine and having two or more condensed aromatic rings substituted with nitrogen atoms (JP-A-5-234681), 4,4',4''-tris(1-naphthylphenylamino)triphenylamine Aromatic amine compounds having a starburst structure such as (J. Lumin., Vol. 72-74, p. 985, 1997), aromatic amine compounds consisting of a tetramer of triphenylamine (Chem. Commun., p. 2175) , 1996), spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), 4 , 4'-N,N'-dicarbazole biphenyl and other carbazole derivatives. Polyvinylcarbazole, polyvinyltriphenylamine (JP-A-7-53953), polyarylene ether sulfone containing tetraphenylbenzidine (Polym.Adv.Tech., Vol. 7, p. 33, 1996), etc. can also be preferably used. .

<Light-emitting layer 5>
The light-emitting layer 5 is a layer that is excited by recombining holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between a pair of electrodes, and has the function of emitting light. .
The light emitting layer 5 is a layer formed between the anode 2 and the cathode 9. The light-emitting layer 5 is formed between the hole-injection layer 3 and the cathode 9 when the hole-injection layer 3 is on the anode 2, and the light-emitting layer 5 is formed between the hole-injection layer 3 and the cathode 9 when the hole-transport layer 4 is on the anode 2. It is formed between the hole transport layer 4 and the cathode 9. It is preferable that the light emitting layer 5 contains a charge transporting material together with a light emitting material.

The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention, but a thicker layer is preferable from the viewpoint that defects are less likely to occur in the layer, while a thinner layer is preferable from the viewpoint of facilitating low driving voltage. . The thickness of the light emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, and usually preferably 200 nm or less, and even more preferably 100 nm or less.

(Light-emitting material)
The luminescent material used for the luminescent layer 5 is not particularly limited as long as it emits light at a desired emission wavelength and does not impair the effects of the present invention, and any known luminescent material can be used.
Examples of the fluorescent material include the following materials.
Examples of fluorescent materials that emit blue light (blue fluorescent materials) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis(2-phenylethenyl)benzene, and derivatives thereof.
Examples of fluorescent materials that emit green light (green fluorescent materials) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al(C ₉ H ₆ NO) ₃ .
Examples of the fluorescent material that emits yellow light (yellow fluorescent material) include rubrene, perimidone derivatives, and the like.
Examples of fluorescent materials that emit red light (red fluorescent materials) include DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran)-based compounds, benzopyran derivatives, and rhodamine derivatives. , benzothioxanthene derivatives, azabenzothioxanthene, and the like.

Examples of phosphorescent materials include materials from groups 7 to 11 of the long period periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long period periodic table). Examples include organometallic complexes containing selected metals. Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.
As the ligand of the organometallic complex, a ligand in which a (hetero)aryl group and pyridine, pyrazole, phenanthroline, etc. are linked, such as a (hetero)arylpyridine ligand and a (hetero)arylpyrazole ligand, is preferable. Particularly preferred are phenylpyridine ligands and phenylpyrazole ligands. Here, the (hetero)aryl group represents at least one of an aryl group and a heteroaryl group.

Preferred phosphorescent materials include tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine)platinum, and tris(2-phenylpyridine)platinum. Examples include phenylpyridine complexes such as -phenylpyridine) osmium and tris(2-phenylpyridine)rhenium, and porphyrin complexes such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethylpalladium porphyrin, and octaphenylpalladium porphyrin.

Polymer-based luminescent materials include poly(9,9-dioctylfluorene-2,7-diyl), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'- (N-(4-sec-butylphenyl))diphenylamine)], poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-2{2,1'-3 }-triazole)], and polyphenylene vinylene materials such as poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene].

In the organic electroluminescent device of the present invention, the luminescent material contained in the luminescent layer 5 is preferably a luminescent low-molecular compound because the half-width is narrow and bright luminescence can be obtained.
The light-emitting low-molecular compound is preferably a light-emitting low-molecular compound having a molecular weight of 5,000 or less, particularly 3,000 or less, for example about 100 to 2,000, and specifically includes the above-mentioned fluorescent materials and phosphorescent materials.
Any one type of these light-emitting low molecular weight compounds may be used alone, or two or more types may be used in any combination and ratio.

