JP2013181072A - Catalyst for producing charge transfer material for organic el - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for producing arylamines, in particular, producing a charge transfer material for organic EL, capable of obtaining a high yield in a relatively short time under mild conditions, which does not cause problems such as discoloration or the like.SOLUTION: A catalyst for producing a charge transfer material for organic EL to be used comprises a palladium compound and an amino-substituted phosphorus compound shown by formula (1), in formula (1), Rto Reach independently indicates a 1-6C alkyl group.

Description

  The present invention relates to a catalyst for producing a charge transport material for organic EL, a method for producing a charge transport material using the same, a composition for an organic electroluminescent element, an organic electroluminescent element, an organic EL display device, and organic EL lighting. .

In recent years, electroluminescent devices using organic thin films (that is, organic electroluminescent devices) have been developed. The organic thin film in the organic electroluminescent device includes a compound having a charge transporting property. For example, an arylamine compound or a triarylamine polymer (hereinafter referred to as “arylamines”) having a high hole mobility may be used. )It has been known.
As a method for producing such a compound having an arylamine skeleton, the Ullmann reaction in which an arylamine is synthesized from an aryl halide and an amine compound using a copper catalyst has been known (Non-patent Document 1, Patent). Reference 1).

  Patent Document 2 reports a technique for synthesizing arylamines using a catalyst composed of a phosphorus compound such as trialkylphosphine and triarylphosphine and a palladium compound.

Chem. Lett. , Pp. 1145 to 1148, 1989

US Pat. No. 4,764,625 Patent No. 4207243

However, the Ullmann reaction represented by Patent Document 1 has a problem that a large amount of copper catalyst is used, a high temperature of 150 ° C. or more and a long reaction time are required, and the reaction yield is low. There is also a problem in terms of the environment in that a copper catalyst is used. Furthermore, by-products such as coloring impurities may be generated.
In addition, although the method of Patent Document 2 can certainly synthesize arylamines with high yield and high selectivity, the phosphorus compound used in this method is easily deactivated by oxygen, moisture, etc. There is a problem that is complicated.

  The present invention provides a catalyst for producing arylamines, particularly a catalyst for producing a charge transport material for organic EL, which can obtain a high yield in a relatively short time under mild conditions and does not cause problems such as coloring. This is the issue.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by using a specific catalyst in the production of arylamines, and have completed the present invention. That is, the present invention is as follows.
[1] A catalyst for producing a charge transport material for organic EL, comprising a palladium compound and an amino-substituted phosphorus compound having a structure represented by the following formula (1).

(In Formula (1), R < ₁ > -R < ₃ > shows a C1-C6 alkyl group each independently.)
[2] A catalyst for producing a charge transport material for organic EL, wherein the amino-substituted phosphorus compound of formula (1) is represented by formula (2).

[3] palladium _{compound, Pd (Oac) 2, Pd} (acac) 2, (CH 3 CN) 2 Pd (NO 2) Cl, 3 and _{(C 10 H 8 N 2)} 2PdCl 2, Pd 2 (dba) A catalyst for producing a charge transport material for organic EL, which is at least one selected from the group consisting of PdCl ₂ .
[4] A method for producing a charge transport material for organic EL, comprising reacting an aryl compound and an amine compound in the presence of a base using the catalyst.

[5] The method for producing a charge transport material for an organic EL, wherein the base is tertiary butoxy sodium.
[6] A charge transport material for organic EL produced by the production method.
[7] A composition for an organic electroluminescence device comprising the charge transport material for organic EL and a solvent.

[8] In an organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate,
An organic electroluminescence device, wherein the organic layer includes a layer formed by wet film formation using the composition for organic electroluminescence device.
[9] The organic electroluminescent element, wherein the layer formed by the wet film formation is a hole injection layer and / or a hole transport layer.

[10] The organic layer includes a hole injection layer, a hole transport layer, and a light emitting layer, and all of the hole injection layer, the hole transport layer, and the light emitting layer are formed by wet film formation. The organic electroluminescent element according to claim 7 or 8, wherein
[11] An organic EL display device including the organic electroluminescent element.
[12] Organic EL illumination including the organic electroluminescent element.

  According to the present invention, arylamines can be synthesized in a relatively short time under mild conditions without using a large amount of copper catalyst. Further, the synthesis work is not complicated, the synthesis can be carried out with high selectivity and high yield, and there are few impurities such as coloring substances.

It is typical sectional drawing which shows an example of embodiment of the organic electroluminescent element of this invention.

Embodiments of the present invention will be described below. However, the description of the constituent elements described below is an example of embodiments of the present invention, and the present invention is not limited to these contents as long as the gist thereof is not exceeded.
[Catalyst for manufacturing charge transport material for organic EL]
The catalyst of the present invention is a catalyst for producing a charge transport material for organic EL, more specifically, a catalyst used for synthesizing arylamines.

  The catalyst is composed of a palladium compound and an amino-substituted phosphorus compound having a structure represented by the following formula (1).

(In Formula (1), R < ₁ > -R < ₃ > shows a C1-C6 alkyl group each independently.)
Here, examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tertiary butyl group, propyl group, neopentyl group, and hexyl group. From the viewpoint of reactivity, a methyl group, an isobutyl group, and a neopentyl group are particularly preferable.

  More preferred is an amino-substituted phosphorus compound represented by the formula (2).

Examples of the palladium compound include Pd (Oac) ₂ , Pd (acac) ₂ , (CH ₃ CN) ₂ Pd (NO ₂ ) Cl, (C ₁₀ H ₈ N ₂ ) ₂ PdCl ₂ , Pd ₂ (dba). ₃ , PdCl _{2 and the} like. Here, “Oac” means acetonato, “acac” means acetriacetonato, and “dba” means 1,5-diphenyl-1,4-pentadiene-3-nat. The palladium compound is preferably Pd ₂ (dba) ₃ .

[Method for producing charge transport material for organic EL]
A charge transport material for organic EL is produced by reacting an aryl compound and an amine compound in the presence of a base using the above-described catalyst.
Here, the amount of the amino-substituted phosphorus compound used as a catalyst is preferably 10 to 2000% by weight, particularly preferably 50 to 1000% by weight, based on the palladium compound.

The solvent used in the reaction is appropriately selected, and examples thereof include benzene, toluene, xylene, 1,4-dioxane and the like.
The reaction conditions may be any reaction under normal pressure or increased pressure, and the reaction temperature is preferably 50 to 200 ° C. The reaction time varies depending on the raw material, catalyst, base and the like used, but is preferably completed in about 2 minutes to 20 hours.

  The base to be used is preferably a strong base, such as metal alkoxide, potassium carbonate, tripotassium phosphate and the like. Examples of the metal alkoxide include alkali metal and alkaline earth metal alkoxides. Examples of the alkali metal alkoxide include lithium methoxide, sodium methoxide, potassium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, lithium- Examples include isopropoxide, sodium-isopropoxide, potassium-isopropoxide, lithium-tertiary butoxide, sodium-tertiary butoxide, potassium-tertiary butoxide and the like.

Examples of the alkaline earth metal alkoxide include magnesium di (methoxide), magnesium di (ethoxide), magnesium di (isopropoxide), magnesium di (potassium-tertiary butoxide), and the like.
Among these bases, alkali metal alkoxides are preferable, and tertiary butoxy sodium is particularly preferable from the viewpoint of yield improvement.
The aryl compound and amine compound that are the raw materials for the synthesis of arylamines can be variously selected depending on the synthesis object.
As an example, arylamines as synthesis objects will be exemplified below, but the present invention is not limited to the synthesis method of these examples.

[Arylamines]
The polymer exemplified here includes a repeating unit represented by the following general formula (1) and has a crosslinkable group.

(In general formula (1),
Ar ^{11 to} Ar ¹³ each independently represents a divalent aromatic group which may have a substituent,
Ar ¹⁴ and Ar ¹⁵ each independently represent an aromatic group which may have a substituent,
Ar ¹⁶ and Ar ¹⁷ each independently represents a direct bond or a divalent aromatic group which may have a substituent,
R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aromatic group which may have a substituent. Indicate
r shows the integer of 0-5.

