JP2010239134A - Organic electroluminescent element, organic el display and organic el illumination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element of low driving voltage and high current efficiency in the organic electroluminescent element having an arylamine compound containing light-emitting layer formed by a wet deposition method. <P>SOLUTION: The organic electroluminescent element includes a positive electrode, a charge transport layer, a light-emitting layer and a negative electrode on a substrate in this order, the charge transport layer and the light-emitting layer adjacently provided, and the charge transport layer and the light-emitting layer are formed by the wet deposition method. The charge transport layer is a layer formed of a composition containing a polymer compound whose terminal group is an aromatic hydrocarbon group which may have a group selected from a group consisting of an alkyl group, an alkoxy group and an aromatic group as a substituent. The light-emitting layer is the layer containing an arylamine compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent element, an organic EL display, and organic EL illumination.

In recent years, an electroluminescent element (organic electroluminescent element) using an organic thin film has been developed. The wet film formation method does not require a vacuum process, is easy to increase in area, and has an advantage that it is easy to mix a plurality of materials having various functions in one layer and a coating liquid for forming the layer. is there.
In Patent Documents 1 and 2, a hole transport layer and a light-emitting layer are formed by a wet film formation method, the hole transport layer is formed using a composition containing a polymer material, and the light-emitting layer is aryl as a light-emitting material. Although it is disclosed that it is formed using a composition containing an amine compound, further improvements in terms of current efficiency and driving voltage are required.

  Patent Document 3 discloses the use of a polymer compound whose terminal group is an aromatic hydrocarbon group as a material for an organic electroluminescence device.

JP 2007-73814 A JP 2008-166629 A JP 2004-292882 A

  An object of the present invention is to provide an organic electroluminescent device having a low driving voltage and high current efficiency in an organic electroluminescent device having a light emitting layer containing an arylamine compound, formed by a wet film formation method. .

As a result of intensive studies to solve the above problems, the present inventors have found that the polymer compound has a terminal end in the charge transport layer containing the polymer compound formed adjacent to the light emitting layer containing the arylamine. The inventors have found that the above problems can be solved by having a group, and have reached the present invention.
That is, the present invention has an anode, a charge transport layer, a light emitting layer, and a cathode on a substrate in this order, and the charge transport layer and the light emitting layer are provided adjacent to each other, and the charge transport layer and the light emitting layer are provided. The layer is an organic electroluminescent device formed by a wet film-forming method, and the charge transporting layer includes a polymer compound in which the terminal group is an aromatic hydrocarbon group which may have a substituent. And the light emitting layer is an organic electroluminescent element characterized by being an arylamine compound-containing layer, and an organic EL display and an organic EL illumination provided with the organic electroluminescent element.

  The organic electroluminescence device of the present invention has high current efficiency and low driving voltage, and further suppresses a decrease in light emission luminance, a voltage increase, generation of a non-light emitting portion (dark spot), a short circuit defect, etc. during constant current driving. Is done.

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

The embodiment of the organic electroluminescent element of the present invention, and the organic EL display and organic EL illumination will be described in detail. The description of the constituent elements described below is an example (representative example) of the embodiment of the present invention. The present invention is not limited to these contents unless it exceeds the gist.
The organic electroluminescent element of the present invention has an anode, a charge transport layer, a light emitting layer, and a cathode in this order on a substrate, and the charge transport layer and the light emitting layer are provided adjacent to each other, and the charge transport layer, And the light-emitting layer is an organic electroluminescent device formed by a wet film-forming method, and the charge transport layer comprises a polymer compound in which a terminal group is an aromatic hydrocarbon group which may have a substituent. An organic electroluminescent element, wherein the light emitting layer is a layer containing an arylamine compound.

<Light emitting layer>
Hereinafter, although the structural requirement of a light emitting layer is demonstrated, this invention is not limited to these.
[Arylamine compound]
The light emitting layer in the present invention is a layer containing an arylamine compound formed by a wet film forming method.

  As the arylamine compound, an N, N, N ′, N′-tetraarylarylenediamine compound represented by the following formula (I ′) is preferable from the viewpoint of excellent durability.

(In formula (I ′), Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent.)
Examples of the aromatic hydrocarbon group of Ar ^{1 to} Ar ⁵ include a benzene ring, a benzene ring such as a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a pyrene ring, a chrysene ring, a naphthacene ring, and a benzophenanthrene ring. A group derived from a condensed ring formed by condensing ˜5.

Among them, Ar ⁵ is preferably a group derived from a chrysene ring in view of high current efficiency, and particularly preferably a compound represented by the following formula (I).

(In formula (I), Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent.)
Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent. Examples of the aromatic hydrocarbon group represented by Ar ^{1 to} Ar ⁴ include a benzene ring such as a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a pyrene ring, a chrysene ring, a naphthacene ring, and a benzophenanthrene ring. A group derived from a condensed ring formed by condensing ˜5. In particular, a phenyl group is preferable for obtaining blue light emission.

As the substituent that the aromatic hydrocarbon group in Ar ^{1 to} Ar ⁴ may have, an alkyl group, an alkenyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group, and the like are preferable. Alkyl groups of oily substituents are preferred.
Further, the molecular weight of the substituent is usually 400 or less, preferably about 250 or less.
When Ar ^{1 to} Ar ⁴ have a substituent, the substitution position is preferably para-position or meta-position, particularly preferably para-position, with respect to the substitution position of the nitrogen atom.

  The molecular weight of the arylamine compound is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, preferably It is 200 or more, more preferably 300 or more, and still more preferably 400 or more. If the molecular weight of the arylamine compound is too small, the heat resistance is remarkably reduced, gas is generated, the film quality is deteriorated when the film is formed, or the morphology of the organic electroluminescent device is changed due to migration, etc. Or may come. On the other hand, if the molecular weight of the arylamine compound is too large, purification of the arylamine compound tends to be difficult, or it may take time to dissolve the arylamine compound in a solvent.

Although the preferable specific example of a compound represented by a formula (I) below is shown, this invention is not limited to these.
<Specific Example of Compound Represented by Formula (I)>

[Light emitting material]
Although the organic electroluminescent element of this invention contains an arylamine compound in a light emitting layer, unless the effect of this invention is impaired, it may contain the other luminescent material.
Hereinafter, examples of the fluorescent light emitting material among other light emitting materials will be given, but the fluorescent light emitting material is not limited to the following examples.

Examples of the fluorescent light-emitting material (blue fluorescent light-emitting material) that emits blue light include naphthalene, perylene, pyrene, anthracene, coumarin, 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 that give red light (red fluorescent light-emitting materials) include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives. Benzothioxanthene derivatives, azabenzothioxanthene and the like.

As the phosphorescent material, for example, a long-period type periodic table (hereinafter referred to as a long-period type periodic table when referred to as “periodic table” unless otherwise specified) is selected from the seventh to eleventh groups. And an organometallic complex containing a metal.
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 complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2- Phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

The molecular weight of the compound used as the light emitting material is the same as that described in the above section [Arylamine compound]. Moreover, a preferable aspect is also the same.
In addition, any 1 type may be used for the luminescent material mentioned above, and 2 or more types may be used together by arbitrary combinations and a ratio.

[Charge transport material]
The charge transport material in the present invention is a compound having charge transport properties such as hole transport properties and electron transport properties.
In the present invention, only one type of charge transport material may be used, or two or more types may be used in any combination and ratio.
In the light emitting layer, it is preferable to use a light emitting low molecular weight compound as a dopant material and a charge transport material as a host material.
The charge transport material may be a compound that has been conventionally used in a light emitting layer of an organic electroluminescent device, and particularly a compound that is used as a host material of the light emitting layer.

  Specific examples of charge transport materials 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, hydrazone compounds Compounds, silazane compounds, silanamine compounds, phosphamine compounds, quinacridone compounds, anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, silole compounds, etc. It is done.

  For example, two or more condensed aromatic rings including two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are substituted with nitrogen atoms. Aromatic amine compounds having a starburst structure (J. Lumin, etc.) such as aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. , 72-74, 985, 1997), an aromatic amine compound comprising a tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 ′, 7, 7 ′. -Fluorene compounds such as tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, 91, 209, 1997), 4,4'-N, N'- Carbazole compounds such as carbazole biphenyl, 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1- Oxadiazole compounds such as naphthyl) -1,3,4-oxadiazole (BND), 2,5-bis (6 ′-(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3 , 4-diphenylsilol (PyPySPyPy) and other silole compounds, bathophenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproin) and other phenanthroline compounds It is done.

