JP5287455B2 - Hole injection transport layer forming composition, method for manufacturing hole injection transport layer forming composition, organic electroluminescence device, organic EL display, and organic EL lighting - Google Patents

Description

The present invention relates to a composition for forming a hole injecting and transporting layer of an organic electroluminescent device and a method for producing the same.
The present invention also provides an organic electroluminescent device having a hole injecting and transporting layer formed using the composition for forming a hole injecting and transporting layer, a method for producing the same, an organic EL display using the organic electroluminescent device, and The present invention relates to organic EL lighting.

  In recent years, an electroluminescent element (organic electroluminescent element) using an organic thin film has been developed. Examples of the method for forming the organic thin film in the organic electroluminescence device include a vacuum deposition method and a wet film formation method.

  The vacuum deposition method has an advantage that it is easy to laminate a plurality of layers (lamination), and therefore, it is easy to improve charge injection from the anode and / or the cathode and to confine excitons in the light emitting layer.

  On the other hand, the wet film formation method does not require a vacuum process, is easy to increase in area, and can be easily mixed with a plurality of materials having various functions in one layer (coating liquid). There is.

  However, since the wet film formation method is difficult to stack, the element formed by the wet film formation is inferior in driving stability to the element formed by the vacuum vapor deposition method, and has not reached the practical level except for a part. is there. For example, two layers can be stacked by using an organic solvent and an aqueous solvent as the solvent of the coating solution, respectively, but it is difficult to stack three or more layers.

In order to solve such a problem in the lamination by the wet film forming method, Patent Document 1 proposes a triarylamine derivative having a polymerizable group as a layer forming material, and a technique for lamination using an organic solvent. Is disclosed.
A compound having such a polymerizable group is usually used for a hole transport layer of an organic electroluminescence device. However, an element having a hole transport layer formed using a compound having a polymerizable group has a problem of low durability and short lifetime.

International Publication No. WO2005 / 083812 Pamphlet

  The present invention relates to a composition for forming a hole injecting and transporting layer containing a compound having a polymerizable group, and enhancing the durability of an organic electroluminescent device having a hole injecting and transporting layer formed using this composition. , A composition for forming a hole injection / transport layer capable of extending the lifetime, a method for producing the same, and a highly durable and long-life organic electroluminescence having a hole injection / transport layer formed using the composition An object is to provide an element, a method for manufacturing the element, an organic EL display using the organic electroluminescent element, and an organic EL illumination.

  As a result of intensive studies by the present inventors, after preparing a composition for forming a hole injecting and transporting layer containing a compound having a polymerizable group, the composition is stored for a certain period and then used for film formation of the hole injecting and transporting layer. Thus, it has been found that the above problems can be solved, and the present invention has been achieved.

That is, the present invention is a composition for forming a hole injecting and transporting layer of an organic electroluminescent device containing a compound having a polymerizable group and an organic solvent, which has been stored for 24 hours or more after the preparation of the composition. A composition for forming a hole injection transport layer,
An organic electroluminescent device having an anode and a cathode, and a hole injecting and transporting layer and a light emitting layer between the anode and the cathode, wherein the hole injecting and transporting layer uses the composition for forming a hole injecting and transporting layer An organic electroluminescence device characterized by being formed by,
An organic EL display and an organic EL illumination, characterized by using the organic electroluminescent element;
A method for producing a composition for forming a hole injecting and transporting layer of an organic electroluminescent device comprising a compound having a polymerizable group and an organic solvent, wherein the composition is stored for 24 hours or more after preparation. Method for producing composition for forming hole injection transport layer,
And a method for producing an organic electroluminescent device having an anode and a cathode, and a hole injecting and transporting layer and a light emitting layer between the anode and the cathode, the composition comprising a compound having a polymerizable group and an organic solvent After the preparation of the organic electroluminescence device, the hole injection transport layer is formed by a wet film forming method using the composition after being stored for 24 hours or more,
Exist.

  ADVANTAGE OF THE INVENTION According to this invention, the lifetime of the organic electroluminescent element which has a positive hole injection transport layer formed using the compound which has a polymeric group can be extended.

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

  Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents. Not.

  The composition for forming a hole injecting and transporting layer of the present invention is a composition for forming a hole injecting and transporting layer of an organic electroluminescent device containing a compound having a polymerizable group and an organic solvent, and after the preparation of the composition , Stored for 22 hours or more.

  When a compound having a polymerizable group such as that used in a hole injection / transport layer of an organic electroluminescent device is stored in an organic solvent for a long time, the compound having a polymerizable group is polymerized during storage, and the organic solvent is converted into an organic solvent. Conventionally, a composition containing a compound having a polymerizable group and an organic solvent has not been stored, because the solubility of the resin may decrease or the viscosity of the composition may increase and the coating property may decrease. After preparation, it was used (deposition of a hole injection transport layer) within at least 20 hours.

However, the present inventors dared to perform an operation of storage on such a composition for forming a hole injecting and transporting layer, and a long-life device can be produced using the composition after storage. It was possible to obtain an unexpected effect.
The reason why such an effect is obtained by storage is presumed as follows.
By storing a composition containing a compound having a polymerizable group and an organic solvent, the materials constituting the composition are homogenized. That is, the solvation between the compound having a polymerizable group and the solvent is promoted, and a homogeneously dissolved or dispersed state is obtained. When a layer is formed by a wet film-forming method using the composition in such a state, it remains after the film is formed by polymerization by heating or the like after the wet film formation, compared to a state where it is not homogeneously dissolved or dispersed. The number of reactive polymerizable groups is reduced. If there is an unreacted polymerizable group in the layer, an oxidation / reduction reaction may be caused by holes / electrons flowing through the device during driving, which may affect the driving life of the device. However, an organic electroluminescent device having a layer formed using the composition of the present invention is considered to have a long driving life because there is no such fear.
Thus, it is advantageous from the viewpoint of production cost that the lifetime of the element can be achieved by a simple operation of storage.

In the present invention, “hole injection transport layer” is a general term for “hole injection layer” and “hole transport layer”. That is, the composition for forming a hole injection transport layer of the present invention may be used for forming a hole injection layer of an organic electroluminescence device, may be used for forming a hole transport layer, It may be used to form both the hole injection layer and the hole transport layer.
Moreover, the composition for forming a hole injection transport layer of the present invention is usually used for forming a hole injection layer and / or a hole transport layer by a wet film forming method.

[Composition for forming hole injection transport layer]
The composition for forming a hole injecting and transporting layer of the present invention contains a compound having a polymerizable group and an organic solvent.

<Compound having a polymerizable group (hereinafter sometimes referred to as “polymerizable compound”)>
The polymerizable group of the polymerizable compound refers to a group that reacts with a group that is the same as or different from the polymerizable group of another molecule located in the vicinity to generate a new chemical bond. For example, by irradiation with heat and / or active energy rays, or by receiving energy from other molecules such as a sensitizer, it reacts with the same or different groups of other molecules located nearby to form a new chemical bond. Examples of the group to be generated are mentioned.

The polymerizable group of the polymerizable compound is not limited, but a group containing an unsaturated double bond, a cyclic ether, a benzocyclobutane ring, or the like is preferable.
Especially, as a polymeric group, the group chosen from the following polymeric group group T from the point that it is easy to insolubilize is preferable.