R ¹¹ and R ¹² may be bonded to each other to form a ring structure.
In addition, the crosslinkable group may be contained in the repeating unit represented by the general formula (1). )
The repeating unit represented by the general formula (1) has only one alkylene group (preferably a quaternary carbon-containing alkylene group). Thus, the main chain contains a non-rigid alkylene group (preferably a quaternary carbon-containing alkylene group), so that even after the polymer is cross-linked and insoluble in an organic solvent, high charge transporting ability and redox Stability can be maintained. In addition, since the main chain contains an alkylene group (preferably a quaternary carbon-containing alkylene group) that suppresses the spread of the π-conjugated system, the singlet excited level after the polymer is crosslinked and insoluble in an organic solvent. In addition, the triplet excited level can be kept high. For this reason, when a layer is formed of a network polymer obtained by crosslinking the present polymer, the layer passes a current even at a low voltage and hardly excites excitons.

In the polymer having a repeating unit represented by the general formula (1), a nitrogen atom is always present between an alkylene group (preferably a quaternary carbon-containing alkylene group) and an alkylene group (preferably a quaternary carbon-containing alkylene group). Exists. For this reason, any of Ar ^{11 to} Ar ¹⁷ can be involved in hole transport. As a result, it is considered that the organic electroluminescent element can be driven with a low voltage.

In the general formula (1), Ar ^{11 to} Ar ¹³ each independently represent a divalent aromatic group which may have a substituent, and Ar ¹⁴ and Ar ¹⁵ each independently have a substituent. Ar ¹⁶ and Ar ¹⁷ each independently represent a direct bond or a divalent aromatic group which may have a substituent.
Here, the “aromatic group” is a general term for an aromatic hydrocarbon group and an aromatic heterocyclic group.

Examples of the monovalent or divalent aromatic hydrocarbon group which may have a substituent constituting Ar ^{11 to} Ar ¹⁷ include, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, and a tetracene ring. , Pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, groups derived from 2 to 5 condensed rings such as fluoranthene ring, fluorene ring, etc., and 2 to 4 of these rings are bonded And the like.

Examples of the monovalent or divalent aromatic heterocyclic group optionally having a substituent constituting Ar ^{11 to} Ar ¹⁷ include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, and a pyrazole. Ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzo Isothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, Quinazolinone Examples thereof include a group derived from a 5- or 6-membered monocyclic ring or a 2-4 condensed ring, such as a ring or an azulene ring, and a group in which 2 to 4 of these rings are bonded.

Ar ^{11 to} Ar ¹⁷ also include groups in which 2 to 4 aromatic hydrocarbon groups and aromatic heterocyclic groups are bonded.
Among them, Ar ^{11 to} Ar ¹⁷ are selected from the group consisting of a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a triphenylene ring, a pyrene ring, a thiophene ring, a pyridine ring, and a fluorene ring from the viewpoint of solubility and heat resistance. A group derived from a ring and a group in which 2 to 4 of these rings are bonded are preferable.

Furthermore, the substituent that the aromatic group in Ar ^{11 to} Ar ¹⁷ may have is not particularly limited, and examples thereof include a group selected from the substituent group Z described later.
Ar ^{11 to} Ar ¹⁷ may have one substituent or two or more. When it has two or more, you may have one type and may have two or more types by arbitrary combinations and arbitrary ratios.

R ¹¹ and R ¹² are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aromatic group which may have a substituent. Indicates.
Examples of the alkyl group represented by R ¹¹ and R ¹² include alkyl groups having usually 1 or more, usually 24 or less, preferably 12 or less, such as a methyl group or an ethyl group.
Examples of the alkoxy group of R ¹¹ and R ¹² include an alkoxy group having usually 1 or more, usually 24 or less, preferably 12 or less, such as a methoxy group or an ethoxy group.

Examples of the aromatic group of R ¹¹ and R ¹² include the same groups as the aromatic groups constituting the Ar ^{14 to} Ar ¹⁵ .
R ¹¹ and R ¹² are preferably groups other than a hydrogen atom among the above groups from the viewpoint of having a quaternary carbon, and among them, from the viewpoint of solubility, an alkyl group having 1 to 12 carbon atoms and 1 to 1 carbon atoms are preferable. 12 alkoxy groups are preferable, and a C1-C12 alkyl group is more preferable.
As the R ¹¹ to R ¹² is a substituent which may have, it is not particularly limited, for example, include groups selected from Substituent Group Z.

(Substituent group Z)
For example, an alkyl group, such as a methyl group or an ethyl group, having usually 1 or more carbon atoms and usually 24 or less, preferably 12 or less;
An alkenyl group having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less, such as a vinyl group;
An alkynyl group such as an ethynyl group, which usually has 2 or more carbon atoms and is usually 24 or less, preferably 12 or less;
For example, an alkoxy group having a carbon number of usually 1 or more and usually 24 or less, preferably 12 or less, such as a methoxy group or an ethoxy group;
For example, an aryloxy group having usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24, such as a phenoxy group, a naphthoxy group, or a pyridyloxy group;
For example, an alkoxycarbonyl group having 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methoxycarbonyl group or an ethoxycarbonyl group;
For example, a dialkylamino group having 2 or more carbon atoms and usually 24 or less, preferably 12 or less, such as a dimethylamino group or a diethylamino group;

For example, a diarylamino group having a carbon number of usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less, such as a diphenylamino group, a ditolylamino group, or an N-carbazolyl group;
An arylalkylamino group having usually 7 carbon atoms, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
For example, an acetyl group, a benzoyl group, etc., an acyl group having usually 2 carbon atoms and usually having 24 or less, preferably 12;
For example, a halogen atom such as a fluorine atom or a chlorine atom;
A haloalkyl group having usually 1 or more and usually 12 or less, preferably 6 or less, such as a trifluoromethyl group;
For example, the number of carbon atoms is usually 1 or more, such as methylthio group or ethylthio group, usually 24 or less,
Preferably 12 or less alkylthio groups;
For example, an arylthio group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, or a pyridylthio group;
For example, a silyl group having a carbon number of usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as a trimethylsilyl group or a triphenylsilyl group;

For example, a siloxy group having 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as trimethylsiloxy group or triphenylsiloxy group;
A cyano group;
For example, an aromatic hydrocarbon ring group having usually 6 or more carbon atoms and usually 36 or less, preferably 24 or less, such as a phenyl group or a naphthyl group;
For example, an aromatic heterocyclic group having 3 or more, preferably 4 or more, usually 36 or less, preferably 24 or less, such as thienyl group or pyridyl group.

Among these substituents, an alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms are preferable from the viewpoint of solubility.
Moreover, each said substituent may have a substituent further, The group etc. which were illustrated to the said substituent group Z etc. are mentioned as the example.
The formula weight of the substituents of Ar ^{11 to} Ar ¹⁷ is preferably 500 or less, more preferably 250 or less, including further substituted substituents. If the formula weight of the substituent is too large, the charge transport ability may be reduced.

The formula weight of Ar ^{11 to} Ar ¹⁷ is usually 65 or more, preferably 75 or more, and is usually 500 or less, preferably 300 or less, more preferably 200 or less. If the formula amount of Ar ^{11 to} Ar ¹⁷ is too large, the solubility before crosslinking may be significantly reduced.
In the general formula (1), r represents the number of repetitions of —Ar ¹³ —N (Ar ¹⁵ ) —. Specifically, r is 0 or more, preferably 1 or more, more preferably 2 or more, and usually represents an integer of 5 or less, preferably 4 or less, more preferably 3 or less. If r is too large, the solubility before the crosslinking reaction may be lowered. Further, by setting r to 1 or more, electrical durability can be ensured.

Ar ^{11 to} Ar ¹³ , Ar ¹⁶ and Ar ¹⁷ may be a group in which two or more monovalent or divalent aromatic groups which may have a substituent are bonded. Examples of such a group include a biphenylene group, a terphenylene group, and the like, and a 4,4′-biphenylene group is preferable from the viewpoint of solubility before crosslinking reaction, charge transport ability, electrical durability, and the like.
The polymer must have a crosslinkable group, and the difference in solubility in a solvent before and after the reaction (insolubilization reaction) caused by irradiation with heat and / or active energy rays due to the presence of the crosslinkable group. Can be generated.

