WO2020012685A1

WO2020012685A1 - Thin film, electronic device, organic electroluminescent element, material for organic electroluminescence, display device, and lighting equipment

Info

Publication number: WO2020012685A1
Application number: PCT/JP2019/005624
Authority: WO
Inventors: 智美菅井; 恵美子御子柴; 杉野　元昭
Original assignee: コニカミノルタ株式会社
Priority date: 2018-07-09
Filing date: 2019-02-15
Publication date: 2020-01-16
Also published as: JP7173145B2; JPWO2020012685A1

Abstract

This thin film comprises a compound having a structure represented by general formula (1).

Description

Thin film, electronic device, organic electroluminescence element, material for organic electroluminescence, display device, and lighting device

<< The present invention relates to a thin film, an electronic device, an organic electroluminescence element, a material for organic electroluminescence, a display device, and a lighting device.

Electronic devices are generally widely used, and examples thereof include solar panels and organic electroluminescent elements. 2. Description of the Related Art An organic electroluminescence element (hereinafter, referred to as an organic EL element) has a configuration including an electrode (anode and a cathode) and a light emitting layer, in which holes injected from the anode and electrons injected from the cathode are recombined in the light emitting layer. This produces excitons. Utilizing the emission of light when the exciton is deactivated.

In recent years, from the viewpoint of power saving and the like, there has been a demand for improved performance of these electronic devices. For example, organic EL elements are widely used as electronic devices, and various organic EL materials have been developed to improve the performance of the organic EL elements. Examples thereof include the organic EL materials described in Patent Literature 1 and Patent Literature 2. In these examples, a pyrimidine compound is used for the organic EL material to improve the performance of the organic EL element.
However, there is a demand for further improvement in the performance of electronic devices, and there is a demand for an electronic device that has a lower driving voltage and a higher driving voltage when stored for a certain period of time, that is, a storage stability that is further improved.

International Publication No. 2004/39786 US Patent Application Publication No. 2007/190355

In view of the above problems, the present invention provides a thin film that contributes to a reduction in drive voltage of an electronic device and an improvement in stability during storage for improving the performance of an electronic device, an electronic device using the thin film, and an organic device using the thin film. An object of the present invention is to provide an electroluminescence element, a material for organic electroluminescence used for the organic electroluminescence element, a display device, and a lighting device.

上記 The above object according to the present invention is solved by the following means.

1. A thin film containing a compound having a structure represented by the following general formula (1).

(In the general formula (1), Ar ₁ to Ar ₃ each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline. Ar ₄ to Ar ₆ each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline ring. n represents an integer of 1 or more and 5 or less, and L independently represents an aromatic hydrocarbon ring or a heterocyclic ring.)

{2. 2. The thin film according to claim 1, wherein in the general formula (1), when n = 2, at least one of L is a heterocyclic ring.

{3. 2. The thin film according to item 1, wherein in the general formula (1), n is 3 or more.

4. 4. The thin film according to any one of items 1 to 3, wherein in the general formula (1), L independently represents a phenyl ring, a pyridine ring, a pyrazine ring, or a pyrimidine ring.

5. 5. The thin film according to any one of items 1 to 4, further comprising an electron injection material.

6. An electrode, an organic electroluminescence device having a plurality of organic functional layers including a light emitting layer,
6. An organic electroluminescence device, wherein at least one of the organic functional layers is the thin film according to any one of Items 1 to 5.

$ 7. 7. The organic electroluminescence device according to claim 6, wherein the thin film, the electron injection layer, and the electrode are stacked in this order.

8. The electrode is mainly composed of silver,
8. The organic electroluminescence device according to claim 6, wherein the organic functional layer is provided adjacent to the electrode.

9. 9. The organic electroluminescence device according to any one of items 6 to 8, wherein the electrode has a thickness of 15 nm or less and is transparent.

{10. An organic electroluminescent material comprising a compound having a structure represented by the following general formula (1).

{11. A display device comprising the organic electroluminescence element according to any one of items 6 to 9.

{12. A lighting device comprising the organic electroluminescent element according to any one of items 6 to 9.

{13. An electronic device comprising an electrode and the thin film according to any one of the first to fifth aspects.

According to the present invention, it is possible to provide an organic electroluminescence device having improved driving voltage and stability during high-temperature storage, and a material for organic electroluminescence used for the organic electroluminescence device. Further, a display device and a lighting device with improved driving voltage and stability during high-temperature storage can be provided.

Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of the display unit A Pixel circuit diagram Schematic diagram of passive matrix type full color display device Schematic diagram of lighting device Schematic diagram showing a cross section of the lighting device

薄膜 The thin film of the present invention is characterized by containing a compound having a structure represented by the following general formula (1). This feature is a technical feature common to the inventions according to claims 1 to 4. Further, the thin film of the present invention may contain other compounds in addition to the compound having the structure represented by the following general formula (1).

<< Compound having a structure represented by the general formula (1) >>

In the general formula (1), Ar ₁ to Ar ₃ each independently represent a hydrogen atom or an aromatic hydrocarbon ring or a heterocyclic ring, and may further have a substituent, and at least one of them is a pyridine ring Or a pyrazine ring, a pyrimidine ring, or a quinazoline ring. That is, Ar ₁ to Ar ₃ each independently represent a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon ring, or a substituted or unsubstituted heterocyclic ring, and at least one of them is a pyridine ring or a pyrazine. Or a pyrimidine ring or a quinazoline ring. Specific examples of the aromatic hydrocarbon ring are not particularly limited, and include, for example, a benzene ring, a naphthyl ring, an anthracene ring, a pyrene ring and the like. Specific examples of the heterocyclic ring are not particularly limited. For example, there is a heterocyclic ring in which a part of carbon atoms in the aromatic hydrocarbon ring is substituted with a hetero atom (an oxygen atom, a nitrogen atom, or a sulfur atom). Pyridine ring, pyrrole ring, furan ring, pyran ring, imidazole ring, pyrazole ring, oxazole ring, pyridazine ring, pyrimidine ring, purine ring, triazine ring, triazole ring, quinoline ring, isoquinoline ring and the like.

In the general formula (1), Ar ₄ to Ar ₆ each independently represent a hydrogen atom or an aromatic hydrocarbon ring or a heterocyclic ring, and may further have a substituent, and at least one of them is a pyridine ring Or a pyrazine ring, a pyrimidine ring, or a quinazoline ring. That is, Ar ₄ to Ar ₆ each independently represent a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon ring, or a substituted or unsubstituted heterocyclic ring, and at least one of them is a pyridine ring or a pyrazine. Or a pyrimidine ring or a quinazoline ring. Specific examples of the aromatic hydrocarbon ring are not particularly limited, and include, for example, a benzene ring, a naphthyl ring, an anthracene ring, a pyrene ring and the like. Specific examples of the heterocyclic ring are not particularly limited. For example, there is a heterocyclic ring in which a part of carbon atoms in the aromatic hydrocarbon ring is substituted with a hetero atom (an oxygen atom, a nitrogen atom, or a sulfur atom). Pyridine ring, pyrrole ring, furan ring, pyran ring, imidazole ring, pyrazole ring, oxazole ring, pyridazine ring, pyrimidine ring, purine ring, triazine ring, triazole ring, quinoline ring, isoquinoline ring and the like.

中 In the general formula (1), n represents an integer of 1 or more and 5 or less.

中 In the general formula (1), L independently represents an aromatic hydrocarbon ring or a heterocyclic ring, and may further have a substituent. That is, L independently represents a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. Specific examples of L include, but are not particularly limited to, for example, a benzene ring, a naphthyl ring, an anthracene ring, a fluorene ring, a pyridine ring, a pyrazine ring, a triazine ring, a pyrimidine ring, a thiophene ring, a benzothiophene ring, an indole ring, and an imidazole ring. And a divalent linking group containing a benzoimidazole ring, a pyrazole ring or a triazole ring, or an azadibenzofuran ring.

