JP2009205981A - Organic electroluminescent element and its manufacturing method - Google Patents

Abstract

An organic electroluminescence device having high light extraction efficiency, little influence on electrical characteristics, and easy to manufacture, and a method for manufacturing the same are provided.
At least one of the layer disposed on the light extraction side from the light emitting layer and the light emitting layer contains a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa. An organic electroluminescent element 10 which is a light scattering layer. A light scattering layer is formed by co-evaporation using an adamantane derivative, a hydrocarbon compound having an alkyl structure, or silicon monoxide as a light scattering inducer.
[Selection] Figure 1

Description

  The present invention relates to an organic electroluminescent device and a method for manufacturing the same.

  In recent years, display devices (light-emitting devices) using organic electroluminescent elements (organic EL elements) have been developed. For example, an anode, an organic layer (for example, a hole transport layer, a light-emitting layer, and an electron transport layer), a cathode, and the like are laminated on a substrate such as glass and the like, and external wiring is connected via a lead-out wiring (terminal) of both electrodes. By connecting and applying an electric field, holes and electrons recombine in the light emitting layer in a region sandwiched between the electrodes to emit light.

  In the case of manufacturing such an organic electroluminescent element, for example, after an anode is formed in a stripe shape on a substrate, an organic layer corresponding to red (R), green (G), and blue (B) is formed by mask deposition or the like. Patterning is performed with a material corresponding to each color so that appears repeatedly. Next, a cathode is formed on the organic layer, and external wiring such as control wiring and signal wiring is connected to terminals (external connection terminals) of the respective electrodes. Thereby, organic electroluminescent elements corresponding to RGB can be arranged to form a pixel, and color display can be performed.

Such an organic electroluminescent element usually has a high light extraction efficiency from the light emitting layer. As a method for improving the light extraction efficiency, at least one of the organic layers sandwiched between the electrodes is a layer in which inorganic fine particles such as SiO ₂ , zirconia, and titanium oxide are dispersed, and the refractive index thereof is changed to that of the light emitting layer. It has been proposed to make it larger than the rate (see Patent Document 1).

Japanese Patent Laid-Open No. 2007-242927

  In the case of forming an organic layer in which inorganic fine particles such as zirconia are dispersed, the method is limited to a specific method, for example, formed by applying a mixture of inorganic fine particles to an organic material constituting the organic layer. Further, when inorganic fine particles such as zirconia are dispersed in the organic layer, the charge mobility is lowered due to the influence on the electric characteristics, and the drive voltage and the light emission efficiency are likely to be lowered.

  An object of the present invention is to provide an organic electroluminescence device that has high light extraction efficiency, suppresses a decrease in charge mobility, and is easy to manufacture, and a method for manufacturing the same.

In order to achieve the above object, the present invention provides the following organic electroluminescence device and method for producing the same.
<1> An organic electroluminescent element in which an organic layer including at least a light-emitting layer is disposed between a pair of electrodes, the layer disposed on a side from which light from the light-emitting layer is extracted and the light-emitting layer At least one layer is a light-scattering layer containing the light-scattering inducing substance whose boiling point or sublimation point is 750 degrees C or less in 10 < ^-3 > Pa, The organic electroluminescent element characterized by the above-mentioned.
<2> The organic electroluminescent element according to <1>, wherein the light scattering layer contains the light scattering inducer and a charge transporting material.
<3> The organic electroluminescent element according to <1> or <2>, wherein the light scattering layer has light scattering properties by crystallization, aggregation, or phase separation of the light scattering inducer.
<4> The organic electroluminescence device according to any one of <1> to <3>, wherein the light scattering inducer is an adamantane derivative represented by the following general formula (1).

In the general formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or an aryl group. A heteroaryl group, an alkoxy group having 1 to 6 carbon atoms, an acyl group, an acyloxy group, an amino group, a nitro group, a cyano group, an ester group, an amide group, a halogen group, a perfluoroalkyl group having 1 to 6 carbon atoms, or Represents a silyl group, and at least one of the R _{1 to} R ₄ is a group having a double bond or a triple bond. X _{1 to} X ₁₂ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group, a heteroaryl group, or a carbon number. It represents a 1-6 alkoxy group, an acyl group, an acyloxy group, an amino group, a nitro group, a cyano group, an ester group, an amide group, a halogen group, a C 1-6 perfluoroalkyl group, or a silyl group.

<5> The organic electroluminescence according to <4>, wherein the content of the adamantane derivative represented by the general formula (1) in the light scattering layer is 5% by mass or more and 90% by mass or less. element.
<6> The organic electroluminescence device according to any one of <1> to <3>, wherein the light scattering inducer is silicon monoxide.
<7> The organic electroluminescent element according to <6>, wherein the content of the silicon monoxide in the light scattering layer is 5% by mass or more and 50% by mass or less.

<8> The organic electroluminescence device according to any one of <1> to <3>, wherein the light scattering inducer is a hydrocarbon compound having an alkyl structure.
<9> The organic compound according to <8>, wherein the hydrocarbon compound having an alkyl structure is a saturated hydrocarbon compound that does not include a double bond and includes an ethylene (—CH ₂ CH ₂ —) structure. Electroluminescent device.
<10> The organic electroluminescent element according to <8> or <9>, wherein the hydrocarbon compound having an alkyl structure is a linear saturated hydrocarbon compound.
<11> The organic electroluminescent element according to any one of <8> to <10>, wherein the hydrocarbon compound having an alkyl structure is solid at room temperature.
<12> The content of the hydrocarbon compound having an alkyl structure in the light scattering layer is 0.1% by mass or more and 70% by mass or less, and any one of <8> to <11> The organic electroluminescent element as described.