A crosslinkable group refers to a group that reacts with the same or different groups of other molecules located nearby by irradiation with heat and / or active energy rays to form a new chemical bond.
Examples of the crosslinkable group include groups shown in the crosslinkable group group T in that it is easily insolubilized. The crosslinkable group is not limited to these.
[Crosslinkable group T]

(In the above formula, R ^{21 to} R ²³ each independently represents a hydrogen atom or an alkyl group which may have a substituent. Ar ²¹ represents an aromatic group which may have a substituent. .
X ¹ , X ² and X ³ each independently represent a hydrogen atom or a halogen atom.
R ²⁴ represents a hydrogen atom or a vinyl group.
The benzocyclobutene ring may have a substituent, and the substituents may be bonded to each other to form a ring. )
Examples of the alkyl group of R ^{21 to} R ²³ include alkyl groups having usually 1 or more, usually 24 or less, preferably 12 or less, such as a methyl group or an ethyl group.

Examples of the aromatic group of Ar ²¹ include the same groups as the aromatic groups constituting the Ar ^{11 to} Ar ¹⁷ .
As the R ²¹ to R ^23, and Ar ²¹ is a substituent which may have, it is not particularly limited, for example, such as a group selected from the substituent group Z can be mentioned.
A group that undergoes insolubilization reaction by cationic polymerization such as a cyclic ether group such as an epoxy group or an oxetane group, or a vinyl ether group is preferred in terms of high reactivity and easy insolubilization. Among these, an oxetane group is particularly preferable from the viewpoint that the rate of cationic polymerization can be easily controlled, and a vinyl ether group is preferable from the viewpoint that a hydroxyl group that may cause deterioration of the device during the cationic polymerization is hardly generated.

A group that undergoes a cycloaddition reaction, such as an arylvinylcarbonyl group such as a cinnamoyl group, or a group derived from a benzocyclobutene ring, is preferred in terms of further improving electrochemical stability.
Of the crosslinkable groups, a group derived from a benzocyclobutene ring is particularly preferable in that the structure after insolubilization is particularly stable.
Specifically, a group represented by the following formula (II) is preferable.

(The benzocyclobutene ring in formula (II) may have a substituent. The substituents may be bonded to each other to form a ring.)
The crosslinkable group may be directly bonded to a monovalent or divalent aromatic group in the molecule, or may be bonded via a divalent group. As the divalent group, a group selected from an —O— group, a —C (═O) — group, or an (optionally substituted) —CH ₂ — group may be selected from 1 to 30 in any order. It is preferable to bind to a monovalent or divalent aromatic group via a divalent group formed by individual linking. Specific examples of the crosslinkable group via these divalent groups, that is, a group containing a crosslinkable group, are as shown in the following <Group T ′ containing crosslinkable group>.
<Group T ′ containing crosslinkable group>

(In the above formula, m represents an integer of 0 to 12, and n represents an integer of 1 to 12.)
Specific examples of the group containing these crosslinkable groups include the following.

(Ratio of crosslinkable groups)
In the present polymer, the crosslinkable groups in one polymer chain are preferably 1 or more on average, more preferably 2 or more on average, and preferably 200 or less on average, more preferably 100 or less on average.
In addition, the crosslinkable group may be contained in any one of Ar ^{11 to} Ar ¹⁷ , R ¹¹ and R ^{12 in} the repeating unit represented by the general formula (1). It may be contained in polymer partial structures other than Formula (1), and may be further contained in any.

The number of crosslinkable groups possessed by the present polymer can be expressed by the number per 1000 molecular weight.
When the number of crosslinkable groups possessed by the present polymer is expressed by the number per 1000 molecular weight, the molecular weight is 1
Per 000, it is usually 3.0 or less, preferably 2.0 or less, more preferably 1.0 or less, and usually 0.01 or more, preferably 0.05 or more.

If this upper limit is exceeded, a flat film cannot be obtained due to cracks, or the crosslinking density becomes too high, resulting in an increase in the number of unreacted crosslinking groups in the crosslinked layer, resulting in the lifetime of the resulting device. May have an effect. On the other hand, if the lower limit value is not reached, insolubilization of the crosslinked layer becomes insufficient, and there is a possibility that a multilayer laminated structure cannot be formed by a wet film forming method.
Here, the number of crosslinkable groups per 1000 molecular weight of the conjugated polymer is calculated from the molar ratio of charged monomers at the time of synthesis and the structural formula, excluding the end groups from the conjugated polymer.

  For example, the case of the target polymer 1 synthesized in Synthesis Example 1 described later will be described.

In the target polymer 1, the molecular weight of the repeating unit excluding the terminal group is 1219.2 on average, and the average number of crosslinkable groups is 0.1076 per repeating unit. When this is calculated by simple proportion, the number of crosslinkable groups per 1000 molecular weight is calculated as 0.088.
The weight average molecular weight (Mw) of the present polymer is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 200,000 or less, and usually 1 5,000 or more, preferably 2,500 or more, more preferably 5,000 or more, and further preferably 20,000 or more.

When the weight average molecular weight exceeds this upper limit, the solubility in a solvent is lowered, so that the film formability may be impaired. On the other hand, if the weight average molecular weight is below this lower limit, the glass transition temperature, melting point and vaporization temperature of the polymer will decrease, and the heat resistance may decrease.
In general, the weight average molecular weight (Mw) 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, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

The number average molecular weight (Mn) in the present polymer is usually 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, and usually 500 or more, preferably 1,500 or more. More preferably, it is 3,000 or more.
Furthermore, the dispersity (Mw / Mn) in the present polymer is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less.

Since the degree of dispersion is preferably as small as possible, the lower limit is ideally 1. When the degree of dispersion of the polymer is within the above range, purification is easy, and solubility in a solvent and charge transporting ability are good.
Examples of repeating units having a partial structure represented by the general formula (1) are shown below.

  Examples of the repeating unit having a crosslinkable group are shown below.

The glass transition temperature of the present polymer is usually 50 ° C. or higher, 80 ° C. or higher, more preferably 100 ° C. or higher, and usually 300 ° C. or lower.
Within the above range, the heat resistance of the polymer is excellent, and the drive life of the resulting element is preferable.
The ionization potential of the present polymer is usually 4.5 eV or more, preferably 4.8 eV or more, and usually 6.0 eV or less, preferably 5.7 eV or less.

Within the above range, the polymer is excellent in charge injecting and transporting ability, and the driving voltage of the resulting device is preferable.
[Specific example of manufacturing method]
In the case of the polymerization method by the Ullmann reaction and the polymerization method by the Buchwald-Hartwig reaction, for example, an aryl halide having the formula (1a) (X represents a halogen atom such as I, Br, Cl, F, etc.) and a formula ( This polymer is synthesized by reacting with the primary aminoaryl or secondary diaminoaryl represented by 2a).

(In the above formula, X represents a halogen atom, and Ar ^{11 to} Ar ¹⁵ , R ¹¹ , R ¹² , and r have the same meaning as in the general formula (1), provided that q is 1).
In the above polymerization method, the reaction for forming an N-aryl bond is usually carried out in the presence of a base such as tert-butoxy sodium. Moreover, it carries out in presence of transition metal catalysts, such as the palladium complex of this invention.

[Charge transport material for organic EL]
Arylamines produced using the catalyst of the present invention are used as charge transport materials for organic EL.
The charge transport material for organic EL is preferably used as a material for forming a hole injection layer and / or a hole transport layer in an organic electroluminescent device. Moreover, it may contain one type of the charge transport material, or may contain two or more types in any combination and in any ratio.

  When forming the hole injection layer and / or hole transport layer of the organic electroluminescence device using the charge transport material for organic EL, the content of the charge transport material in the hole injection layer and / or hole transport layer is In general, it is 1 to 100% by weight, preferably 5 to 100% by weight, and more preferably 10 to 100% by weight. The above range is preferable because the charge transport property of the hole injection layer and / or the hole transport layer is improved, the drive voltage is reduced, and the drive stability is improved.

Moreover, since an organic electroluminescent element can be manufactured simply, it is preferable to use the charge transport material for organic EL for the organic layer formed by a wet film-forming method.
[Composition for organic electroluminescence device]
The composition for organic electroluminescent elements of the present invention contains a charge transport material for organic EL. In addition, the composition for organic electroluminescent elements of the present invention may contain one type of charge transport material for organic EL, or may contain two or more types in any combination and in any ratio. Also good.

{Content of charge transport material for organic EL}
The content of the charge transport material for organic EL in the composition for organic electroluminescence device of the present invention is usually 0.01 to 70% by weight, preferably 0.1 to 60% by weight, more preferably 0.5 to 50%. % By weight.
Within the above range, it is preferable because defects are hardly generated in the formed organic layer and unevenness in film thickness is hardly generated.