(Method for forming light emitting layer)
The light emitting layer in the present invention is formed by a wet film forming method.
In order to form by the wet film-forming method, a composition further containing a solvent is used for the arylamine compound and, if necessary, other light-emitting materials or charge transport materials.
The solvent contained in the composition for forming the light emitting layer (hereinafter sometimes referred to as “the composition for forming the light emitting layer”) is a solvent in which the light emitting low molecular weight compound and the charge transporting material are well dissolved. There is no particular limitation.

The solubility of the solvent is usually 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight of the light-emitting low molecular weight compound and the charge transport material at normal temperature and normal pressure, respectively. % Or more is preferable.
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, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene, and tetralin; halogenated fragrances such as chlorobenzene, dichlorobenzene, and trichlorobenzene Group hydrocarbons: 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethyl Aromatic ethers such as anisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; Alicyclic ketones such as Sanone, Cyclooctanone and Fencon; Alicyclic alcohols such as cyclohexanol and cyclooctanol; Aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Aliphatic alcohols such as butanol and hexanol; Ethylene And aliphatic ethers such as glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA).

Of these, alkanes and aromatic hydrocarbons are preferable. One of these solvents may be used alone, or two or more thereof may be used in any combination and ratio.
In order to obtain a more uniform film, it is preferable that the solvent evaporates from the liquid film immediately after the film formation at an appropriate rate. For this reason, the boiling point of the solvent is usually 80 ° C or higher, preferably 100 ° C or higher, more preferably 120 ° C or higher, and usually 270 ° C or lower, preferably 250 ° C or lower, more preferably 230 ° C or lower.

  The amount of the solvent used is arbitrary as long as the effects of the present invention are not significantly impaired, but is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, particularly preferably 100 parts by weight of the composition for forming a light emitting layer. Is 80 parts by weight or more, preferably 99.95 parts by weight or less, more preferably 99.9 parts by weight or less, and particularly preferably 99.8 parts by weight or less. When the content is lower than the lower limit, the viscosity becomes too high, and the film forming workability may be lowered. On the other hand, when the value exceeds the upper limit, the film thickness obtained by removing the solvent after film formation cannot be obtained, so that film formation tends to be difficult. In addition, when mixing and using 2 or more types of solvents as a composition for light emitting layer formation, it is made for the sum total of these solvents to satisfy | fill this range.

Moreover, the composition for light emitting layer formation in this invention may contain various additives, such as a leveling agent and an antifoamer, for the purpose of improving film forming property.
After application of the composition for forming a light emitting layer, the obtained coating film is dried, and the light emitting layer is removed by removing the solvent for the light emitting layer. The method of the wet film formation method is not limited as long as the effects of the present invention are not significantly impaired. Are a spin coating method and an inkjet method.
The thickness of the light emitting layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the light emitting layer is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

<Charge transport layer>
The charge transport layer in the present invention is a layer formed of a composition containing a polymer compound whose terminal group is an aromatic hydrocarbon group which may have a substituent.
The terminal group is an aromatic hydrocarbon group which may have a substituent. As the aromatic hydrocarbon group, 2 to 5 benzene rings or benzene rings such as a benzene ring, naphthalene ring, phenanthrene ring, anthracene ring, pyrene ring, chrysene ring, naphthacene ring, benzophenanthrene ring are condensed. A group derived from a condensed ring, a group derived from a fluorene ring, a group derived from an indenofluorene ring, and the like. Among these, a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 9-phenanthryl group, and a 2-fluorenyl group are preferable from the viewpoint of charge transportability and electrochemical durability.

  Examples of the substituent that the aromatic hydrocarbon group in the terminal group may have include an alkyl group, an alkenyl group, an alkoxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. Among them, a phenyl group, 1-naphthyl group, 2-naphthyl group, 9-phenanthryl group, aromatic hydrocarbon group such as 2-fluorenyl group, alkyl group such as methyl group, ethyl group, isopropyl group, n-butyl group, tert-butyl group, A diarylamino group such as an N, N-diphenylamino group, an N-carbazolyl group, or an N, N-bis (4-diphenyl) amino group is preferred from the viewpoint of charge transportability and electrochemical durability.

  The polymer compound in the present invention is preferably a polymer compound containing a repeating unit represented by the following formula (II).

(In formula (II), q represents an integer of 0 to 3, and Ar ¹¹ and Ar ¹² each independently have an aromatic hydrocarbon group which may have a substituent, or a substituent. Represents an aromatic heterocyclic group or a direct bond, and Ar ^{13 to} Ar ¹⁵ are each independently an aromatic hydrocarbon group which may have a substituent or an aromatic which may have a substituent. Represents a heterocyclic group.

However, neither Ar ¹¹ nor Ar ¹² is a direct bond. In formula (II), Ar ¹¹ and Ar ¹² are each independently a direct bond, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocycle which may have a substituent. Ar ^{13 to} Ar ¹⁵ each independently represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent.

Examples of the aromatic hydrocarbon group which may have a substituent include, for example, a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, and acenaphthene. Examples thereof include a group derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as a ring, a fluoranthene ring, and a fluorene ring.
Examples of the aromatic heterocyclic group which may have a substituent include a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, and a carbazole ring. , 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, etc. ring It can be mentioned groups derived from 2-4 fused rings.

Ar ^{11 to} Ar ¹⁵ are each independently from 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 in a solvent and heat resistance. A group derived from a ring selected from the group consisting of
In addition, as Ar ^{11 to} Ar ¹⁵ , a divalent group in which one or two or more rings selected from the above group are directly bonded or connected by a —CH═CH— group is preferable, and a biphenylene group and a terphenylene group are also preferable. Is more preferable.
The substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group in Ar ^{11 to} Ar ¹⁵ may have in addition to the insolubilizing group described later is not particularly limited. For example, the following [Substituent group Z] 1 type (s) or 2 or more types selected from are mentioned.

[Substituent group Z]
Preferably an alkyl group having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, such as a methyl group or an ethyl group;
An alkenyl group having preferably 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as a vinyl group;
An alkynyl group having preferably 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as an ethynyl group;
Preferably an alkoxy group having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, such as a methoxy group and an ethoxy group;
Preferably an aryloxy group having 4 to 36 carbon atoms, more preferably 5 to 24 carbon atoms, such as a phenoxy group, a naphthoxy group, and a pyridyloxy group;
An alkoxycarbonyl group having preferably 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as a methoxycarbonyl group and an ethoxycarbonyl group;
A dialkylamino group having preferably 2 to 24 carbon atoms, more preferably 2 to 12 carbon atoms, such as a dimethylamino group and a diethylamino group;
A diarylamino group having preferably 10 to 36 carbon atoms, more preferably 12 to 24 carbon atoms, such as a diphenylamino group, a ditolylamino group, and an N-carbazolyl group;
An arylalkylamino group having preferably 6 to 36 carbon atoms, more preferably 7 to 24 carbon atoms, such as a phenylmethylamino group;
An acyl group having preferably 2 to 24 carbon atoms, preferably 2 to 12 carbon atoms, such as an acetyl group and a benzoyl group;

Halogen atoms such as fluorine atoms and chlorine atoms;
A haloalkyl group having preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, such as a trifluoromethyl group;
Preferably an alkylthio group having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group;
A phenylthio group, a naphthylthio group, a pyridylthio group and the like, preferably an arylthio group having 4 to 36 carbon atoms, more preferably 5 to 24 carbon atoms;
A silyl group having preferably 2 to 36 carbon atoms, more preferably 3 to 24 carbon atoms, such as a trimethylsilyl group and a triphenylsilyl group;
A siloxy group having preferably 2 to 36 carbon atoms, more preferably 3 to 24 carbon atoms, such as a trimethylsiloxy group and a triphenylsiloxy group;
A cyano group;
An aromatic hydrocarbon group having preferably 6 to 36 carbon atoms, more preferably 6 to 24 carbon atoms, such as a phenyl group and a naphthyl group;
Preferably an aromatic heterocyclic group having 3 to 36 carbon atoms, more preferably 4 to 24 carbon atoms, such as a thienyl group and a pyridyl group. Each of the above substituents may further have a substituent. The group illustrated to the said substituent group Z is mentioned.