<13> A method for producing an organic electroluminescent element in which an organic layer including at least a light emitting layer is disposed between a pair of electrodes, the layer disposed on the side from which light from the light emitting layer is extracted and the light emitting layer A method for producing an organic electroluminescent device comprising forming a light scattering layer by depositing a light scattering inducing substance having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa as at least one layer.
<14> The method for producing an organic electroluminescent element according to <13>, wherein the light scattering layer is formed by co-evaporation of the light scattering inducer and a charge transporting material.
<15> The method for producing an organic electroluminescent element according to <13> or <14>, wherein a deposition rate when forming the light scattering layer is 1.0 Å / sec or less.
<16> As the light scattering inducer, an adamantane derivative represented by the following general formula (1), a hydrocarbon compound having an alkyl structure according to any one of <8> to <12>, or silicon monoxide is used. <13>-<15> The manufacturing method of the organic electroluminescent element in any one of the characteristics characterized by the above-mentioned.

In the general formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or an aryl group. A heteroaryl group, an alkoxy group having 1 to 6 carbon atoms, an acyl group, an acyloxy group, an amino group, a nitro group, a cyano group, an ester group, an amide group, a halogen group, a perfluoroalkyl group having 1 to 6 carbon atoms, or Represents a silyl group, and at least one of the R _{1 to} R ₄ is a group having a double bond or a triple bond. X _{1 to} X ₁₂ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group, a heteroaryl group, or a carbon number. It represents a 1-6 alkoxy group, an acyl group, an acyloxy group, an amino group, a nitro group, a cyano group, an ester group, an amide group, a halogen group, a C 1-6 perfluoroalkyl group, or a silyl group.

<17> The method for producing an organic electroluminescent element according to any one of <13> to <16>, comprising a step of performing a heat treatment after the light scattering layer is formed.

  According to the present invention, there are provided an organic electroluminescent device having high light extraction efficiency, reduced charge mobility, and easy to manufacture, and a method for manufacturing the same.

Hereinafter, an organic electroluminescent device and a method for manufacturing the same according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 schematically shows an example of the configuration of an organic electroluminescent device according to the present invention. In the organic electroluminescent element 10, an organic layer (organic EL layer) 16 including at least a light emitting layer 22 is disposed on a support substrate 12 between a pair of electrodes 14 and 18 including an anode and a cathode. 22 is a so-called bottom emission type in which light is extracted from the support substrate 12 side. At least one of the layer 20 and the light emitting layer 22 disposed on the side from which light from the light emitting layer 22 is extracted includes light containing a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa. It is a scattering layer. In the present invention, the light scattering layer refers to a layer having the property of scattering light from the light emitting layer during driving. More specifically, the light scattering layer refers to light emitted by light emitted from the light emitting layer hitting light scattering particles in the light scattering layer (so-called crystallization, phase separation, aggregation of molecules generated by aggregation). In a conventional organic EL device that does not have such a light scattering layer, it is reflected at the interface between the adjacent layer with the light emitting layer or at the interface between the organic layer and the electrode, and is guided out of the organic layer and extracted outside. It refers to a layer that makes it possible to extract light that is not emitted to the outside and improve the light extraction efficiency of the organic EL element.

  The light scattering layer can be confirmed by analysis by X-ray diffraction. Specifically, each of an element (hereinafter referred to as a reference sample) in which a film of only light scattering particles is formed on a Si substrate and an organic EL element having the light scattering layer are measured by X-ray diffraction, and a reference sample is obtained. It can be confirmed whether or not the peak of the organic EL element having the light scattering layer is observed at the same position as the peak position observed in.

The inventors of the present invention have at least one of the layer 20 and the light emitting layer 22 arranged on the side from which light from the light emitting layer 22 is extracted as described above and has a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa. It has been found that if the organic electroluminescent device 10 is a light scattering layer containing a certain light scattering inducer, the light extraction efficiency can be improved. In the organic electroluminescent element 10 including such a light scattering layer, it is considered that the light extraction efficiency is increased by reducing the light propagating through the substrate and guided to the end face of the element 10. Furthermore, a light scattering layer containing a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa can be formed by the same method as the vapor deposition step for forming a normal organic layer, Even if the light scattering inducing substance as described above is contained in the organic layer, there is an advantage that the influence on the charge mobility is small, and the increase in driving voltage and the decrease in luminous efficiency are suppressed.
Hereinafter, the organic electroluminescent device and the method for manufacturing the same according to the present invention will be described in more detail.

<Support substrate>
The support substrate 12 for forming the organic electroluminescent element 10 is not particularly limited as long as it has strength, light transmittance and the like that can support the organic electroluminescent element 10, and a known substrate is used. Can do. For example, zirconia stabilized yttrium (YSZ), inorganic materials such as glass, polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate and other polyesters, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, Organic materials such as poly (chlorotrifluoroethylene) can be mentioned.

  When glass is used as the support substrate 12, it is preferable to use alkali-free glass in order to reduce ions eluted from the glass. When soda lime glass is used, it is preferable to use a glass with a barrier coat such as silica.

When the support substrate 12 made of an organic material is used, it is preferable that the substrate is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability. In particular, when a plastic support substrate 12 is used, it is preferable to provide a moisture permeation preventive layer or a gas barrier layer on one side or both sides of the support substrate 12 in order to suppress the permeation of moisture and oxygen. As a material for the moisture permeation preventing layer or the gas barrier layer, an inorganic material such as silicon nitride or silicon oxide can be suitably used. The moisture permeation preventing layer or the gas barrier layer can be formed by, for example, a high frequency sputtering method.
Moreover, when using a thermoplastic support substrate, you may provide a hard-coat layer, an undercoat layer, etc. further as needed.

  There is no restriction | limiting in particular about the shape of the support substrate 12, a structure, a magnitude | size, etc., According to the use of the organic electroluminescent element 10, a purpose, etc., it can select suitably. In general, the shape of the support substrate 12 is preferably a plate shape from the viewpoints of handleability, ease of forming an organic electroluminescent element, and the like. The structure of the support substrate 12 may be a single layer structure or a laminated structure. Moreover, the support substrate 12 may be comprised with the single member, and may be comprised with two or more members.