{solvent}
The composition for organic electroluminescent elements of the present invention usually contains a solvent. This solvent is preferably one that dissolves the charge transport material for organic EL. Specifically, a solvent capable of dissolving 0.05% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more is suitable for the charge transport material for organic EL.

  Examples of solvents include: aromatic solvents such as toluene, xylene, methicylene, cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene Aliphatic ethers such as glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, Ether solvents such as aromatic ethers such as 2,3-dimethylanisole and 2,4-dimethylanisole; aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate, propylene Organic solvent such as ester solvents such as aromatic esters such as phenyl acid, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, n-butyl benzoate; And organic solvents used in the composition for forming a hole and the composition for forming a hole transport layer. In addition, 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and arbitrary ratios.

Among them, as a solvent contained in the composition for organic electroluminescent elements of the present invention, a solvent having a surface tension at 20 ° C. of usually less than 40 dyn / cm, preferably 36 dyn / cm or less, more preferably 33 dyn / cm or less. Is preferred.
When the organic electroluminescent element composition of the present invention is used to form a coating film by a wet film forming method and the organic EL charge transport material is crosslinked to form an organic layer, the compatibility with the base is high. preferable. This is because the uniformity of film quality greatly affects the uniformity and stability of light emission of the organic electroluminescence device. Therefore, the composition for organic electroluminescent elements used for the wet film-forming method is required to have a low surface tension so that a uniform coating film with higher leveling property can be formed. Therefore, it is preferable to use a solvent having a low surface tension as described above, whereby a uniform layer containing the charge transport material for organic EL can be formed, and a uniform crosslinked layer can be formed.

  Specific examples of the low surface tension solvent include the above-mentioned aromatic solvents such as toluene, xylene, methicylene, cyclohexylbenzene, ester solvents such as ethyl benzoate, ether solvents such as anisole, trifluoromethoxyanisole, penta Examples include fluoromethoxybenzene, 3- (trifluoromethyl) anisole, ethyl (pentafluorobenzoate), and the like.

  On the other hand, as a solvent contained in the composition for organic electroluminescent elements of the present invention, a solvent having a vapor pressure at 25 ° C. of usually 10 mmHg or less, preferably 5 mmHg or less, and usually 0.1 mmHg or more is preferable. . By using such a solvent, it is possible to prepare a composition for an organic electroluminescent device suitable for a process for producing an organic electroluminescent device by a wet film forming method and suitable for the properties of a charge transport material for organic EL. it can.

Specific examples of such a solvent include the above-described aromatic solvents such as toluene, xylene, and methicylene, ether solvents, and ester solvents.
By the way, moisture may cause deterioration of the performance of the organic electroluminescent element, and in particular, may promote a decrease in luminance during continuous driving. Therefore, in order to reduce moisture remaining during wet film formation as much as possible, among the above solvents, those having a water solubility at 25 ° C. of preferably 1% by weight or less are preferred, and solvents having a water content of 0.1% by weight or less Is more preferable.

The content of the solvent contained in the composition for organic electroluminescent elements of the present invention is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and particularly preferably 80% by weight or more. . When the content of the solvent is not less than the above lower limit, the flatness and uniformity of the formed layer can be improved.
<Electron-accepting compound>
When the composition for organic electroluminescent elements of the present invention is used for forming a hole injection layer, it is preferable to further contain an electron-accepting compound from the viewpoint of reducing resistance.

As the electron-accepting compound, a compound having an oxidizing power and an ability to accept one electron from the charge transport material of the present invention is preferable. Specifically, a compound with an electron affinity of 4 eV or more is preferable, and a compound with a compound of 5 eV or more is more preferable.
Examples of such electron-accepting compounds include triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. Examples thereof include one or more compounds selected from the group. Specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (International Publication No. 2005/089024); High valence inorganic compounds such as iron (III) (Japanese Patent Laid-Open No. 11-251067) and ammonium peroxodisulfate; Cyano compounds such as tetracyanoethylene; Tris (pendafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365) Aromatic boron compounds such as: fullerene derivatives and iodine.

  Such a compound is preferably an ionic compound having a structure in which at least one organic group is bonded to an element belonging to Groups 15 to 17 of the periodic table with a carbon atom. In particular, the following formula (I-1) It is preferable that it is a compound represented by these.

In formula (I-1), R ¹¹ represents an organic group bonded to A ¹ by a carbon atom, and R ¹² represents an arbitrary substituent. R ¹¹ and R ¹² may be bonded to each other to form a ring.
The type of R ¹¹ is not particularly limited as long as it is an organic group having a carbon atom at the bonding portion with A ¹ unless it is contrary to the gist of the present invention. The molecular weight of R ¹¹ is a value including a substituent and is usually 1000 or less, preferably 500 or less.

Preferable examples of R ¹¹ include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group from the viewpoint of delocalizing the positive charge. Among them, an aromatic hydrocarbon ring group or an aromatic heterocyclic group is preferable because it delocalizes positive charges and is thermally stable.
The aromatic hydrocarbon ring group is a 5- or 6-membered monocyclic ring or 2 to 5 condensed ring having one free valence, and a group that can delocalize a positive charge on the group. Can be mentioned. Specific examples thereof include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring and fluorene ring having one free valence. Etc.

Examples of the aromatic heterocyclic group include a group having a single free valence, which is a 5- or 6-membered monocyclic ring or a 2-4 condensed ring and in which a positive charge is more delocalized on the group. It is done. Specific examples thereof include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, an indole ring, and a carbazole ring having one free valence. , Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine Ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

Examples of the alkyl group include linear, branched, or cyclic alkyl groups having a carbon number of usually 1 or more and usually 12 or less, preferably 6 or less. Specific examples include methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group and the like.
Examples of the alkenyl group include those having usually 2 or more, usually 12 or less, preferably 6 or less. Specific examples include a vinyl group, an allyl group, and a 1-butenyl group.

Examples of the alkynyl group include those having usually 2 or more, usually 12 or less, preferably 6 or less. Specific examples include ethynyl group and propargyl group.
R ¹² is not particularly limited as long as it is not contrary to the gist of the present invention. The molecular weight of R ¹² is a value including a substituent and is usually 1000 or less, preferably 500 or less.
Examples of R ¹² include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, Examples thereof include an alkylcarbonyloxy group, an alkylthio group, an arylthio group, a sulfonyl group, an alkylsulfonyl group, an arylsulfonyl group, a cyano group, a hydroxyl group, a thiol group, and a silyl group.

Among them, like R ¹¹ , an organic group having a carbon atom at the bonding portion to A ¹ is preferable because of its high electron accepting property. Examples thereof include an alkyl group, an alkenyl group, an alkynyl group, and an aromatic hydrocarbon ring group. An aromatic heterocyclic group is preferred. In particular, an aromatic hydrocarbon ring group or an aromatic heterocyclic group is preferable because it has a large electron accepting property and is thermally stable.
Alkyl group R ^12, an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring group, the aromatic heterocyclic group include the same as those described for R ¹¹ above.

Examples of the amino group include an alkylamino group, an arylamino group, and an acylamino group.
Examples of the alkylamino group include alkylamino groups having one or more alkyl groups usually having 1 or more carbon atoms and usually 12 or less, preferably 6 or less carbon atoms. Specific examples include methylamino group, dimethylamino group, diethylamino group, dibenzylamino group and the like.

As the arylamino group, an arylamino group having at least one aromatic hydrocarbon ring group or aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less is used. Can be mentioned. Specific examples include phenylamino group, diphenylamino group, tolylamino group, pyridylamino group, thienylamino group and the like.
The acylamino group includes an acylamino group having one or more acyl groups having usually 2 or more carbon atoms and usually 25 or less, preferably 15 or less carbon atoms. Specific examples include an acetylamino group and a benzoylamino group.

The alkoxy group includes an alkoxy group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less. Specific examples include a methoxy group, an ethoxy group, and a butoxy group.
Examples of the aryloxy group include an aryloxy group having an aromatic hydrocarbon ring group or an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples include phenyloxy group, naphthyloxy group, pyridyloxy group, thienyloxy group and the like.

Examples of the acyl group include acyl groups having usually 1 or more carbon atoms and usually 25 or less, preferably 15 or less. Specific examples include formyl group, acetyl group, benzoyl group and the like.
The alkoxycarbonyl group includes an alkoxycarbonyl group having usually 2 or more carbon atoms and usually 10 or less, preferably 7 or less. Specific examples include a methoxycarbonyl group and an ethoxycarbonyl group.

