WO2010104183A1

WO2010104183A1 - Composition for organic electroluminescent element, organic electroluminescent element, organic el display, and organic el lighting

Info

Publication number: WO2010104183A1
Application number: PCT/JP2010/054262
Authority: WO
Inventors: 大悟長山; 茂樹長尾; 康嗣山内
Original assignee: 三菱化学株式会社
Priority date: 2009-03-13
Filing date: 2010-03-12
Publication date: 2010-09-16
Also published as: JP2012109286A; TW201042002A

Abstract

Disclosed is a composition for an organic electroluminescent element, which can be used for the manufacture of an organic electroluminescent element having an organic layer that contains a low-molecular-weight molecule and is formed by a wet film formation method, and which can improve the uniformity in film formation. The use of the composition enables the production of an organic electroluminescent element having high performance at low cost. The composition for an organic electroluminescent element is characterized by comprising a light-emitting material, a charge transport material, a high-molecular-weight compound and an organic solvent, wherein the high-molecular-weight compound is composed only of atoms independently selected from the group consisting of a hydrogen atom, an sp2 carbon atom, an sp3 carbon atom, an sp3 oxygen atom and a silicon atom (wherein all of the sp2 carbon atoms contained in the high-molecular-weight compound form an aromatic hydrocarbon group).

Description

Composition for organic electroluminescence device, organic electroluminescence device, organic EL display and organic EL lighting

The present invention relates to a composition for an organic electroluminescence device for forming an organic layer of the organic electroluminescence device. The present invention also relates to an organic electroluminescence device having an organic layer formed using the composition for organic electroluminescence device, an organic EL display, and organic EL illumination.

The organic electroluminescent device usually has an anode, a cathode, and an organic layer such as a light emitting layer and a charge transport layer disposed between the anode and the cathode on a substrate. As a method for forming the organic layer, a vacuum deposition method or a wet film formation method is used.
The vacuum deposition method has advantages such as being able to form a high-quality film uniformly on the substrate, easy to obtain a device that is easy to stack and has excellent characteristics, and that there are very few impurities from the manufacturing process. Many of the organic electroluminescent devices currently in practical use are based on a vacuum deposition method using a low molecular weight material.

On the other hand, the wet film forming method has advantages such as that a vacuum process is not required and a large area can be easily formed, and a plurality of materials having various functions can be put in one layer (coating liquid). is there. When the wet film forming method is used, a polymer material is usually used as the material. However, it is difficult to control the degree of polymerization and molecular weight distribution of polymer materials, deterioration due to terminal residues during continuous driving, high purity of the polymer material itself is difficult, and impurities are included. There is a problem, and there is no practical level other than elements using some polymer materials. Therefore, as an attempt to solve the above problem, in Patent Document 1 and Patent Document 2, an organic layer is formed by a wet film formation method using a low molecular material or the like, but these elements have insufficient luminous efficiency. And practicality was poor.

Further, in Patent Document 3, for example, when forming a light-emitting low molecular material by a wet film formation method by an inkjet method, by adjusting the relative viscosity of the solution with respect to the solvent, the ejection stability of the inkjet or the light emission in the pixel is achieved. It is disclosed to ensure the uniformity of the layer thickness. However, the obtained device characteristics needed to be improved.

Japanese Patent No. 3069139 Japanese Laid-Open Patent Publication No. 11-238359 Japanese Unexamined Patent Publication No. 2008-277322

The present invention provides an organic electroluminescence device having improved film uniformity, low cost and high performance using a composition for an organic electroluminescence device comprising a luminescent material, an electrotransport material, a polymer compound and an organic solvent. The issue is to provide.

In the formation of an organic layer by a wet film forming method, a layer is formed using a composition in which a layer constituent material is dissolved or dispersed in a solvent. Usually, a composition used for wet film formation is prepared with liquid properties (viscosity, surface tension, etc.) according to the application method and application target, but that is not sufficient, and it is not possible to determine the specific properties by studying the present inventors. The inventors have found that the use of a polymer compound has a significant effect on the uniformity of film formation, and have reached the present invention. That is, the present invention is a composition for an organic electroluminescent device comprising a light emitting material, a charge transport material, a polymer compound and an organic solvent, wherein the polymer compound comprises a hydrogen atom, an sp2 carbon atom, an sp3 carbon atom, Composition for organic electroluminescence device, characterized in that it is composed only of atoms selected from the group consisting of sp3 oxygen atoms and silicon atoms (provided that all sp2 carbon atoms contained in the polymer compound are aromatic It exists in the composition for organic electroluminescent elements which comprises a hydrocarbon group, the organic electroluminescent element containing the layer formed using this, an organic EL display, and organic EL illumination.

The reason why the effects of the present invention can be obtained by including the polymer compound is estimated as follows.
The polymer compound in the present invention does not contain a halogen atom or an unsaturated double bond in the structure. Therefore, it is excellent in electrical stability and thermal stability, and even when used as an element, it is unlikely to cause cracking.
More specifically, since it does not have a chemically unstable group, it is difficult to be reduced or oxidized by electrons or holes during driving. In other words, it is difficult to become a trap of electrons and holes, and it is difficult to be decomposed by reduction or oxidation, and gas generation is not caused.
Furthermore, if the polymer compound is soluble in a solvent, the polymer chain has a certain spread in the solution. That is, the free volume of the polymer compound increases. It is presumed that the aggregation of the low molecular weight compounds is suppressed by the low molecular weight compounds entering the gaps between the high molecular weight compounds having an increased free volume.

Furthermore, in the composition for organic electroluminescent elements, it was also found that the rate of change in the viscosity of the composition when the solvent evaporates affects the uniformity of film formation. That is, the present invention further includes the composition for organic electroluminescence device, wherein the viscosity increase coefficient n calculated from {Method for calculating the viscosity increase} is 0.2 or more, and using the composition The organic electroluminescence device includes a layer formed by the above-described method, and the organic EL display and the organic EL lighting.

{Calculation method of thickening coefficient}
After measuring the viscosity of the composition before concentration, the composition (10 g) is dried under reduced pressure, and the composition weight is 1/2 (5 g), 1/3 (3.3 g), 1/4 (2.5 g). The viscosity of the composition concentrated to is measured.
The horizontal axis x is a multiple of the above concentrated concentration (1, 2, 3...), The vertical axis y is the viscosity, and the curve with the measured data is approximated by an exponential function. To calculate the value.
y = μ1 × exp (n × (x−1)) (1)
(In the above formula, μ1 is the viscosity of the composition before concentration, and n is the thickening coefficient.)

A uniform film is formed as a film produced using the composition for organic electroluminescent elements of the present invention. More specifically, when the coating is selectively performed in a region partitioned by the bank, the film thickness distribution in the bank is uniform, and in particular, the film thickness distribution uniformity when a light emitting element is formed in a large area. Will improve.
Moreover, the element containing the film | membrane formed using the composition for organic electroluminescent elements of this invention has a favorable element characteristic, and has especially long drive life.

It is sectional drawing which shows typically an example of the structure of the organic electroluminescent element of this invention. The relationship between the concentration ratio and the viscosity of the composition in the compositions obtained in Examples 1 to 3 and Comparative Example 1 is shown. The vertical axis represents the viscosity (cP) of the composition, and the horizontal axis represents the concentration rate. FIG. 6 is a cross-sectional view schematically showing the structures of measurement sample substrates in Examples 4 to 7 and Comparative Examples 2 to 3. It is a figure which shows the optical microscope photograph (a) and cross-sectional shape (b) of the light emitting layer film obtained in Example 4. FIG. It is a figure which shows the optical microscope photograph (a) and cross-sectional shape (b) of the light emitting layer film obtained in Example 5. FIG. It is a figure which shows the optical microscope photograph (a) and cross-sectional shape (b) of the light emitting layer film obtained in Example 6. FIG. It is a figure which shows the optical microscope photograph (a) and cross-sectional shape (b) of the light emitting layer film obtained by the comparative example 2. It is a figure which shows the optical microscope photograph (a) of the light emitting layer film obtained in Example 7, and the optical microscope photograph (b) of the light emitting layer film obtained in Comparative Example 3.

Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. It is not specified in the contents.

<Composition for organic electroluminescence device>
The composition for an electroluminescent device of the present invention contains a light emitting material, a charge transport material, a polymer compound and an organic solvent, and the polymer compound contains a hydrogen atom, an sp2 carbon atom, an sp3 carbon atom, an sp3 oxygen atom, and It is characterized by comprising only atoms selected from the group consisting of silicon atoms (provided that all sp2 carbon atoms contained in the polymer compound constitute an aromatic hydrocarbon group).

[Polymer compound]
The polymer compound contained in the composition for organic electroluminescence device of the present invention is composed of only an atom selected from the group consisting of a hydrogen atom, sp2 carbon atom, sp3 carbon atom, sp3 oxygen atom and silicon atom, and the polymer All sp2 carbon atoms contained in the compound are polymer compounds characterized in that they constitute an aromatic hydrocarbon group.

Among the polymer compounds in the present invention, a polymer compound composed of a siloxane bond is preferable because it is particularly excellent in chemical stability. More specifically, the polymer compound composed of a siloxane bond is a polymer compound composed of a repeating unit represented by the following formula (X).

(In the formula (X), R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, an aralkyl group, or an aromatic hydrocarbon group.)

In the formula (X), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, an aralkyl group, or an aromatic hydrocarbon group.
Examples of the alkyl group include alkyl groups having 1 to 8 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, Etc.
Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 18 carbon atoms, such as phenyl group, naphthyl group, anthryl group, phenanthryl group, tetralyl group, triphenylyl group, chrysene group, pyrene group, perylene. Group, pentacene group, methylphenyl group, benzyl group, tolyl group, alkylnaphthyl group, and the like.
Examples of the aralkyl group include aralkyl groups having 7 to 30 carbon atoms, such as benzyl group, phenylethyl group, phenylpropyl group, phenylisopropyl group, phenylbutyl group, naphthylmethyl group, naphthylethyl group, naphthylpropyl group, naphthylbutyl. Groups and the like.
In the present invention, the polymer compound comprising a siloxane bond may contain two or more repeating units represented by the above formula (X).