  In addition, in the case of a so-called top emission type in which light is extracted from the side opposite to the support substrate 12, it is not necessary to extract light emission from the substrate 12 side. For example, stainless steel, Fe, Al, Ni, Co, Cu, A metal substrate such as these alloys or a silicon substrate can be used. If it is a metal support substrate, even if it is thin, it has high strength and high gas barrier properties against moisture and oxygen in the atmosphere. When a metal support substrate is used, it is necessary to provide an insulating film for ensuring electrical insulation between the support substrate 12 and the lower electrode 14.

<Organic electroluminescent device>
The organic electroluminescent element according to the present invention can employ, for example, the following layer structure, but is not limited thereto, and may be appropriately determined according to the purpose and the like.

Anode / light-emitting layer / cathode Anode / hole transport layer / light-emitting layer / electron transport layer / cathode Anode / hole transport layer / light-emitting layer / block layer / electron transport layer / cathode Anode / hole transport layer / Light emitting layer / block layer / electron transport layer / electron injection layer / cathode ・ Anode / hole injection layer / hole transport layer / light emission layer / block layer / electron transport layer / cathode ・ Anode / hole injection layer / hole transport Layer / light-emitting layer / block layer / electron transport layer / electron injection layer / cathode • anode / hole transport layer / block layer / light-emitting layer / electron transport layer / cathode • anode / hole transport layer / block layer / light-emitting layer / Electron transport layer / electron injection layer / cathode ・ Anode / hole injection layer / block layer / hole transport layer / light emitting layer / electron transport layer / cathode ・ Anode / hole injection layer / block layer / hole transport layer / light emission Layer / electron transport layer / electron injection layer / cathode

  Normally, the electrode (lower electrode) 14 on the support substrate 12 side is used as an anode, and the electrode (upper electrode) 18 on the sealing substrate (not shown) side is used as a cathode, but the lower electrode 14 is used as a cathode and the upper electrode 18 is used as an anode. It can also be. In the following description, a configuration in which an anode is formed as the lower electrode 14 on the support substrate 12 will be described as appropriate. However, the anode may be formed on the support substrate 12 in reverse from the cathode.

-Anode-
As long as the anode has a function as an electrode for supplying holes to the organic EL layer, its shape, structure, size, etc. are not particularly limited, and it depends on the use, purpose, etc. of the organic electroluminescent element. It can select suitably from a well-known electrode material.
As a material which comprises an anode, a metal, an alloy, a metal oxide, an electroconductive compound, or a mixture thereof is mentioned suitably, for example. As specific examples, conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gold Metals such as silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, and organic conductivity such as polyaniline, polythiophene and polypyrrole Examples thereof include materials and laminates of these and ITO. Among these, a conductive metal oxide is preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

Examples of the method for forming the anode include a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as CVD and plasma CVD method. In view of suitability with the material constituting the anode, the material may be selected as appropriate. For example, when ITO is used as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.
The position where the anode is formed can be appropriately selected according to the use, purpose and the like of the organic electroluminescent element, and may be formed on the entire support substrate 12 or may be formed on a part thereof.

  The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. Further, the mask may be overlapped, and vacuum deposition, sputtering, or the like may be performed, or may be performed by a lift-off method or a printing method.

The thickness of the anode may be appropriately selected according to the material constituting the anode, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.
Further, the resistance value of the anode is preferably 10 ³ Ω / □ or less and more preferably 10 ² Ω / □ or less in order to reliably supply holes to the organic EL layer.

  When light is extracted from the anode side, the light transmittance is preferably 60% or more, and more preferably 70% or more. The transparent anode is described in detail in Yutaka Sawada's “New Development of Transparent Electrode Film” published by CMC (1999), and the matters described here can be applied to the present invention. For example, when using a plastic support substrate with low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

-Cathode-
The cathode usually has a function as an electrode for injecting electrons into the organic layer 16, and there is no particular limitation on the shape, structure, size, etc., and it is known according to the use, purpose, etc. of the organic electroluminescent element. It can select suitably from electrode materials. Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloy, lithium-aluminum alloy, magnesium- Examples thereof include silver alloys, rare earth metals such as indium and ytterbium. These may be used singly or in combination of two or more from the viewpoint of achieving both stability and electron injection.

  Among these, the material constituting the cathode is preferably an alkali metal or an alkaline earth metal from the viewpoint of electron injection, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability. The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01 to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc.) Say. The cathode material is described in detail in, for example, Japanese Patent Laid-Open Nos. 2-15595 and 5-121172, and the materials described in these publications can also be applied to the present invention.

  There is no restriction | limiting in particular about the formation method of a cathode, It can form according to a well-known method. For example, materials constituting the cathode from wet methods such as printing methods and coating methods, physical methods such as vacuum deposition methods, sputtering methods and ion plating methods, chemical methods such as CVD methods and plasma CVD methods, etc. The film can be formed according to a method appropriately selected in consideration of suitability for the above. For example, when a metal or the like is selected as the cathode material, the cathode can be formed according to a sputtering method or the like, one or more of them simultaneously or sequentially.

  What is necessary is just to select the thickness of a cathode suitably according to the material which comprises a cathode, and the taking-out direction of light, and it is about 1 nm-about 5 micrometers normally.

The patterning for forming the cathode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. Further, it may be performed by vacuum deposition, sputtering or the like with overlapping masks, or by a lift-off method or a printing method.
There is no restriction | limiting in particular in the formation position of a cathode, You may form in the whole on the organic layer 16, and may be formed in the part.

  A dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be formed between the cathode and the organic layer 16 in a thickness of 0.1 to 5 nm. This dielectric layer can also be understood as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

-Organic layer-
The organic layer (organic EL layer) 16 is sandwiched between the anode and the cathode and includes at least the light emitting layer 22. Examples of the layers other than the light emitting layer 22 constituting the organic layer 16 include layers such as a hole transport layer, an electron transport layer, a charge block layer, a hole injection layer, and an electron injection layer as described above. As a preferable layer configuration, for example, as shown in FIG. 1, a mode in which a hole transport layer 20, a light emitting layer 22, and an electron transport layer 24 are stacked in this order from the anode 14 side can be mentioned. A charge blocking layer or the like may be provided between 20 and the light emitting layer 22 or between the light emitting layer 22 and the electron transport layer 24. A hole injection layer may be provided between the anode 14 and the hole transport layer 20, and an electron injection layer may be provided between the cathode 18 and the electron transport layer 24. Each layer may be divided into a plurality of secondary layers. Each layer constituting the organic layer 16 can be formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, and a printing method.