(Polymerizable group T)

In the above formula, R ^{91 to} R ⁹⁵ each independently represents a hydrogen atom or an alkyl group.
Ar ⁹¹ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

  In particular, the polymerizable group is preferably a group selected from the following polymerizable group group T ′ from the viewpoint of excellent electrochemical durability.

(Polymerizable group T ′)

  Note that the polymerizable compound may have only one polymerizable group, or may have two or more. When the polymerizable compound has two or more polymerizable groups, the plurality of polymerizable groups may be the same or different from each other.

The polymerizable compound according to the present invention may be a low molecular compound or a high molecular compound, but is a high molecular compound in terms of excellent heat resistance, charge transporting property, film forming property, and the like. Is preferred.
The low molecular weight compound in the present invention refers to a compound having a single molecular weight rather than having a distribution in molecular weight. The polymer compound in the present invention is a compound having a distribution in molecular weight, for example, a compound having a repeating unit in the structure.

  When the polymerizable compound is a low molecular compound, the molecular weight is usually 300 or more, preferably 500 or more, and usually 5000 or less, preferably 2500 or less. If the molecular weight of the polymerizable compound is too small, the charge transport property may be lowered, and if it is too large, the solubility may be lowered.

  On the other hand, the weight average molecular weight when the polymerizable compound is a polymer compound is usually 500 or more, preferably 2000 or more, more preferably 4000 or more, and usually 2,000,000 or less, preferably 500,000 or less, More preferably, it is the range of 200,000 or less. If the weight average molecular weight of the polymerizable compound is below this lower limit, the film formability of the polymerizable compound may be reduced, and the glass transition temperature, melting point and vaporization temperature of the polymerizable compound will decrease, resulting in heat resistance. May be significantly impaired. If the weight average molecular weight exceeds this upper limit, purification of the polymerizable compound may be difficult due to the high molecular weight of impurities.

  The weight average molecular weight is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion. The number average molecular weight is similarly calculated. The same applies to the weight average molecular weight and the number average molecular weight of a hole transporting polymer described later.

The polymerizable compound used in the present invention, a triarylamine derivative, a carbazole derivative, a fluorene derivative, 2,4,6-triphenyl pyridine derivatives, C ₆₀ derivatives, oligothiophene derivatives, phthalocyanine derivatives, porphyrin derivatives, condensed polycyclic Aromatic derivatives, metal complex derivatives and the like can be mentioned, and triarylamine derivatives are particularly preferable.

  Among the triarylamine derivatives, a compound having a partial structure represented by the following formula and a polymerizable group is particularly preferable because of high electrochemical stability and charge transportability.

  Among the particularly preferred polymerizable compounds, specific examples of the low molecular weight compounds include compounds having the structures shown below.

  On the other hand, among the particularly preferred polymerizable compounds, specific examples of those having a repeating unit include compounds having the structures shown below.

  In the composition for forming a hole injecting and transporting layer of the present invention, any one of the polymerizable compounds may be contained alone, or two or more thereof may be contained in any ratio and combination. .

  In the composition for forming a hole injecting and transporting layer of the present invention, the polymerizable 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% by weight or less, more preferably 10% by weight or less. If the content of the polymerizable compound in the composition is too small, it may hinder the formation of the laminated film by the wet film formation method, and if it is too much, the content of the organic solvent or the like is relatively decreased. There is a risk that film-forming properties and the like may be impaired.

<Organic solvent>
There is no restriction | limiting in particular in the kind of organic solvent contained in the composition for positive hole injection transport layer formation of this invention. Specific examples of the organic solvent include aromatic compounds such as toluene, xylene, methicylene and cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene and o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene Aliphatic ethers such as glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, Ether solvents such as aromatic ethers such as 2,3-dimethylanisole and 2,4-dimethylanisole; aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate; Propionic acid phenyl, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, organic solvents such as ester solvents such as benzoic acid n- butyl.
The organic solvent in the composition is preferably an organic solvent capable of dissolving the polymerizable compound at a concentration of 0.05% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. .
As the organic solvent contained in the composition for forming a hole injecting and transporting layer of the present invention, aromatic compounds such as toluene, xylene, methicylene and cyclohexylbenzene are particularly preferable.

  Any one of these organic solvents may be used alone, or two or more thereof may be used in any combination and ratio.

  The content of the organic solvent in the composition for forming a hole injecting and transporting layer of the present invention is usually 1% by weight or more, preferably 20% by weight or more, and usually 99.999% by weight or less, preferably 70% by weight or less. A range of is desirable. When the content of the organic solvent is less than this range, the viscosity of the composition becomes too high, and film forming workability may be lowered. On the other hand, if the content of the organic solvent is larger than this range, the thickness of the film obtained by removing the solvent after coating cannot be obtained, and thus film formation tends to be difficult.

<Hole transporting compound>
When the hole injection transport layer forming composition of the present invention is a hole transport layer forming composition, it may contain a hole transporting compound other than the polymerizable compound described above.
In this case, the content in the total composition of the hole transporting compound including the polymerizable 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, it is preferably 50% by weight or less, preferably 20% by weight or less, and more preferably 10% by weight or less. If the total hole transporting compound content in the composition is too small, a hole transporting layer excellent in charge transporting property cannot be formed. There is a risk that the film properties may be impaired.

  In this case, the hole transporting compound in the composition is 0.05% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more of the hole transporting compound containing a polymerizable compound. An organic solvent that can be dissolved at a concentration of 1 to 5 is preferable.

<Other ingredients>
In addition to the polymerizable compound and the organic solvent, the composition for forming a hole injecting and transporting layer of the present invention includes an electron accepting compound, a leveling agent, a coating improver such as an antifoaming agent, and the like as necessary. Various additives may be included. Further, the composition for forming a hole injection / transport layer of the present invention reduces the solubility of the hole injection / transport layer of an organic electroluminescence device described later, and wet-forms another layer on the hole injection / transport layer. Other additives such as an additive for accelerating the polymerization (crosslinking) reaction of the polymerizable compound that can be performed may be included.

  In this case, as an organic solvent in the composition, a solid component such as a polymerizable compound and an additive is dissolved at a concentration of 0.05% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. It is preferable to use an organic solvent.

  Examples of the additive that accelerates the crosslinking reaction used in the composition for forming a hole injecting and transporting layer of the present invention include polymerization initiation of alkylphenone compounds, acylphosphine oxide compounds, metallocene compounds, oxime ester compounds, azo compounds, onium salts, and the like. And photosensitizers such as an agent, a polymerization accelerator, a condensed polycyclic hydrocarbon, a porphyrin compound, and a diaryl ketone compound. These may be used alone or in combination of two or more.

  When the composition for forming a hole injecting and transporting layer of the present invention contains an additive that promotes such a crosslinking reaction, the content thereof is usually 0.001% by weight or more based on the compound having a polymerizable group, It is preferably 0.005% by weight or more, usually 50% by weight or less, preferably 20% by weight or less. If the content is too small, the effect of promoting the crosslinking reaction due to the blending of the additive that promotes the crosslinking reaction cannot be obtained sufficiently, and if the content is too large, the effect corresponding to the added amount cannot be obtained. In addition, when the content of other components is reduced, the film formability and the like may be reduced.