In the above formula (X), a polymer compound represented by the following formula (X1) is more preferable from the viewpoint of being extremely stable thermally.

(In the above formula (X1), R ² is the same as in the above formula (X). M and n represent an integer of 0 to 2500.)
Here, in the formula (X1), R ² is the same as the formula (X). In addition, when n is 2 or more, R ² contained in one chain may be different from each other.

The reason why the polymer compound comprising a siloxane bond exhibits the effects of the present invention in the polymer compound of the present invention is estimated as follows.
That is, the composition for organic electroluminescent elements in the present invention is a composition containing a light emitting material, a charge transport material, and a solvent. When the composition is formed into a wet film, the low molecular compound easily forms an aggregate during film formation or drying. It is presumed that this aggregate has an influence on device characteristics. On the other hand, the structure of a polymer compound composed of a siloxane bond is a helical structure. That is, by including a high molecular compound composed of a siloxane bond having a helical structure, the low molecular compound is appropriately dispersed in the structure of the high molecular compound, and aggregation of the low molecular compound is suppressed. For this reason, it is presumed that there is no influence of the device characteristics due to the aggregation of the low molecular compounds, and conversely, the low molecular compounds are appropriately dispersed, leading to improvement of the device characteristics.

Specific examples of these polymer compounds include the following, but are not limited to these as long as the effects of the present invention are not impaired.
For example, siloxanes such as dimethyl siloxane, methyl alkyl siloxane, methyl phenyl siloxane, methyl hydrogen siloxane, cyclic siloxane; silicone oils such as alkyl modified siloxane, polyether modified siloxane, polyester modified siloxane, aralkyl modified siloxane, fluoroalkyl modified siloxane, etc. Is mentioned.

In addition, the polymer compound contained in the composition for organic electroluminescent elements of the present invention is a polymer compound represented by the following formula (XX) in that it is chemically and thermally stable. preferable.

(In the above formula (XX), R ³ to R ⁶ each independently represents any of a hydrogen atom, an alkyl group, an aralkyl group, and an aromatic hydrocarbon group, provided that at least one of R ³ to R ⁶ Represents an aromatic hydrocarbon group having 6 or more carbon atoms.)

Here, as the alkyl group, the aralkyl group and the aromatic hydrocarbon group, those similar to those exemplified as preferred examples of the substituent of the polymer compound comprising the siloxane bond are preferable.
Examples of the aromatic hydrocarbon group substituted with at least one of R ³ to R ⁶ include aromatic hydrocarbon groups having 6 to 18 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, Examples thereof include a tetralyl group, a triphenylyl group, a chrysene group, a pyrene group, a perylene group, a pentacene group, a methylphenyl group, a benzyl group, a tolyl group, and an alkylnaphthyl group.
By substituting at least one of R ³ to R ⁶ with an aromatic hydrocarbon group, the polymer compound represented by the formula (XX) acts as a steric hindrance when forming a helical structure. It is presumed that the free volume retained in the molecular compound molecule increases, and the aggregation suppressing effect of the low molecular compound can be exhibited.
The polymer compound in the present invention may contain two or more repeating units represented by the above formula (XX).

The carbon-carbon saturated bond of the formula (XX) is also chemically stable like the siloxane bond, and has a favorable adverse effect on device characteristics, and is a preferable structure. Since the polymer compound represented by the formula (XX) can have a helical structure similarly to the polymer compound represented by the formula (X), it is estimated that aggregation of the light-emitting material and / or the charge transport material is suppressed.

Specific examples of these polymer compounds include the following, but are not limited to these as long as the effects of the present invention are not impaired.
Examples thereof include alkyl styrene such as polystyrene, polymethyl styrene, polyethyl styrene, polypropyl styrene and polybutyl styrene; other polyolefins and polyphenylene.

The weight average molecular weight (Mw) of the polymer compound of the present invention is usually 1,000 or more, preferably 10,000 or more, and usually 1,000,000 or less, preferably 500,000 or less.
Within the above range, the composition in the composition for organic electroluminescent elements exhibits appropriate solubility in the solvent, which is preferable from the viewpoint of good storage stability of the composition.

The glass transition temperature of the polymer compound in the present invention is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 130 ° C. or higher. Further, the higher the glass transition temperature is, the higher the effect of suppressing aggregation of low molecular compounds in the heating process at the time of device preparation is, so there is no particular upper limit, but it is usually 180 ° C. or lower.
Within the above range, the effect of suppressing aggregation of low molecular weight compounds in the heating process at the time of device fabrication is high, and deformation during driving the device is small, which is preferable.

The saturated solubility of the polymer compound in the present invention in toluene at normal temperature and normal pressure is usually 0.02% by weight or more, preferably 0.2% by weight or more, and more preferably 2.0% by weight or more. The upper limit of the saturation solubility of the polymer compound is 50% by weight.
Since the high molecular compound having a saturation solubility within the above range has a sufficiently higher saturation solubility than the low molecular compound contained in the composition, the low molecular compound starts to precipitate first when drying after film formation. At this time, as described above, the precipitated low molecular compound is taken into the helical structure of the high molecular compound in the composition, and the effect of suppressing aggregation between the low molecular compounds can be expected, which is preferable.

The polymer compound contained in the composition for organic electroluminescence device is usually 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, and usually less than 50% by weight, based on the solid content. Preferably it is 40 weight% or less, More preferably, it is 30 weight% or less.
Within the above range, it is preferable in terms of improving the light emitting characteristics of the device, since it exhibits appropriate compatibility with the low molecular component contained in the composition for organic electroluminescent devices.

[Thickening coefficient]
The thickening coefficient in the present invention is calculated from the following {Thickening coefficient calculation method}.

{Calculation method of thickening coefficient}
After measuring the viscosity of the composition (10 g) before concentration, it was dried under reduced pressure, and the composition weight was concentrated to 1/2 (5 g), 1/3 (3.3 g), and 1/4 (2.5 g). The viscosity of the composition is measured.
The horizontal axis x is a multiple of the above concentrated concentration (1, 2, 3...), The vertical axis y is the viscosity, and the curve with the measured data is approximated by an exponential function. To calculate the value.
y = μ ₁ × exp (n × (x−1)) (1)
(In the above formula, μ ₁ is the viscosity of the composition before concentration, and n is the thickening coefficient.)

The method for measuring the viscosity is not particularly limited. For example, the viscosity of the composition is measured using a TV-20 viscometer (manufactured by Toki Sangyo Co., Ltd.) which is an E type rotational viscometer.
The measurement temperature is room temperature (25 ° C.). When measuring with an E-type rotational viscometer, the number of rotations is not particularly limited, but is within the range of 10 to 100 rpm.

(About n)
The thickening coefficient n calculated from the formula (1) is usually 0.2 or more, preferably 0.3 or more, more preferably 0.4 or more, and usually 4 or less, preferably 3 or less, more preferably 2 It is as follows.
Within the above range, the effect of suppressing the flow of the solute in the composition for organic electroluminescent elements is likely to occur, and the flatness of the coating film is sufficient. Further, the leveling is hardly inhibited and the surface roughness of the coating film surface is hardly affected.
In order to make the above-mentioned viscosity coefficient range, the polymer compound contained in the composition for organic electroluminescent elements is usually 1% by weight or more and usually 50% by weight or less in terms of the solid content. Achieved.

The reason why the effect of the present invention is further exhibited by the composition for organic electroluminescent elements of the present invention having a viscosity increase coefficient n of 0.2 or more is presumed as follows. That is, when the value of the thickening coefficient n is within the above range, the flow caused by the local tension change due to local solvent evaporation or the solvent diffusion phenomenon acts in the direction in which the increase in viscosity cancels out. The effect of suppressing the flow of the solute contained in the composition for a light emitting device is likely to occur. When the flow suppression effect occurs, segregation and uneven distribution of solutes in the film are suppressed, and it is assumed that the film formed by the wet film forming method using the composition is excellent in uniformity.

[Constituent Components and Composition of Composition for Organic Electroluminescence Device of the Present Invention]
The composition for an organic electroluminescent device of the present invention further contains a light emitting material and a charge transport material in addition to the above specific polymer compound, and preferably contains them as a low molecular compound.
The molecular weight of the low molecular weight compound in the present invention 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 200 or more, more preferably 300 or more, still more preferably. Is in the range of 400 or more.

{Luminescent low molecular weight compounds}
The composition for organic electroluminescent elements of the present invention preferably contains a light-emitting low molecular compound as the low molecular compound.
The light emitting low molecular compound is not particularly limited as long as it is a compound having a light emitting property defined by a single molecular weight, and a known material can be applied. For example, it may be a fluorescent low molecular weight compound or a phosphorescent low molecular weight compound, but from the viewpoint of internal quantum efficiency, it is preferably a phosphorescent low molecular weight compound.
For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the luminescent low molecular weight compound or to introduce a lipophilic substituent such as an alkyl group.

Hereinafter, examples of the fluorescent light-emitting low molecular compound among the light-emitting low molecular compounds will be described, but the fluorescent light-emitting low molecular compound is not limited to the following examples.
Examples of the fluorescent light emitting material that gives blue light emission (blue fluorescent light emitting material) include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

Examples of the fluorescent light emitting material that gives green light emission (green fluorescent light emitting material) include quinacridone derivatives, coumarin derivatives, aluminum complexes such as Al (C ₉ H ₆ NO) _3, and the like.
Examples of the fluorescent light-emitting material that gives yellow light (yellow fluorescent light-emitting material) include rubrene and perimidone derivatives.

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

As the phosphorescent material, for example, a long-period type periodic table (hereinafter, unless otherwise specified, the term “periodic table” refers to a long-period type periodic table) selected from Group 7 to 11 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 phosphorescent materials 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, octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

In addition, only 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.
Specific examples of the light emitting low molecular weight compound are shown below, but the present invention is not limited to these. Hex represents a hexyl group.