(Charge transporting material)
The charge transporting material is a material having a property of transporting positive charges (holes) or negative charges (electrons), and is not particularly limited as long as it does not impair the effects of the present invention, and known materials can be used.
As the charge transporting material, compounds conventionally used in the light-emitting layer 5 of organic electroluminescent devices can be used, and compounds used as the host material of the light-emitting layer 5 are particularly preferred.
Specific examples of the charge transporting material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which tertiary amines are linked with fluorene groups. , hydrazone-based compounds, silazane-based compounds, silanamine-based compounds, phosphamine-based compounds, quinacridone-based compounds, and other compounds exemplified as hole-transporting compounds for the hole-injecting layer 3. Other examples include electron transporting compounds such as anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and silole compounds.

The charge transporting material includes two or more fused aromatic rings containing two or more tertiary amines represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl. Aromatic amine compounds having a starburst structure such as aromatic diamines substituted with nitrogen atoms (JP-A-5-234681), 4,4',4''-tris(1-naphthylphenylamino)triphenylamine, etc. (J. Lumin., Vol. 72-74, p. 985, 1997), Aromatic amine compound consisting of triphenylamine tetramer (Chem. Commun., p. 2175, 1996), 2,2', Fluorene compounds such as 7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), 4,4'-N,N'- Compounds exemplified as hole-transporting compounds for the hole-transporting layer 4, such as carbazole-based compounds such as dicarbazole biphenyl, can also be preferably used. Others: 2-(4-biphenylyl)-5-(p-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), 2,5-bis(1-naphthyl)-1,3 , 4-oxadiazole (BND) and other oxadiazole compounds, 2,5-bis(6'-(2',2''-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole Also included are silole compounds such as (PyPySPyPy), phenanthroline compounds such as bathophenanthroline (BPhen), and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine).

The charge transporting material described above is preferably used in an amount of 1 to 100 times the weight of the luminescent material.

(Formation of light emitting layer 5 by wet film forming method)
In the organic electroluminescent device of the present invention, the luminescent material contained in the luminescent layer 5 is preferably a luminescent low-molecular compound because it can be easily purified to a high purity.
In the organic electroluminescent device of the present invention, it is preferable to form the light emitting layer 5 by a wet film forming method.

When forming a light-emitting layer by a wet film-forming method, a composition for forming a film (a composition for forming a light-emitting layer) is usually prepared by mixing the material that will become the light-emitting layer 5 with a soluble solvent (a solvent for the light-emitting layer). The composition for forming a light emitting layer is formed into a film by a wet film forming method on a layer corresponding to the lower layer of the light emitting layer 5, usually the hole transport layer 4 or the hole injection layer 3, and then dried. Let it form.

Examples of solvents for the light-emitting layer include aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxy Aromatic ether solvents such as benzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate , methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate and other aromatic ester solvents; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1,2,3,4- Aromatic hydrocarbon solvents such as tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene; Amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; n-decane, cyclohexane, ethylcyclohexane, Alkane solvents such as decalin and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohols such as cyclohexanol and cyclooctanol Solvents include aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fenchone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

In order to obtain a more uniform film, it is preferable that the solvent evaporate from the liquid film immediately after film formation at an appropriate rate. Therefore, the boiling point of the solvent used is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and usually 270°C or lower, preferably 250°C or lower, more preferably 230°C or lower.
The amount of the solvent to be used is arbitrary as long as it does not significantly impair the effects of the present invention, but the total content in the composition for forming a light emitting layer is preferably as large as possible from the viewpoint of ease of film formation due to its low viscosity. A lower value is preferable from the viewpoint of easy formation of a thick film. The content of the solvent in the luminescent layer forming composition is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably It is 99.9% by mass or less, particularly preferably 99% by mass or less.