Moreover, as an electron-accepting compound, the 1 type (s) or 2 or more types of what was mentioned later as an electron-accepting compound contained in the positive hole injection layer of the organic electroluminescent element explained in full detail below can be used.
When the composition for forming a hole injecting and transporting layer of the present invention contains an electron accepting compound, the content thereof is usually 0.001% by weight or more, preferably 0.005% by weight or more with respect to the compound having a polymerizable group. In general, it is 50% by weight or less, preferably 20% by weight or less. If the content is too small, the effect of improving the charge mobility due to the compounding of the electron accepting compound cannot be obtained sufficiently, and if the content is too large, the effect commensurate with the added amount cannot be obtained. If the content of the component is reduced, the film formability may be lowered.

<Save>
The composition for forming a hole injecting and transporting layer of the present invention is prepared after the composition for forming a hole injecting and transporting layer is prepared by using the above-described blending components blended in the composition, that is, after the preparation of the composition is completed. The composition is stored for 22 hours or longer.
In the present invention, “storage for 22 hours or more” means that, after the preparation of the composition is completed, it takes 22 hours or more to use the composition. For example, only when the composition is allowed to stand at a specific place. Does not mean.

  Here, the completion of the preparation of the composition for forming a hole injecting and transporting layer refers to the time when the above-described polymerizable compound is completely dissolved in the organic solvent. That is, the time when the polymerizable compound is added to the organic solvent and the amount of the polymerizable compound in which the organic solvent should be dissolved is dissolved.

In the present invention, the storage period after the preparation of the composition for forming a hole injecting and transporting layer is usually 22 hours or more, preferably 1 day or more (this 1 day means 24 hours), usually 60 days or less, preferably Is 30 days or less, more preferably 15 days or less, more preferably 11 days or less, particularly preferably 7 days or less, and most preferably 3 days (72 hours) or less.
Within the above range, the polymerizable compound in the composition and the organic solvent are sufficiently homogenized, so that the effects of the present invention can be obtained satisfactorily.

Preferred conditions for storage include the following conditions.
The storage temperature is usually 40 ° C. or lower, preferably 30 ° C. or lower, usually 0 ° C. or higher, preferably 10 ° C. or higher.
Within the above range, since the solid content is difficult to precipitate, the resulting film has good uniformity. Further, since the polymerizable group of the polymerizable compound contained in the composition is difficult to react, the homogeneity between the polymerizable compound and the organic solvent in the composition is improved, and the uniformity of the resulting film is good.
The storage humidity is usually 0.001% or more, usually 50% or less, preferably 20%.
Within the above range, moisture mixed into the composition is reduced, and the polymerizable group is less likely to react, which is preferable. The lower limit is ideally 0%.
The storage atmosphere is preferably an inert gas atmosphere, and specific examples of the inert gas include nitrogen, argon, etc., and these mixed gases may be used, but nitrogen is preferable in terms of easy handling. It is.
The storage pressure is usually atmospheric pressure.

  The composition for forming a hole injecting and transporting layer of the present invention is preferably stored in a sealed container in order to prevent volatilization of the organic solvent. Moreover, it is preferable that it is a container which can light-shield from the point which can suppress decomposition | disassembly / superposition | polymerization of the polymeric compound etc. by ultraviolet light. As the storage container, for example, a brown screw mouth bottle with packing, a pressurized tank made of stainless steel, and the like are preferable.

[Method of manufacturing organic electroluminescent element]
The method for producing an organic electroluminescent element of the present invention is a method for producing an organic electroluminescent element having an anode and a cathode, and a hole injection transport layer and a light emitting layer between the anode and the cathode, After preparing a composition containing a compound having an organic solvent and storing the composition, the hole injecting and transporting layer is formed by a wet film forming method using the composition after being stored for 22 hours or more.

Here, about the compounding component of a composition containing the compound which has a polymeric group, and an organic solvent, a composition, etc. in <the composition for positive hole injection transport layer formation> of this invention <compound which has a polymeric group ( Hereinafter, it may be referred to as “polymerizable compound”), <organic solvent>, <hole transporting compound> and <other components>, and the preferred embodiments are also the same.
The environment when the composition containing the compound having a polymerizable group and the organic solvent is prepared and stored for 22 hours or more is the same as that described in <Preservation> of [Composition for forming hole injection transport layer]. It is the same as that of description in a term, and its preferable aspect is also the same.
Moreover, about the structure and wet film-forming method of an organic electroluminescent element, the thing of the item of the below-mentioned [organic electroluminescent element] is mentioned.

[Organic electroluminescence device]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode, a cathode, and a hole injection transport layer and a light emitting layer formed between the anode and the cathode, the hole injection transport layer Is formed using the composition for forming a hole injecting and transporting layer of the present invention.
In the organic electroluminescence device of the present invention, the composition for forming a hole injection transport layer of the present invention may be used for forming a hole injection layer or a hole transport layer. It may be used to form a layer.

  Below, the layer structure of the organic electroluminescent element manufactured using the composition for hole injection transport layer formation of this invention, its general formation method, etc. are demonstrated with reference to FIG. As described above, the composition for forming a hole injection transport layer of the present invention may be used for forming a hole transport layer or a hole injection layer. The case where it uses for doing is illustrated and demonstrated.

  FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, The light emitting layer, 6 represents a hole blocking layer, 7 represents an electron transport layer, 8 represents an electron injection layer, and 9 represents a cathode.

  The organic electroluminescent element usually has a first electrode, a light emitting layer and a second electrode formed on the substrate 1, as shown in FIG. In addition, there may be a case where only the hole injection layer 3 is included between the hole transport layer 4 and a hole transport layer 4 and a hole injection layer 3. When only the hole injection layer 3 is provided in the organic electroluminescent element, the light emitting layer 5 is formed on the hole injection layer 3. Further, when both the hole transport layer 4 and the hole injection layer 3 are provided, the light emitting layer 5 is formed on the hole transport layer 4 in which the hole injection layer 3 and the hole transport layer 4 are laminated. Is done.

  In such an organic electroluminescent device, when the organic layer between the anode 2 and the cathode 9 is formed by a wet film forming method, the material for each layer described below is dispersed or dissolved in a solvent to form a coating composition. And a film may be formed using this coating composition.

  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, an ink jet method, a screen printing method, It refers to a method of forming a film using an ink containing a solvent, such as gravure printing, flexographic printing, and offset printing. Among these wet film forming methods, a die coating method, a roll coating method, a spray coating method, an ink jet method, and a flexographic printing method are preferable from the viewpoint of easy patterning.

{substrate}
The substrate 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

{anode}
An anode 2 is provided on the substrate 1. The anode 2 plays a role of hole injection into a layer on the light emitting layer 5 side (such as the hole injection layer 3 or the light emitting layer 5).
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when the anode 2 is formed 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, these are used as an appropriate binder. The anode 2 can also be formed by dispersing it in a resin solution and applying it onto the substrate 1. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

  The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

  The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

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

{Hole injection layer}
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5, and is usually formed on the anode 2. The hole injection layer 3 may be formed by a vacuum deposition method or a wet film formation method.