{Charge transporting low molecular weight compounds}
The composition for organic electroluminescent elements of the present invention preferably contains a charge transporting low molecular weight compound as the low molecular weight compound.
In the present invention, only one kind of charge transporting low molecular weight compound may be used, or two or more kinds may be used in any combination and ratio.

In the light emitting layer, it is preferable to use a light emitting material as a dopant material and a charge transporting low molecular weight compound as a host material.
The charge transporting low molecular weight compound may be a compound that has been conventionally used in a light emitting layer of an organic electroluminescence device, and particularly a compound that is used as a host material of the light emitting layer.
Specific examples of charge transporting low molecular weight compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which tertiary amines are linked by a fluorene group. , Hydrazone compounds, silazane compounds, silanamine compounds, phosphamine compounds, quinacridone compounds, anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, silole compounds Etc.

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 such as aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine (J Lumin., 72-74, 985, 1997), an aromatic amine compound composed of a tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 ′, 7, Fluorene compounds such as 7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synth. Metals, 91, 209, 1997), 4,4′- , Carbazole compounds such as N′-dicarbazole biphenyl, 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5 -Oxadiazole compounds such as bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5-bis (6 '-(2', 2 "-bipyridyl))-1, Silole compounds such as 1-dimethyl-3,4-diphenylsilole (PyPySPyPy), phenanthroline such as bathophenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproin) System compounds and the like.

Specific examples of the charge transporting low molecular weight compound are shown below, but the present invention is not limited thereto. Bu represents a butyl group.

{Organic solvent}
The composition for organic electroluminescent elements of the present invention usually further contains an organic solvent.
The solubility parameter (Hildebrand Solubility Parameter) of the organic solvent contained in the composition for organic electroluminescence device of the present invention is usually 8 cal / cm ³ or more, preferably 8.5 cal / cm ³ or more, and usually 11 cal / cm ³ or less. Preferably, it is 10.5 cal / cm ³ or less.

Furthermore, as the solubility of the organic solvent, the luminescent low molecular weight compound and the charge transporting low molecular weight compound are each usually 0.01% by weight or more, preferably 0.05% by weight or more, at room temperature and normal pressure. It is preferable to dissolve 0.1% by weight or more.

Although the specific example of an organic solvent is given to the following, unless the effect of this invention is 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 effect of the present invention is 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 or more with respect to 100 parts by weight of the organic electroluminescent element composition. The amount is preferably 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, if 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 organic electroluminescent elements, it is made for the sum total of these solvents to satisfy | fill this range.
Moreover, the composition for organic electroluminescent elements in this invention may contain various additives, such as a leveling agent and an antifoamer, for the purpose of improving film forming property.

{Other materials}
Furthermore, surfactants, viscosity modifiers, filler particles and the like may be included as may be contained in the composition for organic electroluminescent elements of the present invention.
As the surfactant, various types such as anionic, cationic, nonionic, and amphoteric surfactants can be used, but nonionic is preferable in that it has a low possibility of adversely affecting electrical characteristics. It is preferable to use a surfactant.

Examples of the anionic surfactant include alkyl sulfate ester surfactants such as “Emar 10” (manufactured by Kao Corporation), alkyl naphthalene sulfonate surfactants such as “Perex NB-L”, and the like. Special polymeric surfactants such as “Homogenol L-18” and “Homogenol L-100” can be mentioned. Of these, special polymer surfactants are preferred, and special polycarboxylic acid type polymer surfactants are more preferred.

Examples of the cationic surfactant include alkylamine salt surfactants such as “Acetamine 24” (manufactured by Kao Corporation), and quaternary ammonium salt interfaces such as “Cotamine 24P” and “Cotamine 86W”. Examples include activators. Of these, quaternary ammonium salt surfactants are preferred, and stearyltrimethylammonium salt surfactants are more preferred.

Examples of the nonionic surfactant include silicone surfactants such as “SH8400” (manufactured by Torre Silicone), “KP341” (manufactured by Silicone), “FC430” (manufactured by Sumitomo 3M), Fluorine surfactants such as “F470” (Dainippon Ink Chemical Co., Ltd.), “DFX-18” (Neos), etc., “Emulgen 104P” (Kao Corporation), polyoxyethylene such as “Emulgen A60” And surface active agents. Of these, silicone surfactants are preferable, and so-called polyether-modified or aralkyl-modified silicone surfactants having a structure in which a side chain of a polyether group or an aralkyl group is added to polydimethylsiloxane are more preferable.

Two or more kinds of surfactants may be combined. Silicone surfactant / fluorine surfactant, silicone surfactant / special polymer surfactant, fluorine surfactant / special polymer surfactant Examples include combinations of agents. Of these, silicone surfactants / fluorine surfactants are preferred. Examples of the silicone surfactant / fluorine surfactant combination include polyether-modified silicone surfactant / oligomer-type fluorine surfactant. Specifically, for example, “TSF4460” (manufactured by GE Toshiba Silicone) / “DFX-18” (manufactured by Neos), “BYK-300” (manufactured by BYK Chemie) / “S-393” (manufactured by Seimi Chemical) ), “KP340” (manufactured by Shin-Etsu Silicone) / “F-478” (manufactured by Dainippon Ink & Co.), “SH7PA” (manufactured by Tore Silicone) / “DS-401” (manufactured by Daikin), “L-77” (Nihon Unicar Co., Ltd.) / "FC4430" (Sumitomo 3M Co., Ltd.).

The content of the surfactant in the composition for organic electroluminescent elements of the present invention is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 1% by weight or less, preferably 0.2% by weight. It is as follows.
Moreover, in order to adjust a viscosity, the viscosity modifier may be contained. Examples of the viscosity adjusting agent include polymer thickeners such as polystyrene, polyurethane, and polyamide, and solvent-type diluents such as high-boiling aromatics, ketones, and esters.

The content of the viscosity modifier in the organic electroluminescent device composition of the present invention is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 1% by weight or less, preferably 0.2% by weight. It is as follows.
In addition, filler particles may be included for adjusting the coating film thickness and electrical characteristics. Examples of the filler particles include organic pigments such as phthalocyanine and anthraquinone, and inorganic pigments such as silica and titanium oxide.
The content of the filler particles in the composition for organic electroluminescent elements of the present invention is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 1% by weight or less, preferably 0.5% by weight or less. It is.

[Physical properties of organic electroluminescent element composition]
The surface tension of the composition for organic electroluminescent elements of the present invention is usually 25 mN / m or more, preferably 28 mN / m or more, and usually 40 mN / m or less, preferably 35 mN / m or less.
When it is within the above range, the ejection stability in ink jet or nozzle printing is good.
Moreover, the boiling point of the composition for organic electroluminescent elements of the present invention is usually 150 ° C. or higher, preferably 170 ° C. or higher, and usually 270 ° C. or lower, preferably 250 ° C. or lower.
Within the above range, the ejection stability and the uniformity of coating and drying are good.

Moreover, the vapor pressure of the composition for organic electroluminescent elements of the present invention is usually 1 Pa or higher, preferably 10 Pa or higher, and usually 200 Pa or lower, preferably 100 Pa or lower.
Within the above range, the ejection stability and the uniformity of coating and drying are good.
Moreover, the specific gravity of the composition for organic electroluminescent elements of the present invention is usually 0.8 or more, preferably 0.85 or more, and usually 1.0 or less, preferably 0.95 or less.
When it is within the above range, the ejection stability in ink jet or nozzle printing is good.

[Usage]
The composition for organic electroluminescent elements of the present invention is particularly preferably used for a wet film-forming method.
The wet film forming method in the present invention is a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, a composition jet method, a nozzle printing method, It refers to a method of forming a film using a composition containing an organic solvent, such as screen printing, gravure printing, flexographic printing, and offset printing. From the viewpoint of easy patterning, a die coating method, a roll coating method, a spray coating method, a composition jet method, and a flexographic printing method are preferable.

Among these, it is particularly preferable to use an ink jet method and a nozzle print method because selective wet film formation in a region partitioned by banks is easy.
In addition, it is especially preferable that the composition for organic electroluminescent elements of this invention is used for formation of the light emitting layer in an organic electroluminescent element.

<The manufacturing method of the composition for organic electroluminescent elements of this invention>
Although an example of the manufacturing method of the composition for organic electroluminescent elements of this invention is shown below, this invention is not limited to these.
In particular, the composition for an organic electroluminescent element of the present invention can be produced by combining the methods described below, particularly preferable methods.

[Dissolution process]
In the manufacturing method of the composition for organic electroluminescent elements of this invention, it has a melt | dissolution process normally.
The dissolution step refers to a step of stirring a mixed liquid obtained by mixing a solid with an organic solvent so that it cannot be visually confirmed that the solid is floating.

The composition for organic electroluminescent elements of the present invention can be produced by adding and dissolving a rheology adjusting agent when dissolving a low molecular compound in an organic solvent.
The rheology preparation agent is a material added to change the viscoelastic behavior of the solution. For example, inorganic materials such as silica and clay, polymers and oligomers described in the above (non-light-emitting polymer), etc. These organic materials are mentioned. Among these, polymer-based rheology adjusters, that is, the polymers described in the above (non-light-emitting polymer) are suitably used for the composition for organic electroluminescent elements.
The molecular weight of the rheology preparation agent is usually 1,000 or more, preferably 10,000 or more, and usually 1,000,000 or less, preferably 500,000 or less.

(solubility condition)
The temperature in the dissolution step is usually 30 ° C. or higher, preferably 50 ° C. or higher, and usually 100 ° C. or lower, preferably 80 ° C. or lower.
Within the above range, it is preferable in that a desired concentration can be obtained without evaporating the organic solvent and changing the concentration or decreasing the solubility.
When the solute is dissolved in the solvent, it may be dissolved while stirring. In that case, the stirring speed is usually 10 rpm or more, preferably 20 rpm or more, and usually 200 rpm or less, preferably 100 rpm or less.
The atmosphere in the dissolution step is not particularly limited as long as the effects of the present invention are not impaired, and examples thereof include an inert gas. As an inert gas, nitrogen, argon, etc. are mentioned, for example, Nitrogen is preferable at the point which is easy to handle.