As a method for removing the solvent after wet film formation, heating or reduced pressure can be used. As the heating means used in the heating method, a clean oven or a hot plate is preferable because heat is applied evenly to the entire film.
The heating temperature in the heating step is arbitrary as long as it does not significantly impair the effects of the present invention, but a higher temperature is preferred from the standpoint of shortening the drying time, and a lower temperature is preferred from the standpoint of causing less damage to the material. The upper limit of the heating temperature is usually 250°C or lower, preferably 200°C or lower, and more preferably 150°C or lower. The lower limit of the heating temperature is usually 30°C or higher, preferably 50°C or higher, and more preferably 80°C or higher. By setting it below the above upper limit, the temperature becomes lower than the heat resistance of commonly used charge transporting materials or phosphorescent materials, and decomposition and crystallization can be suppressed. By setting the heating temperature to the above lower limit or higher, it is possible to avoid prolonging the time required to remove the solvent. The heating time in the heating step is appropriately determined depending on the boiling point and vapor pressure of the solvent in the composition for forming a light emitting layer, the heat resistance of the material, and the heating conditions.

<Hole blocking layer 6>
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8, which will be described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.
The hole blocking layer 6 has the roles of blocking holes moving from the anode 2 from reaching the cathode 9 and efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. have The physical properties required of the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap, that is, a large difference between HOMO and LUMO, and an excited triplet level (T1 ) is high.

Examples of materials for the hole blocking layer 6 that satisfy these conditions include bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolate)aluminum. mixed ligand complexes such as bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum dinuclear metal complexes, distyrylbiphenyl derivatives, etc. triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (JP-A-11-242996), 7-41759) and phenanthroline derivatives such as bathocuproine (Japanese Patent Application Laid-open No. 10-79297). A compound having at least one pyridine ring substituted at the 2, 4, and 6 positions described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer 6.

There is no restriction on the method for forming the hole blocking layer 6, and it can be formed in the same manner as the method for forming the light emitting layer 5 described above.
The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

<Electron transport layer 7>
The electron transport layer 7 is provided between the light emitting layer 5 or the hole element layer 6 and the electron injection layer 8 for the purpose of further improving the current efficiency of the device.
The electron transport layer 7 is formed of a compound that can efficiently transport electrons injected from the cathode 9 toward the light emitting layer 5 between the electrodes to which an electric field is applied. The electron-transporting compound used in the electron-transporting layer 7 is one that has high electron injection efficiency from the cathode 9 or the electron-injecting layer 8, has high electron mobility, and can efficiently transport the injected electrons. It must be a compound.

Examples of electron-transporting compounds that meet these conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Application Laid-Open No. 194393/1983), metal complexes of 10-hydroxybenzo[h]quinoline, and oxa Diazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), Quinoxaline compound (JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N,N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous Examples include high quality silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

The film thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The electron transport layer 7 is formed in the same manner as the light emitting layer 5 by being laminated on the light emitting layer 5 or the hole blocking layer 6 by a wet film formation method or a vacuum evaporation method. Usually, a vacuum evaporation method is often used.

<Electron injection layer 8>
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.
In order to efficiently inject electrons, it is preferable to use a metal with a low work function as the material forming the electron injection layer 8. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium.
The thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

An extremely thin insulating film of LiF, MgF ₂ , Li ₂ O, Cs ₂ CO ₃ or the like with a film thickness of about 0.1 to 5 nm is inserted as an electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7. It is also an effective method to improve the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, Vol. 44, 1245, 1997; SID 04 Digest, 2004, 154).
Furthermore, organic electron transport materials such as nitrogen-containing heterocyclic compounds such as bathophenanthroline and metal complexes such as aluminum complexes of 8-hydroxyquinoline are doped with alkali metals such as sodium, potassium, cesium, lithium, and rubidium ( (described in JP-A No. 10-270171, JP-A No. 2002-100478, JP-A No. 2002-100482, etc.), it is possible to improve electron injection and transport properties and achieve both excellent film quality. preferable. The film thickness in this case is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 8 is formed by laminating the light emitting layer 5 or the hole blocking layer 6 or the electron transporting layer 7 thereon by a wet film formation method or a vacuum evaporation method in the same manner as the light emitting layer 5.
The details of the wet film forming method are the same as those for the light-emitting layer 5 described above.