<Material of hole injection layer>
The material of the hole injection layer 3 is contained in the hole injection layer 3.
When the hole injection layer 3 is formed by a wet film formation method, the material for forming the hole injection layer 3 is usually mixed with an appropriate solvent (solvent for the hole injection layer) to form the hole injection layer. A coating composition (hereinafter sometimes referred to as “hole injection layer forming composition”) is prepared, and this hole injection layer forming composition is applied to the lower layer of the hole injection layer 3 by an appropriate technique. The hole injection layer 3 is formed by coating on a corresponding layer (usually an anode), forming a film, and drying.
The material of the hole injection layer 3 is not particularly limited as long as it can form the hole injection layer 3. Hereinafter, the material of the hole injection layer will be described.

As a material for the hole injection layer 3, it is preferable to use a hole transporting compound.
Examples of the hole transporting compound include a high molecular weight hole transporting compound and a low molecular weight hole transporting compound.

(High molecular weight hole transporting compound)
The high molecular weight hole transporting compound (hereinafter referred to as “hole transporting polymer” as appropriate) used as the material of the hole injection layer 3 is not particularly limited as long as it has hole transporting properties. A compound having an ionization potential of .5 eV to 5.5 eV is preferable. The ionization potential is defined as the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of a material to the vacuum level, and can be measured directly by photoelectron spectroscopy or electrochemically. It can also be obtained by correcting the participation potential obtained with respect to the reference electrode. In the case of the latter method, for example, when a saturated sweet potato electrode (SCE) is used as a reference electrode, it is represented by the following formula ("Molecular Semiconductors", Springer-Verlag, 1985, pp. 98).
Ionization potential = oxidation potential (vs. SCE) + 4.3 eV

  The weight average molecular weight of the hole transporting polymer used as the material of the hole injection layer 3 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1000 or more, preferably 2000 or more, more preferably 3000 or more, Usually, it is 500,000 or less, preferably 200,000 or less, more preferably 100,000 or less.

  Examples of the hole transporting polymer include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, and the like. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness, solubility in solvents, and visible light transmittance.

  Of the aromatic amine compounds, aromatic tertiary amine compounds are particularly preferable. In addition, the aromatic tertiary amine compound here 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 a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less is more preferable from the viewpoint of the surface smoothing effect.

  Only 1 type may be used for a positive hole transport polymer, and it may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the hole transporting polymer in the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10% by weight or more, preferably in terms of the weight percentage with respect to the whole hole injection layer 3. Is 30% by weight or more, usually 99.9% by weight or less, preferably 99% by weight or less. In addition, when using together 2 or more types of hole transportable polymers, it is made for the total content of these to be contained in the said range.

(Low molecular weight hole transport compound)
As a material for the hole injection layer 3, a low molecular weight hole transporting compound may be used.
The low molecular weight hole transporting compound can be appropriately selected from various compounds conventionally used as a hole injecting / transporting thin film forming material in an organic electroluminescence device. Among them, those having high solvent solubility are preferable.
Preferable examples of the low molecular weight hole transporting compound include aromatic amine compounds. Of these, aromatic tertiary amine compounds are particularly preferred.

  The molecular weight of the low molecular weight hole transporting compound is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 200 or more, preferably 400 or more, more preferably 600 or more, and usually 5000 or less, preferably Is not more than 3000, more preferably not more than 2000, still more preferably not more than 1700, particularly preferably not more than 1400. If the molecular weight is too small, the heat resistance tends to be low, whereas if the molecular weight of the low molecular weight hole transporting compound is too large, synthesis and purification tend to be difficult.

  In addition, a low molecular weight hole transportable compound may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

(Hole-transporting compound content)
The total proportion of the hole transporting compounds in the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired, and is a weight percentage with respect to the whole hole injection layer 3 and is usually 10% by weight or more. , Preferably 30% by weight or more, and usually 99.9% by weight or less, preferably 99% by weight or less. In addition, when using together 2 or more types of hole transportable compounds, it is preferable that these total content is contained in the said range.

  The concentration of the hole transporting compound in the composition for forming a hole injection layer is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably 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, coating properties may be reduced and film thickness unevenness may occur, and if it is too low, defects may occur in the film. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

(Electron-accepting compound)
As a material for the hole injection layer 3, it is preferable to use an electron accepting compound in addition to a hole transporting compound. The kind of electron-accepting compound is arbitrary as long as the effects of the present invention are not significantly impaired. Examples thereof include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pendafluorophenyl) borate and triphenylsulfonium tetrafluoroborate; No. 251067), high-valence inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris (pendafluorophenyl) borane (JP-A-2003-31365); fullerene derivatives ; Iodine etc. are mentioned.

  Of the above compounds, an onium salt substituted with an organic group is preferable in terms of having strong oxidizing power, and an inorganic compound having a high valence is preferable, and an onium salt substituted with an organic group in terms of being soluble in various solvents, A cyano compound and an aromatic boron compound are preferable. Furthermore, an onium salt substituted with an organic group is most preferable from the viewpoint of achieving both strong oxidizing power and high solubility.

  As a material for the hole injection layer 3, any one of the electron-accepting compounds may be used alone, or two or more may be used in any combination and ratio.

  The content of the electron-accepting compound in the hole injection layer 3 and the composition for forming the hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired. It is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 100% by weight or less, preferably 60% by weight or less, and more preferably 50% by weight or less. A larger amount of the electron-accepting compound is preferable because it is more easily insolubilized, and can be insolubilized in a short time. However, if it is excessively large, the film formability is lowered, and the charge injection / transport property is lowered. There is a fear. In addition, when using together 2 or more types of electron-accepting compounds, it is made for the total content of these to be contained in the said range.

(Other ingredients)
As a material for the hole injection layer 3, in addition to the above-described hole transporting polymer, electron accepting compound, and low molecular weight hole transporting compound, in addition to the above-described hole transporting polymer, other components, as long as the effects of the present invention are not significantly impaired. May be included. Examples of other components include various light emitting materials, electron transporting compounds, binder resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

(Solvent for hole injection layer)
As the solvent for the hole injection layer to be contained in the composition for forming the hole injection layer, any solvent can be used as long as the hole injection layer 3 can be formed. However, among the materials of the hole injection layer 3 such as the above-described hole transporting compound and electron accepting compound, those capable of dissolving at least one, preferably all of the materials are preferable. As specific solubility, a hole transporting compound such as a hole transporting polymer is usually 0.005% by weight or more, particularly 0.5% by weight or more, and particularly 1% by weight or more at room temperature and normal pressure. It is preferable to dissolve the electron-accepting compound in an amount of usually 0.001% by weight or more, particularly 0.1% by weight or more, and particularly 0.2% by weight or more.

  As the hole injection layer solvent, a hydrophobic solvent is preferably used, and preferred solvents include ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents. Specifically, examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1, 3 -Aromatic ethers such as dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole; ethyl acetate, n-butyl acetate, Aliphatic esters such as ethyl lactate and n-butyl lactate; Aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate; benzene, toluene, xylene, etc. Aromatic carbonization Motokei solvent; N, N-dimethylformamide, N, N-amide solvent of dimethylacetamide and the like; dimethyl sulfoxide and the like. Any one of these may be used alone, or two or more thereof may be used in any combination and ratio. However, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve the electron-accepting compound and the hole-transporting polymer, so it is preferable to use a mixture with an ether solvent and an ester solvent. .