[Filtration process]
It is preferable to further filter after dissolution.
The time for filtration is preferably either immediately after the dissolution step (when heated, after cooling to the storage temperature), or just before taking out from the storage container when filling the storage container, or a combination thereof. .
The absolute filtration accuracy of the filter used for the filtration of the present invention is usually 0.5 μm or less, preferably 0.1 μm or less.

<Organic electroluminescent device>
Below, the layer structure of the organic electroluminescent element manufactured using the composition for organic electroluminescent elements 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 bank, 6 represents a light emitting layer, 7 represents a cathode, 8 represents an electron injection layer, 9 represents an electron transport layer, and 11 represents an electron blocking layer.

[substrate]
The substrate serves as a support for the organic electroluminescence device, and quartz or glass plates, metal plates or metal foils, plastic films, sheets, or the like are 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 plays a role of hole injection into the layer on the light emitting layer side.
This anode is usually made of metal such as aluminum, gold, silver, nickel, palladium, platinum, metal oxide such as indium and / or tin oxide, metal halide such as copper iodide, carbon black, or poly It is composed of conductive polymers such as (3-methylthiophene), polypyrrole and polyaniline.
The anode is usually formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution is used. The anode can also be formed by dispersing and coating the substrate. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or an anode can be formed by applying a conductive polymer on a substrate (Appl. Phys. Lett., 60). Volume, 2711, 1992).

The anode usually has a single-layer structure, but it can also have a laminated structure composed of a plurality of materials if desired.
The thickness of the anode 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 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 opaqueness is acceptable, the thickness of the anode is arbitrary, and the anode may be the same as the substrate. Furthermore, it is also possible to laminate different conductive materials on the anode.
For the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve the hole injection property, the anode surface is treated with ultraviolet (UV) / ozone, oxygen plasma or argon plasma. Is preferred.

[Hole injection layer]
The hole injection layer is a layer that transports holes from the anode to the light emitting layer, and is usually formed on the anode.
The method for forming the hole injection layer according to the present invention may be a vacuum vapor deposition method or a wet film formation method, and is not particularly limited. However, from the viewpoint of reducing dark spots, the hole injection layer may be formed by a wet film formation method. preferable.
The thickness of the hole injection layer 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 the hole injection layer is formed by wet film formation, the material for forming the hole injection layer is usually mixed with an appropriate solvent (hole injection layer solvent) to form a composition for film formation (hole injection). Layer forming composition), and applying this hole injection layer forming composition onto a layer corresponding to the lower layer of the hole injection layer (usually an anode) by an appropriate technique, A hole injection layer is formed by drying.

(Hole transporting compound)
The composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as a constituent material of the hole injection layer.
The hole transporting compound is a compound having a hole transporting property that is usually used in a hole injection layer of an organic electroluminescence device, and may be a polymer compound or the like, a monomer 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 to the hole injection layer. 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 may contain any one of these compounds alone, or may contain two or more. In the case of containing two or more kinds of hole transporting compounds, the combination is arbitrary, but one or more kinds of aromatic tertiary amine polymer compounds and one or two kinds of other hole transporting compounds. It is preferable to use the above in combination.

Among the above 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 two groups of Ar ¹ to Ar ⁵ that are bonded to the same N atom may be bonded to each other to form a ring.

(In the above formulas, Ar ⁶ to Ar ¹⁶ each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. R ⁵ and R ⁶ each independently represents a hydrogen atom or an arbitrary substituent.)

The aromatic hydrocarbon group and aromatic heterocyclic group of Ar ¹ to Ar ¹⁶ include a benzene ring, a naphthalene ring, a phenanthrene ring, and a thiophene from the viewpoint of the solubility, heat resistance, and hole injection / transport properties 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 ⁵ and R ⁶ are optional substituents, examples of the substituent include alkyl groups, alkenyl groups, alkoxy groups, silyl groups, siloxy groups, aromatic hydrocarbon groups, aromatic heterocyclic groups, and the like. .

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 hole injection layer preferably contains an electron-accepting compound, and therefore the hole-injection layer composition preferably also 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 having an electron affinity of 4 eV or more is preferable, and a compound of 5 eV or more is more preferable.

Examples of the electron-accepting compound include a triaryl boron compound, a metal halide, a Lewis acid, an organic acid, an onium salt, a salt of an arylamine and a metal halide, and a salt of an arylamine and a Lewis acid. 1 type, or 2 or more types of compounds etc. chosen from are mentioned. More specifically, an onium salt substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (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, tris (pendafluorophenyl) borane (Japanese Patent Laid-Open No. 2003) Aromatic boron compounds; fullerene derivatives; iodine and the like. In addition, only 1 type may be used for an electron-accepting compound, and 2 or more types may be used together by arbitrary combinations and arbitrary ratios.

Since these electron accepting compounds oxidize the hole transporting compound, the conductivity of the hole injection layer can be improved.
The content of the electron-accepting compound 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.

(solvent)
At least one of the solvents contained in the hole injection layer composition is preferably a solvent that can dissolve the material of the hole injection layer.
Moreover, the boiling point of a solvent is 110 degreeC or more normally, Preferably it is 140 degreeC or more, More preferably, it is 200 degreeC or more, and is 400 degrees C or less normally, Preferably it is 300 degrees C or less. If the boiling point of the solvent is too low, the drying speed of the formed film is high, and the film quality may deteriorate. Moreover, if the boiling point of the solvent is too high, the temperature of the drying process increases, which may adversely affect other layers and the substrate 1 (for example, a glass substrate).

Examples of solvents include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like. Specifically, examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3- And aromatic ethers such as dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole. Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate. Further, examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. Etc. 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 as a solvent.

Among the solvents described above, a solvent having a high ability to dissolve the material of the hole injection layer (dissolving ability) or a high affinity with the material is preferable. This is because a composition having a concentration excellent in the efficiency of the film forming process can be prepared by arbitrarily setting the concentration of the composition for the hole injection layer.
In addition, 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and arbitrary ratios.

(Other ingredients)
As a material for the hole injection layer, other components may be further contained in addition to the hole transporting compound and the 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, 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and arbitrary ratios.

(Film formation method)
After preparing the composition for the hole injection layer, the composition is applied onto a layer (usually an anode) corresponding to the lower layer of the hole injection layer by a wet film forming method, and dried to form the hole injection layer. Form. After application, usually drying is performed by heating or the like. The heating means used in the heating step is not limited as long as the effects of the present invention are not significantly impaired. Examples of the heating means include a clean oven, a hot plate, infrared rays, a halogen heater, and microwave irradiation. Among them, a clean oven and a hot plate are preferable in order to uniformly apply heat to the entire film. However, when the composition for hole injection layers contains the arylamine polymer of the present invention, crosslinking is performed after coating.

In the case of forming a layer by a vacuum deposition method, first, one or more materials (hole transporting compound, electron accepting compound, etc.) are put in a crucible installed in a vacuum vessel (two or more types). When using the material, put it in each crucible) and evacuate the inside of the vacuum vessel to about 10 ⁻⁴ Pa with an appropriate vacuum pump. Then, the crucible is heated (each crucible is heated when two or more materials are used), and the evaporation amount is controlled to evaporate (when two or more materials are used, the evaporation amount is controlled independently). And a hole injection layer is formed on the anode of the substrate placed facing the crucible. In addition, when using 2 or more types of materials, they can also be put into a crucible, can be heated and evaporated, and can be used for formation of a positive hole injection layer.

The thickness of the hole injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. If the film thickness is too thin, the hole injection ability may be insufficient, and if it is too thick, the resistance may be increased.
In addition, although a positive hole injection layer is good also as a structure which consists of a single layer, it is good also as a structure by which the several layer was laminated | stacked. In the latter case, the plurality of layers may be layers made of the same material or layers made of different materials.

[Hole transport layer]
The formation method of the hole transport layer 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 may be formed by a wet film formation method from the viewpoint of reducing dark spots. preferable.
The hole transport layer can be formed on the hole injection layer when there is a hole injection layer and on the anode when there is no hole injection layer. The organic electroluminescent device of the present invention may have a configuration in which the hole transport layer is omitted.
The material for forming the hole transport layer is preferably a material having high hole transportability and capable of efficiently transporting injected holes. Therefore, it is preferable that the ionization potential is small, the transparency to visible light is high, the hole mobility is large, the stability is high, and impurities that become traps are not easily generated during manufacturing or use. In many cases, since it is in contact with the light emitting layer, it is preferable not to quench the light emitted from the light emitting layer or reduce the efficiency by forming an exciplex with the light emitting layer.

As a material of such a hole transport layer, any material that has been conventionally used as a constituent material of a hole transport layer may be used. For example, as a hole transport compound used in the above-described hole injection layer What was illustrated is mentioned. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatics Group derivatives, metal complexes and the like.

In addition, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes Derivatives, poly (p-phenylene vinylene) derivatives, and the like. These may be any of an alternating copolymer, a random polymer, a block polymer, or a graft copolymer. Further, it may be a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer.

Of these, polyarylamine derivatives and polyarylene derivatives are preferred.
The polyarylamine derivative is preferably a polymer containing a repeating unit represented by the following formula (II). In particular, the polymer is preferably composed of a repeating unit represented by the following formula (II). In this case, Ar ^a or Ar ^b may be different in each repeating unit.

(In formula (II), Ar ^a and Ar ^b each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which 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, a fluorene ring, and a group in which these rings are linked by a direct bond.

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. Or 2-4 fused ring group derived from and these rings include a group formed by connecting a direct bond or two or more rings.

In view of solubility and heat resistance, Ar ^a and Ar ^b are each independently selected from the group consisting of a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, pyrene ring, thiophene ring, pyridine ring, and fluorene ring. A group derived from a selected ring or a group formed by linking two or more benzene rings (for example, a biphenyl group or a terphenyl group) is preferable.
Among these, a group derived from a benzene ring (phenyl group), a group formed by connecting two benzene rings (biphenyl group), and a group derived from a fluorene ring (fluorenyl group) are preferable.

Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group in Ar ^a and Ar ^b may have include an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, and a dialkyl. Examples thereof include an amino group, a diarylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group.

As the polyarylene derivative, an arylene group such as an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent exemplified as Ar ^a or Ar ^b in the formula (II) is used as ^a repeating unit. The polymer which has is mentioned.
As the polyarylene derivative, a polymer having a repeating unit represented by the following formula (III-1) and / or the following formula (III-2) is preferable.

(In the formula (III-1), R ^a , R ^b , R ^c and R ^d are each independently an alkyl group, an alkoxy group, a phenylalkyl group, a phenylalkoxy group, a phenyl group, a phenoxy group, an alkylphenyl group, Represents an alkoxyphenyl group, an alkylcarbonyl group, an alkoxycarbonyl group, or a carboxy group, and t and s each independently represent an integer of 0 to 3. When t or s is 2 or more, they are contained in one molecule. A plurality of R ^a or R ^b may be the same or different, and adjacent R ^a or R ^b may form a ring.)

(In the formula (III-2), R ^e and R ^f are each independently the same as R ^a , R ^b , R ^c or R ^d in the formula (III-1). Independently represents an integer of 0 to 3. When r or u is 2 or more, a plurality of R ^e and R ^f contained in one molecule may be the same or different, and adjacent R ^e or R ^f may form a ring, and X represents an atom or a group of atoms constituting a 5-membered ring or a 6-membered ring.)
Examples of X, -O -, - BR - , - NR -, - SiR 2 -, - PR -, - SR -, - it is or they are formed by bonding group - CR _2. R represents a hydrogen atom or an arbitrary organic group. The organic group in the present invention is a group containing at least one carbon atom.

Further, the polyarylene derivative has a repeating unit represented by the following formula (III-3) in addition to the repeating unit represented by the above formula (III-1) and / or the above formula (III-2). Is preferred.

(In the formula (III-3), Ar ^c to Ar ^j each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. Independently represents 0 or 1.)
Specific examples of Ar ^c to Ar ^j are the same as Ar ^a and Ar ^b in the formula (II).
Specific examples of the above formulas (III-1) to (III-3) and specific examples of polyarylene derivatives include those described in Japanese Patent Application Laid-Open No. 2008-98619.

When the hole transport layer is formed by a wet film formation method, a composition for forming a hole transport layer is prepared in the same manner as the formation of the hole injection layer, followed by heat drying after the wet film formation.
The composition for forming a hole transport layer contains a solvent in addition to the above hole transport compound. The solvent used is the same as that used for the composition for forming a hole injection layer. The film forming conditions, heat drying conditions, and the like are the same as in the case of forming the hole injection layer.

In the case where the hole transport layer is formed by the vacuum deposition method, the film forming conditions are the same as those in the case of forming the hole injection layer.
The hole transport layer may contain various light emitting materials, electron transport compounds, binder resins, coatability improvers, and the like in addition to the hole transport compound.
The hole transport layer may also be a layer formed by crosslinking a crosslinkable compound. The crosslinkable compound is a compound having a crosslinkable group, and forms a network polymer compound by crosslinking.

Examples of this crosslinkable group include groups derived from cyclic ethers such as oxetane and epoxy; groups derived from unsaturated double bonds such as vinyl, trifluorovinyl, styryl, acrylic, methacryloyl and cinnamoyl; benzo Examples include groups derived from cyclobutene.
The crosslinkable compound may be any of a monomer, an oligomer, and a polymer. The crosslinkable compound may have only 1 type, and may have 2 or more types by arbitrary combinations and ratios.

As the crosslinkable compound, it is preferable to use a hole transporting compound having a crosslinkable group. Examples of the hole transporting compound include those exemplified above, and those having a crosslinkable group bonded to the main chain or side chain with respect to these hole transporting compounds. In particular, the crosslinkable group is preferably bonded to the main chain via a linking group such as an alkylene group. In particular, the hole transporting compound is preferably a polymer containing a repeating unit having a crosslinkable group, and the above formula (II) and formulas (III-1) to (III-3) can be used as a crosslinkable group. Is preferably a polymer having a repeating unit bonded directly or via a linking group.

As the crosslinkable compound, it is preferable to use a hole transporting compound having a crosslinkable group. Examples of hole transporting compounds include nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives; triphenylamine derivatives Silole derivatives; oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like. Among them, nitrogen-containing aromatic derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives; triphenylamine derivatives, silole derivatives, condensed polycyclic aromatic derivatives, metal complexes, etc. Particularly preferred are triphenylamine derivatives.

In order to form a hole transport layer by crosslinking a crosslinkable compound, a composition for forming a hole transport layer in which a crosslinkable compound is dissolved or dispersed in a solvent is usually prepared and formed by wet film formation. Crosslink.
The composition for forming a hole transport layer may contain an additive for promoting a crosslinking reaction in addition to the crosslinking compound. Examples of additives that accelerate the crosslinking reaction include polymerization initiators and polymerization accelerators such as alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts; condensed polycyclic hydrocarbons, And photosensitizers such as porphyrin compounds and diaryl ketone compounds.

Further, it may contain a coating property improving agent such as a leveling agent and an antifoaming agent; an electron accepting compound; a binder resin;
In the composition for forming a hole transport layer, the crosslinkable compound is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, usually 50% by weight or less, preferably 20%. It is contained by weight% or less, more preferably 10% by weight or less.

After forming a composition for forming a hole transport layer containing a crosslinkable compound at such a concentration on a lower layer (usually a hole injection layer), the crosslinkable compound is formed by heating and / or irradiation with electromagnetic energy such as light. A network polymer compound is formed by crosslinking.
Conditions such as temperature and humidity during film formation are the same as those during wet film formation of the hole injection layer.
The heating method after film formation is not particularly limited. As heating temperature conditions, it is 120 degreeC or more normally, Preferably it is 400 degrees C or less.

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 laminated body having a deposited layer 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.
In the case of irradiation with electromagnetic energy such as light, a method of irradiating directly using an ultraviolet / visible / infrared light source such as an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a halogen lamp or an infrared lamp, or the above-mentioned light source is incorporated. Examples include a mask aligner and a method of irradiation using a conveyor type light irradiation device. In electromagnetic energy irradiation other than light, for example, there is a method of irradiation using a device that irradiates a microwave generated by a magnetron, a so-called microwave oven. 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.

Irradiation of electromagnetic energy such as heating and light may be performed individually or in combination. When combined, the order of implementation is not particularly limited.
The film thickness of the hole transport layer thus formed is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{bank}
Banks may be provided in a pattern on the substrate or the hole transport layer. The shape of the bank pattern is not particularly limited and is appropriately selected according to the shape of the light emitting layer 6, the shape of the cathode, and the like, but is preferably a mesh pattern or a stripe pattern.
When the layer provided in the region partitioned by the bank is a light emitting layer, a pattern obtained by inverting the pattern of the light emitting region can be used. When provided for the purpose of partitioning the cathode, etc., the bank can be used as a cathode partition, and can be used for striped patterning of the cathode in an organic electroluminescent panel.
Also, the cross-sectional shape of the bank is not particularly limited. For example, the cross-sectional shape may be a rectangular shape, a semicircular shape, a reverse-tapered trapezoidal shape, a tapered trapezoidal shape, or the like. Also good. Further, the shape seen from the upper surface of the bank is not particularly limited, and may be a shape having an opening such as a rectangle, an ellipse, a rectangle with rounded corners, or a linear shape.

The bank material is not particularly limited as long as it is a material that can form a bank in a desired pattern. For example, the bank may have a charge transport property. In the case where the bank has a charge transporting property, there is an advantage that unevenness of light emission of the element can be reduced even when there is a residue of bank material (separation failure) in the light emitting surface.
Specifically, the bank material may be a resist material such as a screen printing resist material or a photoresist, or a material used for forming the hole transport layer.

Since the screen printing resist material prints the resin only on necessary portions, when the screen printing resist material is used as the bank material, it is relatively less wasteful and can easily cope with a large area. Further, since a developing step is not necessary, there is an advantage that the characteristics of the hole transport layer are not deteriorated by a developer or the like. In addition, since photoresists are widely used, when photoresist is used as a bank material, known conditions can be used as process conditions, high precision of microfabrication, and positive type, negative type, etc. Advantages that cross-sectional shapes such as reverse tapered trapezoidal shapes and tapered trapezoidal shapes can be produced relatively easily by appropriately setting conditions such as material selection, exposure, development, baking, etc. There is.

In addition, as an advantage of using the material used for forming the hole transport layer as the material of the bank, for example, even if a residue remains on the hole transport layer after patterning, the functional layer is affected. Is less likely to affect Alternatively, by using photolithography using a tone mask, etc., it is possible to simplify the manufacturing process by forming a structure having a concave cross-sectional shape and using both a hole transport layer and a bank as a material of the hole transport layer. Can be mentioned.

As the photoresist used as the bank material, either a positive type or a negative type can be used. Examples of the positive photoresist include TELR-P003 PM (manufactured by Tokyo Ohka Kogyo Co., Ltd.) and MCPR i7010N (manufactured by Rohm and Haas Co., Ltd.). An example of a negative photoresist is ZPN2464 (manufactured by Nippon Zeon). The photoresist to be used is preferably selected according to the purpose of forming the bank. For example, when forming for inkjet printing, it is preferable to use a photoresist suitable for forming a bank having a tapered cross section. On the other hand, when a bank is formed as a cathode barrier in a passive matrix display or the like, it is desirable to use a photoresist suitable for forming a bank having a reverse tapered cross section.

In addition, as the material similar to the hole transport layer, the material described in the above-described hole injection layer and hole transport layer, hole blocking layer, light emitting layer, electron transport layer, electron injection layer, which will be described later, Any material described in the column such as the electron blocking layer can be used. Among these, in order to satisfactorily apply different emission colors in the present embodiment, a layer adjacent to the light emitting layer is preferable from the viewpoint that it is desirable to form the light emitting layer immediately after the bank is formed.