<Cathode 9>
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side, such as the electron injection layer 8 or the light emitting layer 5. As the material for the cathode 9, it is possible to use the materials used for the anode 2, but in order to efficiently inject electrons, it is preferable to use a metal with a low work function, such as tin, magnesium, etc. , indium, calcium, aluminum, silver, or alloys thereof. Examples of the material for the cathode 9 include alloy electrodes with low work functions such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In terms of stability of the device, it is preferable to protect the cathode 9 made of a metal with a low work function by laminating a metal layer having a high work function and being stable against the atmosphere on the cathode 9. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.
The film thickness of the cathode is usually the same as that of the anode 2.

<Other constituent layers>
Although the above description has focused on the element having the layer structure shown in FIG. 1, the above-described elements may be used between the anode 2 and cathode 9 and the light-emitting layer 5 in the organic electroluminescent element according to the present embodiment, as long as the performance is not impaired. In addition to the layers described, it may have any other layers, and any layers other than the light-emitting layer 5 may be omitted.
For example, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light emitting layer 5 for the same purpose as the hole blocking layer 8. The electron blocking layer prevents electrons moving from the light-emitting layer 5 from reaching the hole-transporting layer 4, thereby increasing the probability of recombination with holes within the light-emitting layer 5 and reducing the generated excitons. It has the role of confining holes in the light emitting layer 5 and the role of efficiently transporting holes injected from the hole transport layer 4 toward the light emitting layer 5.
Properties required of the electron blocking layer include high hole transportability, a large energy gap, that is, a large difference between HOMO and LUMO, and a high excited triplet level (T1).

When the light-emitting layer 5 is formed by a wet film formation method, it is preferable to form the electron blocking layer by a wet film formation method as well, since this facilitates device manufacture.
For this reason, it is preferable that the electron blocking layer also has compatibility with wet film formation, and the material used for such an electron blocking layer is a copolymer of dioctylfluorene and triphenylamine (International Publication No. 2004/084260).

The structure is opposite to that shown in FIG. It is also possible to stack them in the order of 2. Furthermore, it is also possible to provide the organic electroluminescent element according to this embodiment between two substrates, at least one of which is highly transparent.

It is also possible to have a structure in which the layer structure shown in FIG. 1 is stacked in multiple stages, that is, a structure in which a plurality of light emitting units are stacked. In this case, it is preferable to use V ₂ O ₅ or the like as a charge generation layer instead of the interface layer between the stages, that is, between the light emitting units, since the barrier between the stages will be reduced, and this is more preferable from the viewpoint of luminous efficiency and driving voltage. The interfacial layer means two layers, for example, when the anode is ITO and the cathode is Al.
The present invention can be applied to any type of organic electroluminescent device, such as a single device, a device arranged in an array, or a structure in which an anode and a cathode are arranged in an XY matrix.

[Organic EL display]
The organic EL display of the present invention has the organic electroluminescent element of the present invention. There are no particular restrictions on the format or structure of the organic EL display, and it can be assembled using the organic electroluminescent device of the present invention according to a conventional method.
For example, the organic EL display of the present invention can be formed by the method described in "Organic EL Display" (Ohmsha, published August 20, 2004, written by Shizushi Tokito, Chihaya Adachi, and Hideyuki Murata). can do.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The present invention is not limited to the following examples, and the present invention can be implemented with arbitrary changes without departing from the gist thereof.