  The content of the solvent for the hole injection layer in the composition for forming the hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10% by weight or more, preferably 30% by weight or more, more preferably. Is in the range of 50% by weight or more, usually 99.999% by weight or less, preferably 99.99% by weight or less, more preferably 99.9% by weight or less. In addition, when mixing and using 2 or more types of solvents as a solvent for positive hole injection layers, it is made for the sum total of these solvents to satisfy | fill this range.

<Film formation method>
After preparing the composition for forming the hole injection layer, the composition is obtained by applying and forming a film on the layer corresponding to the lower layer of the hole injection layer 3 (usually the anode 2) by a wet film formation method. The hole injection layer 3 is formed by drying the coated film and removing the solvent for the hole injection layer. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be adopted.

  The thickness of the hole injection layer 3 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

{Hole transport layer}
In FIG. 1, a hole transport layer 4 is formed on the hole injection layer 3.
In the present embodiment, the hole transport layer 4 is a layer obtained by film-forming the composition for forming a hole injection / transport layer of the present invention by the above-described wet film-forming method. 4 polymerizes (crosslinks) the polymerizable compound in the composition for forming a hole injecting and transporting layer of the present invention by irradiation with heat and / or active energy rays (ultraviolet rays, electron beams, infrared rays, microwaves, etc.). It is a layer obtained.

  The heating method for crosslinking the polymerizable compound after forming the hole injection / transport layer forming composition of the present invention on the hole injection layer 3 by a wet film forming method is not particularly limited. Examples thereof include heat drying and reduced pressure drying. As a condition in the case of heat drying, the deposited layer is usually heated to 120 ° C. or higher, preferably 400 ° C. or lower. 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 crosslinking by irradiation with active energy rays such as light, a method of irradiating directly using an ultraviolet / visible / infrared light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a halogen lamp, an infrared lamp, or the above-mentioned light source And a mask aligner with a built-in, a method of irradiating 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. The irradiation time is preferably set to conditions necessary for reducing the solubility of the film, but is usually 0.1 seconds or longer, preferably 10 hours or shorter.

  The irradiation of active energy rays such as heating and light may be performed alone or in combination. When combining 2 or more types, the order of implementation is not particularly limited.

  The active energy ray irradiation including heating and light is performed in an atmosphere not containing moisture such as a nitrogen gas atmosphere in order to reduce the amount of moisture contained in the layer and / or the amount of moisture adsorbed on the surface after the execution. Is preferred. For the same purpose, when combined with heating and / or irradiation of active energy rays such as light, it is particularly preferable to perform at least the step immediately before the formation of the organic light emitting layer in an atmosphere containing no moisture such as a nitrogen gas atmosphere. .

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

In addition, when forming the positive hole injection layer 3 using the composition for positive hole injection transport layer formation of this invention, the positive hole transport layer 4 may be formed by the vacuum evaporation method other than the said method.
The organic electroluminescent device of the present invention may have a configuration in which the hole transport layer 4 is omitted. In that case, the hole injection layer 3 is formed using the hole injection transport layer forming composition of the present invention.

{Light emitting layer}
When the hole injection layer 3 or the hole transport layer 4 is provided, the light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes to which an electric field is applied, and becomes a main light emitting source.
The light emitting layer 5 may be formed by a vacuum vapor deposition method or a wet film formation method, but is laminated by a wet film formation method using the hole injection transport layer forming composition of the present invention. In order to obtain the effect, it is preferable to form the film by a wet film forming method.

<Light emitting layer material>
The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) as a constituent material, and preferably a compound having a hole transporting property (hole transporting compound) or an electron transport. A compound (electron transporting compound) having the following properties: There is no particular limitation on the light-emitting material, and a material that emits light at a desired light emission wavelength and has favorable light emission efficiency may be used. Moreover, it is preferable to contain two or more charge transport compounds. Furthermore, the light emitting layer 5 may contain other components as long as the effects of the present invention are not significantly impaired. The light emitting layer may be formed by a wet film formation method or a vacuum deposition method, but is preferably formed by a wet film formation method.

  In addition, when forming the light emitting layer 5 with a wet film-forming method, it is preferable to use a low molecular weight material with a molecular weight of 10,000 or less as the light emitting material.

(Luminescent material)
Any known material can be applied as the light emitting material. For example, a fluorescent material or a phosphorescent material may be used, but a phosphorescent material is preferable from the viewpoint of internal quantum efficiency.
For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the molecules of the luminescent material or introduce a lipophilic substituent such as an alkyl group into the luminescent material.

Hereinafter, although the example of a fluorescent dye is mentioned among light emitting materials, a fluorescent dye is not limited to the following illustrations.
Examples of the fluorescent dye that gives blue light emission (blue fluorescent dye) include naphthalene, perylene, pyrene, anthracene, chrysene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of fluorescent dyes that give green light emission (green fluorescent dyes) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al (C ₉ H ₆ NO) ₃ .

Examples of fluorescent dyes that give yellow light (yellow fluorescent dyes) include rubrene and perimidone derivatives.
Examples of fluorescent dyes that give red luminescence (red fluorescent dyes) include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzoates. Examples thereof include thioxanthene derivatives and azabenzothioxanthene.

  As the phosphorescent material, for example, a long-period type periodic table (hereinafter referred to as a long-period type periodic table when referred to as “periodic table” unless otherwise specified) is selected from the seventh to eleventh groups. And an organometallic complex containing a metal.

  Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

  As the ligand of the complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

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

  The molecular weight of the compound used as the light emitting material is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, Preferably it is 200 or more, More preferably, it is 300 or more, More preferably, it is the range of 400 or more. If the molecular weight of the luminescent material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be reduced when the film is formed, or the morphology of the organic electroluminescent element will be changed due to migration, etc. Sometimes come. On the other hand, if the molecular weight of the luminescent material is too large, it tends to be difficult to purify the compound, or it may take time to dissolve the compound in a solvent.

  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.

  The content ratio of the light emitting material in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.05% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight. In addition, it is usually 35% by weight or less, preferably 25% by weight or less, and more preferably 20% by weight or less. If the amount of the light emitting material is too small, uneven light emission may occur. If the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of luminescent material, it is made for the total content of these to be contained in the said range.

(Hole transporting compound)
The light emitting layer 5 may contain a hole transporting compound as a constituent material thereof. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as (low molecular weight hole transporting compound) in the hole injection layer 3 described above. For example, two or more condensed aromatic rings containing two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are bonded to the nitrogen atom. Aromatic amine compounds having a starburst structure such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. (Journal of Luminescence, 1997, Vol.72-74, pp.985), an aromatic amine compound comprising a tetramer of triphenylamine (Chemical Communi). ations, 1996, pp. 2175), spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synthetic Metals, 1997, Vol. 91, pp. 209) and the like.