Examples of the aryloxycarbonyl group include those having an aromatic hydrocarbon ring group or an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples include a phenoxycarbonyl group and a pyridyloxycarbonyl group.
Examples of the alkylcarbonyloxy group include alkylcarbonyloxy groups having usually 2 or more carbon atoms and usually 10 or less, preferably 7 or less. Specific examples include an acetoxy group and a trifluoroacetoxy group.

The alkylthio group includes an alkylthio group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less. Specific examples include a methylthio group and an ethylthio group.
The arylthio group includes an arylthio group having usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 14 or less. Specific examples include a phenylthio group, a naphthylthio group, and a pyridylthio group.

Specific examples of the alkylsulfonyl group and the arylsulfonyl group include a mesyl group and a tosyl group.
Specific examples of the sulfonyloxy group include a mesyloxy group and a tosyloxy group.
Specific examples of the silyl group include a trimethylsilyl group and a triphenylsilyl group.

As described above, the groups exemplified as R ¹¹ and R ¹² may be further substituted with other substituents as long as not departing from the spirit of the present invention. The type of the substituent is not particularly limited, and examples thereof include a halogen atom, a cyano group, a thiocyano group, and a nitro group, in addition to the groups exemplified as R ¹¹ and R ¹² . Among them, from the viewpoint of not hindering the heat resistance and electron acceptability of the ionic compound (electron-accepting compound), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an aromatic hydrocarbon ring group, an aromatic complex A cyclic group is preferred.

In formula (I-1), A ¹ is a long-period periodic table (hereinafter referred to as “periodic table” unless otherwise specified).
In this case, the long period periodic table is used. ) Is preferably an element belonging to Group 17, and from the viewpoint of electron acceptability and availability, an element prior to the fifth period (third to fifth periods) of the periodic table is preferable. That is, as A ¹ , any ^one of an iodine atom, a bromine atom, and a chlorine atom is preferable.

In particular, from the viewpoint of electron acceptability and compound stability, an ionic compound in which A ¹ in formula (I-1) is a bromine atom or an iodine atom is preferable, and an ionic compound having an iodine atom is most preferable.
In formula (I-1), Z ₁ ^n1- represents a counter anion. The type of the counter anion is not particularly limited, and may be a monoatomic ion or a complex ion. However, the larger the size of the counter anion, the more the negative charge is delocalized, and the positive charge is also delocalized thereby increasing the electron accepting ability. Therefore, the complex ion is preferable to the monoatomic ion.

n ₁ is an arbitrary positive integer corresponding to the ionic value of the counter anion Z ₁ ⁿ¹⁻ . The value of n ₁ is not particularly limited, but is preferably 1 or 2, and most preferably 1.
Specific examples of Z ₁ ^n1- include hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchloric acid. Ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, isocyanate ion, Hydrosulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, hexachloroantimonate ion; carboxylate ion such as acetate ion, trifluoroacetate ion, benzoate ion; methanesulfonic acid, trifluoromethanesulfonate ion, etc. Sulfonate ion; alkoxy ion such as methoxy ion and t-butoxy ion Tetrafluoroborate periodate ion and hexane tetrafluoroborate periodate ion.

Further, as the counter anion Z ₁ ⁿ¹⁻ , in ^terms of the stability of the compound and solubility in the solvent, the negative charge is delocalized due to its large size, and the positive charge is also delocalized accordingly. The complex ion represented by the following formula (I-2) is particularly preferable because the electron accepting ability increases.

In formula (I-2), each E ³ independently represents an element belonging to Group 13 of the long-period periodic table. Of these, a boron atom, an aluminum atom, and a gallium atom are preferable, and a boron atom is preferable from the viewpoint of stability of the compound and ease of synthesis and purification.
In formula (I-2), Ar ^{31 to} Ar ³⁴ each independently represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group. Examples of the aromatic hydrocarbon ring group and the aromatic heterocyclic group include a 5- or 6-membered monocyclic ring having 2 free valences similar to those exemplified above for R ¹¹ or 2 to 4 A condensed ring is mentioned. Among them, a benzene ring, naphthalene ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring and isoquinoline ring having one free valence are preferable from the viewpoint of stability and heat resistance of the compound. .

The aromatic hydrocarbon ring group and the aromatic heterocyclic group exemplified as Ar ^{31 to} Ar ³⁴ may be further substituted with another substituent as long as not departing from the gist of the present invention. The type of the substituent is not particularly limited, and any substituent can be applied, but an electron-withdrawing group is preferable.
Illustrative examples of preferred electron-withdrawing groups as the substituent that Ar ^{31 to} Ar ³⁴ may have include halogen atoms such as fluorine atom, chlorine atom and bromine atom; cyano group; thiocyano group; nitro group; mesyl group Alkylsulfonyl groups such as tosyl group; arylsulfonyl groups such as tosyl group; acyl groups such as formyl group, acetyl group, benzoyl group and the like, usually having 1 or more, usually 12 or less, preferably 6 or less; methoxycarbonyl group, ethoxycarbonyl An alkoxycarbonyl group having 2 or more carbon atoms, usually 10 or less, preferably 7 or less; a phenoxycarbonyl group, a pyridyloxycarbonyl group or the like, and usually having 3 or more carbon atoms, preferably 4 or more and usually 25 or less. An aryloxycarbonyl group having an aromatic hydrocarbon ring group or an aromatic heterocyclic group of preferably 15 or less; A non-carbonyl group; an aminosulfonyl group; a trifluoromethyl group, a pentafluoroethyl group, etc., a fluorine atom on a linear, branched or cyclic alkyl group having usually 1 or more, usually 10 or less, preferably 6 or less carbon atoms. And haloalkyl groups substituted with halogen atoms such as atoms and chlorine atoms.

Especially, it is more preferable that at least one group among Ar ^{31 to} Ar ³⁴ has one or two or more fluorine atoms or chlorine atoms as a substituent. In particular, it is most preferably a perfluoroaryl group in which all the hydrogen atoms of Ar ^{31 to} Ar ³⁴ are substituted with fluorine atoms from the viewpoint of efficiently delocalizing negative charges and having an appropriate sublimation property. preferable. Specific examples of the perfluoroaryl group include a pentafluorophenyl group, a heptafluoro-2-naphthyl group, and a tetrafluoro-4-pyridyl group.

The molecular weight of the electron-accepting compound in the present invention is usually 100 to 5000, preferably 300 to 3000, and more preferably 400 to 2000.
Within the above range, the positive charge and the negative charge are sufficiently delocalized, the electron accepting ability is good, and it is preferable that the charge transport is not hindered.
Specific examples of the electron accepting compound suitable for the present invention are shown below, but the present invention is not limited thereto.

The composition for organic electroluminescent elements of the present invention may contain one of the electron accepting compounds as described above alone, or may contain two or more kinds in any combination and ratio.
When the composition for organic electroluminescent elements of the present invention contains an electron-accepting compound, the content of the electron-accepting compound in the composition for organic electroluminescent elements of the present invention is usually 0.0005% or more by weight, preferably 0.8. 001% by weight or more, usually 20% by weight or less, preferably 10% by weight or less. The ratio of the electron-accepting compound to the charge transport material of the present invention in the composition for organic electroluminescent elements is usually 0.5% by weight or more, preferably 1% by weight or more, more preferably 3% by weight or more. Usually, it is 80 weight% or less, Preferably it is 60 weight% or less, More preferably, it is 40 weight% or less.
When the content of the electron-accepting compound in the composition for organic electroluminescent elements is not less than the above lower limit, the electron acceptor accepts electrons from the charge transport material, and the formed organic layer is preferably reduced in resistance. The following is preferable because defects are hardly generated in the formed organic layer and unevenness in film thickness hardly occurs.

<Cation radical compound>
As the cation radical compound, an ionic compound composed of a cation radical which is a chemical species obtained by removing one electron from a hole transporting compound and a counter anion is preferable. However, when the cation radical is derived from a hole transporting polymer compound, 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 compound described above as the hole transporting compound. A chemical species obtained by removing one electron from a compound preferable as a hole transporting compound is preferable in terms of amorphousness, visible light transmittance, heat resistance, solubility, and the like.
Here, the cation radical compound can be generated by mixing the hole transporting compound and the electron accepting compound. That is, by mixing the above hole transporting compound and the above electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the cation radical of the hole transporting compound is paired with the cation radical. A cation ion compound composed of an anion is generated.
In addition to the above-mentioned components, the composition for organic electroluminescence device of the present invention contains the components contained in the composition for forming a hole injection layer and the composition for forming a hole transport layer, which will be described later. It may contain.