The film thickness of the bank is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10 nm or more, preferably 100 nm or more, and usually 100 μm or less, preferably 10 μm or less. Thereby, the film thickness nonuniformity of the functional layer (here, the light emitting layer 6) or a layer formed after the functional layer can be suppressed. In particular, when the first layer formed on the hole transport layer is the light emitting layer 6, it is preferable that the film thickness of the bank is larger than the film thickness of the light emitting layer 6.

The width of the bank is arbitrary as long as the effects of the present invention are not significantly impaired. However, the width is usually 1 μm or more, preferably 10 μm or more in terms of the resolution of the photoresist and the adhesion between the layer provided with the bank and the bank. . In addition, since the region where the bank is usually provided is usually a non-light-emitting region of the organic electroluminescent device, it is usually 500 μm or less, preferably 100 μm or less from the viewpoint of the light emission efficiency and light emitting area of the organic electroluminescent device. .

[Light emitting layer]
When a hole injection layer is provided on the hole injection layer or a hole transport layer, a light emitting layer is provided on the hole transport layer. The light emitting layer is a layer that is excited by recombination of holes injected from the anode and electrons injected from the cathode between the electrodes 2 and 9 to which an electric field is applied, and becomes a main light emitting source.
The light emitting layer is preferably formed by a wet film formation method using the composition for organic electroluminescent elements of the present invention. That is, it is preferable that the composition for organic electroluminescent elements of the present invention is a composition for forming a light emitting layer.

{Method for forming light emitting layer}
When the light emitting layer is formed by a wet film forming method, the compound described in the above [Low molecular compound] section is dissolved in a solvent to prepare a composition for the light emitting layer, and the composition is applied and dried. Moreover, you may make it bridge | crosslink after application | coating as needed. Film formation, drying, crosslinking, and the like may be performed in the same manner as the hole injection layer and the hole transport layer.

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.

[Hole blocking layer]
A hole blocking layer may be provided between the light emitting layer and an electron injection layer described later. The hole blocking layer is a layer stacked on the light emitting layer so as to be in contact with the cathode side interface of the light emitting layer.
This hole blocking layer has a role of blocking holes moving from the anode from reaching the cathode and a role of efficiently transporting electrons injected from the cathode toward the light emitting layer.
The physical properties required for the material constituting the hole blocking layer include high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). It is expensive. Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolate) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed ligand complexes of: metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes; distyryl biphenyl derivatives Styryl compounds (Japanese Patent Laid-Open No. 11-242996); triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (Japan) JP-A-7-41759); phenanthroline derivatives such as bathocuproine (Japanese Patent Application Laid-Open No. 10-79297) Broadcast), and the like. Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-position described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer.

In addition, the material of a hole-blocking layer may use 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios.
There is no restriction | limiting in the formation method of a hole-blocking layer. 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 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. If the hole blocking layer is too thin, the light emission efficiency may be reduced due to insufficient hole blocking capability, and if the hole blocking layer is too thick, the voltage of the device may increase.

[Electron transport layer]
An electron transport layer 7 may be provided between the light emitting layer and an electron injection layer described later.
The electron transport layer 7 has a role of further improving the light emission efficiency of the device.
The physical properties required for the material constituting the electron transport layer 7 include that electrons injected from the cathode can be efficiently transported in the direction of the light emitting layer between the electrodes 2 and 9 to which an electric field is applied. Examples of the material that satisfies such conditions include an electron transporting compound. Among them, usually, a compound that has high electron injection efficiency from the cathode or the electron injection layer and has high electron mobility and can efficiently transport the injected electrons is used. For example, a metal complex such as an aluminum complex of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), a metal complex of 10-hydroxybenzo [h] quinoline, an oxadiazole derivative, 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 6-207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-33159), 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide N-type zinc sulfide, n-type zinc selenide And so on.

In addition, the material of the electron carrying layer 7 may use 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios.
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 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 is a layer that plays a role of efficiently injecting electrons injected from the cathode into the light emitting layer. In order to perform electron injection efficiently, the material for forming the electron injection layer is preferably a metal having a low work function.
Examples include alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium. In this case, the thickness of the electron injection layer is preferably 0.1 nm or more and 5 nm or less.
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 ( Described in Japanese Laid-Open Patent Publication No. 10-270171, Japanese Laid-Open Patent Publication No. 2002-1000047, Japanese Laid-Open Patent Publication No. 2002-1000048, and the like, thereby improving electron injection / transport properties and achieving excellent film quality. It is preferable because it becomes possible. 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 an electron injection layer may use 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios.
There is no restriction | limiting in the formation method of an electron injection layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

[cathode]
The cathode plays a role of injecting electrons into a layer (such as an electron injection layer or a light emitting layer) on the light emitting layer side.
As the material for the cathode, the same materials as those used for the anode can be used. However, a metal having a low work function is preferable for efficient electron injection. For example, a suitable metal such as tin, magnesium, indium, 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.

Note that one type of cathode material may be used, or two or more types may be used in any combination and in any ratio.
The thickness of the cathode is usually the same as that of the anode.
Further, for the purpose of protecting the cathode made of a low work function metal, it is preferable to further stack a metal layer (not shown) 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 use 1 type and may use 2 or more types together by arbitrary combinations and arbitrary ratios.

[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 and the cathode in addition to the layers 3 to 8 described above, and an arbitrary layer may be omitted. Good.

Examples of the layer that may be included include an electron blocking layer. The electron blocking layer is a layer provided between the hole injection layer or the hole transport layer and the light emitting layer. This electron blocking layer increases the recombination probability of holes and electrons in the light emitting layer by preventing electrons moving from the light emitting layer from reaching the hole injection layer or the hole transport layer, It plays a role of confining the generated excitons in the light emitting layer and a role of efficiently transporting holes injected from the hole injection layer in the direction of the light emitting layer. 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 material of the electron blocking layer include a high hole transport ability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, when the light emitting layer is produced 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 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios.

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 and the light emitting layer 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 ), etc. Inserting the formed ultra-thin insulating film (thickness is usually 0.1 nm to 5 nm) is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152). Japanese Laid-Open Patent Publication No. 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 the board | substrate 1 in reverse order. For example, in the case of the layer configuration of FIG. 1, the other components on the substrate 1 are a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, a hole injection layer, and an anode. You may provide in order.
Furthermore, the organic electroluminescent element according to the present invention can be configured by, for example, laminating components other than the substrate between two substrates, at least one of which is transparent.

Further, for example, a structure in which a plurality of components (light emitting units) other than the substrate are stacked (a structure in which a plurality of light emitting units are stacked) may be used. In that case, instead of the interface layer between the steps (between the light emitting units) (in the case where 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 the stages is reduced, which is more preferable from the viewpoint of luminous efficiency and driving voltage.

Further, the organic electroluminescent device 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, and the anode and the cathode are X- You may apply to the structure arrange | positioned at Y matrix form.
Each of the layers 1 to 9 described above may contain components other than those described as materials as long as the effects of the present invention are not significantly impaired.

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

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

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

Example 1
Using the composition (A) prepared as follows, the viscosity increase coefficient was calculated as follows.
(Preparation of composition (A))
The organic compounds (C3), (C4), and the iridium complex (D2) shown below are used as a solvent in a ratio of (C3) :( C4) :( D2) = 10: 10: 1 (weight ratio) as a solvent. Was dissolved so as to have a solid concentration of 1% by weight, and filtered using a PTFE (polytetrafluoroethylene) membrane filter having a pore size of 0.2 μm.

Next, a non-light-emitting polymer represented by the following structural formula (HP1) (weight molecular weight Mw = about 500,000) was added so as to be 1/5 (weight ratio) with respect to the solid content of the solution. The organic electroluminescent element composition of the present invention was prepared.

(Calculation of thickening coefficient)
The viscosity of the composition (A) prepared as described above was measured with a TV-20 viscometer (manufactured by Toki Sangyo Co., Ltd.) which is an E-type rotational viscometer. Subsequently, the solvent component was gradually volatilized under a reduced pressure atmosphere while stirring the composition (A) (10 g) with a magnetic stirrer in a glass petri dish. The viscosity of the composition when the weight of the composition is reduced to 1/2 (5 g), 1/3 (3.3 g), and 1/4 (2.5 g), respectively, is the same as the composition before concentration. Measured.

The measured results of the relationship between the concentration ratio and the viscosity of the composition are shown in Table 1, and a graph of this is shown in FIG.
Table 2 shows the viscosity increase coefficient calculated from the exponential approximation curve obtained from FIG.

(Example 2)
Using the composition (B) prepared as follows, the thickening coefficient was calculated in the same manner as in Example 1.
The measured results of the relationship between the concentration ratio and the viscosity of the composition are shown in Table 1, and a graph of this is shown in FIG.
Table 2 shows the viscosity increase coefficient calculated from the exponential approximation curve obtained from FIG.

(Preparation of composition (B))
In Example 1 (Preparation of composition (A)), the non-light-emitting polymer represented by the formula (HP1) was replaced with the non-light-emitting polymer ADS200RE (American Dye Source represented by the following formula (HP2)). Except that the solid content of the solution was changed from 1/5 (weight ratio) to 1/10 (weight ratio). It melt | dissolved and the composition (B) for organic electroluminescent elements of this invention was prepared.

(Example 3)
Using the composition (C) prepared as follows, the thickening coefficient was calculated in the same manner as in Example 1.
The measured results of the relationship between the concentration ratio and the viscosity of the composition are shown in Table 1, and a graph of this is shown in FIG.
Table 2 shows the viscosity increase coefficient calculated from the exponential approximation curve obtained from FIG.

(Preparation of composition (C))
The non-light emitting polymer represented by the formula (HP1) used in Example 1 was replaced with the non-light emitting polymer KF-96-10000CS represented by the following formula (HP3) (weight molecular weight Mw = about 60,000). (Shin-Etsu Silicone Co., Ltd.) was dissolved in the same manner as in Example 1 except that the solid content of the solution was changed from 1/5 (weight ratio) to 1/10 (weight ratio). The composition (C) for organic electroluminescent elements of the invention was prepared.