のうち Of these, L preferably independently represents a phenyl ring, a pyridine ring, a pyrazine ring, or a pyrimidine ring. These may further have a substituent.

When n = 2, at least one of L is preferably a heterocyclic ring. That is, when n = 2, at least one of L is preferably a substituted or unsubstituted heterocyclic ring. Specific examples of the heterocyclic ring are not particularly limited, and include the same examples as described above.

中 In the general formula (1), n is preferably 3 or more and 5 or less. Further, it is preferable that n is 3 or more and 5 or less, and L independently represents a phenyl ring, a pyridine ring, a pyrazine ring, or a pyrimidine ring. These may have a substituent.

The substituent used in the general formula (1) is not particularly limited, but for example, an alkyl group (eg, a methyl group, an ethyl group, a trifluoromethyl group, an isopropyl group), an aryl group (eg, a phenyl group) , A heteroaryl group (eg, a pyridyl group, a carbazolyl group, etc.), a halogen atom (eg, a fluorine atom, etc.), a cyano group, or a fluorinated alkyl group, and those used in the exemplified compounds described later are also preferable. .

<< Synthesis example of compound having structure represented by general formula (1) >>
<Synthesis example 1>
Synthesis of compound (1) of the present invention

1.8 g (4.64 mmol) of compound (1-1), 0.84 g (2.55 mmol) of compound (1-2), 1.28 g (9.28 mmol) of potassium carbonate, and 5 mL of pure water And 43 mL of THF, and the mixture was stirred at room temperature for 30 minutes while flowing nitrogen gas. Thereafter, 0.575 g (0.348 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 0.142 g (0.348 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl were charged and stirred. The mixture was refluxed for 7 hours while heating. After completion of the reaction, the mixture was cooled to room temperature, water was added, and the mixture was stirred and filtered. THF was added to the obtained crude crystals, and the mixture was suspended and stirred under reflux with heating, cooled to room temperature, filtered and dried to obtain 1.56 g of a solid. The obtained solid was purified by sublimation to obtain 1.04 g (yield: 65%) of compound (1). The structure was confirmed by ¹ H-NMR.

<Synthesis Example 2>
Synthesis of compound (49) of the present invention

1.7 g (4.34 mmol) of compound (49-1), 0.82 g (2.48 mmol) of compound (49-2), 0.92 g (6.68 mmol) of potassium carbonate, and 4 mL of pure water in a 200 mL four-headed colben And THF (40 mL), and the mixture was stirred at room temperature for 30 minutes while flowing nitrogen gas. Thereafter, 0.144 g (0.25 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 0.102 g (0.25 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl were added thereto and stirred. The mixture was refluxed for 7 hours. After completion of the reaction, the mixture was cooled to room temperature, water was added, and the mixture was stirred and filtered. THF was added to the obtained crude crystals, and the mixture was suspended and stirred under reflux with heating, cooled to room temperature, filtered and dried to obtain 1.02 g of a solid. The obtained solid was purified by sublimation to obtain 0.90 g (yield: 60%) of compound (49). The structure was confirmed by ¹ H-NMR.

<< Specific Example of Compound Having Structure Represented by General Formula (1) >>
Specific examples of the compound having the structure represented by the general formula (1) are shown below. These compounds are merely examples, and the present invention is not limited thereto.

The method of using the thin film of the present invention described above is not particularly limited, and can be used for various products. Examples of products using the thin film of the present invention include various electronic devices such as solar panels and organic EL elements. These electronic devices have electrodes formed of metal or the like, and the thin film.

有機 The organic electroluminescent material of the present invention is characterized by containing a compound having a structure represented by the general formula (1). The general formula (1) is as described above.

Further, the plurality of nitrogen-containing heterocycles in the compound having the structure represented by the general formula (1) have an interaction with silver, which reduces the diffusion distance of silver atoms and suppresses the aggregation of silver. it can. Thereby, a uniform film of an electrode containing silver as a main component can be achieved. Details of the electrodes will be described later. Further, since the compound of the present invention can suppress the crystallinity, it can be easily laminated at the time of film formation and can improve smoothness. Further, by suppressing the aggregation of silver, it is possible to suppress an increase in grain boundaries of silver atoms, so that it is possible to suppress a decrease in drive voltage and a rise in drive voltage over time.

The heteroatom in the compound having the structure represented by the general formula (1) interacts with an alkali metal, an alkaline earth metal, or a rare earth used as an electron injecting material. Diffusion of each metal, alkaline earth metal, and rare earth atom into the light emitting layer can be suppressed, and a decrease in driving voltage and an increase in driving voltage over time can be suppressed.

<< Constituent Layer of Organic EL Element >>
The constituent layers of the organic EL device of the present invention will be described. In the organic EL device of the present invention, the electrodes mean an anode and a cathode. Preferred specific examples of the layer structure of the various organic functional layers sandwiched between the anode and the cathode are shown below, but the present invention is not limited thereto.
(I) anode / light emitting layer unit / electron transport layer / cathode (ii) anode / hole transport layer / light emitting layer unit / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer unit / hole blocking Layer / electron transport layer / cathode (iv) anode / hole transport layer / emission layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / emission Layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode

Further, the light emitting layer unit may have a non-light emitting intermediate layer between the plurality of light emitting layers, and may have a multi-photon unit configuration in which the intermediate layer is a charge generating layer. In this case, as the charge generation layer, ITO (indium tin oxide), IZO (indium zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, CuAlO ₂ , CuGaO ₂ , a conductive inorganic compound layer such as SrCu ₂ O ₂ , LaB ₆ , RuO ₂ , a two-layer film such as Au / Bi ₂ O ₃ , SnO ₂ / Ag / SnO ₂ , ZnO / Ag / ZnO, Bi ₂ Multilayer films such as O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO ₂ , fullerenes such as C ₆₀ , oligothiophenes, metal phthalocyanines, metal-free phthalocyanines And conductive organic compound layers such as metal porphyrins and metal-free porphyrins. In addition, the charge generation layer has a function of promoting the transfer of electrons between the plurality of light emitting layers, and preferably contains an alkali metal such as lithium, an alkaline earth metal, a rare earth, or the like. In addition, the function and configuration of the charge generation layer may be the same as those of the electron injection layer described later.
Hereinafter, each layer constituting the organic EL device of the present invention will be described.

《Organic functional layer》
The organic EL device of the present invention has an anode, a plurality of organic functional layers including a light emitting layer, and a cathode in this order. That is, the organic functional layer according to the present invention is located between the anode and the cathode.
The organic EL element of the present invention has a plurality of organic functional layers, and the organic functional layer includes a light emitting layer and the above-described thin film of the present invention. Note that the number of the light emitting layers may be one or plural.

Further, it is preferable that the organic functional layer has a layer containing a compound having the structure represented by the general formula (1) and an electron injection material. That is, it is preferable that an electron injecting material is included in the thin film as the organic functional layer, or that an organic functional layer (an electron injecting layer described later) in which an electron injecting material is included is provided separately from the thin film.
When an electron injection layer described later is present, it is also preferable that the thin film, the electron injection layer, and the cathode are stacked in this order.

<< Light-emitting layer >>
The light-emitting layer used in the present invention is a layer that emits light by recombination of electrons and holes injected from an electrode or an electron transport layer and a hole transport layer, and a light-emitting portion is in the light-emitting layer. May be the interface between the light emitting layer and the adjacent layer.
The total sum of the thicknesses of the light emitting layers is not particularly limited. Preferably, it is adjusted to a range of 2 nm to 5 μm. The total thickness of the light emitting layer is more preferably adjusted in the range of 2 to 200 nm, and particularly preferably adjusted in the range of 5 to 100 nm.