The molecular weight of the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group in Ar ^{11 to} Ar ¹⁵ may have in addition to the insolubilizing group described below is preferably 500 or less, including the substituted group, and is 250 or less. Is more preferable.
From the viewpoint of solubility, the substituents that the aromatic hydrocarbon group and aromatic heterocyclic group in Ar ^{11 to} Ar ¹⁵ may have are each independently an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkoxy groups are preferred.

In addition, when m is 2 or more, the repeating unit represented by the formula (II) has two or more Ar ¹⁴ and Ar ¹⁵ . In that case, Ar ¹⁴ and Ar ¹⁵ may be the same or different. Further, Ar ¹⁴ and Ar ¹⁵ may be bonded to each other directly or via a linking group to form a cyclic structure.

[Explanation of q]
In the formula (II), q represents an integer of 0 to 3.
q is usually 0 or more, usually 3 or less, preferably 2 or less. When q is 2 or less, synthesis of a monomer as a raw material is easier.
[Repetition unit ratio, etc.]
The polymer compound in the present invention is preferably a polymer compound containing one or more repeating units represented by the formula (II).

  When the polymer compound in the present invention has two or more kinds of repeating units, examples thereof include a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. A random copolymer is preferable from the viewpoint of solubility in a solvent. An alternating copolymer is preferable in that the charge transport ability is further enhanced.

[Insolubilized group]
The polymer compound in the present invention preferably has a group containing an insolubilizing group as a substituent.
The insolubilizing group is a group that reacts by irradiation with heat and / or active energy rays, and is a group having an effect of lowering solubility in an organic solvent or water after the reaction than before the reaction.
In the present invention, the insolubilizing group is preferably a dissociating group or a crosslinkable group.
The polymer compound has a group containing an insolubilizing group as a substituent, but the position having the insolubilizing group may be in the repeating unit represented by the formula (II) or represented by the formula (II). You may have in parts other than a repeating unit, for example, a terminal group.

(Dissociable group)
The polymer compound in the present invention preferably has a dissociation group as an insolubilizing group from the viewpoint of excellent charge transport ability after insolubilization (after dissociation reaction).

  Here, the dissociating group refers to a group that dissociates from a bonded aromatic hydrocarbon ring at 70 ° C. or more and is soluble in a solvent. Here, being soluble in a solvent means that the compound is dissolved in toluene at 0.1% by weight or more at room temperature in a state before reacting by irradiation with heat and / or active energy rays. The solubility in toluene is preferably 0.5% by weight or more, more preferably 1% by weight or more.

Such a dissociating group is preferably a group that thermally dissociates without forming a polar group on the aromatic hydrocarbon ring side, and more preferably a group that dissociates thermally by a reverse Diels-Alder reaction.
Furthermore, it is preferably a group that thermally dissociates at 100 ° C. or higher, and preferably a group that thermally dissociates at 300 ° C. or lower.

Specific examples of the dissociating group are as follows, but the present invention is not limited thereto.
A specific example in the case where the dissociating group is a divalent group is as shown in <Divalent dissociating group group A> below.
<Divalent dissociation group A>

A specific example in the case where the dissociating group is a monovalent group is as shown in <Monovalent dissociating group B> below.
<Monovalent dissociation group B>

(Dissociation group position and ratio)
In the present invention, the number of dissociation groups contained in one polymer compound chain is preferably 5 or more on average, more preferably 10 or more on average, more preferably 50 or more on average. Below this lower limit, the solubility of the polymer compound in the coating solvent before heating may be low, and the effect of lowering the solubility of the compound in the solvent after heating may also be reduced.

Further, the number of dissociation groups possessed by the polymer compound in the present invention is usually 0.01 or more, preferably 0.1 or more, more preferably 0.2 or more, per 1000 molecular weight of the polymer compound. In addition, it is usually 10 or less, preferably 5 or less. Within this range, a suitable solubility difference is obtained before and after insolubilization (dissociation reaction), which is preferable.
When the polymer compound in the present invention has a dissociation group as an insolubilizing group, Ar ¹¹ , Ar ¹² or Ar ¹⁴ may be a group in which at least one is selected from <divalent dissociation group A>. Ar ¹³ and Ar ¹⁵ may be a group selected from <monovalent dissociation group B>.

(Crosslinkable group)
In addition, the polymer compound in the present invention has a crosslinkable group as an insolubilizing group, so that it can be dissolved in a solvent before and after a reaction (insolubilizing reaction) caused by irradiation with heat and / or active energy rays. This is preferable in that a large difference can be generated.
Here, the 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.

  [Crosslinkable group T]

(In formula, R < ¹ > -R < ⁵ > represents a hydrogen atom or an alkyl group each independently. Ar < ³¹ > may have the aromatic hydrocarbon group or substituent which may have a substituent. Represents an aromatic heterocyclic group.)
Groups that are insolubilized by cationic polymerization, such as cyclic ether groups such as epoxy groups and oxetane groups, and vinyl ether groups are preferred because they are highly reactive and easily insolubilized. 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 from the viewpoint of further improving electrochemical stability.
Among the crosslinkable groups, a group derived from a benzocyclobutene ring is particularly preferable in that the structure after insolubilization is particularly stable.
The crosslinkable group may be directly bonded to the aromatic hydrocarbon group or aromatic heterocyclic group in the molecule, but 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 an aromatic hydrocarbon group or an aromatic heterocyclic group via a divalent group formed by connecting them individually.

[Synthesis method]
The compound having a terminal group can be synthesized by selecting a raw material according to the structure of the target compound and using a known method.
The compound having a terminal group comprises a halide represented by the general formula (Va) and a secondary amine compound represented by the general formula (Vb) as in the following formula: potassium carbonate, tert-butoxy sodium, triethylamine. In the presence of a base such as, it is obtained by reacting with a halide represented by the general formula (Vd) and a secondary amine compound represented by the general formula (Ve) under the same conditions. If necessary, a transition metal catalyst such as copper or a palladium complex can also be used.
Further, the compound having a terminal group includes a halide represented by the general formula (Va) as shown in the following formula and a boron compound represented by the general formula (Vc) such as potassium carbonate, tert-butoxy sodium, triethylamine, etc. In the presence of a base, the polymer is successively polymerized and then reacted under the same conditions with a halide represented by the general formula (Vd) and a boron compound represented by the general formula (Vf). If necessary, a transition metal catalyst such as copper or a palladium complex can also be used.

  That is, a compound having a terminal group is obtained by reacting Formula (Va) with Formula (Vb) to form an N—Ar bond (for example, Buchwald-Hartwig coupling, Ullmann coupling, etc.), or by formula (Va). And the formula (Vc) are sequentially polymerized by a reaction (for example, Suzuki coupling) to form an Ar-Ar bond, and after forming a polymer, a reagent capable of reacting with end groups on both sides is allowed to act. can get.

(In the formula, X represents a halogen atom or a sulfonate group such as a CF ₃ SO ₂ O— group, and Ar ′ has an aromatic hydrocarbon group or a substituent which may have a substituent. R ′ represents a hydroxy group or an alkoxy group that may be bonded to each other to form a ring, and Ar ^{a to} Ar ^g may each independently have a substituent. And a divalent aromatic heterocyclic group which may have a valent aromatic hydrocarbon group or a substituent.)
In the compound having a terminal group, at least one of Ar ^a or Ar ^b and Ar ^a or Ar ^c preferably contains a divalent group represented by the following formula (VI).

(In the formula, each of R ⁵¹ and R ⁵² independently represents a hydrogen atom, an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. Represents an alkyl group which may have a group, and R ⁵¹ and R ⁵² may be bonded to each other to form a ring.)
Hereinafter, preferred specific examples of Ar ^a and Ar ^c are shown below, but the present invention is not limited thereto.

  Although the preferable specific example of a formula (Vb) is shown below, this invention is not limited to these.

Although the preferable specific example of a formula (Vb) is shown below, this invention is not limited to these.

Hereinafter, preferred specific examples of Ar ^d and Ar ^f are shown, but the present invention is not limited thereto.

Although the preferable specific example of a formula (Ve) is shown below, this invention is not limited to these.