However, in the organic electroluminescent device according to the present invention, in any layer configuration, at least one of the layer 20 and the light emitting layer 22 arranged on the side from which light from the light emitting layer 22 is extracted is 10 ^−3. A light scattering layer containing a light scattering inducing substance having a boiling point or sublimation point of 750 ° C. or lower at Pa is formed. The light emitting layer 22 or the layer 20 disposed on the side from which light is extracted from the light emitting layer 22 contains a certain amount of the light scattering inducing substance as described above, so that the light scattering inducing substance is crystallized, aggregated, or phase separated. Thus, light scattering is imparted, and light from the light emitting layer can be extracted efficiently. Two or more light scattering layers may be provided. For example, all organic layers on the side from which light from the light emitting layer is extracted including the light emitting layer may be used as the light scattering layer. In this case, the light scattering inducing substances contained in each layer may be the same type or different types.

  According to the experiments by the present inventors, a layer disposed in the light extraction side of the light emitting layer rather than doping the light emitting layer with a light scattering inducing substance to form a light scattering layer (in FIG. 1, in FIG. When the transport layer 20) is doped with a light scattering inducing substance to form a light scattering layer, the light extraction efficiency can be improved more easily. Further, the cathode side layer and the anode side layer have an anode side layer (holes). It is easier to improve the light extraction efficiency if the light scattering layer is formed by doping the transport layer, hole injection layer, etc.) with a light scattering inducer.

The light scattering inducer is not particularly limited as long as it has a boiling point or sublimation point of 750 ° C. or lower, more preferably 550 ° C. or lower at 10 ⁻³ Pa, and it imparts light scattering properties. However, those that do not deteriorate the electrical properties (charge transportability) are preferred. Specific examples include (A) an adamantane derivative represented by the following general formula (1), (B) a hydrocarbon compound having an alkyl structure, and (C) silicon monoxide. These substances can be deposited together with the material constituting the organic layer to form a film, and can induce light scattering properties while hardly reducing the electrical characteristics of the organic layer.

(A) Adamantane derivative When forming the organic layer, in addition to the organic material for forming the organic layer, for example, by co-evaporation, the organic layer is organic so that a predetermined amount of the adamantane derivative represented by the general formula (1) is included. Form a layer. If the organic layer is formed so as to contain a certain amount or more of the adamantane derivative, a part of the adamantane derivative is crystallized, and the organic layer becomes cloudy and becomes a layer having a light scattering property (light scattering layer).
FIG. 2 shows X-ray diffraction results when a 100% adamantane film, a 75% organic material + 25% adamantane film, and a 45% organic material + 55% adamantane film are formed on a Si substrate. It is a graph which shows a result. A first peak was observed at the same position in the 100% adamantane film and the 55% doped adamantane film.
Specific examples of the adamantane derivative include those represented by the following general formula (1).

In the general formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or an aryl group. A heteroaryl group, an alkoxy group having 1 to 6 carbon atoms, an acyl group, an acyloxy group, an amino group, a nitro group, a cyano group, an ester group, an amide group, a halogen group, a perfluoroalkyl group having 1 to 6 carbon atoms, or Represents a silyl group, and at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond. X _{1 to} X ₁₂ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group, a heteroaryl group, or a carbon number. 1 to 6 alkoxy groups, acyl groups, acyloxy groups, amino groups, nitro groups, cyano groups, ester groups, amide groups, halogen groups, perfluoroalkyl groups having 1 to 6 carbon atoms, and silyl groups.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl (that is, 2 -Butyl), isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.

Examples of the alkenyl group having 2 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include vinyl, allyl (that is, 1- (2-propenyl)), 1- (1- Propenyl), 2-propenyl, 1- (1-butenyl), 1- (2-butenyl), 1- (3-butenyl), 1- (1,3-butadienyl), 2- (2-butenyl), 1 -(1-pentenyl), 5- (cyclopentadienyl), 1- (1-cyclohexenyl) and the like.

Examples of the alkynyl group having 2 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include ethynyl, propargyl (that is, 1- (2-propynyl)), 1- (1- Propynyl), 1-butadiynyl, 1- (1,3-pentadiynyl) and the like.

Examples of the aryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include phenyl, o-tolyl (that is, 1- (2-methylphenyl)), m-tolyl, p-tolyl, 1- (2,3-dimethylphenyl), 1- (3,4-dimethylphenyl), 2- (1,3-dimethylphenyl), 1- (3,5-dimethylphenyl), 1- (2,5 -Dimethylphenyl), p-cumenyl, mesityl, 1-naphthyl, 2-naphthyl, 1-anthranyl, 2-anthranyl, 9-anthranyl and 4-biphenylyl (ie 1- (4-phenyl) phenyl), 3 -Biphenylyls such as biphenylyl, 2-biphenylyl, 4-p-terphenylyl (i.e. 1-4- (4-biphenylyl) phenyl), 4-m-terphenylyl (i.e. And terphenylyls such as 1-4- (3-biphenylyl) phenyl).

Examples of the heteroaryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include a nitrogen atom, an oxygen atom, a sulfur atom, and the like as the hetero atom contained therein. Specifically, Examples include imidazolyl, pyrazolyl, pyridyl, pyrazyl, pyrimidyl, triazinyl, quinolyl, isoquinolinyl, pyrrolyl, indolyl, furyl, thienyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, azepinyl and the like.

Examples of the alkoxy group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methoxy, ethoxy, isopropoxy, cyclopropoxy, n-butoxy, tert-butoxy, cyclohexyloxy , Phenoxy and the like.

Examples of the acyl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include acetyl, benzoyl, formyl, and pivaloyl.

Examples of the acyloxy group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include acetoxy, benzoyloxy, and the like.