The light-emitting layer can be formed by using a light-emitting dopant or a host compound described later and forming a film by, for example, a vacuum evaporation method or a wet method. The wet method is also called a wet process. For example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, a spray coating method, a curtain coating method, an LB method (Langmuir Blodgett) (Langmuir Bloodgett method)).
The light emitting layer of the organic EL device of the present invention preferably contains a light emitting dopant (phosphorescent light emitting dopant, fluorescent light emitting dopant, etc.) compound and a host compound.

(1) Light-Emitting Dopant A light-emitting dopant (also referred to as a light-emitting dopant, a dopant compound, or simply a dopant) will be described.
Examples of the luminescent dopant include a phosphorescent dopant (also referred to as a phosphorescent dopant, a phosphorescent compound, and a phosphorescent compound), and a fluorescent dopant (also referred to as a fluorescent dopant, a fluorescent compound, and a fluorescent compound). .) Can be used.

(1.1) Phosphorescent dopant A phosphorescent dopant is a compound in which light emission from an excited triplet is observed, and specifically, a compound that emits phosphorescent light at room temperature (25 ° C.). The phosphorescent dopant is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., and a preferable phosphorescence quantum yield is 0.1 or more.
The phosphorescence quantum yield can be measured by the method described in Spectroscopy II, 4th Edition, pp. 398 (1992 edition, Maruzen) of Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents. However, the phosphorescent dopant used in the present invention only needs to achieve the above-mentioned phosphorescent quantum yield (0.01 or more) in any of the solvents.

(2) In principle, two types of light emission from the phosphorescent dopant can be given. One is an energy transfer type. In the energy transfer type, the excited state of the light emitting host compound is generated by the recombination of the carrier on the host compound to which the carrier is transported, and the energy is transferred to the phosphorescent dopant to obtain light emission from the phosphorescent dopant. Things. The other is a carrier trap type. In the carrier trap type, a phosphorescent dopant serves as a carrier trap, carriers are recombined on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. In either case, the condition is that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

(1.2) Fluorescent dopant As the fluorescent dopant, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squarium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, Examples include perylene dyes, stilbene dyes, polythiophene dyes, rare earth complex fluorescent materials, and compounds having a high fluorescence quantum yield represented by laser dyes.

[Use in combination with a conventionally known dopant]
The light emitting dopant used in the present invention may be used in combination of plural kinds of compounds, or may be used in combination of phosphorescent dopants having different structures or in combination of phosphorescent dopant and fluorescent dopant.
Here, as the luminescent dopant, conventionally known compounds described in WO 2013/061850 can be suitably used, but the present invention is not limited thereto.

[Host compound]
The host compound (also referred to as a light-emitting host or a light-emitting host compound) that can be used in the present invention has a mass ratio of 20% or more in the layer contained in the light-emitting layer and a room temperature ( (25 ° C.) is defined as a compound having a phosphorescence quantum yield of phosphorescence at less than 0.1. Preferably, the phosphorescence quantum yield is less than 0.01. Further, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more.

ホスト The host compound that can be used in the present invention is not particularly limited, and a compound that is conventionally used in an organic EL device can be used. Typically, those having a basic skeleton such as a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound, or a carboline derivative or a diazacarbazole derivative (here Wherein the diazacarbazole derivative is one in which at least one carbon atom of a hydrocarbon ring constituting a carboline ring of the carboline derivative is substituted with a nitrogen atom.

As the known host compound that can be used in the present invention, a compound that has a hole transporting ability and an electron transporting ability, prevents a longer wavelength of light emission, and has a high Tg (glass transition temperature) is preferable.
In the present invention, a conventionally known host compound may be used alone or in combination of two or more. By using a plurality of host compounds, charge transfer can be adjusted, and the efficiency of the organic EL device can be increased. In addition, by using a plurality of conventionally known compounds, it is possible to mix different luminescence, and thus, it is possible to obtain an arbitrary luminescence color.

Further, the host compound used in the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (polymerizable host compound). Good. Further, as the host compound used in the present invention, one or more of such compounds may be used.

Specific examples of the known host compound include the compounds described in the following documents.
JP-A-2001-257076, JP-A-2002-308855, JP-A-2001-313179, JP-A-2002-319493, JP-A-2001-357977, JP-A-2002-334786, JP-A-2002-8860, JP-A-2002-334787, JP-A-2002-15871, JP-A-2002-334788, JP-A-2002-43056, JP-A-2002-334789, JP-A-2002-75645, JP-A-2002-338579, and JP-A-2002-338579. JP-A-2002-105445, JP-A-2002-343568, JP-A-2002-141173, JP-A-2002-352957, JP-A-2002-203683, JP-A-2002-363227, JP-A-2002-231453, and JP-A-2002-231453. JP-A-2003-3165, JP-A-2002-234888, JP-A-2003-27048, JP-A-2002-255934, JP-A-2002-260861, JP-A-2002-280183, JP-A-2002-299060, and 2002 JP-A-302516, JP-A-2002-305083, JP-A-2002-305084, and JP-A-2002-308837.

"cathode"
As the cathode, a metal having a low work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof are used as an electrode material. Specific examples of such electrode materials include aluminum, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among them, a mixture of an electron-injecting metal and a second metal that is a stable metal having a large work function value, such as a magnesium / silver mixture, from the viewpoint of durability against electron injection and oxidation. Preferred are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like.
The cathode is particularly preferably composed mainly of silver. Examples of the alloy containing silver as a main component include silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), silver indium (AgIn), and the like.
The “main component” in the present invention means that the content is 50% by mass or more in the film or layer, preferably 80% by mass or more, more preferably 90% by mass or more. .

The cathode using an alloy containing silver as a main component may have a configuration in which the cathode is divided into a plurality of layers and stacked as necessary.
The thickness of the cathode is selected in the range of usually 10 nm to 5 μm, preferably 50 to 200 nm. When an alloy containing silver as a main component is used, the film thickness is preferably 15 nm or less, more preferably 12 nm or less. When an alloy containing silver as a main component is used, the thickness is preferably 4 nm or more. That is, when an alloy containing silver as a main component is used, the film thickness is more preferably in the range of 4 to 12 nm. When the film thickness is within the range, the component of light absorbed or reflected by the film can be further reduced, the light transmittance can be further maintained, and the conductivity of the layer can be further ensured.

As described above, when the cathode mainly contains silver, the cathode is preferably adjacent to the organic functional layer containing the compound having the structure represented by the general formula (1), that is, the thin film.
The thin film is preferably adjacent to the cathode. Even when the cathode is formed on the thin film, the thin film may be formed on the cathode. Further, the cathode may be formed on the thin film, the thin film may be further formed on the cathode, and the cathode may be sandwiched between the two thin films.

When a cathode mainly composed of silver is formed on the thin film, silver atoms constituting the cathode interact with a compound having a structure represented by the general formula (1) contained in the thin film. I do. As a result, the diffusion distance of silver atoms on the surface of the thin film is reduced, and aggregation (migration) of silver at a specific portion can be suppressed.
That is, a silver atom first forms a two-dimensional nucleus on the surface of the thin film having an atom having an affinity for the silver atom, and forms a two-dimensional single crystal layer around the nucleus. -Van der Merwe (FM type) is formed.

Generally, silver atoms attached on the surface of the thin film are bonded while diffusing on the surface to form a three-dimensional nucleus, and grow in a three-dimensional island shape (Volume-type). It is considered that film growth in a Weber (VW type) facilitates film formation in an island shape.
However, in the present invention, it is assumed that the compound having the structure represented by the general formula (1) contained in the thin film suppresses island growth and promotes layer growth.
Therefore, a cathode having a small thickness but a uniform thickness can be obtained. As a result, it is possible to obtain a transparent electrode that has sufficient conductivity while maintaining light transmittance due to the thin film thickness.

Further, as described above, by suppressing the aggregation of silver at a specific portion, it is possible to suppress an increase in grain boundaries of silver atoms at the interface between the cathode and the thin film. Drive voltage can be suppressed from increasing.