  Methods for purifying compounds include “Separation and Purification Technology Handbook” (1993, edited by The Chemical Society of Japan), “Advanced separation of trace components and difficult-to-purify substances by chemical conversion method” (1988, IP Corporation). Issued by C.), or the methods described in the section “Separation and purification” of “Experimental Chemistry Course (4th edition) 1” (1990, edited by The Chemical Society of Japan) can be used. It is. Specifically, extraction (including suspension washing, boiling washing, ultrasonic washing, acid-base washing), adsorption, occlusion, melting, crystallization (including recrystallization from solvent, reprecipitation), distillation (atmospheric pressure) Distillation, vacuum distillation), evaporation, sublimation (atmospheric pressure sublimation, vacuum sublimation), ion exchange, dialysis, filtration, ultrafiltration, reverse osmosis, pressure osmosis, zone lysis, electrophoresis, centrifugation, flotation separation, sedimentation separation, Magnetic separation, various chromatography (shape classification: column, paper, thin layer, capillary, mobile phase classification: gas, liquid, micelle, supercritical fluid. Separation mechanism: adsorption, distribution, ion exchange, molecular sieve, chelate, gel filtration , Exclusion, affinity) and the like.

  Product confirmation and purity analysis methods include gas chromatograph (GC), high performance liquid chromatograph (HPLC), high speed amino acid analyzer (polymer compound), capillary electrophoresis measurement (CE), size exclusion chromatograph (SEC). ), Gel permeation chromatography (GPC), cross-fractionation chromatography (CFC), mass spectrometry (MS, LC / MS, GC / MS, MS / MS), nuclear magnetic resonance apparatus (NMR (1HNMR, 13CNMR)), Fourier Conversion infrared spectrophotometer (FT-IR), UV-visible near-infrared spectrophotometer (UV.VIS, NIR), electron spin resonance apparatus (ESR), transmission electron microscope (TEM-EDX), electron beam microanalyzer (EPMA) , Metal elemental analysis (ion chromatograph, inductively coupled plasma-emission spectroscopy (ICP-AES) atomic absorption Analysis (AAS), fluorescent X-ray analyzer (XRF)), nonmetal element analysis, trace analysis (ICP-MS, GF-AAS, optionally a GD-MS), etc., are applicable.

[Molecular weight of polymer compounds]
The weight average molecular weight (Mw) of the polymer compound in the present invention is usually 20000 or more, preferably 40000 or more, and usually 2000000 or less, preferably 1000000 or less.
The number average molecular weight (Mn) is usually 1000000 or less, preferably 800000 or less, more preferably 500000 or less, and usually 5000 or more, preferably 10,000 or more, more preferably 20000 or more.

If the weight average molecular weight exceeds this upper limit, purification may become difficult due to the high molecular weight of impurities, and if the weight average molecular weight falls below this lower limit, the glass transition temperature, melting point, vaporization temperature, etc. will decrease. Therefore, heat resistance may be significantly impaired.
Further, the dispersity (Mw / Mn: Mw represents a weight average molecular weight and Mn represents a number average molecular weight) of the polymer compound of the present invention is usually 2.40 or less, preferably 2.10 or less, more preferably It is 2.00 or less, Preferably it is 1.00 or more, More preferably, it is 1.10 or more, Most preferably, it is 1.20 or more. If this upper limit is exceeded, the effects of the present invention may not be obtained, for example, purification becomes difficult, solubility in a solvent decreases, or charge transport ability decreases.

  Usually, the weight average molecular weight and the number average molecular weight are 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. By converting, the weight average molecular weight and the number average molecular weight are calculated.

Here, SEC measurement conditions are shown.
The column is TSKgel GMHXL (manufactured by Tosoh Corporation) or a column having a resolution equal to or higher than this,
Particle size: 9mm
Column size: 7.8 mm inner diameter × 30 cm length Guaranteed number of theoretical plates: Two of about 14000 TP / 30 cm are used, and the column temperature is 40 ° C.

The moving bed is selected from tetrahydrofuran and chloroform that do not adsorb to the filler, and the flow rate is 1.0 ml / min. The injection concentration is 0.1% by weight, and the injection amount is 0.10 ml. RI is used as a detector.
The molecular weight distribution is determined by converting the elution time of the sample into the molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) having a known molecular weight. In the SEC measurement, the elution time is shorter for the high molecular weight component, and the elution time is longer for the low molecular weight component.

In addition, the measuring instrument used for measuring the weight average molecular weight (Mw) and the degree of dispersion (Mw / Mn) of the present invention is limited to the measuring instrument as long as it can perform the same measurement as above. Instead, other measuring devices may be used, but the above measuring devices are preferably used.
Hereinafter, preferred specific examples of the polymer compound in which the terminal group in the present invention is an aromatic hydrocarbon group which may have a substituent are shown, but the present invention is not limited thereto.
<Specific examples of polymer compounds>

(Composition)
When the charge transport layer is formed by a wet film-forming method, a hole-transporting compound constituting the charge transport layer and, if necessary, other components are mixed with an appropriate solvent to form a film-forming composition (hereinafter referred to as a film-forming composition) And may be referred to as “composition for forming a charge transport layer”).
The content of the hole transporting compound in the charge transport layer forming composition is usually 0.1% by weight or more, preferably 0.5% by weight or more, usually 50% by weight or less, preferably 20% by weight or less. . In addition, in the composition for charge transport layer formation, 2 or more types of hole transportable compounds may be contained, In that case, it is preferable that the sum total of 2 or more types becomes said range.

The composition for forming a charge transport layer according to the present invention usually contains a solvent.
The solvent contained in the composition for forming a charge transport layer according to the present invention is not particularly limited, but is usually 0.1% by weight, preferably 0.5% by weight, more preferably 1.0%. It is a solvent that dissolves by weight% or more.
The boiling point of the solvent is usually 110 ° C. or higher, preferably 140 ° C. or higher, particularly 200 ° C. or higher, usually 400 ° C. or lower, and preferably 300 ° C. or lower. If the boiling point of the solvent is too low, the drying speed is too high and the film quality may be deteriorated. Further, if the boiling point of the solvent is too high, it is necessary to increase the temperature of the drying step, which may adversely affect other layers and the substrate.

  Specific examples include aromatic compounds 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 glycol-1 -Aliphatic ethers such as monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3 Ether solvents such as aromatic ethers such as dimethylanisole and 2,4-dimethylanisole; aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate, propion Phenyl, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, organic solvent an ester solvents such as benzoic acid n- butyl. These may be used alone or in combination of two or more.

The composition for forming a charge transport layer may contain other components as long as the effects of the present invention are not impaired. Examples of other components include various electron-accepting compounds, light emitting materials, binder resins, leveling agents, coating properties improving agents such as antifoaming agents, and the like. In addition, only 1 type may be used for another component, and 2 or more types may be used together in the combination and ratio of simmering.
When there is a single organic layer between the anode and the light emitting layer, that is, when there is only a charge transport layer, the charge transport layer forming composition preferably contains an electron accepting compound.

As the electron-accepting compound, a compound having an oxidizing power and an ability to accept one electron from the above-described hole-transporting compound 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 the electron-accepting compound include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, iron (III) chloride (Japanese Patent Laid-Open No. 11-251067). Publication), high valence inorganic compounds such as ammonium peroxodisulfate, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365), fullerene derivatives, iodine Etc.

Of the above-mentioned compounds, an onium salt substituted with an organic group, a high-valence inorganic compound, and the like are preferable because they have strong oxidizing power. In addition, an onium salt substituted with an organic group, a cyano compound, an aromatic boron compound, or the like is preferable because it is highly soluble in various solvents and can be applied to form a film by a wet film formation method.
Specific examples of onium salts substituted with organic groups, cyano compounds, and aromatic boron compounds suitable as electron-accepting compounds include those described in WO 2005/089024, and preferred examples thereof are also the same. is there. Examples thereof include compounds represented by the following structural formulas, but are not limited thereto.

In addition, an electron-accepting compound may be used individually by 1 type, and may use 2 or more types by arbitrary combinations and a ratio.
The content of the electron-accepting compound in the composition for forming a charge transport layer is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 20% by weight or less, preferably 10% by weight or less. The first charge transport layer forming composition may contain two or more types of electron accepting compounds, and in that case, the total of the two or more types is preferably within the above range.