Examples of the amino group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, pyrrolidino, piperidino, morpholino and the like. Can be mentioned.

Examples of the ester group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include methyl ester (that is, methoxycarbonyl), ethyl ester, isopropyl ester, phenyl ester, benzyl ester, and the like.

Examples of the amide group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include N, N-dimethylamide (that is, dimethylaminocarbonyl) and N-phenylamide linked by a carbon atom of the amide. N, N-diphenylamide, N-methylacetamide (that is, acetylmethylamino), N-phenylacetamide, N-phenylbenzamide and the like linked by a nitrogen atom of the amide.

Examples of the halogen represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ include trifluoromethyl, pentafluoroethyl, 1-perfluoropropyl, and 2-perfluoro. Examples include propyl and perfluoropentyl.

The silyl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ is preferably one having 1 to 18 carbon atoms, such as trimethylsilyl, triethylsilyl, triisopropylsilyl, triphenylsilyl, methyldiphenylsilyl. , Dimethylphenylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl and the like.

Said R < ₁ > -R < ₄ > and X < ₁ > -X < ₁₂ > may be further substituted by another substituent. For example, examples of the alkyl group substituted with an aryl group include benzyl, 9-fluorenyl, 1- (2-phenylethyl), 1- (4-phenyl) cyclohexyl, etc., and the aryl group substituted with a heteroaryl group Examples thereof include 1- (4-N-carbazolyl) phenyl, 1- (3,5-di (N-carbazolyl)) phenyl, 1- (4- (2-pyridyl) phenyl) and the like.

R _{1 to} R ₄ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, an ester group, or a silyl group, and more preferably a hydrogen atom. , An alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, and a silyl group, and particularly preferably a hydrogen atom, an alkyl group, and an aryl group.

X _{1 to} X ₁₂ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an amino group, an ester group, or a silyl group, and more preferably a hydrogen atom. , An alkyl group and an aryl group, particularly preferably a hydrogen atom.

The alkyl group having 1 to 6 carbon atoms represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclopentyl, and cyclohexyl are more preferable, and methyl, ethyl, tert-butyl, n-hexyl, and cyclohexyl are more preferable, and methyl and ethyl are particularly preferable.

The aryl group represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ is preferably phenyl, o-tolyl, 1- (3,4-dimethylphenyl), 1- (3,5-dimethylphenyl). , 1-naphthyl, 2-naphthyl, 9-anthranyl, and biphenylyls and terphenylyls, more preferably phenyl, biphenylyls, and terphenylyls, and more preferably phenyl.

The hydrogen atom represented by R _{1 to} R ₄ and X _{1 to} X ₁₂ may be a deuterium atom, and is preferably a deuterium atom.

  Part or all of the hydrogen atoms contained in the compound represented by the general formula (1) may be substituted with deuterium atoms.

At least one of R _{1 to} R ₄ is a double bond or a group having a triple bond. Examples of the double bond include C═C, C═O, C═S, C═N, N = N, S = O, P = O, etc., preferably C = C, C = O, C = N, S = O, P = O, more preferably C = C, C = O, C = N, particularly preferably C = C. Examples of the triple bond include C≡C and C≡N, and preferably C≡C.

As the group having a double bond or triple bond of R _{1 to} R ₄ , an aryl group is preferable, and among them, a phenyl group, a biphenylyl group, and a terphenylyl group represented by the following are preferable, and a phenyl group is particularly preferable.

At least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, but the number of R _{1 to} R ₄ having a double bond or a triple bond is preferably 2 to 4, 3 -4 is more preferable, and 4 is particularly preferable.

When the number of R _{1 to} R ₄ having a double bond or triple bond is 1 to 3, R _{1 to} R ₄ consisting of only the remaining single bond is a hydrogen atom, an alkyl group, an alkoxy group, or a silyl group. Preferably, a hydrogen atom, an alkyl group, and a silyl group are preferable, and a hydrogen atom and an alkyl group are particularly preferable.

R _{1 to} R ₄ and X _{1 to} X ₁₂ may be linked to each other to form a ring structure. For example, as described below, X ₂ , X ₃ , and X ₉ may be linked to each other to form a diamantane structure, and X ₄ , X ₅ , and X ₁₂ are linked to each other to form a triamantane structure. May be formed. These diamantane structure and triamantane structure may be further substituted with a substituent.

  In the present invention, the compound represented by the general formula (1) (adamantane derivative) is preferably mixed and contained. Preferably, compounds having different groups having a double bond, or compounds having different numbers of substitution can be used in combination. Examples of the group having a double bond include the above phenyl group, biphenylyl group, and terphenylyl group, and examples thereof include compounds having 1 to 4 substitutions. For example, a mono-substituted product having a substitution number of 1 and a tetra-substitution product having a substitution number of 4 can be used.

In the present invention, when a plurality of compounds represented by the general formula (1) are mixed and used, the mixing ratio is preferably in the range of 1:99 to 99: 1 by mass ratio for one compound. More preferably, it is in the range of 20:80 to 80:20.
By using a mixture of a plurality of compounds represented by the general formula (1), further improvement in luminous efficiency and improvement in driving durability can be achieved.

  Specific examples of the compound represented by the general formula (1) used in the present invention are given below, but the compound of the present invention is not limited to these.

  In addition, when there is too little content of the adamantane derivative in a light-scattering layer, it will exist in a light-scattering layer, hardly crystallizing, and there exists a possibility that light-scattering property cannot fully be exhibited. On the other hand, for example, an adamantane derivative having a charge transporting property can form a light scattering layer with substantially only an adamantane derivative, but the electrical characteristics are easily affected by the degree of crystallinity. For this reason, it is preferable to form a light scattering layer by using a charge transporting material in combination with an adamantane derivative that has no or a small charge transporting performance.

  The content of the adamantane derivative in the light scattering layer is preferably 5% by mass or more and 90% by mass or less, more preferably 35%, in order to reliably impart light scattering properties by doping the adamantane derivative and to suppress changes in electrical characteristics. It is not less than 90% by mass.