Further, when the thin film is formed on the cathode, it is considered that silver atoms constituting the cathode interact with atoms having an affinity for silver atoms contained in the thin film, and the mobility is suppressed. Can be Thereby, the surface smoothness of the cathode is improved, so that irregular reflection can be suppressed, and the light transmittance can be improved.
It is presumed that such an interaction suppresses a change in the film quality of the cathode due to a physical stimulus such as heat or temperature, thereby improving the durability.

The cathode can be manufactured by forming a thin film of a general electrode material other than an alloy containing silver as a main component by a method such as evaporation or sputtering. Further, from the viewpoint of lowering the driving voltage and further improving the luminous efficiency, the element life and the like, the sheet resistance value of the cathode is several hundred Ω / sq. (Ω / □) or less, preferably 50 Ω / sq. The following is more preferable, and especially 25 Ω / sq. The following is preferred. Although the lower limit is not particularly specified, for example, 1 Ω / sq. The above can be considered.
In order to transmit the emitted light, it is convenient if either the anode or the cathode of the organic EL element is transparent or translucent to improve the light emission luminance. The light transmittance of the cathode is preferably 30% or more, and more preferably 50% or more. More preferably, it is 70% or more. The upper limit is not particularly defined, but may be, for example, 95% or less.
In addition, a transparent or translucent cathode can be manufactured by forming the above metal on the cathode in a thickness of 1 to 20 nm and then manufacturing a conductive transparent material mentioned in the description of the anode described later thereon. . By applying this, an element in which both the anode and the cathode have transparency can be manufactured.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and preferably contains a compound having a structure represented by the general formula (1) as described above. That is, the electron transport layer is preferably the thin film. In a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided with a single layer or a plurality of layers. Further, an electron injection / transport layer that also contains a material included in the electron injection layer described below may be provided.
The electron transporting layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. As a constituent material of the electron transporting layer, any one of conventionally known compounds may be selected and used in combination. Is also possible.

Examples of conventionally known materials used for the electron transport layer (hereinafter, referred to as electron transport materials) include polycyclic aromatic hydrocarbons such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, and naphthalene perylene; Heterocyclic tetracarboxylic anhydride, carbodiimide, fluorenylidenemethane derivative, anthraquinodimethane and anthrone derivative, oxadiazole derivative, carboline derivative, or carbon atom of a hydrocarbon ring constituting a carboline ring of the carboline derivative Derivatives having a ring structure in which at least one is substituted by a nitrogen atom, hexaazatriphenylene derivatives, and the like.
Further, in the oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as the electron transporting material.
Polymer materials in which these materials are introduced into a polymer chain, or in which these materials are used as a polymer main chain, can also be used.

Also, metal complexes of 8-quinolinol derivatives, for example, tris (8-quinolinol) aluminum (Alq) ₃ , tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like; , Cu, Ca, Sn, Ga or Pb can be used as the electron transport material.
In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like, can also be used as the electron transporting material.
Further, an inorganic semiconductor such as n-type Si or n-type SiC can also be used as the electron transporting material.

The electron transport layer is preferably formed by thinning an electron transport material by, for example, a vacuum evaporation method, a wet method, or the like. The wet method is also called a wet process. For example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, a spray coating method, a curtain coating method, an LB method (Langmuir Blodgett) (Langmuir @ Blodgett method)).

The thickness of the electron transport layer is not particularly limited, but is usually about 5 to 5000 nm, preferably 5 to 200 nm. The electron transport layer may have a single-layer structure composed of one or more of the above materials.
Further, an n-type dopant such as a metal compound such as a metal complex and a metal halide may be doped.

As an example of a conventionally known electron transporting material preferably used for forming an electron transporting layer of the organic EL device of the present invention, compounds described in WO 2013/061850 can be suitably used. It is not limited to.

<< Injection layer: electron injection layer (cathode buffer layer), hole injection layer >>
The injection layer is provided as needed, and has an electron injection layer and a hole injection layer, and may be present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. .
The injection layer is a layer provided between the electrode and the organic functional layer for lowering the driving voltage and improving the light emission luminance. The injection layer is described in detail in Chapter 2, Chapter 2, “Electrode Materials” (pages 123 to 166) of “Organic EL Device and Its Forefront of Industrialization (published by NTT Corporation on November 30, 1998)”. And a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, and JP-A-8-288069. Examples of the anode buffer layer include, as specific examples, a phthalocyanine buffer layer represented by copper phthalocyanine, a hexaazatriphenylene derivative buffer layer described in JP-T-2003-519432, JP-A-2006-135145, and the like; Oxide buffer layers such as vanadium oxide, amorphous carbon buffer layers, polymer buffer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene, and tris (2-phenylpyridine) iridium complexes. Orthometalated complex layer.

The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586. Specific examples of the cathode buffer layer include a metal buffer layer represented by strontium and aluminum, an alkali metal compound buffer layer represented by lithium, lithium fluoride, sodium fluoride, and potassium fluoride; magnesium fluoride; Examples include an alkaline earth metal compound buffer layer represented by cesium oxide, a rare earth metal compound buffer layer represented by ytterbium and scandium, and an oxide buffer layer represented by aluminum oxide. The buffer layer (injection layer) is desirably an extremely thin film, and the thickness is preferably in the range of 0.1 nm to 5 μm, depending on the material.

As described above, the organic functional layer preferably contains a compound having a structure represented by the general formula (1).

For example, when the electron transport layer and the cathode are adjacent to each other and the electron injection layer is not provided, the electron transport layer contains an electron injection material in addition to the compound having the structure represented by the general formula (1). Is also preferable (that is, an electron injection transport layer is provided). In such a case, and when silver is used as a main component of the cathode, as described above, by suppressing the aggregation of silver at a specific portion, the drive voltage decreases and the drive voltage increases with time. Can be suppressed.

For example, when an electron transport layer, an electron injection layer, and a cathode are laminated in this order, the electron transport layer contains a compound having a structure represented by the general formula (1) (the electron transport layer corresponds to the thin film). ), It is also preferable that the electron injection layer contains an electron injection material. In this case, the compound having the structure represented by the general formula (1) interacts with an alkali metal, an alkaline earth metal, a rare earth, or the like used as an electron injection material, and diffuses the electron injection material into the light emitting layer. Therefore, it is considered that a decrease in the drive voltage and a rise in the drive voltage over time can be suppressed.

<< Blocking layer: hole blocking layer, electron blocking layer >>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A-11-204258 and JP-A-11-204359, and page 237 of "Organic EL Devices and Their Forefront of Industrialization (published by NTT Corporation on November 30, 1998)". There is a hole blocking (hole block) layer.

The hole blocking layer has a function of an electron transporting layer in a broad sense, and is made of a hole blocking material having a function of transporting electrons and having an extremely small ability to transport holes. The hole blocking layer can improve the probability of recombination of electrons and holes by blocking holes while transporting electrons.
In addition, the above-described structure of the electron transport layer can be used as a hole blocking layer, if necessary.
The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.
In the hole blocking layer, a carbazole derivative, a carboline derivative, or a diazacarbazole derivative (here, a diazacarbazole derivative is one in which one of carbon atoms constituting a carboline ring is a nitrogen atom) Is preferable.).

On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material having a function of transporting holes and having an extremely small ability to transport electrons. The electron blocking layer can improve the recombination probability of electrons and holes by blocking electrons while transporting holes.
In addition, the configuration of the hole transport layer described below can be used as an electron blocking layer as needed. The thickness of the hole blocking layer and the electron transporting layer according to the present invention is preferably 3 to 100 nm, more preferably 5 to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.
The hole transporting material has any of hole injection or transport and electron barrier properties, and may be any of an organic substance and an inorganic substance. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include a stilbene derivative, a silazane derivative, an aniline-based copolymer, a conductive polymer oligomer, particularly a thiophene oligomer.
Further, azatriphenylene derivatives described in JP-T-2003-519432, JP-A-2006-135145, and the like can also be used as the hole transport material.