[Organic electroluminescence device]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode and a cathode and an organic layer between the anode and the cathode on a substrate, wherein the organic layer contains a charge transport material for organic EL. It includes a layer formed by a wet film formation method using the composition for an organic electroluminescent element of the invention. In the organic electroluminescence device of the present invention, the layer formed by the wet film formation method is preferably a hole injection layer and / or a hole transport layer, and in particular, this organic layer is a hole injection layer, a hole injection layer, or a hole injection layer. A transport layer and a light emitting layer are provided, and all of the hole injection layer, the hole transport layer and the light emitting layer are preferably formed by a wet film forming method.

  In the present invention, the wet film forming method is a film forming method, that is, a coating method, for example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary A method of forming a film by employing a wet film formation method such as a coating method, an ink jet method, a nozzle printing method, a screen printing method, a gravure printing method, or a flexographic printing method, and drying the coated film. Among these film forming methods, spin coating, spray coating, ink jet, nozzle printing, and the like are preferable.

Hereinafter, an example of an embodiment of the layer configuration of the organic electroluminescence device of the present invention and a general formation method thereof will be described with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent element 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, 5 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 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film or a sheet is usually used. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. The substrate is preferably made of a material having a high gas barrier property since the organic electroluminescence device is hardly deteriorated by the outside air. For this reason, in particular, when a material having a low gas barrier property such as a synthetic resin substrate is used, it is preferable to provide a dense silicon oxide film on at least one surface of the substrate to lower the gas barrier property.

{anode}
The anode 2 has a function of injecting holes into the layer on the light emitting layer 5 side.
The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, or platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; a carbon black and a poly (3 -Methylthiophene), polypyrrole, polyaniline and other conductive polymers.

  In general, the anode 2 is often formed by a dry method such as a sputtering method or a vacuum deposition method. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution is used. It can also be formed by dispersing and coating on a substrate. In the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or an anode can be formed by applying a conductive polymer on a substrate (Appl. Phys. Lett., 60). Volume, 2711, 1992).

The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first anode.
The thickness of the anode 2 may be determined according to required transparency and material. In particular, when high transparency is required, a thickness at which visible light transmittance is 60% or more is preferable, and a thickness at which 80% or more is more preferable. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is unnecessary, the thickness of the anode 2 may be arbitrarily set according to the required strength, and in this case, the anode 2 may have the same thickness as the substrate.

In the case where another layer is formed on the surface of the anode 2, impurities on the anode 2 are removed by performing treatments such as ultraviolet / ozone, oxygen plasma, and argon plasma before the film formation, and the ionization potential thereof. It is preferable to improve the hole injection property by adjusting.
{Hole injection layer}
The layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection transport layer or a hole transport layer. When there are two or more layers responsible for transporting holes from the anode 2 side to the light emitting layer 5 side, the layer closer to the anode side may be referred to as the hole injection layer 3. The hole injection layer 3 is preferably formed from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5 side. When forming the hole injection layer 3, the hole injection layer 3 is usually formed on the anode 2.

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.
The formation method of the hole injection layer may be a vacuum deposition method or a wet film formation method. In terms of excellent film forming properties, it is preferable to form the film by a wet film forming method.
The hole injection layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. Further, the hole injection layer preferably contains a cation radical compound, and particularly preferably contains a cation radical compound and a hole transporting compound.

Hereinafter, a general method for forming a hole injection layer will be described. In the organic electroluminescence device of the present invention, the hole injection layer is formed by a wet film formation method using the composition for an organic electroluminescence device of the present invention. It is preferably formed by.
<Hole transporting compound>
The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3. In the case of a wet film forming method, a solvent is usually further contained. It is preferable that the composition for forming a hole injection layer has high hole transportability and can efficiently transport injected holes. For this reason, it is preferable that the hole mobility is high and impurities that become traps are less likely to be generated during production or use. Moreover, it is preferable that it is excellent in stability, has a small ionization potential, and has high transparency to visible light. In particular, when the hole injection layer is in contact with the light emitting layer, those that do not quench the light emitted from the light emitting layer or those that form an exciplex with the light emitting layer and do not decrease the light emission efficiency are preferable.

  The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked by a fluorene group, hydrazones Compound, silazane compound compound, quinacridone compound and the like.

Of the above-described exemplary compounds, an aromatic amine compound is preferable and an aromatic tertiary amine compound is particularly preferable from the viewpoint of amorphousness and visible light transmittance. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.
The type of the aromatic tertiary amine compound is not particularly limited, but is a polymer compound having a weight average molecular weight of 1,000 to 1,000,000 (polymerization compound in which repeating units are linked) from the viewpoint of easily obtaining uniform light emission due to the surface smoothing effect. Is preferably used. Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In the formula (I), Ar ¹¹ and Ar ¹² are each independently an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Each of Ar ^{13 to} Ar ¹⁵ independently represents an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent; It represents a linking group selected from the following group of linking groups, and among Ar ^{11 to} Ar ¹⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.

(In the above formulas, Ar ^{16 to} Ar ²⁶ each independently represents an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent. R ²¹ and R ²² each independently represents a hydrogen atom or an arbitrary substituent.)
As the aromatic hydrocarbon ring group and the aromatic heterocyclic group of Ar ^{16 to} Ar ²⁶ , one or two free valences are selected from the viewpoint of the solubility, heat resistance, and hole injecting and transporting property of the polymer compound. The benzene ring, naphthalene ring, phenanthrene ring, thiophene ring, and pyridine ring are preferable, and the benzene ring and naphthalene ring having one or two free valences are more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include those described in International Publication No. 2005/089024.
Since the hole injection layer 3 can improve the conductivity of the hole injection layer by oxidation of the hole transporting compound, the hole injection layer 3 contains the above-described electron-accepting compound or the above-described cation radical. It preferably contains a compound.

Cationic radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, 12, 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, 94, 7716) It is also produced by oxidative polymerization (dehydrogenation polymerization).
Oxidative polymerization here refers to oxidation of a monomer chemically or electrochemically with peroxodisulfate in an acidic solution. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is polymerized by oxidation, and a cation radical that is removed from the polymer repeating unit by using an anion derived from an acidic solution as a counter anion is removed. Generate.

<Formation of hole injection layer by wet film formation method>
When the hole injection layer 3 is formed by a wet film forming method, a material for forming the hole injection layer is usually mixed with a soluble solvent (hole injection layer solvent) to form a film forming composition (hole An injection layer forming composition), and applying the hole injection layer forming composition onto a layer (usually an anode) corresponding to the lower layer of the hole injection layer, forming a film, and then drying. Let it form.

  The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effects of the present invention are not significantly impaired, but in terms of film thickness uniformity, the lower one is preferable. From the viewpoint that defects are less likely to occur in the hole injection layer, a higher value is preferable. Specifically, it is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, particularly preferably 0.5% by weight or more, and on the other hand, 70% by weight. It is preferably not more than 60% by weight, more preferably not more than 60% by weight, particularly preferably not more than 50% by weight.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.
Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and anisole. , Aromatic ethers such as phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole and 2,4-dimethylanisole.

Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.
Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, methylnaphthalene and the like. It is done. Examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide.

In addition to these, dimethyl sulfoxide and the like can also be used.
Formation of the hole injection layer 3 by a wet film formation method is usually performed after preparing a composition for forming a hole injection layer, and then forming the composition on a layer (usually the anode 2) corresponding to the lower layer of the hole injection layer 3 The film is formed by coating and drying.
In general, the hole injection layer 3 is dried by heating or drying under reduced pressure after film formation.

<Formation of hole injection layer by vacuum deposition>
When the hole injection layer 3 is formed by vacuum vapor deposition, one or more of the constituent materials of the hole injection layer 3 (the above-described hole transporting compound, electron accepting compound, etc.) are usually vacuumed. Put in a crucible installed in the container (when using two or more kinds of materials, usually put each in separate crucibles), evacuate the vacuum container to about 10 ^-4 Pa with a vacuum pump, then heat the crucible (When using two or more types of materials, each crucible is usually heated) and evaporated while controlling the amount of evaporation of the material in the crucible (when using two or more types of materials, each is usually independent. The hole injection layer is formed on the anode on the substrate placed facing the crucible. When two or more kinds of materials are used, the hole injection layer can be formed by putting the mixture in a crucible and heating and evaporating the mixture.