As a method for forming an organic layer (light scattering layer) containing an adamantane derivative, it can be formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, a printing method, etc., but it is used in the present invention. Since the light scattering inducer can be deposited, it is preferably formed by deposition. For example, a light scattering layer can be formed by co-evaporating an adamantane derivative and a charge transporting material.
When the light scattering layer is formed by vapor deposition, the vapor deposition rate is preferably formed at a thickness of 1.0 kg / sec or less. With such a deposition rate, the adamantane derivative can be easily crystallized, and light scattering can be effectively imparted. In addition, it is preferable that the lower limit of a vapor deposition rate shall be 0.05 kg / sec or more from viewpoints of productivity.

(B) Hydrocarbon compound having an alkyl structure A light scattering layer containing a hydrocarbon compound having an alkyl structure may be provided. That is, by performing co-evaporation so that a predetermined amount of a hydrocarbon compound having an alkyl structure is included together with an organic material that forms the organic layer (for example, a host material), the organic layer becomes cloudy and has an optical scattering property. (Light scattering layer). In this case, it is considered that light scattering properties are imparted by the phase separation between the host material and the hydrocarbon compound having an alkyl group structure.
The hydrocarbon compound having an alkyl structure that serves as a light scattering material is a saturated hydrocarbon compound that does not include a double bond and includes an ethylene (—CH ₂ CH ₂ —) structure, from the viewpoint of forming a film at a relatively low temperature by vapor deposition. It is preferable that it is a linear saturated hydrocarbon compound. If the hydrocarbon compound having an alkyl structure is a saturated hydrocarbon compound, the hydrocarbon compound having an alkyl structure is solid at room temperature (25 ° C.) from the viewpoint of constituting an organic layer after film formation. Is preferred.
Specific examples of the derivatives preferably include those represented by the following structural formulas 1-1 to 7-5.

If the content of the hydrocarbon compound having an alkyl group structure in the light scattering layer is too small, it will be present in the light scattering layer with almost no phase separation. May increase. The content of the hydrocarbon compound having an alkyl structure is preferably 0.1% by mass or more and 70% by mass in order to reliably impart light scattering properties by the hydrocarbon compound having an alkyl structure and to suppress a change in electrical characteristics. Hereinafter, it is preferably 0.1% by mass or more and 50% by mass or less.
In addition, when forming an organic layer containing a hydrocarbon compound having an alkyl structure, it may be formed by a transfer method, a printing method, or the like, but a vapor deposition method from the point that a normal method for forming an organic layer can be applied. Is preferred. A preferable vapor deposition rate is 1.0 Å / sec or less and 0.05 Å / sec or more as in the case of using an adamantane derivative from the viewpoint of imparting light scattering properties, productivity, and the like.

(C) Silicon monoxide (SiO)
When forming an organic layer, it is good also as a light-scattering layer containing silicon monoxide (SiO). That is, even when a film is formed by co-evaporation of an organic material for forming an organic layer and SiO, the organic layer becomes cloudy and becomes a light scattering layer. In this case, it is considered that light scattering is imparted by the aggregation of SiO in the organic layer. If the content of SiO in the light scattering layer is too small, sufficient light scattering properties cannot be imparted. Conversely, if the content is too large, the influence on the electrical characteristics may be increased. In consideration of imparting light scattering properties and influence on electrical characteristics, the content of SiO is preferably 5% by mass to 50% by mass, more preferably 5% by mass to 20% by mass.

  When a light scattering layer containing silicon monoxide (SiO) is formed by co-evaporation, the deposition rate is 1 Å / sec or less and 0.05 Å / sec as described above from the viewpoint of imparting light scattering properties, productivity, and the like. The above is preferable.

  In addition, after forming a light-scattering layer, you may perform the heat processing for promoting light-scattering property (white turbidity). In particular, when SiO is used as the light scattering inducer, it becomes clouded with time and exhibits light scattering properties. However, the light scattering properties can be promoted by heating after film formation. The heating temperature is preferably 40 to 90 ° C, more preferably 40 to 60 ° C.

  The organic electroluminescent device 10 according to the present invention includes a light scattering layer in which at least one of the layer 20 and the light emitting layer 22 disposed on the side from which the light from the light emitting layer 22 is extracted includes the light scattering inducer as described above. However, materials used in known organic EL layers can be used other than the light scattering inducer contained in the light scattering layer. Hereinafter, each layer will be specifically described.

-Light emitting layer-
The light-emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines holes and electrons. It is a layer which has the function to provide and to emit light.
The light emitting layer may be composed of only a light emitting material, or may be a mixed layer of a host material and a light emitting material. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, and the dopant may be one type or two or more types. The host material is preferably a charge transport material. The host material may be one type or two or more types, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Furthermore, the light emitting layer may contain a material (binder) that does not have charge transporting properties and does not emit light.
Further, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors.

  Examples of fluorescent materials that can be used in the present invention include, for example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives. , Condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styryl Of amine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidin compounds, metal complexes of 8-quinolinol derivatives and pyromethene derivatives And various metal complexes typified by metal complex, polythiophene, polyphenylene, polyphenylene vinylene polymer compounds include compounds such as organic silane derivatives.

Examples of the phosphorescent material that can be used in the present invention include complexes containing transition metal atoms or lanthanoid atoms.
Although it does not specifically limit as a transition metal atom, Preferably, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum are mentioned, More preferably, they are rhenium, iridium, and platinum.
Examples of lanthanoid atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

Examples of the ligand of the complex include G. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H. Yersin, “Photochemistry and Photophysics of Coordination Compounds,” Springer-Verlag, 1987, Akio Yamamoto. Examples of the ligands described in the book “Organic Metal Chemistry-Fundamentals and Applications-” published in 1982 by Hankabosha.
Specific ligands are preferably halogen ligands (preferably chlorine ligands), nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketones Ligand (for example, acetylacetone), carboxylic acid ligand (for example, acetic acid ligand), carbon monoxide ligand, isonitrile ligand, cyano ligand, more preferably nitrogen-containing Heterocyclic ligand. The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

  The phosphorescent material is preferably contained in the light emitting layer in an amount of 0.1 to 40% by mass, and more preferably 0.5 to 20% by mass.