As the hole transporting material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.
Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl; 1,1-bis (4-di-p-tolyl Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' － (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbene; N-phenylcarbazole, and two condensed aromatic rings described in US Pat. No. 5,061,569. In the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308688 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which triphenylamine units described in (3) are linked in a three-star burst type Is mentioned.

Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain, can also be used.
Further, inorganic compounds such as p-type Si and p-type SiC can also be used as the hole injection material and the hole transport material.

、 Also, JP-A-11-251067, J.P. Huang @ et. al. A so-called p-type hole transport material as described in a well-known document (Applied Physics Letters 80 (2002), p. 139) can also be used. In the invention, it is preferable to use these materials since a light emitting element with higher efficiency can be obtained.

The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method. it can.
The thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a one-layer structure composed of one or more of the above materials.

Alternatively, a hole transporting layer having a high p property and doped with an impurity may be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, and J.P. Appl. Phys. , 95, 5773 (2004).
In the present invention, it is preferable to use such a hole-transporting layer having a high p-property because a device with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more) as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as CuI, ITO, SnO ₂ , and ZnO.
Alternatively, a material such as IDIXO (In ₂ O ₃ —ZnO) which can form an amorphous and transparent conductive film may be used. The anode may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering and forming a pattern of a desired shape by a photolithography method. Alternatively, when the pattern accuracy is not so required (about 100 μm or more), a pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

Alternatively, when a substance that can be applied such as a conductive organic compound is used, a wet film forming method such as a printing method and a coating method can be used. When light is extracted from this anode, it is desirable that the light transmittance is greater than 10%, and the sheet resistance of the anode is several hundred Ω / sq. The following is preferred. Further, the film thickness depends on the material, but is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

《Support substrate》
The support substrate (hereinafter, also referred to as a base, a substrate, a base, a support, or the like) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, and the like, and is transparent. Or opaque. When light is extracted from the support substrate side, the support substrate is preferably transparent. Preferred examples of the transparent support substrate include glass, quartz, and a transparent resin film. A particularly preferred support substrate is a resin film that can provide flexibility to the organic EL element.

Examples of the resin film include polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide , Polyether sulfone (PES), polyphenylene sulfide, polysulfones Polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, cycloolefin-based resins such as ARTON (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals, Inc.), etc. Film.

An inorganic or organic coating or a hybrid coating of both may be formed on the surface of the resin film. Hybrid coating was measured by a method conforming to JIS K 7129-1992, the water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)%) following gas 0.01g ^/ m 2 · 24h Preferably, it is a barrier film. Furthermore, the hybrid coating, oxygen permeability was measured by the method based on JIS K 7126-1987 ^{^{is, 1 × 10 -3 mL / m}} 2 · 24h · atm or less, the water vapor permeability, 1 × ^{10 -5} it is preferable g ^/ m 2 · 24h or less of a high gas barrier film.

As a material for forming the gas barrier layer, any material may be used as long as it has a function of suppressing intrusion of a substance that causes deterioration of the element such as moisture and oxygen, and examples thereof include silicon oxide, silicon dioxide, and silicon nitride. . Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and a layer made of an organic material. The order of laminating the inorganic layer and the organic functional layer is not particularly limited, but it is preferable that both layers are alternately laminated plural times.

There is no particular limitation on the method of forming the gas barrier layer, and examples thereof include a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, and an atmospheric pressure plasma weight method. A legal method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used. However, a method based on an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferred.
Examples of the opaque support substrate include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, and a ceramic substrate.

The external extraction yield at room temperature of the light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.
Here, the external extraction quantum yield (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons flowing to the organic EL element × 100.
In addition, a hue improving filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color of the organic EL element into multiple colors using a phosphor may be used in combination. When a color conversion filter is used, λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Method of manufacturing organic EL element >>
As an example of a method for producing an organic EL element, a method for producing an element comprising an anode / a hole injection layer / a hole transport layer / a light emitting layer / a hole blocking layer / an electron transport layer / a cathode buffer layer (electron injection layer) / a cathode Will be described.
First, a thin film made of a desired electrode material, for example, a material for an anode, is formed on an appropriate substrate so as to have a thickness of 1 μm or less, preferably 10 to 200 nm, to produce an anode.
Next, a thin film containing an organic compound, such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode buffer layer, which are element materials, is formed thereon.

As a method for forming a thin film, for example, a thin film can be formed by a vacuum evaporation method, a wet method (also referred to as a wet process), or the like.
Examples of the wet method include a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, a spray coating method, a curtain coating method, and an LB method. However, as the wet method, a method having high suitability for a roll-to-roll method such as a die coat method, a roll coat method, an ink jet method, a spray coat method or the like is preferable from the viewpoint of forming a precise thin film and high productivity. . Further, a different film formation method may be applied to each layer.

Examples of the liquid medium for dissolving or dispersing the organic EL material such as the luminescent dopant used in the present invention include, for example, methyl ethyl ketone, ketones such as cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, Aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as dimethylformamide (DMF) and DMSO can be used.
In addition, as a dispersing method, dispersing can be performed by a dispersing method such as ultrasonic wave, high shear force dispersion and media dispersion.

After these layers are formed, a thin film made of a material for a cathode is formed thereon to a thickness of 1 μm or less, preferably in a range of 50 to 200 nm, and a desired organic EL element can be obtained by providing a cathode. .
The order can be reversed, and the cathode, the cathode buffer layer, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode can be formed in this order.
It is preferable that the organic EL element of the present invention is manufactured from the hole injection layer to the cathode consistently by one evacuation, but it may be taken out in the middle and subjected to a different film forming method. At that time, it is preferable to perform the operation under a dry inert gas atmosphere.

《Sealing》
Examples of the sealing means used in the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive.
The sealing member only needs to be disposed so as to cover the display area of the organic EL element, and may have a concave plate shape or a flat plate shape. The transparency and the electrical insulation are not particularly limited.

Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.
Examples of the polymer plate include those formed from polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone, and the like.
Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film or a metal film can be preferably used because the element can be thinned.
Further, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ mL / m ² · 24 h · atm or less, and is measured by a method according to JIS K 7129-1992. is water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably one of the following ^{^{1 × 10 -3 g / m 2}} · 24h.
To process the sealing member into a concave shape, sand blasting, chemical etching, or the like is used.

Specific examples of the adhesive include an acrylic acid-based oligomer, a photocurable and thermosetting adhesive having a reactive vinyl group of a methacrylic acid-based oligomer, and a moisture-curable adhesive such as 2-cyanoacrylate. be able to. Further, a heat and chemical curing type (two-liquid mixing) of an epoxy type or the like can be used. In addition, hot melt type polyamide, polyester, and polyolefin can be used. In addition, a cationic curing type ultraviolet curing epoxy resin adhesive can be used.

Since the organic EL element may be deteriorated by the heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, a desiccant may be dispersed in the adhesive. The application of the adhesive to the sealing portion may be performed by using a commercially available dispenser or by printing such as screen printing.

In addition, it is also preferable to form an encapsulation film by coating the electrode and the organic functional layer on the outside of the electrode facing the support substrate with the organic functional layer interposed therebetween, and forming an inorganic or organic material layer in contact with the support substrate. Can be. In this case, the material for forming the film may be any material having a function of suppressing intrusion of elements that cause deterioration of the element such as moisture or oxygen, and for example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.
Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and a layer made of an organic material. The method for forming these films is not particularly limited, and examples thereof include a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, and an atmospheric pressure plasma. A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorocarbon or silicone oil may be injected in a gas phase or a liquid phase. preferable. It is also possible to use a vacuum. Further, a hygroscopic compound can be sealed inside.
Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate) Etc.), metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, perchloric acid) Barium, magnesium perchlorate, etc.), and sulfates, metal halides and perchloric acids are preferably anhydrous salts.