The degree of vacuum at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa) or more and 9.0 × 10 ⁻⁶ Torr ( 12.0 × 10 ⁻⁴ Pa) or less. The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 to 5.0 liters / second or more. The film forming temperature at the time of vapor deposition is not limited as long as the effects of the present invention are not significantly impaired, but it is preferably performed at 10 ° C. or higher and 50 ° C. or lower.
The hole injection layer 3 may be cross-linked similarly to the hole transport layer 4 described later.

{Hole transport layer}
The hole transport layer 4 is a layer having a function of transporting holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescence device of the present invention, but it is preferable to form this layer in terms of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. . When forming the hole transport layer 4, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. Further, when there is the hole injection layer 3 described above, it is formed between the hole injection layer 3 and the light emitting layer 5.

The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less.
The formation method of the hole transport layer 4 may be a vacuum deposition method or a wet film formation method. In terms of excellent film forming properties, it is preferable to form the film by a wet film forming method.
Hereinafter, a general method for forming a hole transport layer will be described. In the organic electroluminescence device of the present invention, the hole transport layer is formed by a wet film formation method using the composition for organic electroluminescence device of the present invention. Preferably it is formed.

  The hole transport layer 4 usually contains a hole transport compound. As the hole-transporting compound contained in the hole-transporting layer 4, in particular, two or more tertiary compounds represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl Aromatic diamines containing two or more condensed aromatic rings containing an amine and substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234811), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine An aromatic amine compound having a starburst structure (J. Lumin., 72-74, 985, 1997), an aromatic amine compound comprising a tetramer of triphenylamine (Chem. Commun., 2175) 1996), 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synth. Metals, 91). , 209 pp., 1997), 4,4'-N, carbazole derivatives such as N'- dicarbazole biphenyl. Also, for example, polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), polyarylene ether sulfone (Polym. Adv. Tech., 7, 33, 1996) containing tetraphenylbenzidine, etc. It can be preferably used.

<Formation of hole transport layer by wet film formation method>
When forming a hole transport layer by a wet film formation method, in general, in the same manner as in the case of forming the above-described hole injection layer by a wet film formation method, holes are used instead of the hole injection layer forming composition. It forms using the composition for transport layer formation.
When the hole transport layer is formed by a wet film forming method, the composition for forming a hole transport layer usually further contains a solvent. As the solvent used in the composition for forming a hole transport layer, the same solvent as the solvent used in the composition for forming a hole injection layer can be used.

The concentration of the hole transporting compound in the composition for forming a hole transport layer can be in the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer.
Formation of the hole transport layer by a wet film formation method can be performed in the same manner as the hole injection layer film formation method described above.

<Formation of hole transport layer by vacuum deposition>
When the hole transport layer is formed by the vacuum deposition method, the hole transport layer is usually used instead of the hole injection layer forming composition in the same manner as in the case of forming the hole injection layer by the vacuum deposition method. It can form using the composition for layer formation. The film formation conditions such as the degree of vacuum at the time of vapor deposition, the vapor deposition rate, and the temperature can be formed under the same conditions as those for the vacuum vapor deposition of the hole injection layer.

{Light emitting layer}
The light emitting layer 5 is a layer having a function of emitting light when excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between a pair of electrodes. . The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9, and the light-emitting layer is formed between the hole injection layer and the cathode when there is a hole injection layer on the anode. When there is a hole transport layer on the surface, it is formed between the hole transport layer and the cathode.

The film thickness of the light emitting layer 5 is arbitrary as long as the effects of the present invention are not significantly impaired. However, a thicker film is preferable in that the film is less likely to be defective. On the other hand, a thinner film is preferable in terms of easy driving voltage. . For this reason, it is preferably 3 nm or more, more preferably 5 nm or more, and on the other hand, it is usually preferably 200 nm or less, and more preferably 100 nm or less.
The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) and preferably contains a material having a charge transporting property (charge transporting material).

<Light emitting material>
The light emitting material emits light at a desired light emission wavelength, and is not particularly limited as long as the effect of the present invention is not impaired, and a known light emitting material can be applied. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, but a material having good light emission efficiency is preferred, and a phosphorescent light emitting material is preferred from the viewpoint of internal quantum efficiency.
Examples of the fluorescent light emitting material include the following materials.

Examples of the fluorescent light-emitting material that gives blue light emission (blue fluorescent light-emitting material) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of the fluorescent light emitting material that gives green light emission (green fluorescent light emitting material) include quinacridone derivatives, coumarin derivatives, aluminum complexes such as Al (C ₉ H ₆ NO) _3, and the like.

Examples of the fluorescent light-emitting material that gives yellow light (yellow fluorescent light-emitting material) include rubrene and perimidone derivatives.
Examples of fluorescent light-emitting materials (red fluorescent light-emitting materials) that emit red light include, for example, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) -based compounds, benzopyran derivatives, rhodamine derivatives. Benzothioxanthene derivatives, azabenzothioxanthene and the like.

Examples of the phosphorescent material include organometallic complexes containing a metal selected from Groups 7 to 11 of the long-period periodic table. 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 such as a (hetero) arylpyridine ligand or (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. In particular, a phenylpyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of preferred phosphorescent materials include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, and tris. Examples thereof include phenylpyridine complexes such as (2-phenylpyridine) osmium and tris (2-phenylpyridine) rhenium, and porphyrin complexes such as octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethyl palladium porphyrin, and octaphenyl palladium porphyrin.

Polymeric light-emitting 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}- And polyfluorene-based materials such as poly [2-methoxy-5- (2-hexylhexyloxy) -1,4-phenylenevinylene].

<Charge transport material>
The charge transport material is a material having a positive charge (hole) or negative charge (electron) transport property, and is not particularly limited as long as the effect of the present invention is not impaired, and a known light emitting material can be applied.
As the charge transporting material, a compound or the like conventionally used in a light emitting layer of an organic electroluminescence device can be used, and a compound used as a host material of the light emitting layer is particularly preferable.

  Specific examples of charge transporting materials include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which tertiary amines are linked by a fluorene group. , Hydrazone compounds, silazane compounds, silanamin compounds, phosphamine compounds, quinacridone compounds, and the like as examples of hole transporting compounds in the hole injection layer, anthracene compounds, pyrene compounds, Examples thereof include electron transporting compounds such as carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds and silole compounds.

In addition, for example, two or more condensed aromatic rings including two or more tertiary amines typified by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl have nitrogen atoms. Substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-
Aromatic amine compounds having a starburst structure such as naphthylphenylamino) triphenylamine (J. Lumin., 72-74, 985, 1997), tetraamines of triphenylamine Compound (Chem. Commun., 2175, 1996), 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-
Holes in the hole transport layer of fluorene compounds such as spirobifluorene (Synth. Metals, 91, 209, 1997), carbazole compounds such as 4,4′-N, N′-dicarbazole biphenyl, etc. The compounds exemplified as the transporting compound can also be preferably used. In addition, 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole (BND), 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3,4- Examples include silole compounds such as diphenylsilole (PyPySPyPy) and phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproin).

<Formation of light emitting layer by wet film formation method>
The method for forming the light emitting layer may be a vacuum deposition method or a wet film formation method, but a wet film formation method is preferable and a spin coating method and an ink jet method are more preferable because of excellent film forming properties. In particular, when a hole injection layer or a hole transport layer, which is a lower layer of a light emitting layer, is formed using the composition for an organic electroluminescent element of the present invention, it is easy to form a layer by a wet film formation method. It is preferable to employ a membrane method. When the light emitting layer is formed by a wet film forming method, the light emitting layer is usually used instead of the hole injection layer forming composition in the same manner as in the case of forming the hole injection layer by the wet film forming method. The resulting material is formed using a composition for forming a light emitting layer prepared by mixing a soluble solvent (solvent for the light emitting layer).