(Comparative Example 1)
Using the composition (D) prepared as described below, the thickening coefficient was calculated in the same manner as in Example 1.
The measured results of the relationship between the concentration ratio and the viscosity of the composition are shown in Table 1, and a graph of this is shown in FIG.
Table 2 shows the viscosity increase coefficient calculated from the exponential approximation curve obtained from FIG.

(Preparation of composition (D))
In Example 1, a composition was prepared in the same manner as in Example 1 except that the non-light-emitting polymer represented by the formula (HP1) was not added, to obtain a composition (D).

<Evaluation of ink-jet film formability>
Example 4
The measurement sample shown in FIG. 3 was produced and the film shape of the light emitting layer formed by the inkjet method was evaluated.

(Create measurement sample substrate)
<Preparation of substrate with transparent conductive film>
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate with a thickness of 120 nm (manufactured by Sanyo Vacuum Co., Ltd., sputtered film) is 2 mm wide using normal photolithography and hydrochloric acid etching. An anode was formed by patterning the stripes. The substrate on which the anode is formed 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 a nitrogen blow, and finally UV irradiation. Ozone cleaning was performed.

<Formation of hole injection layer>
Next, a composition for forming a hole injection layer was prepared. 2% by weight of a polymer having a repeating structure of the following formula (IV) (weight average molecular weight 60000) and 0.4% by weight of an electron-accepting compound represented by the following formula (A1) are dissolved in ethyl benzoate as a solvent. A composition for forming a hole injection layer having a solid content concentration of 2.4% by weight was obtained.

On the substrate on which the anode was formed, a film was formed by spin coating using the composition for forming a hole injection layer. Spin coating was performed in an air atmosphere at a temperature of 23 ° C. and a relative humidity of 50%, the spinner rotation speed was 1500 rpm, and the spinner time was 30 seconds. After film formation, the film was dried on a hot plate at 80 ° C. for 1 minute, and then baked in an oven atmosphere at 230 ° C. for 1 hour to crosslink the polymer, thereby forming a 30 nm thick hole injection layer.

<Formation of hole transport layer>
Next, a composition for forming a hole transport layer was prepared. A polymer having a repeating structure of the following formula (V) (weight average molecular weight 95000) 1.4% by weight was dissolved in cyclohexylbenzene as a solvent to obtain a composition for forming a hole transport layer. Cyclohexylbenzene was obtained by adding a molecular sieve to a commercial product and dehydrated. The composition for forming a hole transport layer was prepared in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm.

The substrate on which the hole injection layer was formed was placed in a nitrogen glove box, and was applied onto the hole injection layer by the spin coating method using the composition for forming a hole transport layer. The spinner speed was 1500 rpm and the spinner time was 30 seconds. After film formation, the polymer was crosslinked by baking on a hot plate at 230 ° C. for 1 hour to form a 30 nm-thick hole transport layer.
Preparation of the composition for forming a hole transport layer, application by spin coating, and baking were all performed in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a water concentration of 1.0 ppm without being exposed to the atmosphere.

<Formation of undercoat layer>
0.25 g of polyvinyl pyrrolidone K-90 (manufactured by Nippon Shokubai Co., Ltd.) as hydrophilic compound-1, 0.75 g of polyvinyl pyrrolidone K-30 (manufactured by Nippon Shokubai Co., Ltd.) as hydrophilic compound-2, poly as a coating property adjusting agent 1 mg of ether-modified polydimethylsiloxane BYK-330 (manufactured by BYK-Chemie), 100 g of propylene glycol monomethyl ether as solvent-1 and 100 g of 3-methoxy-1-butanol as solvent-2 are mixed and mixed thoroughly. A composition for a pulling layer was prepared.
Using this undercoat layer composition, an undercoat layer was formed by spin coating to form a dry film thickness of 70 nm on the hole transport layer. Drying was carried out on a hot plate at 80 ° C. for 1 minute.

<Bank formation>
First, a photosensitive composition for forming a bank was prepared.
<Binder resin-1>
The resin produced in Synthesis Example 1 below was used.

[Synthesis Example 1: Production of binder resin-1]
145 parts by weight of propylene glycol monomethyl ether acetate was stirred while purging with nitrogen, and the temperature was raised to 120 ° C. To this, 20 parts by weight of styrene, 57 parts by weight of glycidyl methacrylate and 82 parts by weight of monoacrylate FA-513M (manufactured by Hitachi Chemical Co., Ltd.) having a tricyclodecane skeleton were added dropwise, and stirring was continued at 140 ° C. for 2 hours. Next, the inside of the reaction vessel was purged with air, 0.7 part by weight of trisdimethylaminomethylphenol and 0.12 part by weight of hydroquinone were added to 27 parts by weight of acrylic acid, and the reaction was continued at 120 ° C. for 6 hours. Thereafter, 52 parts by weight of tetrahydrophthalic anhydride (THPA) and 0.7 parts by weight of triethylamine were added and reacted at 120 ° C. for 3.5 hours to obtain binder resin-1 which is an alkali-soluble resin represented by the following formula. . The weight average molecular weight (Mw) of this resin was about 8000.

<Ethylenic unsaturated compound-1>
Dipentaerythritol hexaacrylate (DPHA) (Nippon Kayaku Co., Ltd.)
<Ethylenic unsaturated compound-2>
DECONAL ACRYLATE DA-314 (manufactured by Nagase ChemteX Corporation)

<Photopolymerization initiator-1>
Irgacure 907 (Ciba Special Chemicals)

<Coating property preparation agent-1>
Polyether-modified polydimethylsiloxane BYK-330 (by Big Chemie)
<Liquid repellent component-1>
Megafuck RS-102 (manufactured by DIC)
<Solvent-1>
Propylene glycol monomethyl ether acetate

48 g of binder resin-1, 24 g of ethylenically unsaturated compound-1, 24 g of ethylenically unsaturated compound-2, 5 g of ethylenically unsaturated compound-3, 3 g of photopolymerization initiator-1 A liquid repellent photosensitive composition for forming a bank was prepared by blending 0.1 g of -1, 0.6 g of liquid repellent component-1 and 310 g of solvent-1 and mixing them well.

This liquid repellent photosensitive composition was applied onto the above-described undercoat layer by spin coating so as to have a dry film thickness of 2 μm, thereby forming a liquid repellent photosensitive composition layer. Drying was performed by vacuum drying for 1 minute, and further at 80 ° C. for 1 minute on a hot plate.
Thereafter, a matrix quartz photomask with a synthetic quartz photomask held at a gap of 100 μm, a line width of 30 μm and a line pitch of 100 μm is applied to the liquid repellent photosensitive composition layer forming surface at a high pressure of 3 kW. Exposure was performed using mercury at an exposure condition of 300 mJ / cm ² .

Next, using an aqueous solution containing 0.5% by weight of tetramethylammonium hydroxide (TMAH) and 2% by weight of special grade ethanol as a developing solution, shower development at a water pressure of 0.1 MPa is performed at 23 ° C. for 30 seconds, followed by washing spray. For 30 seconds and then drained with compressed air.
Thereafter, this was post-baked in an oven at 230 ° C. for 30 minutes to obtain a substrate having a matrix pattern formed using the liquid repellent photosensitive composition layer.
In addition, the formation process of the matrix pattern of this liquid repellent photosensitive composition layer was implemented under the yellow light which cut | disconnected ultraviolet light.

<Inkjet film formation>
The composition (A) (1.5 g) obtained in Example 1 was vacuum degassed and then filled into an ink jet cartridge DMC-11610 (manufactured by Fuji Film Dimatics), and an ink jet printer DMP-2831 ( Manufactured by Fuji Film Dimatics Co., Ltd.), a droplet volume of about 1 drop is formed in a region partitioned by a liquid repellent bank having a height of 2 μm, an opening width of 70 μm square, and an interval of 100 μm. The discharge voltage was adjusted so as to be 11 pl, and 3 drops per 1 block (pixel) were landed in order. Moreover, it landed on the area | region of 100 division x 100 division as a whole, ie, the area | region of a 10 square mm area. Thereafter, the applied droplet-shaped composition was preliminarily dried under reduced pressure conditions (1 Torr or less), and then baked in a vacuum oven at 130 ° C. for 1 hour to obtain a matrix-patterned light emitting layer film.

<Measurement of light-emitting layer film shape>
As described above, the state of the in-bank pixel film thickness in the portion inside the 10 mm × 10 sections from the four corners of the 10 mm square region of the light emitting layer coated with the ink jet is measured with an optical microscope (manufactured by OLYMPUS) and three-dimensional It was observed and measured with a contact-type surface shape measuring device Vertscan (manufactured by Ryoka System). FIG. 4 shows an optical micrograph (a) and a cross-sectional shape (b) obtained.

(Example 5)
In Example 4, except that the composition (A) in <Inkjet film formation> was changed to the composition (B) obtained in Example 2, <Inkjet film formation> and <Measurement of the shape of the light emitting layer film> was performed.
FIG. 5 shows an optical micrograph (a) and a cross-sectional shape (b) obtained.

(Example 6)
In Example 4, except that the composition (A) in <Inkjet film formation> was changed to the composition (C) obtained in Example 3, <Inkjet film formation> and <Measurement of the shape of the light emitting layer film> was performed.
FIG. 6 shows an optical micrograph (a) and a cross-sectional shape (b) obtained.

(Comparative Example 2)
In Example 6, except that the composition (A) in <Inkjet film formation> was changed to the composition (D) obtained in Comparative Example 1, <Inkjet film formation> and <Measurement of the shape of the light emitting layer film> was performed.
FIG. 6 shows an optical micrograph (a) and a cross-sectional shape (b) obtained.

As shown in FIGS. 4 to 6, when the composition for organic electroluminescence device of the present invention is used, the film shape of the light emitting layer is uniform. In other words, in the case of an element, current concentration that occurs when the film is formed non-uniformly does not easily occur, so the drive life is long. Moreover, the organic electroluminescent element having such a film does not cause a short circuit or a dark spot.