  In the light emitting layer 5, only one kind of hole transporting compound may be used, or two or more kinds may be used in any combination and ratio.

  The content ratio of the hole transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight. % Or more, usually 65% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

(Electron transporting compound)
The light emitting layer 5 may contain an electron transporting compound as a constituent material thereof. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5, -Bis (6 '-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7 -Diphenyl-1,10-phenanthroline (BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4 , 4′-bis (9-carbazole) -biphenyl (CBP), etc. In the light emitting layer 5, only one type of electron transporting compound may be used, or two or more types may be combined arbitrarily. It may be used in combination with so and proportions.

  The content ratio of the electron transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight. In addition, it is usually 65% by weight or less, preferably 50% by weight or less, and more preferably 40% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

<Formation of light emitting layer>
When forming the light emitting layer 5 by a wet film-forming method, the above-mentioned material is dissolved in an appropriate solvent (light emitting layer solvent) to prepare a coating composition (light emitting layer forming composition). Is used to form a film.

  As the light emitting layer solvent to be contained in the light emitting layer forming composition which is a coating composition for forming the light emitting layer 5 by a wet film forming method, any solvent can be used as long as the light emitting layer can be formed. Can do. However, those capable of dissolving the light-emitting material, the hole transporting compound, and the electron transporting compound are preferable. Specifically, the solubility of the light emitting material, the hole transporting compound or the electron transporting compound is usually 0.01% by weight or more, particularly 0.05% by weight or more, particularly 0.1% at normal temperature and normal pressure. It is preferable to dissolve by weight% or more.

  As the solvent for the light emitting layer, the same solvents as those exemplified as the organic solvent contained in the composition for forming a hole injecting and transporting layer of the present invention can be used. These organic solvents may use only 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  The content of the solvent for the light emitting layer in the composition for forming the light emitting layer 5 for forming the light emitting layer 5 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 0. It is 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, and more preferably 50% by weight or less. In addition, when mixing and using 2 or more types of solvents as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.

  A composition for forming a light-emitting layer for forming the light-emitting layer 5 described above is applied by a wet film forming method on the hole-injecting layer 3 when there is no hole-transporting layer 4 or the hole-transporting layer 4. After film formation, the obtained coating film is dried and the light emitting layer solvent is removed, whereby the light emitting layer 5 is formed. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be adopted.

  The thickness of the light emitting layer 5 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 thickness of the light emitting layer 5 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 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

  The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have

  The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high. Examples of the material for the hole blocking layer satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Further, a compound having at least one pyridine ring substituted at positions 2, 4, and 6 described in International Publication No. 2005-022962 is also preferable as a material for the hole blocking layer 6.

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

  There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

{Electron transport layer}
An electron transport layer 7 may be provided between the light emitting layer 5 and an electron injection layer 8 described later.
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the device, and efficiently transports electrons injected from the cathode 9 between the electrodes to which an electric field is applied in the direction of the light emitting layer 5. Formed from a compound capable of

  As an electron transport compound used for the electron transport layer 7, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons are transported efficiently with high electron mobility. The compound which can be used is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like.

  In addition, the material of the electron carrying layer 7 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron carrying layer 7. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Electron injection layer}
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the light emitting layer 5. In order to perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

  In addition, the material of the electron injection layer 8 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron injection layer 8. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

{cathode}
The cathode 9 plays a role of injecting electrons into a layer (such as the electron injection layer 8 or the light emitting layer 5) on the light emitting layer 5 side.

  As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, a metal having a low work function is preferable. For example, tin, magnesium, indium, A suitable metal such as calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

  In addition, the material of the cathode 9 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The film thickness of the cathode 9 is usually the same as that of the anode 2.

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

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

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

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

  In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

Further, at the interface between the cathode 9 and the light emitting layer 5 or the electron transport layer 7, for example, lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ). Inserting an ultrathin insulating film (0.1 to 5 nm) formed by the above method is also an effective method for improving the efficiency of the device (Applied Physics Letters, 1997, Vol. 70, pp. 152; (Kaihei 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, pp. 1245; SID 04 Digest, pp. 154, etc.).

  Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the case of the layer configuration of FIG. 1, the other components on the substrate 1 are the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the positive layer. The hole injection layer 3 and the anode 2 may be provided in this order.

  Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.

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

  Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.

  Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

[Organic EL display]
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.

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

[Preparation of composition for forming hole injection transport layer]
{Example 1}
A composition for forming a hole injecting and transporting layer containing a polymerizable compound (weight average molecular weight 158,000) represented by the following structural formula (H1) was prepared with the following component composition.

<Composition for forming hole injection transport layer>
Solvent Toluene Solid concentration 0.4 wt%

  Among the compositions after preparation (immediately after it was confirmed that the polymerizable compound (H1) was completely dissolved in toluene), 9 samples of the present invention samples 1-1 to 1-9 were placed in a brown sample bottle and nitrogen. The container was sealed under an atmosphere and stored for a period shown in Table 1 at room temperature (25 ° C.) under light shielding. Note that “no storage of comparative sample 1” means a solution immediately after the dissolution of the composition was confirmed.

{Example 2}
A composition for forming a hole injecting and transporting layer containing the polymerizable compound (H1) was prepared by blending the components shown below.

<Composition for forming hole injection transport layer>
Solvent Cyclohexylbenzene Solid concentration 1.4% by weight

  After preparation (immediately after it was confirmed that the polymerizable compound (H1) was completely dissolved in cyclohexylbenzene), the sample 2-1 of the present invention was sealed in a brown sample bottle under a nitrogen atmosphere and shielded from light. The sample was stored at room temperature (25 ° C.) for the period shown in Table 2. Incidentally, “no storage of Comparative Sample 2” means a solution immediately after the dissolution of the composition was confirmed.

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

  First, a hole transporting polymer compound having a repeating structure represented by the following structural formula (P1) (weight average molecular weight: 26500, number average molecular weight: 12000), 4-isopropyl-4 represented by the following structural formula (A1) A composition for forming a hole injection layer containing '-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and ethyl benzoate was prepared. The concentration of compound (P1) and compound (A1) in the composition was 2.0% by weight for compound (P1) and 0.8% by weight for compound (A1). This composition was applied onto the anode 2 by spin coating under the following conditions, and then heated and dried at 230 ° C. for 3 hours in the air to obtain a hole injection layer 3 having a thickness of 30 nm.

<Film formation conditions for hole injection layer 3>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In air

  Subsequently, the composition for forming a hole injection / transport layer of the inventive sample 1-1 (storage period 1 day) prepared and stored in Example 1 was applied onto the hole injection layer 3 by spin coating under the following conditions. Then, the hole transport layer 4 having a film thickness of 20 nm was formed by polymerization (crosslinking) by heating at 230 ° C. for 1 hour in nitrogen.

<Film formation conditions for hole transport layer 4>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen

  Next, a composition for forming a light emitting layer containing organic compounds (C1), (C2), (D1) represented by the following structural formula and xylene as a solvent was prepared. The contents of the organic compounds (C1), (C2), and (D1) in the composition are 1.0% by weight for (C1), 1.0% by weight for (C2), and 0.1% for (D1). %Met. This composition was applied onto the hole transport layer 4 by spin coating under the following conditions, and then heated and dried in nitrogen at 130 ° C. for 1 hour to form a light emitting layer 5 having a thickness of 60 nm.