  Examples of the host material contained in the light emitting layer in the present invention include those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton, those having a triazine skeleton, and aryl. Examples thereof include materials having a silane skeleton and materials exemplified in the sections of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer described later.

  Although the thickness of a light emitting layer is not specifically limited, Usually, it is preferable that they are 1 nm-500 nm, it is more preferable that they are 5 nm-200 nm, and it is still more preferable that they are 10 nm-100 nm.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. Specifically, the hole injection layer and the hole transport layer are carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamines. Derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, organosilane derivatives, carbon In addition, a layer containing various metal complexes represented by an Ir complex having phenylazole or phenylazine as a ligand is preferable.
The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 200 nm. The thickness of the hole injection layer is preferably 0.1 nm to 200 nm, more preferably 0.5 nm to 200 nm, and still more preferably 1 nm to 200 nm.
The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

-Electron injection layer, electron transport layer-
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and the electron transport layer are triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, Carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles as ligands It is preferably a layer containing various metal complexes typified by metal complexes, organosilane derivatives, and the like.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and still more preferably 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

-Hole blocking layer-
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light emitting layer on the cathode side.
Examples of the organic compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

Using the functional material constituting each layer as described above, the lower electrode 14, the organic layer 16, and the upper electrode 18 are sequentially formed on the support substrate 12, for example, a pair of electrodes 14 as shown in FIG. , 18, the organic electroluminescent device 10 in which the organic layer 16 including at least the light emitting layer 22 is sandwiched is formed. The organic electroluminescent device 10 according to the present invention has a boiling point or sublimation point of 750 ° C. at 10 ⁻³ Pa at least one of the layer disposed on the side from which the light from the light emitting layer 22 is extracted and the light emitting layer 22. It forms so that it may become the light-scattering layer containing the light-scattering inducer which is the following.

-Sealing-
After the cathode is formed on the organic layer 16, it is covered and sealed with a sealing member (protective layer) in order to suppress deterioration of the organic electroluminescent element due to moisture or oxygen. As the sealing member, glass, metal, plastic, or the like can be used.
Further, external wires such as control wires and signal wires are connected to the electrodes 14 and 18, respectively. Thereby, the display apparatus by an organic electroluminescent element can be manufactured.
In addition, when manufacturing the display apparatus provided with the organic electroluminescent element which concerns on this invention, the drive system is not limited, Both a passive matrix system and an active matrix system can be employ | adopted.

The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234658, and JP-A-8-2441047. The driving method described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

In the examples, an organic electroluminescent element having the following standard configuration was formed on a glass substrate (the thickness in parentheses is the thickness of each layer). Each organic layer was formed using a vacuum deposition apparatus (1 × 10 ⁻⁶ torr).
1) Formation of anode An indium tin oxide (hereinafter abbreviated as ITO) film deposited to a thickness of 100 nm on a glass substrate of 25 mm × 25 mm × 0.7 mm (manufactured by Tokyo Sanyo Vacuum Co., Ltd.) A transparent support substrate was used. The ITO film on the transparent support substrate was patterned by etching and then washed.

2) Formation of hole injection / transport layer Hole injection layer: 4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine (abbreviated as 2-TNATA) and 2,3,5,6 -Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (abbreviated as F4-TCNQ) was co-deposited so that F4-TCNQ was 1.0 mass% with respect to 2-TNATA. The thickness was 160 nm.
Hole transport layer: formed with N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviated as α-NPD). The thickness was 10 nm.

3) Formation of light emitting layer Light emitting layer: hole transporting host material N, N′-dicarbazolyl-1,3-benzene (abbreviated as mCP) and polyvalent metal complex Pt-1 were co-evaporated. The deposition rate of each component was adjusted so that the mixing ratio of mCP and Pt-1 was 85% by mass: 15% by mass. The film thickness of the light emitting layer was 60 nm.

4) Formation of electron transport / injection layer Subsequently, the following electron transport layer and electron injection layer were provided on the light emitting layer.
Electron transport layer: Aluminum (III) bis (2-methyl-8-quinolato) -4-phenylphenolate (abbreviated as BAlq) was deposited to a thickness of 39 nm.
Electron injection layer: Bathocuproine (abbreviated as BCP) was deposited to a thickness of 1 nm.

5) Formation of cathode and the like Further, after depositing LiF to a thickness of 1 nm, patterning was performed using a shadow mask to provide Al having a thickness of 100 nm as a cathode. Each layer was provided by resistance heating vacuum deposition.

  The produced laminate was put in a glove box substituted with nitrogen gas, and sealed using a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba).

The standard configuration of the organic EL element in the examples is as follows. ITO was the anode, Al was the cathode, and the light emitting layer was formed of mCP and Pt-1.
ITO (100 nm) /2-TNATA+1.0% F4-TCNQ (160 nm) / NPD (10 nm) / mCP + 15% Pt-1 (60 nm) / BAlq (39 nm) / BCP (1 nm) / LiF (1 nm) / Al (100 nm )
The structural formula of the material used for each layer is shown below.

<Example 1>
The film was formed by doping 2-TNATA with 35% of the adamantane derivative of the above structural formula AD-4 (that is, the co-evaporation ratio at the time of forming the hole injection layer was 2-TNATA (64% by mass), AD− An organic electroluminescent device having the above-mentioned standard structure was manufactured except for 4 adamantane derivative (35% by mass) and F4-TCNQ (1.0% by mass).

External wiring was connected to both electrodes of the manufactured organic electroluminescence device, and external quantum efficiency and driving voltage were measured. The light extraction efficiency was evaluated from the increase in external quantum efficiency when the drive voltage and drive current were under the same conditions.
The change (increase) in the light extraction efficiency of the organic electroluminescence device of Example 1 was measured on the basis of the light extraction efficiency (8.4%) of the organic electroluminescence device having the standard configuration.