  Moreover, when a leveling agent is included, examples of the leveling agent include a silicon-based surfactant and a fluorine-based surfactant. Any one of the leveling agents may be used alone, or two or more thereof may be used in any combination and ratio. The content of the leveling agent in the first charge transport layer forming composition is usually 0.0001% by weight or more, preferably 0.001% by weight or more, and usually 1% by weight or less, preferably 0.1% by weight. % Or less. If the content of the leveling agent is too low, the leveling may be poor. If it is too high, the charge transport ability of the film may be reduced.

  Moreover, when an antifoamer is included, examples of the antifoamer include silicon oil, fatty acid ester, and phosphate ester. Any one type of antifoaming agent may be used alone, or two or more types may be used in any combination and ratio. The content of the antifoaming agent in the first charge transport layer forming composition is usually 0.0001% by weight or more, preferably 0.001% by weight or more, and usually 1% by weight or less, preferably 0.1%. It is in the range of weight percent or less. If the content of the antifoaming agent is too low, the defoaming effect may not be sufficient, and if it is too high, the charge transporting ability of the film may be reduced.

[Film formation method]
The charge transport layer in the present invention is formed by a wet film formation method.
In the present invention, the wet film forming method includes, for example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary coating method, ink jet method, screen printing. This method is a wet film formation method such as a method, a gravure printing method, or a flexographic printing method. Among these film forming methods, a spin coating method, a spray coating method, and an ink jet method are preferable. This is because the liquid property specific to the coating composition used for the organic electroluminescent element is matched.

When a layer is formed by a wet film forming method, usually, a charge transport layer material is mixed with an appropriate solvent to prepare a film forming composition, and the composition is applied to the lower layer by an appropriate method. It coats on the layer to perform and forms into a film by drying. This drying may be heat drying or reduced pressure drying.
When forming a film using an insolubilizing compound, the insolubilizing compound undergoes an insolubilizing reaction and forms a layer by heating and / or irradiation with active energy rays after application as described above.

When the insolubilization method is heating, the heating method is not particularly limited, but the heating condition is that a film formed at 120 ° C. or higher, preferably 400 ° C. or lower is heated. The heating time is usually 1 minute or longer, preferably 24 hours or shorter.
The heating means is not particularly limited, and means such as placing a substrate or a laminate having the formed film on a hot plate or heating in an oven is used. For example, conditions such as heating on a hot plate at 120 ° C. or more for 1 minute or more can be used.

  When the insolubilization method is based on irradiation with active energy rays, direct irradiation using an ultraviolet, visible or infrared light source such as an ultra high pressure mercury lamp, high pressure mercury lamp, halogen lamp or infrared lamp, or the aforementioned light source Examples include a mask aligner incorporated and a method of irradiation using a conveyor type light irradiation device. Further, for example, there is a method of irradiating using a so-called microwave oven that irradiates a microwave generated by a magnetron. As the irradiation time, it is preferable to set conditions necessary for reducing the solubility of the film, but irradiation is usually performed for 0.1 seconds or longer, preferably 10 hours or shorter.

You may perform a heating and / or irradiation of an active energy ray individually or in combination, respectively. When combined, the order of implementation is not particularly limited.
In order to reduce the amount of moisture contained in the layer and / or the amount of moisture adsorbed on the surface of the layer after the heating and / or irradiation with active energy rays, it is performed in an atmosphere not containing moisture such as a nitrogen gas atmosphere. preferable. When performing heating and / or irradiation with active energy rays for the same purpose, it is particularly preferable to perform at least the process immediately before the formation of the upper layer in an atmosphere containing no moisture such as a nitrogen gas atmosphere.
The thickness of the insolubilized film thus formed in the present invention is usually 3 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and usually 100 nm or less, preferably 80 nm or less, more preferably 50 nm or less.

<Reason why the present invention is effective>
The reason why the device according to the present invention has a high current efficiency of the obtained element and can provide effects such as a decrease in light emission luminance and a voltage increase during driving at a constant current is estimated as follows.
When the light emitting layer is formed by a wet film forming method, the interaction with the lower layer of the light emitting layer, the charge transport layer provided adjacent to the anode side of the light emitting layer in the present invention, as compared with the case of forming by a vacuum deposition method However, it is large because the coating liquid easily penetrates into the lower layer, and the lower layer component easily elutes into the light emitting layer.
Furthermore, when the terminal group of the polymer compound contained in the charge transport layer is an aromatic hydrocarbon group which may have a substituent, the charge from the terminal group to the arylamine compound having a similar structure can be reduced. Delivery takes place.
From this, it is presumed that when the terminal group is an aromatic hydrocarbon group, the above-described effect is exhibited.

<Organic electroluminescent device>
Below, the layer structure of the organic electroluminescent element manufactured with the method of this invention, its general formation method, etc. are demonstrated with reference to FIG.

FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device according to 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.
In the case of the element shown in FIG. 1, the hole transport layer corresponds to the charge transport layer.

(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, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

(anode)
The anode 2 serves to inject holes into the layer on the light emitting layer side.
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming the anode 2 using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution It is also possible to form the anode 2 by dispersing it and applying it onto the substrate 1. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.
The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, 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 about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

  For the purpose of removing impurities adhering to the anode 2 and adjusting the ionization potential to improve the hole injection property, the surface of the anode 2 is treated with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma. It is preferable to do.

(Hole injection layer)
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5, and is usually formed on the anode 2.
The method for forming the hole injection layer 3 according to the present invention may be a vacuum deposition method or a wet film formation method, and is not particularly limited, but the hole injection layer 3 is formed by a wet film formation method from the viewpoint of reducing dark spots. It is preferable.
The thickness of the hole injection layer 3 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

<Formation of hole injection layer by wet film formation method>
When forming the hole injection layer 3 by wet film formation, the material for forming the hole injection layer 3 is usually mixed with an appropriate solvent (hole injection layer solvent) to form a film-forming composition (positive A composition for forming a hole injection layer), and applying the composition for forming a hole injection layer on a layer (usually an anode) corresponding to the lower layer of the hole injection layer 3 by an appropriate technique. The hole injection layer 3 is formed by coating and drying.

(Hole transporting compound)
The composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as constituent materials of the hole injection layer.
As long as the hole transporting compound is a compound having a hole transporting property, which is usually used in a hole injection layer of an organic electroluminescence device, a monomer or the like may be a polymer compound or the like. Although it may be a low molecular weight compound, it is preferably a high molecular weight compound.
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 2 to the hole injection layer 3. Examples of hole transporting compounds include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by a fluorene group, hydrazone derivatives, silazane derivatives, silanamines Derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon and the like.

In the present invention, the derivative includes, for example, an aromatic amine derivative and includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton. It may be a mer.
The hole transporting compound used as the material for the hole injection layer 3 may contain any one of these compounds alone, or may contain two or more. When two or more hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or two other hole transporting compounds are used. It is preferable to use the above in combination.

Among the above-mentioned examples, an aromatic amine compound is preferable from the viewpoint of amorphousness and visible light transmittance, and an aromatic tertiary amine compound is particularly preferable. 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 from the viewpoint of uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymerizable compound in which repeating units are linked) is further included. preferable. Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In Formula (I), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Ar ^{3 to} Ar ⁵ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Represents a linking group selected from the group of linking groups, and among Ar ^{1 to} Ar ⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.

(In said each formula, Ar < ⁶ > -Ar < ¹⁶ > represents each independently the aromatic hydrocarbon group which may have a substituent, or the aromatic heterocyclic group which may have a substituent. R ¹ and R ² each independently represents a hydrogen atom or an arbitrary substituent.))
As the aromatic hydrocarbon group and the aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ , a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene from the viewpoint of the solubility, heat resistance, hole injection / transport property of the polymer compound A group derived from a ring or a pyridine ring is preferred, and a group derived from a benzene ring or a naphthalene ring is more preferred.

The aromatic hydrocarbon group and aromatic heterocyclic group of Ar ^{1 to} Ar ¹⁶ may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. As the substituent, an alkyl group, an alkenyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group and the like are preferable.
When R ¹ and R ² are optional substituents, examples of the substituent include an alkyl group, an alkenyl group, an alkoxy group, a silyl group, a siloxy group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. .

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.
In addition, as a hole transporting compound, a conductive polymer (PEDOT / PSS) obtained by polymerizing 3,4-ethylenedioxythiophene (3,4-ethylenedioxythiophene), a polythiophene derivative, in high molecular weight polystyrene sulfonic acid. Is also preferred. Moreover, the end of this polymer may be capped with methacrylate or the like.