《Protective film, protective plate》
A protective film or a protective plate may be provided on the side facing the support substrate with the organic functional layer therebetween, outside the sealing film or the sealing film in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, the mechanical strength is not always high. Therefore, it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, a glass plate, a polymer plate / film, a metal plate / film, etc. similar to those used for the sealing can be used. It is preferable to use

《Light extraction》
The organic EL element emits light inside a layer having a higher refractive index than air (having a refractive index of about 1.7 to 2.1), and can extract only about 15 to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (the interface between the transparent substrate and air) at an angle θ equal to or larger than the critical angle causes total reflection and cannot be extracted outside the element. Further, light is totally reflected between the transparent electrode or the light emitting layer and the transparent substrate, and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the element side direction.

As a method of improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and air (US Pat. No. 4,774,435), a method of condensing light on the substrate (Japanese Patent Application Laid-Open No. 63-31479), a method of forming a reflective surface on a side surface of an element or the like (Japanese Patent Application Laid-Open No. 220394/1990), A method in which a flat layer having an intermediate refractive index is introduced to form an anti-reflection film (Japanese Patent Laid-Open No. 62-172691), and a flat layer having a lower refractive index than the substrate is introduced between the substrate and the light-emitting body. Method (Japanese Patent Application Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside world) (Japanese Patent Application Laid-Open No. 11-283751), and the like. There is.

In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light-emitting body, or a diffraction grating between any of the substrate, the transparent electrode layer, and the light-emitting layer (including between the substrate and the outside). Can be preferably used.
In the present invention, by combining these means, it is possible to obtain a device having higher luminance and more excellent durability.

If a medium with a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, light emitted from the transparent electrode has a higher efficiency of being taken out as the refractive index of the medium is lower. .
Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of a transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is more preferably 1.35 or less.
Also, the thickness of the low refractive index medium is desirably at least twice the wavelength in the medium. This is because the effect of the low-refractive-index layer is reduced when the thickness of the low-refractive-index medium becomes about the wavelength of light and the thickness of the electromagnetic wave oozing out by evanescent enters the substrate.

(4) The method of introducing a diffraction grating into an interface that causes total reflection or any of the media is characterized in that the effect of improving light extraction efficiency is high. This method utilizes the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction. According to this method, a diffraction grating is introduced into one of the layers or a medium (in a transparent substrate or a transparent electrode) for light that cannot be emitted due to total reflection between layers of light generated from the light emitting layer. By doing so, the light is diffracted and the light is taken out.

It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so a general one-dimensional diffraction grating that has a periodic refractive index distribution only in a certain direction diffracts only light traveling in a specific direction. And light extraction efficiency does not increase so much.
However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency is increased.

As described above, the position where the diffraction grating is introduced may be between any layers or in a medium (in a transparent substrate or a transparent electrode), but is preferably near the organic light emitting layer where light is generated.
At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.
The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, a honeycomb lattice, or the like.

《Light collecting sheet》
The organic EL element of the present invention is processed on the light extraction side of the substrate, for example, to provide a microlens array-like structure, or in combination with a so-called condensing sheet, in a specific direction, for example, with respect to the element light emitting surface. By condensing light in the front direction, the luminance in a specific direction can be increased.
As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it is smaller than this, the effect of diffraction occurs and coloring occurs, and if it is too large, the thickness becomes undesirably thick.

As the condensing sheet, for example, a sheet practically used in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.
As the shape of the prism sheet, for example, a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm may be formed on the base material, or a shape in which the vertex angle is rounded, and the pitch is randomly changed. The shape may be a bent shape or another shape.
Further, in order to control the light emission angle from the light emitting element, a light diffusing plate / film may be used in combination with the light collecting sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

《Applications》
The organic EL element of the present invention can be used for display devices, displays, various light emitting devices, and the like. Light emitting devices include, for example, lighting devices (home lighting, vehicle interior lighting), clocks and backlights for LCDs, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, and light sources. Examples include, but are not limited to, light sources for sensors. In particular, it can be effectively used for a backlight of a liquid crystal display device and a light source for illumination.

有機 In the organic EL device of the present invention, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, or the electrode and the light emitting layer may be patterned. All layers of the element may be patterned, and a conventionally known method can be used for manufacturing the element.

The emission color of the organic EL device of the present invention or the compound of the present invention is shown in FIG. 7.16 on page 108 of “New Edition of Color Science Handbook” (edited by The Japan Society for Color Science, edited by The University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (manufactured by Konica Minolta) is applied to the CIE chromaticity coordinates.
When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when measured at the 2 ° viewing angle front luminance by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

《Display device》
The organic EL element of the present invention can be used for a display device.
The display device of the present invention includes the organic EL element of the present invention. Although the display device may be single-color or multi-color, a multi-color display device will be described here.
In the case of a multicolor display device, a shadow mask is provided only when a light emitting layer is formed, and a film can be formed on one surface by an evaporation method, a casting method, a spin coating method, an inkjet method, a printing method, or the like.
When patterning is performed only on the light emitting layer, the method is not particularly limited, but is preferably an evaporation method, an inkjet method, a spin coating method, or a printing method.

The configuration of the organic EL element included in the display device is selected from the above-described configuration examples of the organic EL element as necessary.
The method for manufacturing the organic EL element is as described in the above-described one embodiment of the method for manufacturing the organic EL element of the present invention.
When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the anode having a positive polarity and the cathode having a negative polarity. Also, even if a voltage is applied in the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The waveform of the applied AC may be arbitrary.

The multicolor display device can be used as a display device, a display, and various light emission light sources. In display devices and displays, full-color display is possible by using three types of organic EL elements emitting blue, red, and green light.
Examples of the display device and the display include a television, a personal computer, a mobile device, an AV device, a teletext display, an information display in a car, and the like. In particular, the display device may be used as a display device for reproducing a still image or a moving image, and when used as a display device for reproducing a moving image, the driving method may be either a simple matrix (passive matrix) method or an active matrix method.
Lighting sources include home lighting, interior lighting, backlights for watches and LCDs, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, and light sources for optical sensors. However, the present invention is not limited to these.

Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of a display device including an organic EL element. FIG. 3 is a schematic diagram of a display such as a mobile phone for displaying image information by light emission of an organic EL element.

The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, a wiring unit C that electrically connects the display unit A and the control unit B, and the like.
The control unit B is electrically connected to the display unit A via the wiring unit C, and sends a scanning signal and an image data signal to each of the plurality of pixels based on external image information. Then, the pixels for each scanning line sequentially emit light according to the image data signal according to the scanning signal, perform image scanning, and display image information on the display unit A.

FIG. 2 is a schematic diagram of a display device using an active matrix system, and is a schematic diagram of a display unit A.
The display section A has a wiring section C including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 on a substrate. The main members of the display unit A will be described below.
FIG. 2 shows a case where light emitted from the pixel 3 (emitted light L) is extracted in the direction of the white arrow (downward).

The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid and are connected to the pixels 3 at orthogonal positions (details are shown in the drawing). Not).
When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light in accordance with the received image data.
By appropriately arranging pixels in a red region, pixels in a green region, and pixels in a blue region on the same substrate, full-color display becomes possible.

Next, a light emitting process of the pixel will be described. FIG. 3 is a schematic diagram showing a circuit of a pixel.
The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. Full-color display can be performed by using red, green, and blue light-emitting organic EL elements as the organic EL elements 10 in a plurality of pixels and juxtaposing them on the same substrate.

(3) In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 via the data line 6. Then, when a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on. Then, the image data signal applied to the drain is transmitted to the capacitor 13 and the gate of the driving transistor 12.