(Example 7)
(Preparation of composition (E))
The organic compounds (C5) and (D3) shown below are in a ratio of (C5) :( D3) = 100: 10 (weight ratio), and cyclohexylbenzene is used as a solvent, resulting in a solid content concentration of 1.0% by weight. Then, the solution was filtered using a PTFE membrane filter having a pore size of 0.2 μm.

Next, the polymer compound (silicone oil KF-96-10CS: weight molecular weight Mw = about 10 million) represented by the formula (HP3) is 1/10 (weight ratio) with respect to the solid content of the solution. And dissolved sufficiently to prepare the organic electroluminescent element composition (E) of the present invention.
Next, <Inkjet film formation> was performed in the same manner as in Example 4 except that the composition (A) in <Inkjet film formation> was changed to the composition (E) in Example 4, and the film formation state Were observed with an optical microscope. The results are shown in FIG.

(Comparative Example 3)
(Preparation of composition (F))
In Example 7, the composition for organic electroluminescent elements (F) was obtained like Example 7 except not adding a high molecular compound.
Next, <Inkjet film formation> was performed in the same manner as in Example 4 except that the composition (A) in <Inkjet film formation> was changed to the composition (F) in Example 4, and the film formation state Were observed with an optical microscope. The result is shown in FIG.

As shown in FIG. 8, when the composition for organic electroluminescent elements of the present invention is used, the fine structure seen in the light emitting layer is reduced. That is, by containing a high molecular compound, aggregation of low molecular compounds is suppressed and a homogeneous film is formed. An organic electroluminescent device having such a film has high efficiency and long life.

(Example 8)
(Preparation of composition (G))
The following organic compounds (C6), (C7), and (D4) and (D5) are combined with (C6) :( C7) :( D4) :( D5) = 25: 75: 5: 7 (weight ratio) In this ratio, cyclohexylbenzene was used as a solvent, and it was dissolved so as to have a solid content concentration of 5% by weight, followed by filtration using a PTFE membrane filter having a pore size of 0.2 μm.

Subsequently, the polymer compound represented by the structural formula (HP3) is added so as to be 1/100 (weight ratio) with respect to the solid content of the solution, and sufficiently dissolved, and the composition for an organic electroluminescent device of the present invention. A product (G) was prepared.

(Creation of organic electroluminescence device)
The same processes as in Example 4 were performed up to <Preparation of substrate with transparent conductive film>, <Formation of hole injection layer>, and <Formation of hole transport layer> in Example 4.

<Formation of light emitting layer>
Subsequently, application | coating by the spin coat method was performed using the composition (G) on the positive hole transport layer. The spinner speed was 1700 rpm and the spinner time was 120 seconds. After film formation, baking was performed at 130 ° C. for 1 hour under reduced pressure on a hot plate to remove the solvent and form a light emitting layer having a thickness of 55 nm.
Preparation of the composition for the light emitting layer, application by spin coating, and baking were all carried out in a nitrogen glove box having an oxygen concentration of 1.0 ppm and a moisture concentration of 1.0 ppm without being exposed to the atmosphere.

<Formation of hole element layer and electron transport layer>
Here, the substrate on which the light-emitting layer was formed was transferred into an organic layer deposition apparatus, evacuated until the degree of vacuum in the apparatus was 2.4 × 10 ⁻⁴ Pa or less, and then the following compound (C8) Were stacked by a vacuum deposition method to obtain a hole blocking layer. The deposition rate was controlled in the range of 0.7 to 0.8 liter / second, and a hole blocking layer having a thickness of 10 nm was formed by laminating on the light emitting layer. The degree of vacuum during vapor deposition was 2.4 to 2.7 × 10 ⁻⁴ Pa.

Subsequently, the following Alq3 (C9) was heated and evaporated to form an electron transport layer. The degree of vacuum during deposition is 0.4 to 1.6 × 10 ⁻⁴ Pa, the deposition rate is controlled in the range of 1.0 to 1.5 Å / sec, and the film is deposited on the hole blocking layer to a thickness of 20 nm. The electron transport layer was formed.

Here, the element that had been deposited up to the electron transport layer was transferred to a cathode deposition apparatus, and a 2 mm wide stripe shadow mask was brought into close contact with the element so as to be orthogonal to the ITO ITO stripe as a mask for cathode deposition. .
As an electron injection layer, first, lithium fluoride (LiF) was controlled using a molybdenum boat at a deposition rate of 0.1 to 0.4 liter / second and a degree of vacuum of 3.2 to 6.7 × 10 ⁻⁴ Pa. A film having a thickness of 0.5 nm was formed on the electron transport layer. Next, aluminum as a cathode is similarly heated by a molybdenum boat and controlled at a deposition rate of 0.7 to 5.3 liters / second and a degree of vacuum of 2.8 to 11.1 × 10 ⁻⁴ Pa. An aluminum layer was formed. The substrate temperature during the above two-layer deposition was kept at room temperature.

<Encapsulation of element>
Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, a sealing process was performed by the method described below.
In a nitrogen glove box, a photocurable resin (30Y-437 manufactured by ThreeBond Co., Ltd.) with a width of about 1 mm is applied to the outer periphery of a 23 mm × 23 mm glass plate, and a moisture getter sheet (manufactured by Dynic Co., Ltd.) in the center. Was installed. On this, the board | substrate which complete | finished cathode formation was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.

As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The luminance half life of this device is shown in Table 3.

Example 9
(Preparation of composition (H))
In Example 8 (Preparation of composition (G)), except that the polymer compound represented by the above formula (HP3) was changed to the polymer compound represented by the following formula (HP4), it was the same as Example 8. Thus, a composition (H) for an organic electroluminescence device of the present invention was prepared.

(Creation of organic electroluminescence device)
Next, an organic electroluminescence device was produced in the same manner as in Example 8 except that in the <Emission layer formation> of Example 8, the composition (H) was used instead of the composition (G). The luminance half life of this device is shown in Table 3.

(Example 10)
(Preparation of composition (I))
Example 8 (Preparation of composition (G)) In Example 8, except that the polymer compound represented by the formula (HP4) was changed to the polymer compound represented by the following formula (HP5). Thus, a composition (I) for an organic electroluminescence device of the present invention was prepared.

(Creation of organic electroluminescence device)
Next, an organic electroluminescent device was produced in the same manner as in Example 8 except that in the <Formation of light emitting layer> in Example 8, the composition (I) was used instead of the composition (G). The luminance half life of this device is shown in Table 3.

(Comparative Example 4)
(Preparation of composition (J))
In Example 8 (Preparation of composition (G)), a composition (J) for an organic electroluminescent element of the present invention was prepared in the same manner as in Example 8, except that the polymer compound was not added.

(Creation of organic electroluminescence device)
Next, an organic electroluminescence device was produced in the same manner as in Example 8 except that in the <Emission layer formation> of Example 8, the composition (J) was used instead of the composition (G). The luminance half life of this device is shown in Table 3. It can be seen that the organic electroluminescent device of the present invention has a long lifetime.

Here, the luminance half-life is shown as a relative value with Comparative Example 4 as 1.0.

This application is based on a Japanese patent application filed on March 13, 2009 (Japanese Patent Application No. 2009-061664), the contents of which are incorporated herein by reference.

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.

1 Substrate
2 Anode
3 Hole injection layer
4 hole transport layer
5 banks
6 Light emitting layer
7 Cathode
8 Electron injection layer
9 Electron transport layer
10c Organic electroluminescent device
11 Electron blocking layer

Claims

A composition for an organic electroluminescent device comprising a light emitting material, a charge transport material, a polymer compound and an organic solvent,
The polymer compound is composed only of atoms selected from the group consisting of hydrogen atoms, sp2 carbon atoms, sp3 carbon atoms, sp3 oxygen atoms, and silicon atoms (provided that all sp2 carbon atoms contained in the polymer compound are included) Constitutes an aromatic hydrocarbon group). A composition for organic electroluminescent elements, characterized in that
The composition for an organic electroluminescent element according to claim 1, wherein the main skeleton of the polymer compound is composed of a siloxane bond.
The composition for an organic electroluminescent element according to claim 1, wherein the polymer compound contains a repeating unit represented by the following formula (XX).

(In the above formula (XX), R 3 to R 6 each independently represents any of a hydrogen atom, an alkyl group, an aralkyl group, and an aromatic hydrocarbon group, provided that at least one of R 3 to R 6 Represents an aromatic hydrocarbon group having 6 or more carbon atoms.)
The composition for an organic electroluminescent device according to any one of claims 1 to 3, wherein the polymer compound is contained in an amount of 0.5 wt% or more and less than 50 wt% based on the solid content.
5. The composition for organic electroluminescent elements according to claim 1, wherein the thickening coefficient n calculated from {Thickening coefficient calculation method} below is 0.2 or more. .
{Calculation method of thickening coefficient}
After measuring the viscosity of the composition before concentration, the composition (10 g) is dried under reduced pressure, and the composition weight is 1/2 (5 g), 1/3 (3.3 g), 1/4 (2.5 g). The viscosity of the composition concentrated to is measured.
The horizontal axis x is a multiple of the above concentrated concentration (1, 2, 3...), The vertical axis y is the viscosity, and the curve with the measured data is approximated by an exponential function. To calculate the value.
y = μ1 × exp (n × (x−1)) (1)
(In the above formula, μ1 is the viscosity of the composition before concentration, and n is the thickening coefficient.)
A method for producing an organic electroluminescent device, comprising forming a film by an inkjet method or a nozzle printing method using the composition for an organic electroluminescent device according to any one of claims 1 to 5.
In an organic electroluminescence device having an anode and a cathode on the substrate, and an organic layer disposed between the anode and the cathode,
An organic electroluminescent device, wherein at least one of the organic layers is an organic layer formed of the composition for organic electroluminescent devices according to any one of claims 1 to 5.
An organic EL display comprising the organic electroluminescent element according to claim 7.
An organic EL illumination comprising the organic electroluminescent element according to claim 7.