  The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably in terms of film thickness uniformity. Is 0.1% by weight or more, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If this concentration is too high, film thickness unevenness may occur, and if it is too low, defects may occur in the formed hole injection layer.

(Electron-accepting compound)
The composition for forming a hole injection layer preferably contains an electron accepting compound as a constituent material of the hole injection layer.
The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is further 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. More specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (International Publication No. WO 2005/089024); High-valent inorganic compounds such as iron (III) chloride (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; Aromatic boron compounds such as); fullerene derivatives; iodine; sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, camphor sulfonate ions, and the like.

These electron accepting compounds can improve the conductivity of the hole injection layer by oxidizing the hole transporting compound.
The content of the electron-accepting compound in the hole-injecting layer or the composition for forming a hole-injecting layer with respect to the hole-transporting compound is usually 0.1 mol% or more, preferably 1 mol% or more. However, it is usually 100 mol% or less, preferably 40 mol% or less.

(Other components)
As a material for the hole injection layer, other components may be further contained in addition to the above-described hole transporting compound and electron accepting compound as long as the effects of the present invention are not significantly impaired. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

(solvent)
At least one of the solvents of the composition for forming a hole injection layer used in the wet film formation method is preferably a compound that can dissolve the constituent material of the hole injection layer. The boiling point of this solvent is usually 110 ° C. or higher, preferably 140 ° C. or higher, particularly 200 ° C. or higher, usually 400 ° C. or lower, and preferably 300 ° C. or lower. If the boiling point of the solvent is too low, the drying speed is too high and the film quality may be deteriorated. Further, if the boiling point of the solvent is too high, it is necessary to increase the temperature of the drying process, which may adversely affect other layers and the substrate.

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, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, aromatic ethers such as 2,4-dimethylanisole, and the like.

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-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Can be mentioned.
Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, and the like.

In addition, dimethyl sulfoxide and the like can also be used.
These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

(Film formation method)
After preparing the composition for forming the hole injection layer, the composition is applied on the layer corresponding to the lower layer of the hole injection layer 3 (usually the anode 2) by wet film formation, and dried. The hole injection layer 3 is formed.
The temperature in the film forming step is preferably 10 ° C. or higher, and preferably 50 ° C. or lower, in order to prevent film loss due to the formation of crystals in the composition.
Although the relative humidity in a film-forming process is not limited unless the effect of this invention is impaired remarkably, it is 0.01 ppm or more normally and 80% or less normally.
After the film formation, the film of the composition for forming a hole injection layer is usually dried by heating or the like. Examples of the heating means used in the heating step include a clean oven, a hot plate, infrared rays, a halogen heater, microwave irradiation and the like. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film.

  The heating temperature in the heating step is preferably heated at a temperature equal to or higher than the boiling point of the solvent used in the composition for forming a hole injection layer as long as the effects of the present invention are not significantly impaired. In the case of a mixed solvent containing two or more types of solvents used in the hole injection layer, at least one type is preferably heated at a temperature equal to or higher than the boiling point of the solvent. In consideration of an increase in the boiling point of the solvent, the heating step is preferably performed at 120 ° C. or higher, preferably 410 ° C. or lower.

  In the heating step, the heating time is not limited as long as the heating temperature is not lower than the boiling point of the solvent of the composition for forming a hole injection layer and sufficient insolubilization of the coating film does not occur. Is less than a minute. If the heating time is too long, the components of the other layers tend to diffuse, and if it is too short, the hole injection layer tends to be inhomogeneous. Heating may be performed in two steps.

<Formation of hole injection layer by vacuum deposition>
When the hole injection layer 3 is formed by vacuum deposition, one or more of the constituent materials of the hole injection layer 3 (the aforementioned hole transporting compound, electron accepting compound, etc.) are placed in a vacuum container. Put in crucibles installed (in case of using two or more materials, put them in each crucible), evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with a suitable vacuum pump, and then heat the crucible (two types When using the above materials, heat each crucible) and evaporate by controlling the amount of evaporation (when using two or more materials, evaporate by independently controlling the amount of evaporation) and face the crucible Then, the hole injection layer 3 is formed on the anode 2 of the substrate placed on the substrate. In addition, when using 2 or more types of materials, the hole injection layer 3 can also be formed by putting those mixtures into a crucible, heating and evaporating.

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, usually 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 Å / second or more and usually 5.0 Å / second or less. The film forming temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher, preferably 50 ° C. or lower.

[Hole transport layer]
The method for forming the hole transport layer 4 according to the present invention may be a vacuum deposition method or a wet film formation method, and is not particularly limited, but the hole transport layer 4 is formed by a wet film formation method from the viewpoint of reducing dark spots. It is preferable.
The hole transport layer 4 can be formed on the hole injection layer 3 when there is a hole injection layer and on the anode 2 when there is no hole injection layer 3.
As the material for forming the hole transport layer and the film forming method, the materials and methods described in the above section <Charge transport layer> can be used. The preferred embodiment is also the same.
The film thickness of the hole transport layer 4 thus formed is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Light emitting layer}
A light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes to which an electric field is applied, and becomes a main light emitting source.
The material and method for forming the light emitting layer are formed by the material and method described in the above section <Light emitting layer>. The preferred embodiment is also the same.

{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. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Further, a compound having at least one pyridine ring substituted at positions 2, 4, and 6 described in International Publication No. 2005-022962 is also preferable as a material for the hole blocking layer 6.

In addition, the material of the hole-blocking layer 6 may use only 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
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.

{Electron transport layer}
An electron transport layer 7 may be provided between the light emitting layer 5 and an electron injection layer 8 described later.
The electron transport layer 7 is provided for the purpose of further improving the current efficiency of the device, and efficiently transports electrons injected from the cathode 9 between the electrodes to which an electric field is applied in the direction of the light emitting layer 5. Formed from a compound capable of
As an electron transport compound used for the electron transport layer 7, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons are transported efficiently with high electron mobility. The compound which can be used is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( 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-type zinc sulfide, n-type Sele Zinc oxide and the like.

In addition, the material of the electron carrying layer 7 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of the electron carrying layer 7. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.
The film thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Electron injection layer}
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into 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, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport compound 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.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

In addition, the material of the electron injection layer 8 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of the electron injection layer 8. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

{cathode}
The cathode 9 plays a role of injecting electrons into a layer (such as the electron injection layer 8 or the light emitting layer 5) 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, a metal having a low work function is preferable. For example, tin, magnesium, indium, A suitable metal such as calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In addition, the material of the cathode 9 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The film thickness of the cathode 9 is usually the same as that of the anode 2.
Further, for the purpose of protecting the cathode 9 made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

{Other layers}
The organic electroluminescent element according to the present invention may have another configuration without departing from the gist thereof. For example, as long as the performance is not impaired, an arbitrary layer may be provided between the anode 2 and the cathode 9 in addition to the layers described above, and an arbitrary layer may be omitted. .

<Electron blocking layer>
Examples of the layer that may be included include an electron blocking layer.
The electron blocking layer is provided between the hole injection layer 3 or the hole transport layer 4 and the light emitting layer 5 and prevents electrons moving from the light emitting layer 5 from reaching the hole injection layer 3. Thus, the probability of recombination of holes and electrons in the light emitting layer 5 is increased, the excitons generated are confined in the light emitting layer 5, and the holes injected from the hole injection layer 3 are efficiently collected. There is a role to transport in the direction of. In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting material, it is effective to provide an electron blocking layer.

  The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer 5 is formed as an organic layer according to the present invention by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (International Publication No. 2004/084260).

In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

Further, at the interface between the cathode 9 and the light emitting layer 5 or the electron transport layer 7, for example, lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ). It is also an effective method to improve the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; (Kaihei 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154, etc.).

Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the case of the layer configuration in FIG. The hole injection layer 3 and the anode 2 may be provided in this order.
Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.

Further, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interface layer between the steps (between the light emitting units) (when the anode is ITO and the cathode is Al, these two layers), for example, a charge made of vanadium pentoxide (V ₂ O ₅ ) or the like. When a generation layer (Carrier Generation Layer: CGL) is provided, the barrier between stages is reduced, which is more preferable from the viewpoint of current efficiency and driving voltage.

Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.
Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

<Organic EL display and organic EL lighting>
The organic EL display and the organic EL illumination of the present invention are provided with the organic electroluminescent element of the present invention as described above. There is no restriction | limiting in particular about the type and structure of an organic electroluminescent display and organic electroluminescent illumination, It can assemble in accordance with a conventional method using the organic electroluminescent element of this invention.
For example, the organic EL display and the organic EL display of the present invention can be obtained by the method described in “Organic EL display” (Ohm, August 20, 2004, published by Shizushi Tokito, Chiba Adachi, Hideyuki Murata). EL illumination can be formed.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and the present invention can be arbitrarily modified and implemented without departing from the gist thereof.
(Synthesis Example 1)

  Aniline (0.951 g, 10.2 mmol), Compound M1 (0.125 g, 0.642 mmol), Compound M2 (3.50 g, 5.43 mmol), and sodium tert-butoxy (3.34 g, 34.8 mmol), Toluene (25 ml) was charged, the inside of the system was sufficiently purged with nitrogen, and the mixture was heated to 50 ° C. (solution A). Tri-t-butylphosphine (0.18 g, 0.87 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.11 g, 0.11 mmol) and heated to 50 ° C. ( Solution B). In a nitrogen stream, solution B was added to solution A and heated to reflux for 1.5 hours. After confirming disappearance of the raw material, Compound M2 (3.22 g, 5.00 mmol) was added. After heating to reflux for 2 hours, more compound M2 (0.07 g, 0.11 mmol) was added. The mixture was further heated under reflux for 2 hours, the reaction solution was allowed to cool, and the reaction solution was dropped into ethanol (250 ml) to crystallize the crude polymer.

  The obtained crude polymer was dissolved in 200 ml of toluene, bromobenzene (0.34 g, 2.1 mmol) and tert-butoxy sodium (3.34 g, 34.8 mmol) were charged, and the inside of the system was sufficiently purged with nitrogen. Warmed to 50 ° C. (Solution C). Tri-t-butylphosphine (0.09 g, 0.48 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.06 g, 0.06 mmol) and heated to 50 ° C. ( Solution D). In a nitrogen stream, solution D was added to solution C, and heated to reflux for 2.5 hours. To this reaction solution, a toluene (2 ml) solution of N, N-diphenylamine (1.84 g, 10.9 mmol) and a solution D prepared again were added, and the mixture was further heated and refluxed for 6 hours. The reaction solution was allowed to cool and toluene was distilled off, followed by dropwise addition to ethanol (300 ml) to obtain a crude polymer.

  This crude polymer was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was separated by filtration. The obtained polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified three times by column chromatography to obtain Target 1 (3.59 g).

Example 1
The organic electroluminescent element shown in FIG. 1 was produced.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 with a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film product) using ordinary photolithography technology and hydrochloric acid etching Then, the anode 2 was formed by patterning into stripes having a width of 2 mm.
The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with an aqueous surfactant solution, water cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, and water cleaning with ultrapure water, followed by drying with compressed air, and finally UV irradiation. Ozone cleaning was performed.

  First, a hole transporting polymer material having a repeating structure represented by the following formula (PX1) (weight average molecular weight: 93000, number average molecular weight: 55000), 4-isopropyl-4′-methyldiphenyl represented by the following formula (A1) A coating solution for forming a hole injection layer containing iodonium tetrakis (pentafluorophenyl) borate and ethyl benzoate was prepared. This coating solution was formed on the anode 2 by spin coating under the following conditions to obtain a hole injection layer 3 having a thickness of 40 nm.

<Coating liquid for hole injection layer formation>
Solvent Ethyl benzoate Coating solution concentration PX1: 2.0% by weight
A1: 0.4% by weight
<Film formation conditions for hole injection layer 3>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In air Heating condition In air 230 ° C 3 hours

  Subsequently, an organic electroluminescence containing a hole transporting polymer material having a repeating structure represented by the following formula (P1) (weight average molecular weight: 55000, number average molecular weight: 35000) (target product 1 synthesized in Synthesis Example 1) A device composition was prepared, formed into a film by spin coating under the following conditions, and insolubilized by heating to form a hole transport layer 4 having a thickness of 20 nm.

<Composition for forming hole transport layer>
Solvent Cyclohexylbenzene Solid Concentration P1: 1.4 wt%
<Film formation conditions for hole transport layer 4>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coating atmosphere In nitrogen Heating conditions In nitrogen, 230 ° C, 1 hour

Next, in forming the light emitting layer 5, the organic electroluminescent element composition shown below is prepared using the following formulas (H1) and (D1), and spin coating is performed on the hole transport layer 4 under the following conditions. Thus, the light emitting layer 5 was obtained with a film thickness of 40 nm.

<Light emitting layer forming coating solution>
Solvent Cyclohexylbenzene Coating solution concentration H1: 3.40% by weight
D1: 0.34% by weight
<Film-forming conditions of the light emitting layer 5>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen Heating condition Under reduced pressure (0.1 MPa), 130 ° C., 1 hour

Here, the substrate on which the light emitting layer 5 has been formed is transferred into a vacuum vapor deposition apparatus connected to a nitrogen glove box, and exhausted until the degree of vacuum in the apparatus is 1.5 × 10 ⁻⁴ Pa or less. The following formula (C1) was laminated by a vacuum deposition method to obtain a hole blocking layer 6. The deposition rate was controlled in the range of 0.5 to 1.5 liters / second, and the hole blocking layer 6 having a film thickness of 10 nm was formed by being laminated on the light emitting layer 5. The degree of vacuum at the time of vapor deposition was 2-4 × 10 ⁻⁵ Pa.

Subsequently, the compound represented by the following formula 3 (C2) was heated and evaporated to form the electron transport layer 7. The degree of vacuum during vapor deposition is 2-4 × 10 ⁻⁵ Pa, the vapor deposition rate is controlled in the range of 0.5-1.0 〜 / sec, and a film with a film thickness of 30 nm is laminated on the hole blocking layer 6. An electron transport layer 7 was formed.

  Here, the element that has been vapor-deposited up to the electron transport layer 7 is transported in vacuum to a chamber connected to the hole blocking layer 6 and the chamber in which the electron transport layer 7 is vapor-deposited, and 2 mm as a mask for cathode vapor deposition. A stripe-shaped shadow mask having a width was brought into close contact with the element so as to be orthogonal to the ITO stripe of the anode 2.

First, lithium fluoride (LiF) is controlled as the electron injection layer 8 at a deposition rate of 0.08 to 0.15 liters / second and a degree of vacuum of 2.5 to 5.5 × 10 ⁻⁵ Pa using a molybdenum boat. A film having a thickness of 0.5 nm was formed on the electron transport layer 7. Next, aluminum is similarly heated as a cathode 9 by a molybdenum boat and controlled at a deposition rate of 0.5 to 1.5 liters / second and a degree of vacuum of 2.0 to 5.5 × 10 ⁻⁵ Pa to a film thickness of 80 nm. An aluminum layer was formed. The substrate temperature during the above two-layer deposition was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, sealing treatment was performed by the method described below.
In a nitrogen glove box, a photocurable resin 30Y-437 (manufactured by Three Bond) is applied to the outer periphery of a 23 mm × 23 mm size glass plate with a width of about 1 mm, and a moisture getter sheet (manufactured by Dynic) is applied to the center. Was installed. On this, the board | substrate which completed cathode formation was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Thereafter, only the region where the photocurable resin was applied was irradiated with ultraviolet light to cure the resin.

As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.
Table 1 shows the characteristics of this element.

表１に示すが如く、本発明の有機電界発光素子は、駆動電圧が低く、電流効率が高い素子であることが分かる。
（合成例２）

As shown in Table 1, it can be seen that the organic electroluminescent element of the present invention is an element having a low driving voltage and high current efficiency.
(Synthesis Example 2)

  Aniline (5.955 g, 63.94 mmol), Compound M1 (0.657 g, 3.365 mmol), 9,9-hexyl 2,7-dibromofluorene (16.56 g, 33.64 mmol), and sodium tert-butoxy ( 20.6 g, 215 mmol) and toluene (100 ml) were charged, and the system was sufficiently purged with nitrogen and heated to 50 ° C. (solution A). Tri-t-butylphosphine (1.1 g, 5.38 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.7 g, 0.67 mmol) and heated to 50 ° C. ( Solution B). In a nitrogen stream, solution B was added to solution A and heated to reflux for 1.5 hours. After confirming disappearance of the raw material, 4,4'-dibromobiphenyl (10.29 g, 32.98 mmol) was added. After heating to reflux for 1.5 hours, the reaction solution was allowed to cool, and the reaction solution was dropped into ethanol to crystallize the crude polymer, which was collected by filtration and dried.