伝達 By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the driving of the drive transistor 12 is turned on. The driving transistor 12 has a drain connected to the power supply line 7, a source connected to the electrode of the organic EL element 10, and from the power supply line 7 to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

When the scanning signal is transferred to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even when the driving of the switching transistor 11 is turned off, the capacitor 13 holds the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on. Then, the emission of the organic EL element 10 continues until the next scanning signal is applied. When the next scanning signal is applied by the sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.
That is, the organic EL element 10 emits light by providing a switching transistor 11 and a driving transistor 12 as active elements to the organic EL elements 10 of each of the plurality of pixels, and emitting light of the organic EL elements 10 of each of the plurality of pixels 3 It is carried out. Such a light emitting method is called an active matrix method.

Here, the light emission of the organic EL element 10 may be a light emission of a plurality of gradations by a multi-valued image data signal having a plurality of gradation potentials, or a predetermined light emission amount on / off by a binary image data signal. Good. Further, the holding of the potential of the capacitor 13 may be continued until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
The present invention is not limited to the active matrix method described above, but may be a passive matrix light emission drive in which the organic EL element emits light in accordance with a data signal only when a scanning signal is scanned.

FIG. 4 is a schematic view of a display device using a passive matrix system. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape facing each other with the pixel 3 interposed therebetween.
When the scanning signal of the scanning line 5 is applied by the sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.
In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.
By using the organic EL device of the present invention, a display device with improved luminous efficiency was obtained.

《Lighting device》
The organic EL element of the present invention can be used for a lighting device.
The lighting device of the present invention includes the organic EL element of the present invention.
The organic EL device of the present invention may be used as an organic EL device having a resonator structure. The intended use of the organic EL device having such a resonator structure is, for example, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, a light source of an optical sensor, and the like. Not limited. Further, it may be used for the above purpose by causing laser oscillation.
Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or an exposure light source, a projection device of a type for projecting an image, or a type of a type for directly recognizing a still image or a moving image. It may be used as a display device (display).
When used as a display device for reproducing moving images, a driving method may be either a passive matrix method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more kinds of the organic EL elements of the present invention having different emission colors.

For example, when a plurality of light-emitting materials are used, white light can be obtained by simultaneously emitting a plurality of light-emitting colors and mixing colors. As a combination of a plurality of emission colors, those containing three emission maximum wavelengths of the three primary colors of red, green and blue, or two emission using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. What contained the maximum wavelength may be used.

In the method for forming an organic EL device of the present invention, a mask is provided only when a light-emitting layer, a hole transport layer, an electron transport layer, or the like is formed, and the layers may be simply arranged such as by applying different masks. Since the other layers are common, patterning such as a mask is not necessary. For example, an electrode film can be formed on one surface by a vapor deposition method, a casting method, a spin coating method, an inkjet method, a printing method, or the like, and productivity is improved.
According to this method, unlike a white organic EL device in which light-emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves emit white light.

[One embodiment of lighting device]
The non-light-emitting surface of the organic EL element of the present invention is covered with a glass case, and a glass substrate having a thickness of 300 μm is used as a sealing substrate. An epoxy-based photocurable adhesive (Luxtrack LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is overlaid on the cathode and closely adhered to the transparent support substrate. Then, UV light is irradiated from the glass substrate side, cured, and sealed, so that a lighting device as shown in FIGS. 5 and 6 can be formed.
FIG. 5 is a schematic view of a lighting device, in which the organic EL element (the organic EL element 101 in the lighting device) of the present invention is covered with a glass cover 102 (the sealing operation with the glass cover is a lighting operation). The test was performed in a glove box under a nitrogen atmosphere (in an atmosphere of a high-purity nitrogen gas having a purity of 99.999% or more) without bringing the organic EL element 101 in the apparatus into contact with the atmosphere.
FIG. 6 is a cross-sectional view of the lighting device. In FIG. 6, reference numeral 105 denotes a cathode, 106 denotes an organic functional layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with a nitrogen gas 108 and a water catching agent 109 is provided.
By using the organic EL element of the present invention, a lighting device with improved luminous efficiency was obtained.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but unless otherwise specified, “parts by weight” or “% by weight” is used.

In the present embodiment, an organic EL element is described as an example, but the thin film of the present invention is not limited to this, and can be used for various electronic devices other than the organic EL element.

[Example 1]
(Production of organic EL element)
<Preparation of Organic EL Element 1-1>
A 150 nm thick ITO (indium tin oxide) film was formed on a 50 mm × 50 mm glass substrate having a thickness of 0.7 mm as an anode. After patterning, the transparent substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Next, the substrate was dried with dry nitrogen gas and subjected to UV ozone cleaning for 5 minutes. Thereafter, the transparent substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus.

Each of the evaporation crucibles in the vacuum evaporation apparatus was filled with the constituent material of each layer in an amount optimal for producing each element. The crucible for vapor deposition used was made of a molybdenum or tungsten resistance heating material.
After the pressure was reduced to a degree of vacuum of 1 × 10 ⁻⁴ Pa, the deposition crucible containing HAT-CN (1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile) was energized and heated. Then, vapor deposition was performed on the ITO transparent electrode at a vapor deposition rate of 0.1 nm / sec to form a hole injection layer having a layer thickness of 10 nm.

Then, α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) was deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. Was formed. CBP (4,4'-Bis (carbazol-9-yl) biphenyl) as a host compound, Ir (ppy) ₃ (Tris (2-phenylpyridinato) iridium (III)) as a luminescent dopant, 90% and 10%, respectively. A co-evaporation was performed at a deposition rate of 0.1 nm / sec so as to be a volume% to form a light emitting layer having a layer thickness of 30 nm.

Thereafter, the comparative compound 1 (electron transporting layer (1)) and LiQ (8-hydroxyquinolinato lithium) (electron transporting layer (2)) were deposited at a deposition rate of 0.1 nm / sec to 50% and 50% volume%, respectively. To form an electron transport layer having a thickness of 30 nm. Note that the electron transport layer (a layer obtained by combining the electron transport layer (1) and the electron transport layer (2)) corresponds to a thin film in the present invention.
Further, LiQ was deposited at a deposition rate of 0.1 nm / sec to form an electron injection layer having a thickness of 2 nm, and then aluminum was deposited at a deposition rate of 0.1 nm / sec to form a cathode having a thickness of 100 nm.
The non-light-emitting surface side of the device was covered with a can-shaped glass case under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and wiring for taking out electrodes was provided, thereby producing an organic EL device 1-1.

<Preparation of organic EL elements 1-2 to 1-35>
The organic EL devices 1-2 to 1-1-2 were prepared in the same manner as the organic EL device 1-1 except that the compounds contained in the electron transport layers (1) and (2) and the electron injection layer were changed as shown in Table I. 35 were produced.
In Table I, "-" indicates that no component was contained.

(Evaluation)
(1) Measurement of Relative Drive Voltage For each organic EL device produced, the front luminance was measured on both the transparent electrode side (that is, the transparent substrate side) and the counter electrode side (that is, the cathode side) of each organic EL device. , And the voltage when the sum was 1000 cd / m ² was measured as the driving voltage (V). The luminance was measured using a spectroradiometer CS-1000 (manufactured by Konica Minolta).
The driving voltage obtained above was applied to the following equation to determine the relative driving voltage of each organic EL element with respect to the driving voltage of the organic EL element 1-1.
Relative drive voltage (%) = (drive voltage of each organic EL element / drive voltage of organic EL element 1-1) × 100
The smaller the obtained numerical value, the better the result.

(2) Measurement of change in relative drive voltage under high-temperature storage The organic EL device produced above was allowed to emit light at a temperature of 80 ° C. under a constant current of ^2.5 mA / cm ² , The driving voltage was measured 100 hours after the start.
By comparing the obtained driving voltages before and after the high-temperature storage, the amount of change in the driving voltage (a value obtained by subtracting the driving voltage after the high-temperature storage from the driving voltage before the high-temperature storage) was obtained.
The change amount of the drive voltage obtained above is applied to the following equation, and the relative value of the change amount of the drive voltage of each organic EL element with respect to the change amount of the drive voltage of the organic EL element 1-1 is determined by the relative drive under high-temperature storage. It was obtained as a voltage change.
Relative drive voltage change rate (%) under high temperature storage = (drive voltage change amount of each organic EL element / drive voltage change amount of organic EL element 1-1) × 100
The smaller the obtained numerical value, the better the result.