  Examples of the solvent include, for example, ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, alkane solvents, halogenated aromatic hydrocarbon solvents, aliphatic solvents, and the like mentioned for the formation of the hole injection layer. Examples thereof include alcohol solvents, alicyclic alcohol solvents, aliphatic ketone solvents, and alicyclic ketone solvents. Although the specific example of a solvent is given to the following, as long as the effect of this invention is not impaired, it is not limited to these.

  For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2 -Aromatic ether solvents such as methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic ester solvents such as ethyl, ethyl benzoate, propyl benzoate, n-butyl benzoate; toluene, xylene, methicylene, cyclohexylbenzene, tetralin, 3-ilopropylbiphenyl, 1 Aromatic hydrocarbon solvents such as 2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene and methylnaphthalene; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; Alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; cyclohexanol And alicyclic alcohol solvents such as cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fenkon. Of these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

{Hole blocking layer}
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 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 a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high.

Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Styryl compound (Japanese Patent Laid-Open No. 11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-t
Examples include triazole derivatives such as ert-butylphenyl) -1,2,4-triazole (JP-A-7-41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in WO2005 / 022962 is also preferable as a material for the hole blocking layer.

There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less. is there.

{Electron transport layer}
The electron transport layer 7 is provided between the light emitting layer 5 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 between electrodes to which an electric field is applied in the direction of the light emitting layer 5. As the electron transporting compound used for the electron transport layer 7, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons can be efficiently transported with high electron mobility. It must be a compound.

  Specific examples of the electron transporting compound used in the electron transporting layer include, for example, metal complexes such as an aluminum complex of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), 10-hydroxybenzo [h] quinoline Metal complexes, oxadiazole derivatives, distyryl biphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948) Description), quinoxaline compound (JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type Hydrogenated amorphous silicon carbide, n Zinc sulfide, etc. n-type zinc selenide.

The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and is usually 300 nm or less, preferably 100 nm or less.
The electron transport layer 7 is formed by laminating on the hole blocking layer 6 by a wet film formation method or a vacuum deposition method in the same manner as described above. Usually, a vacuum deposition method is used.

{Electron injection layer}
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 perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport material represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.) also improves electron injection / transport and makes it possible to achieve both excellent film quality. preferable.

The thickness of the electron injection layer 8 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 transport layer 7 thereon by a wet film formation method or a vacuum deposition method.
The details in the case of the wet film forming method are the same as those in the case of the light emitting layer described above.

{cathode}
The cathode 9 plays a role of injecting electrons into a layer (such as an electron injection layer or a light emitting layer) on the light emitting layer 5 side.
As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, it is preferable to use a metal having a low work function. , Metals such as indium, calcium, aluminum, silver, or alloys thereof are used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

From the viewpoint of device stability, it is preferable to protect a cathode made of a metal having a low work function by laminating a metal layer having a high work function and stable to the atmosphere on the cathode. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.
The thickness of the cathode is usually the same as that of the anode.
{Other layers}
The organic electroluminescent element of the present invention may further have other layers as long as the effects of the present invention are not significantly impaired. That is, any other layer described above may be provided between the anode and the cathode.

{Other element configurations}
The organic electroluminescent device of the present invention has a structure opposite to that described above, that is, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, and a hole injection layer on the substrate. It is also possible to laminate in the order of the anode.
When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent element, or may be used in a configuration in which a plurality of organic electroluminescent elements are arranged in an array, The anode and the cathode may be used in a configuration in which they are arranged in an XY matrix.

[Organic EL display device]
The organic EL display device of the present invention uses the above-described organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic electroluminescent display apparatus of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.
For example, the organic EL display device of the present invention can be obtained by the method described in “Organic EL display” (Ohm, published on Aug. 20, 2004, Shizushi Tokito, Chiba Adachi, Hideyuki Murata). Can be formed.

[Organic EL lighting]
The organic EL illumination of the present invention uses the above-described organic electroluminescent element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic EL illumination of this invention, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.
[Synthesis of Polymer 1]

  Compound 1 (12.0 g, 34.33 mmol), Compound 2 (0.3528 g, 1.8068 mmol), Compound 3 (5.6373 g, 18.0684 mmol) and tert-butoxy sodium (20.08 g, 208.95 mmol), Toluene (60 ml) was charged, the inside of the system was sufficiently purged with nitrogen, and the mixture was heated to 60 ° C. (solution A). To a 60 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.762 g, 0.72 mmol) was added 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo [ 3.3.3] Undecane (TiBTaPU) (1.98 g, 5.792 mmol) was added and warmed to 60 ° C. (solution B). Solution B was added to solution A in a nitrogen stream and heated to reflux for 2.0 hours. After confirming that compounds 1 to 3 had disappeared, compound 3 (4.71717 g, 15.3580 mmol) was additionally added. After heating at reflux for 1.0 hour, compound 4 (0.9908 g, 1.8068 mmol) was added. After heating under reflux for 1.0 hour, the reaction solution was allowed to cool, and the reaction solution was dropped into 1250 ml of ethanol to crystallize crude polymer 1.

  The obtained crude polymer 1 was dissolved in 300 ml of toluene, bromobenzene (1.42 g) and tert-butoxy sodium (25.0 g) were charged, the inside of the system was sufficiently purged with nitrogen, and the mixture was heated to 60 ° C. ( Solution C). To a 30 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.476 g), 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo [3.3. 3] Undecane (TiBTaPU) (1.25 g) was added and heated to 60 ° C. (solution D). In a nitrogen stream, solution D was added to solution C, and heated to reflux for 2 hours. N, N-diphenylamine (7.6 g) was added to this reaction solution (solution E), and 2,8,8, were added to a 30 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.476 g). 9-Triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane (TiBTaPU) (1.25 g) was added and heated to 60 ° C. (solution F). In a nitrogen stream, solution F was added to solution E, and the mixture was heated to reflux for 4 hours. The reaction solution was allowed to cool and added dropwise to an ethanol / water (1300 ml / 100 ml) solution to obtain an end-capped crude polymer 1.

This end-capped crude polymer 1 was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was separated by filtration. The obtained polymer is dissolved in toluene, washed with dilute hydrochloric acid,
Reprecipitation was performed with ethanol containing ammonia. The polymer collected by filtration was purified by column chromatography to obtain the target polymer 1 (4.2 g, yield 23%). In addition, the coloring derived from a catalyst was not recognized.

Weight average molecular weight (Mw) = 86900
Number average molecular weight (Mn) = 59100
Dispersity (Mw / Mn) = 1.47

DESCRIPTION OF SYMBOLS 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 device

Claims (12)

A catalyst for producing a charge transport material for organic EL, comprising a palladium compound and an amino-substituted phosphorus compound having a structure represented by the following formula (1).

(In Formula (1), R < ₁ > -R < ₃ > shows a C1-C6 alkyl group each independently.) The catalyst for producing a charge transport material for organic EL according to claim 1, wherein the amino-substituted phosphorus compound of the formula (1) is represented by the formula (2).

Palladium compounds from Pd (Oac) ₂ , Pd (acac) ₂ , (CH ₃ CN) ₂ Pd (NO ₂ ) Cl, (C ₁₀ H ₈ N ₂ ) ₂ PdCl ₂ , Pd ₂ (dba) ₃ and PdCl ₂ The catalyst for producing a charge transport material for organic EL according to claim 1 or 2, which is at least one selected from the group consisting of:   The manufacturing method of the charge transport material for organic EL including using the catalyst in any one of Claims 1-3, and making an aryl compound and an amine compound react in presence of a base.   The manufacturing method of the charge transport material for organic EL of Claim 4 whose base is tertiary butoxy sodium.   An organic EL charge transport material produced by the production method according to claim 4.   The composition for organic electroluminescent elements containing the charge transport material for organic EL of Claim 6, and a solvent. In an organic electroluminescence device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate,
An organic electroluminescent device, wherein the organic layer includes a layer formed by wet film formation using the composition for an organic electroluminescent device according to claim 7.   The organic electroluminescent element according to claim 8, wherein the layer formed by the wet film formation is a hole injection layer and / or a hole transport layer.   The organic layer has a hole injection layer, a hole transport layer, and a light emitting layer, and all of the hole injection layer, the hole transport layer, and the light emitting layer are formed by wet film formation. The organic electroluminescent element according to claim 8 or 9, characterized in that   The organic electroluminescence display containing the organic electroluminescent element as described in any one of Claims 8-10.   Organic electroluminescent illumination containing the organic electroluminescent element as described in any one of Claims 8-10.

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