<Film formation conditions of the light emitting layer 5>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen

Here, the substrate on which the light emitting layer 5 is formed is transferred into a vacuum vapor deposition apparatus, and after the apparatus is roughly evacuated by an oil rotary pump, the degree of vacuum in the apparatus becomes 3.0 × 10 ⁻⁴ Pa or less. Then, the hole blocking layer 6 was formed by stacking the compound represented by the following structural formula (C3) on the light emitting layer 5 by a vacuum deposition method. At this time, the vapor deposition rate was controlled in the range of 0.3 to 0.8 Å / second, and a hole blocking layer 6 having a thickness of 5 nm was formed by laminating on the light emitting layer 5. The degree of vacuum at the time of deposition was 1.3 to 2.0 × 10 ⁻⁴ Pa.

Subsequently, tris (8-hydroxyquinolinate) aluminum was heated and evaporated to form an electron transport layer 7. The degree of vacuum during deposition is 1.1 to 1.7 × 10 ⁻⁴ Pa, the deposition rate is controlled in the range of 0.5 to 1.1 Å / sec, and a film with a thickness of 30 nm is formed on the hole blocking layer 6. To form an electron transport layer 7.

Here, the element that has been deposited up to the electron transport layer 7 is once taken out from the vacuum deposition apparatus into the atmosphere, and a 2 mm wide striped shadow mask is used as a cathode deposition mask. The device was placed in close contact with each other so as to be orthogonal to each other, placed in another vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus was 5.6 × 10 ⁻⁴ Pa or less in the same manner as the organic layer.

As the electron injection layer 8, first, lithium fluoride (LiF) was controlled at a deposition rate of 0.03 to 0.2 liter / second and a degree of vacuum of 3.0 to 5.6 × 10 ⁻⁴ Pa using a molybdenum boat. A film having a thickness of 0.5 nm was formed on the electron transport layer 7. Next, aluminum is similarly heated by a molybdenum boat as the cathode 9 and controlled at a deposition rate of 0.5 to 6.5 liters / second and a degree of vacuum of 1.2 to 10.7 × 10 ⁻⁴ Pa to a film thickness of 80 nm. An aluminum layer was formed. The substrate temperature during the above two-layer deposition was kept at room temperature.

Subsequently, in order to prevent the element from being deteriorated by moisture in the atmosphere during storage, 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 size glass plate, and a moisture getter sheet (manufactured by Dynic) is applied to 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.

  About the obtained organic electroluminescent element, the continuous drive test was done on condition of the following, the normalization life when the case of the below-mentioned comparative example 1 was set to 1 was investigated, and the result was shown in Table 3.

<Drive conditions>
Temperature Room temperature Drive method DC drive (DC drive)
Initial luminance 2,500 cd / m ²

  From Table 3, it was found that a long-life device can be obtained by using the composition for forming a hole injecting and transporting layer of the present invention.

{Examples 1-2 to 1-9}
In Example 1-1, instead of the sample 1-1 of the present invention, the composition for forming a hole injection transport layer prepared in Example 1 (samples 1-2 to 1-9 of the present invention) was used. 1 was produced in the same manner as in Example 1-1 except that the hole transport layer 4 was formed.
About each obtained organic electroluminescent element, the continuous drive test was done like Example 1-1, the normalization lifetime when the case of the below-mentioned comparative example 1 was set to 1 was investigated, and a result is shown in Table 3. It was.
From Table 3, it was found that a long-life device can be obtained by using the composition for forming a hole injecting and transporting layer of the present invention.

{Comparative Example 1}
In Example 1-1, the hole transport layer 4 was formed using the composition for forming a hole injection transport layer (Comparative Sample 1) immediately after the preparation in Example 1 instead of the inventive sample 1-1. Others were the same as Example 1-1, and produced the organic electroluminescent element shown in FIG.
About the obtained organic electroluminescent element, it carried out similarly to Example 1-1, and performed the continuous drive test.

{Example 2-1}
In Example 1-1, in forming the hole transport layer 4, instead of the sample 1-1 of the present invention, the composition for forming a hole injection transport layer prepared and stored in Example 2 (sample 2 of the present invention) The organic electroluminescent device shown in FIG. 1 was produced in the same manner as in Example 1-1 except that the light emitting layer 5 and the hole blocking layer 6 were formed as follows.

<Light emitting layer>
A composition for forming a light emitting layer containing the organic compounds (C1), (C2), (D1) represented by the above structural formula and cyclohexylbenzene as a solvent was prepared. The contents of the organic compounds (C1), (C2), and (D1) in the composition are 1.6% by weight for (C1), 1.6% by weight for (C2), and 0.16% for (D1). %Met. The composition was applied by spin coating on the hole transport layer 4 under the following conditions, and then dried by heating at 130 ° C. for 1 hour under reduced pressure (0.1 MPa), thereby forming the light-emitting layer 5 having a thickness of 40 nm. Formed.

<Film formation conditions of the light emitting layer 5>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen

<Hole blocking layer>
The substrate on which the layers up to the light-emitting layer 5 were formed was placed in a vacuum vapor deposition apparatus in the same manner as in Example 1-1, evacuated, and a compound represented by the following structural formula (C4) was formed by the vacuum vapor deposition method. A hole blocking layer 6 was formed by laminating a film thereon. At this time, the vapor deposition rate was controlled in the range of 0.3 to 0.8 Å / second, and the hole blocking layer 6 having a thickness of 10 nm was formed by stacking on the light emitting layer 5. The degree of vacuum at the time of deposition was 1.3 to 2.0 × 10 ⁻⁴ Pa.

About the obtained organic electroluminescent element, the continuous drive test was done like Example 1-1, the normalization lifetime when the case of the below-mentioned comparative example 2 was set to 1 was investigated, and the result was shown in Table 4. .
From Table 4, it was found that a long-life device can be obtained by using the composition for forming a hole injecting and transporting layer of the present invention.

{Comparative Example 2}
In Example 2-1, the hole transport layer 4 was formed using the composition for forming a hole injection transport layer (comparative sample 2) immediately after preparation in Example 2 instead of the inventive sample 2-1. Others were the same as Example 2-1, and produced the organic electroluminescent element shown in FIG.
About the obtained organic electroluminescent element, it carried out similarly to Example 1-1, and performed the continuous drive test.

{Example 3-1}
The organic electroluminescent element shown in FIG. 1 was produced in the same manner as in Example 2-1, except that the light emitting layer 5 was formed as follows.

<Light emitting layer>
A light emitting layer forming composition containing organic compounds (C5) and (D2) represented by the following structural formula and cyclohexylbenzene as a solvent was prepared. The contents of the organic compounds (C5) and (D2) in the composition were 2.3% by weight for (C5) and 0.23% by weight for (D2). The composition was applied onto the hole transport layer 4 by spin coating under the following conditions, and then dried by heating at 100 ° C. for 1 hour under reduced pressure (0.1 MPa), whereby the light emitting layer 5 having a thickness of 55 nm was formed. Formed.