  25.9 g of the resulting crude polymer was dissolved in 500 ml of toluene, and bromobenzene (4.2 g, 26.5 mmol) and tert-butoxy sodium (8.2 g, 85.3 mmol) were charged, and the system was sufficiently purged with nitrogen And heated to 50 ° C. (solution C). Tri-t-butylphosphine (43 g, 2.16 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.28 g, 0.27 mmol) and heated to 50 ° C. (solution D ). In a nitrogen stream, solution D was added to solution C, and heated to reflux for 2 hours. N, N-diphenylamine (13.2 g, 78.1 mmol) was added to the reaction solution, and the mixture was further heated to reflux for 4.5 hours. The reaction solution was allowed to cool and dropped into an ethanol / water mixture to crystallize the crude polymer, which was collected by filtration and dried.

  24.1 g of the obtained crude polymer was dissolved in 490 ml of toluene, and N, N-diphenylamine (6.6 g, 33.64 mmol) and tert-butoxy sodium (10.3 g, 107 mmol) were charged, and the system was sufficiently filled with nitrogen. Replace and warm to 50 ° C. (solution E). Tri-t-butylphosphine (0.55 g, 2.96 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.35 g, 0.34 mmol) and heated to 50 ° 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 dropped into an ethanol / water mixture to crystallize the crude polymer, which was collected by filtration and dried.

  This crude polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The obtained polymer was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was separated by filtration. The polymer collected by filtration was purified by column chromatography to obtain 16.0 g of the target compound 2.

(Synthesis Example 3)
Aniline (5.955 g, 63.94 mmol), Compound M1 (0.657 g, 3.365 mmol), 9,9-hexyl 2,7-dibromofluorene (16.56 g, 33.64 mmol), and sodium tert-butoxy ( 20.6 g, 215 mmol) and toluene (100 ml) were charged, and the system was sufficiently purged with nitrogen and heated to 50 ° C. (solution A). Tri-t-butylphosphine (1.1 g, 5.38 mmol) was added to a 5 ml toluene solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.7 g, 0.67 mmol) and heated to 50 ° C. ( Solution B). In a nitrogen stream, solution B was added to solution A and heated to reflux for 1.5 hours. After confirming disappearance of the raw material, 4,4′-dibromobiphenyl (10.29 g, 32.98 mmol) was added. After heating to reflux for 1.5 hours, the reaction solution was allowed to cool, and the reaction solution was dropped into ethanol to crystallize the crude polymer, which was collected by filtration and dried.

25.9 g of the resulting crude polymer was dissolved in 500 ml of toluene, and bromobenzene (4.2 g, 26.5 mmol) and tert-butoxy sodium (8.2 g, 85.3 mmol) were charged, and the system was sufficiently purged with nitrogen And heated to 50 ° C. (solution C). Tri-t-butylphosphine (43 g, 2.16 mmol) was added to a toluene 5 ml solution of tris (dibenzylideneacetone) dipalladium chloroform complex (0.28 g, 0.27 mmol) and heated to 50 ° C. (solution D ). In a nitrogen stream, solution D was added to solution C, and heated to reflux for 2 hours. N, N-diphenylamine (13.2 g, 78.1 mmol) was added to the reaction solution, and the mixture was further heated to reflux for 4.5 hours. The reaction solution was allowed to cool and dropped into an ethanol / water mixture to crystallize the crude polymer, which was collected by filtration and dried.
This crude polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The obtained polymer was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was separated by filtration. The polymer collected by filtration was purified by column chromatography to obtain 16.0 g of the target product 3.

(Example 2)
The hole injection layer 3 was formed in the same manner as in Example 1.
Subsequently, a composition for an organic electroluminescence device containing the target compound 2 synthesized in Synthesis Example 2 was prepared, formed into a film by spin coating under the following conditions, and insolubilized by heating to transport a hole having a thickness of 20 nm. Layer 4 was formed.

<Composition for forming hole transport layer>
Solvent Cyclohexylbenzene Solid content Polymer 2-1: 1.4% by weight
<Film formation conditions for hole transport layer 4>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coating atmosphere In nitrogen Heating conditions In nitrogen, 230 ° C, 1 hour

  Next, in forming the light emitting layer 5, the organic electroluminescent element composition shown below is prepared using the following formulas (H2) and (D1), and spin coating is performed on the hole transport layer 4 under the following conditions. Thus, the light emitting layer 5 was obtained with a film thickness of 40 nm.

<Light emitting layer forming coating solution>
Solvent Cyclohexylbenzene Coating solution concentration H2: 3.40% by weight
D1: 0.34% by weight
<Film-forming conditions of the light emitting layer 5>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen Heating condition Under reduced pressure (0.1 MPa), 130 ° C., 1 hour

Subsequently, a hole blocking layer 6 was formed in the same manner as in Example 1.
Subsequently, vapor deposition was performed by heating tris (8-quinolinolato) aluminum (Alq3) so as to have a film thickness of 30 nm, whereby the electron transport layer 7 was formed.
Subsequently, in the same manner as in Example 1, an electron injection layer 8 and a cathode 9 were formed, and sealing treatment was performed.
As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained.
Table 2 shows the characteristics of this element.

Example 3
In Example 2, an organic electroluminescence device was produced in the same manner as in Example 2, except that the target 3 synthesized in Synthesis Example 3 was used instead of the target 2.
Table 2 shows the characteristics of this element.

  As shown in Table 2, it can be seen that the organic electroluminescent device of the present invention is a device having high current efficiency and high power efficiency.

  The present invention relates to various fields in which organic electroluminescent elements are used, for example, light sources (for example, light sources of copiers, flat panel displays (for example, for OA computers and wall-mounted televisions) and surface light emitters). It can be suitably used in the fields of liquid crystal displays and backlights of instruments), display panels, indicator lamps and the like.

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

Claims (10)

On a substrate, an anode, a charge transport layer, a light emitting layer, and a cathode are provided in this order. The charge transport layer and the light emitting layer are provided adjacent to each other, and the charge transport layer and the light emitting layer are formed by a wet film formation method. The charge transport layer is an aromatic carbonization which may have a substituent whose group is selected from the group consisting of an alkyl group, an alkoxyl group and an aromatic group. It is a layer formed using a composition containing a polymer compound that is a hydrogen group,
The light emitting layer is a layer containing an arylamine compound. The organic electroluminescent element according to claim 1, wherein the arylamine compound is a compound represented by the following formula (I).

(In formula (I), Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent.) The organic electroluminescent element according to claim 1 or 2, wherein the polymer compound is a polymer compound containing a repeating unit represented by the following formula (II).

(In Formula (II), q represents an integer of 0 to 3, Ar ¹¹ and Ar ¹² each independently have an aromatic hydrocarbon group which may have a substituent, or a substituent. Represents an aromatic heterocyclic group or a direct bond, and Ar ^{13 to} Ar ¹⁵ are each independently an aromatic hydrocarbon group which may have a substituent or an aromatic which may have a substituent. Represents a heterocyclic group, provided that neither Ar ¹¹ nor Ar ¹² is a direct bond.)   The organic electroluminescent element according to claim 1, wherein the polymer compound has an insolubilizing group.   The organic electroluminescent element according to claim 4, wherein the insolubilizing group is a crosslinkable group. The organic electroluminescent element according to claim 5, wherein the crosslinkable group is selected from the following crosslinkable group T.
<Crosslinkable group T>

  The organic electroluminescent device according to claim 4, wherein the insolubilizing group is a dissociating group. The organic electroluminescent element according to claim 7, wherein the dissociating group is selected from the following <divalent dissociating group A> and <monovalent dissociating group B>.
<Divalent dissociation group A>

<Monovalent dissociation group B>

  An organic EL display comprising the organic electroluminescent element according to claim 1.   An organic EL illumination comprising the organic electroluminescent element according to claim 1.

Images