[Example 1]
As a composition for forming a hole injection layer, 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the following formula (P-1) and a hole transporting polymer compound represented by the following formula (HI-1) A composition was prepared in which 0.6% by mass of an electron-accepting compound was dissolved in phenylcyclohexane.

[Example 2]
As a composition for forming a hole injection layer, 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) and a hole transporting polymer compound represented by the above formula (HI-1) A composition was prepared in which 0.6% by mass of an electron-accepting compound was dissolved in anisole.

[Comparative example 1]
As a composition for forming a hole injection layer, 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) and a hole transporting polymer compound represented by the above formula (HI-1) A composition was prepared in which 0.6% by mass of an electron-accepting compound was dissolved in ethyl benzoate.

[Comparative example 2]
As a composition for forming a hole injection layer, a composition was prepared in which 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) was dissolved in phenylcyclohexane. .

[Measurement of absorbance]
The absorbance at a wavelength of 500 nm (absorbance (500)) and the absorbance at a wavelength of 800 nm (absorbance (800)) of the prepared composition for forming a hole injection layer were measured using a spectrophotometer U-3900H (manufactured by Hitachi). It was measured using
The measurement conditions were as follows.
Measurement condition:
Measurement mode: Wavelength scan Data mode: Abs
Starting wavelength: 1000nm
Ending wavelength: 200nm
Scan speed: 300nm/min
Sampling interval: 0.50nm
Slit: 5nm
Light source switching wavelength: 340nm
Cell length: 10mm
The organic solvent contained in each composition for forming a hole injection layer was used for the reference measurement.

The measured results are shown in Table 1.

As shown in the results in Table 1, the hole injection layer forming compositions of Examples 1 and 2 had an absorbance (500) of 0.2 or more, an absorbance (800) of 0.05 or more, and charge transport properties. It can be seen that a sufficient amount of cation radicals necessary for improvement are generated, the hole transportability is high, and it is possible to drive the organic electroluminescent device at low voltage and extend its life.
On the other hand, the hole injection layer forming compositions of Comparative Examples 1 and 2 had very small values of absorbance (500) and absorbance (800), and the amount of cation radicals generated was necessary for improving charge transport properties. Less is.

[Example 3]
A hole-only device (hereinafter referred to as HOD) was produced by the following method.
A transparent conductive film of indium tin oxide (ITO) deposited to a thickness of 50 nm on a glass substrate (manufactured by Geomatec, sputter-deposited film) was formed into a 2 mm wide film using ordinary photolithography technology and hydrochloric acid etching. The anode was formed by patterning into stripes. The substrate on which ITO was patterned was washed in the following order: ultrasonic cleaning with an aqueous surfactant solution, washing with ultrapure water, ultrasonic washing with ultrapure water, and washing with ultrapure water, and then dried with compressed air. Finally, ultraviolet ozone cleaning was performed.
As a composition for forming a hole injection layer, 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) and a hole transporting polymer compound represented by the above formula (HI-1) A composition was prepared in which 0.6% by mass of an electron-accepting compound was dissolved in phenylcyclohexane.
This solution was spin-coated on the substrate in the atmosphere and dried on a hot plate in the atmosphere at 95° C. for 30 minutes to form a uniform thin film with a thickness of 100 nm, which was used as a hole injection layer.

Next, a compound represented by the following formula (HT-1) was co-evaporated onto the hole injection layer at a rate of 1 Å/sec by vacuum evaporation to form a hole transport layer with a thickness of 40 nm.

Subsequently, a 2 mm wide striped shadow mask as a mask for cathode deposition was placed in close contact with the substrate so as to be perpendicular to the ITO stripe of the anode, and was placed in another vacuum deposition apparatus. Then, silver was heated with a molybdenum boat to form a silver layer with a thickness of 80 nm at a deposition rate of 1 to 8.6 Å/sec to form a cathode.
HOD was obtained in the manner described above.

[Example 4]
As a composition for forming a hole injection layer, 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) and a hole transporting polymer compound represented by the above formula (HI-1) HOD was produced in the same manner as in Example 3, except that a composition in which 0.6% by mass of the electron-accepting compound was dissolved in anisole instead of phenylcyclohexane was used.