<Film formation conditions of the light emitting layer 5>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In nitrogen

  The obtained organic electroluminescence device was subjected to a continuous driving test under the following conditions, and the normalized lifetime when the case of Comparative Example 3 described later was set to 1 was examined. The results are shown in Table 5.

<Drive conditions>
Temperature Room temperature Drive method DC drive (DC drive)
Initial luminance 500 cd / m ²

  From Table 5, it was found that a device having a long lifetime can be obtained by using the composition for forming a hole injecting and transporting layer of the present invention.

{Comparative Example 3}
In Example 3-1, the hole transport layer 4 was formed using the composition for forming a hole injection transport layer (Comparative Sample 2) immediately after preparation in Example 2 instead of the inventive sample 2-1. Others were the same as Example 3-1, and produced the organic electroluminescent element shown in FIG.
About the obtained organic electroluminescent element, it carried out similarly to Example 3-1, and performed the continuous drive test.

[Preparation of coating solution for forming hole injection transport layer]
{Example 4}
A composition for forming a hole injecting and transporting layer containing a polymerizable compound (weight average molecular weight: 55,000) represented by the following structural formula (H2) was prepared by blending the components shown below.

<Composition for forming hole injection transport layer>
Solvent Cyclohexylbenzene Solid concentration 1.4% by weight

  Among the compositions after preparation (immediately after it was confirmed that the polysynthetic compound (H2) was completely dissolved in cyclohexylbenzene), the sample 4-1 of the present invention was sealed in a brown sample bottle in the air and shielded from light. The sample was stored at room temperature (25 ° C.) for the period shown in Table 6. Note that “no storage of comparative sample 4” means a solution immediately after the dissolution of the composition was confirmed.

[Production of organic electroluminescence device]
{Example 4-1}
The organic electroluminescent element shown in FIG. 1 was produced.
In the same manner as in Example 1-1, the anode 2 was formed on the glass substrate 1.
First, a hole-transporting polymer material having a repeating structure represented by the following structural formula (P2), 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) represented by the above structural formula (A1) A composition for forming a hole injection layer containing borate and ethyl benzoate was prepared. The concentration of compound (P2) and compound (A1) in the composition was 2.0% by weight for compound (P2) and 0.4% by weight for compound (A1). This composition was applied on the anode 2 by spin coating under the following conditions, and then polymerized (crosslinked) by heating at 230 ° C. for 1 hour in the air to obtain a hole injection layer 3 having a thickness of 30 nm.

<Film formation conditions for hole injection layer 3>
Spinner speed 1500rpm
Spinner rotation time 30 seconds Spin coat atmosphere In air

  Subsequently, the composition for forming a hole injection / transport layer of the inventive sample 4-1 (storage period 24 hours) prepared and stored in Example 4 was applied onto the hole injection layer 3 by spin coating under the following conditions. Then, the hole transport layer 4 having a film thickness of 20 nm was formed by polymerization (crosslinking) by heating at 230 ° C. for 1 hour in nitrogen.

<Film formation conditions for hole transport layer 4>
Spinner speed 1500rpm
Spinner rotation time 120 seconds Spin coat atmosphere In nitrogen

  Next, a composition for forming a light emitting layer containing an organic compound (C6) represented by the following structural formula, an organic compound (D2) represented by the above structural formula, and cyclohexylbenzene as a solvent was prepared. Concentrations of the organic compounds (C6) and (D2) in the composition were 3.4% by weight for the organic compound (C6) and 0.34% by weight for the organic compound (D2). The composition was applied by spin coating on the hole transport layer 4 under the following conditions, and then dried by heating at 130 ° C. for 1 hour under reduced pressure (0.1 MPa), thereby forming the light-emitting layer 5 having a thickness of 40 nm. Formed.

<Film formation conditions of the light emitting layer 5>
Spinner speed 1200rpm
Spinner rotation time 120 seconds Spin coat atmosphere In nitrogen

The substrate on which the layers up to the light emitting layer 5 were formed was placed in a vacuum vapor deposition apparatus in the same manner as in Example 1-1 and evacuated, and a compound represented by the following structural formula (C7) was formed on the light emitting layer 5 by vacuum vapor deposition. A hole blocking layer 6 was formed by laminating the film. At this time, the vapor deposition rate was controlled in the range of 0.8 to 1.0 kg / second, and the hole blocking layer 6 having a thickness of 10 nm was formed on the light emitting layer 5. The degree of vacuum during vapor deposition was 0.8 to 2.0 × 10 ⁻⁴ Pa.

After the electron transport layer 7, film formation was performed in the same manner as in Example 1-1, and sealing treatment was similarly performed.
About the obtained organic electroluminescent element, a continuous drive test was performed under the following conditions, and in the case of Comparative Example 4 described later, the normalized lifetime when the time for the luminance to be reduced to 80% of the initial luminance was set to 1 was investigated. The results are shown in Table 7.

<Drive conditions>
Temperature Room temperature Drive method DC drive (DC drive)
Initial luminance 3,000 cd / m ²

  From Table 7, it was found that a long-life device can be obtained by using the composition for forming a hole injecting and transporting layer of the present invention.

{Comparative Example 4}
In Example 4-1, the hole transport layer 4 was formed using the composition for forming a hole injection transport layer (Comparative Sample 4) immediately after preparation in Example 4 instead of the inventive sample 4-1. Otherwise, the organic electroluminescent element shown in FIG. 1 was produced in the same manner as in Example 4-1.
About the obtained organic electroluminescent element, the continuous drive test was done like Example 4-1.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode

Claims (9)

A composition for forming a hole injecting and transporting layer of an organic electroluminescent device comprising a compound having a polymerizable group and an organic solvent, wherein the composition is stored for at least 24 hours after the preparation. A composition for forming a hole injection transport layer.   The composition for forming a hole injection transport layer according to claim 1, wherein the storage is performed in an atmosphere of 40 ° C. or less.   The composition for forming a hole injecting and transporting layer according to claim 1 or 2, wherein the compound having a polymerizable group is a triarylamine derivative.   The composition for forming a hole injecting and transporting layer according to any one of claims 1 to 3, wherein the compound having a polymerizable group is a polymer compound.   5. An organic electroluminescent device comprising an anode and a cathode, and a hole injecting and transporting layer and a light emitting layer between the anode and the cathode, wherein the hole injecting and transporting layer is any one of claims 1 to 4. An organic electroluminescent device, characterized by being formed using the composition for forming a hole injecting and transporting layer.   An organic EL display using the organic electroluminescent element according to claim 5.   6. An organic EL illumination using the organic electroluminescent element according to claim 5. A method for producing a composition for forming a hole injecting and transporting layer of an organic electroluminescent device comprising a compound having a polymerizable group and an organic solvent, wherein the composition is stored for 24 hours or more after preparation. The manufacturing method of the composition for positive hole injection transport layer formation. A method for producing an organic electroluminescent device having an anode and a cathode, and a hole injection transport layer and a light emitting layer between the anode and the cathode,
After preparing a composition containing a compound having a polymerizable group and an organic solvent, storing the composition for 24 hours or more, and then forming the hole injecting and transporting layer by a wet film-forming method using the composition. A method for producing an organic electroluminescent device, which is characterized by the following.

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