<Examples 2 to 18>
A light scattering layer was formed by doping each of the light scattering inducers shown in Table 1 below, and an organic electroluminescence device was manufactured. For these organic electroluminescent elements, the light extraction efficiency and the driving voltage were measured in the same manner as in Example 1.
Table 1 shows the results of the light extraction efficiency and the driving voltage of the organic electroluminescence devices manufactured in Examples 1 to 18.

  As can be seen from the results shown in Table 1, in the organic electroluminescent elements of Examples 1 to 18, the light extraction efficiency was improved as compared with the organic electroluminescent elements having the standard configuration, and the drive voltage was hardly decreased. In particular, when a light scattering layer doped with a light scattering inducing substance is provided on the organic layer on the anode side, that is, the organic layer containing 2-TNATA or NPD, the light extraction efficiency is greatly improved.

As mentioned above, although this invention was demonstrated, this invention is not limited to the said embodiment and Example. For example, the organic electroluminescent element of the present invention may be a top emission type or a type that emits light from both sides. In the case of double-sided light emission, at least one of the layers arranged on both sides with the light-emitting layer as a boundary, a light scattering layer containing a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa What is necessary is just to form.

It is the schematic which shows an example of a structure of the organic electroluminescent element which concerns on this invention. It is a graph which shows the result of the X-ray diffraction of the film | membrane which changed the density | concentration of adamantane on the Si substrate.

Explanation of symbols

10 ... Organic electroluminescent device (organic EL device)
DESCRIPTION OF SYMBOLS 12 ... Support substrate 14 ... Lower electrode 16 ... Organic layer (organic EL layer)
DESCRIPTION OF SYMBOLS 18 ... Upper electrode 20 ... Hole transport layer 22 ... Light emitting layer 24 ... Electron transport layer

Claims (17)

An organic electroluminescent element in which an organic layer including at least a light emitting layer is disposed between a pair of electrodes, wherein at least one of the layer disposed on the side of extracting light from the light emitting layer and the light emitting layer An organic electroluminescence device comprising a light scattering layer containing a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa.   The organic electroluminescence device according to claim 1, wherein the light scattering layer includes the light scattering inducer and a charge transporting material.   The organic electroluminescent element according to claim 1, wherein the light scattering layer has light scattering properties by crystallization, aggregation, or phase separation of the light scattering inducing substance. The organic electroluminescence device according to any one of claims 1 to 3, wherein the light scattering inducer is an adamantane derivative represented by the following general formula (1).

(In General Formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or aryl. Group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group, ester group, amide group, halogen group, perfluoroalkyl group having 1 to 6 carbon atoms, Or a silyl group, wherein at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, X _{1 to} X ₁₂ are each independently a hydrogen atom or a group having 1 to 6 carbon atoms. Alkyl group, alkenyl group having 2 to 6 carbon atoms, alkynyl group having 2 to 6 carbon atoms, aryl group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano Group, Ester group, an amido group, a halogen group, a perfluoroalkyl group having 1 to 6 carbon atoms, or a silyl group.)   5. The organic electroluminescent element according to claim 4, wherein the content of the adamantane derivative represented by the general formula (1) in the light scattering layer is 5% by mass or more and 90% by mass or less.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the light scattering inducer is silicon monoxide.   The organic electroluminescence device according to claim 6, wherein the content of the silicon monoxide in the light scattering layer is 5 mass% or more and 50 mass% or less.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the light scattering inducer is a hydrocarbon compound having an alkyl structure. 9. The organic electroluminescent device according to claim 8, wherein the hydrocarbon compound having an alkyl structure is a saturated hydrocarbon compound not containing a double bond and containing an ethylene (—CH ₂ CH ₂ —) structure. .   The organic electroluminescence device according to claim 8 or 9, wherein the hydrocarbon compound having an alkyl structure is a linear saturated hydrocarbon compound.   The organic electroluminescent device according to any one of claims 8 to 10, wherein the hydrocarbon compound having an alkyl structure is solid at room temperature.   12. The content of the hydrocarbon compound having an alkyl structure in the light scattering layer is 0.1% by mass or more and 70% by mass or less. 12. Organic electroluminescent element. A method of manufacturing an organic electroluminescent element in which an organic layer including at least a light emitting layer is disposed between a pair of electrodes, wherein at least one of a layer disposed on a side from which light from the light emitting layer is extracted and the light emitting layer As a single layer, a method for producing an organic electroluminescent device comprising forming a light scattering layer by depositing a light scattering inducer having a boiling point or sublimation point of 750 ° C. or lower at 10 ⁻³ Pa.   14. The method of manufacturing an organic electroluminescent device according to claim 13, wherein the light scattering layer is formed by co-evaporating the light scattering inducer and a charge transporting material.   The method for producing an organic electroluminescent element according to claim 13 or 14, wherein a deposition rate at the time of forming the light scattering layer is 1.0 Å / sec or less. As the light scattering inducer, an adamantane derivative represented by the following general formula (1), a hydrocarbon compound having an alkyl structure according to any one of claims 8 to 12, or silicon monoxide is used. The method for producing an organic electroluminescent element according to claim 13, wherein:

(In General Formula (1), R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or aryl. Group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano group, ester group, amide group, halogen group, perfluoroalkyl group having 1 to 6 carbon atoms, Or a silyl group, wherein at least one of R _{1 to} R ₄ is a group having a double bond or a triple bond, X _{1 to} X ₁₂ are each independently a hydrogen atom or a group having 1 to 6 carbon atoms. Alkyl group, alkenyl group having 2 to 6 carbon atoms, alkynyl group having 2 to 6 carbon atoms, aryl group, heteroaryl group, alkoxy group having 1 to 6 carbon atoms, acyl group, acyloxy group, amino group, nitro group, cyano Group, Ester group, an amido group, a halogen group, a perfluoroalkyl group having 1 to 6 carbon atoms, or a silyl group.)   The method for producing an organic electroluminescent element according to claim 13, further comprising a step of performing a heat treatment after the light scattering layer is formed.