[Comparative example 3]
As a composition for forming a hole injection layer, a composition in which 3.0% by mass of a hole transporting polymer compound having a repeating structure represented by the above formula (P-1) was dissolved in phenylcyclohexane was used. Except for the above, an HOD was produced in the same manner as in Example 3.

[HOD evaluation]
Regarding the HODs obtained in Examples 3 and 4 and Comparative Example 3, the voltage was measured when a current was applied so that the current density was 10 mA/cm ² .
The measurement results are shown in Table 2.

As shown in Table 2, the composition used in Comparative Example 3 has very small values of absorbance (500) and absorbance (800), as is clear from the absorbance measurement results of Comparative Example 2, and the charge transport Since the composition generates a small amount of cation radicals necessary for improving properties, it is difficult to drive the device at low voltage and extend its life.
In contrast, in Examples 3 and 4, low voltage driving is possible.

1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent element

Claims (8)

In a composition for an organic electroluminescent device containing an organic polymer compound having a repeating unit represented by the following formula (1) and an organic solvent, the absorbance at an optical path length of 10 mm and a wavelength of 500 nm is 0.2 or more; A composition for an organic electroluminescent device, characterized in that the absorbance at a wavelength of 800 nm and a wavelength of 800 nm is 0.05 or more.

[In formula (1),
Ar ⁵¹ is an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group in which a plurality of groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are connected.
Ar ⁵² is at least one selected from the group consisting of a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, or the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group. It is a divalent group in which one group is connected to a plurality of groups directly or via a linking group.
Ar ⁵¹ and Ar ⁵² may form a ring via a single bond or a connecting group.
Ar ⁵¹ and Ar ⁵² may have a substituent and/or a crosslinking group.
Ar ⁵² includes a partial structure represented by the following formula (2). ]

[In formula (2), R ⁶⁰¹ and R ⁶²¹ are each independently a hydrogen atom or an alkyl group which may have a substituent and/or a crosslinking group, and at least one of R ⁶⁰¹ and R ⁶²¹ is , an alkyl group which may have a substituent and/or a crosslinking group.
Ring Ar ⁶⁰¹ and ring Ar ⁶²¹ each independently contain a monocyclic or condensed divalent aromatic hydrocarbon group that may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group. It is a divalent aromatic heterocyclic group which is a monocyclic or condensed ring which may have one ring, and -* represents a bond with an adjacent atom. ] The ring Ar ⁶⁰¹ and the ring Ar ⁶²¹ are each independently a 1,4-phenylene group which may have a substituent and/or a crosslinking group, or one of the ring Ar ⁶⁰¹ and the ring Ar ⁶²¹ is One is a 1,4-phenylene group that may have a substituent and/or a crosslinking group, and the other is a 2,7-fluorenyl group that may have a substituent and/or a crosslinking group. The composition for an organic electroluminescent device according to claim 1, characterized in that: 3. The organic electroluminescent device according to claim 1, wherein the organic solvent contains at least one selected from the group consisting of an ether solvent, a ketone solvent, and a hydrocarbon solvent. Composition. The composition for an organic electroluminescent device according to any one of claims 1 to 3, wherein the absorption at wavelengths of 500 nm and 800 nm is derived from cation radical species. An organic electroluminescent device comprising a substrate, an anode, an organic layer, and a cathode provided on the substrate, wherein the organic layer is the organic electroluminescent device according to any one of claims 1 to 4. An organic electroluminescent device comprising an organic layer formed using a device composition. 6. The organic electroluminescent device according to claim 5, wherein the organic layer includes a light emitting layer, and the light emitting layer is formed by a wet film forming method. 7. The organic electroluminescent device according to claim 5, wherein the light-emitting layer contains a light-emitting low-molecular compound. An organic EL display comprising the organic electroluminescent device according to any one of claims 5 to 7.

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