[Example 2]
(Production of organic EL element)
<Preparation of Organic EL Element 2-1>
After forming ITO (indium tin oxide) into a film with a thickness of 150 nm as an anode on a glass substrate having a size of 50 mm × 50 mm and a thickness of 0.7 mm, performing patterning, and then forming a transparent substrate provided with the ITO transparent electrode. Was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes, and then this transparent substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus.

Each of the evaporation crucibles in the vacuum evaporation apparatus was filled with the constituent material of each layer in an amount optimal for producing each element. The crucible for vapor deposition used was made of a molybdenum or tungsten resistance heating material.
After the pressure was reduced to a degree of vacuum of 1 × 10 ⁻⁴ Pa, a current was passed through a crucible for vapor deposition containing HAT-CN (1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile), and the mixture was heated and vaporized. A hole injection layer having a thickness of 10 nm was formed by vapor deposition on the ITO transparent electrode at a rate of 0.1 nm / sec.

Then, α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) was deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. Was formed.
CBP as a host compound and Ir (ppy) ₃ as a light emitting dopant were co-deposited at a deposition rate of 0.1 nm / sec to 90% and 10% by volume, respectively, to form a light emitting layer having a layer thickness of 30 nm.

Thereafter, Comparative Compound 2 and KF were co-deposited at a deposition rate of 0.1 nm / sec so as to be 85% and 15% by volume, respectively, to form an electron transport layer having a thickness of 30 nm. Note that the electron transport layer corresponds to the thin film in the present invention.
Thereafter, silver and magnesium were co-deposited at a deposition rate of 0.1 nm / sec so as to be 90% and 10% by volume, respectively, to form a cathode having a thickness of 15 nm.
The non-light-emitting surface side of the above element was covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and wiring for taking out electrodes was provided, thereby producing an organic EL element 2-1.

<Preparation of organic EL elements 2-2 to 2-18>
Organic EL devices 2-2 to 2-18 were fabricated in the same manner as in the organic EL device 2-1 except that the compound ratio of the electron transport layer and the silver and magnesium components of the cathode were changed as shown in Table II. .
In the organic EL elements 2-1 to 2-18, the electron transport layer contains 15% of KF, but in Table II, the notation of KF is omitted.

(Evaluation)
(1) Measurement of Relative Drive Voltage For each organic EL device produced, the front luminance was measured on both the transparent electrode side (that is, the transparent substrate side) and the counter electrode side (that is, the cathode side) of each organic EL device. , And the voltage when the sum was 1000 cd / m ² was measured as the driving voltage (V). The luminance was measured using a spectroradiometer CS-1000 (manufactured by Konica Minolta).
The drive voltage obtained above was applied to the following equation to determine the relative drive voltage of each organic EL element with respect to the drive voltage of the organic EL element 2-1.
Relative drive voltage (%) = (drive voltage of each organic EL element / drive voltage of organic EL element 2-1) × 100
The smaller the obtained numerical value, the better the result.

(2) Measurement of change in relative drive voltage under high-temperature storage The organic EL device produced above was allowed to emit light at a temperature of 80 ° C. under a constant current of ^2.5 mA / cm ² , The driving voltage was measured 100 hours after the start.
By comparing the obtained driving voltages before and after the high-temperature storage, the amount of change in the driving voltage (a value obtained by subtracting the driving voltage after the high-temperature storage from the driving voltage before the high-temperature storage) was obtained.
The change amount of the drive voltage obtained above is applied to the following equation, and the relative value of the change amount of the drive voltage of each organic EL element with respect to the change amount of the drive voltage of the organic EL element 2-1 is determined by the relative drive under high-temperature storage. It was obtained as a voltage change.
Relative drive voltage change rate (%) under high temperature storage = (drive voltage change amount of each organic EL element / drive voltage change amount of organic EL element 2-1) × 100
The smaller the obtained numerical value, the better the result.

[Example 3]
(Production of organic EL element)
<Preparation of Organic EL Element 3-1>
A glass substrate having a size of 50 mm × 50 mm and a thickness of 0.7 mm was ultrasonically cleaned with isopropyl alcohol. Next, after drying with a dry nitrogen gas, this glass substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus.

Each of the evaporation crucibles in the vacuum evaporation apparatus was filled with the constituent material of each layer in an amount optimal for producing each element. The crucible for vapor deposition used was made of a molybdenum or tungsten resistance heating material.
After reducing the pressure to a degree of vacuum of 1 × 10 ⁻⁴ Pa, a vapor deposition mask was attached to the glass substrate, and a crucible for vapor deposition containing Al was heated as an anode. Then, vapor deposition was performed on the glass substrate at a vapor deposition rate of 0.1 nm / sec to form a patterned anode having a layer thickness of 100 nm.
Next, HAT-CN (1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile) is deposited on the anode at a deposition rate of 0.1 nm / sec to form a hole injection layer having a thickness of 10 nm. did.

Further, α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) was vapor-deposited on the hole injection layer at a vapor deposition rate of 0.1 nm / sec. Was formed.
CBP as a host compound and Ir (ppy) ₃ as a light emitting dopant were co-deposited at a deposition rate of 0.1 nm / sec to 90% and 10% by volume, respectively, to form a light emitting layer having a layer thickness of 30 nm.

Thereafter, as an electron transport layer, Alq ₃ was deposited at a deposition rate of 0.1 nm / sec to form an electron transport layer having a thickness of 30 nm.
Thereafter, Comparative Compound 3 and LiQ were co-deposited at a deposition rate of 0.1 nm / sec to 50% and 50% volume%, respectively, to form an electron injection layer having a thickness of 2 nm. Note that the electron injection layer corresponds to the thin film in the present invention.
Thereafter, silver was deposited at a deposition rate of 0.1 nm / sec to form a cathode having a thickness of 15 nm.
The non-light-emitting surface side of the above element was covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode lead-out wiring was provided to produce an organic EL element 3-1.

<Preparation of organic EL elements 3-2 to 3-21>
Organic EL devices 3-2 to 3--3 were formed in the same manner as the organic EL device 3-1 except that the compound of the electron injection layer, the ratio of silver to magnesium of the cathode, and the thickness of the cathode were changed as shown in Table III. 21 was produced.
In the organic EL elements 3-1 to 3-21, the electron injection layer contains 50% of LiQ, but the description of LiQ is omitted in Table III.

(Evaluation)
(1) Measurement of relative drive voltage For each organic EL element produced, the front luminance was measured on both the transparent electrode side (that is, the transparent substrate side) and the counter electrode side (that is, the cathode side) of each organic EL element. , And the voltage when the sum was 1000 cd / m ² was measured as the driving voltage (V). The luminance was measured using a spectroradiometer CS-1000 (manufactured by Konica Minolta).
The driving voltage obtained above was applied to the following equation to determine the relative driving voltage of each organic EL element with respect to the driving voltage of the organic EL element 3-1.
Relative drive voltage (%) = (drive voltage of each organic EL element / drive voltage of organic EL element 3-1) × 100
The smaller the obtained numerical value, the better the result.

(2) Measurement of change in relative drive voltage under high-temperature storage The organic EL device produced above was allowed to emit light at a temperature of 80 ° C. under a constant current of ^2.5 mA / cm ² , The driving voltage was measured 100 hours after the start.
By comparing the obtained driving voltages before and after the high-temperature storage, the amount of change in the driving voltage (a value obtained by subtracting the driving voltage after the high-temperature storage from the driving voltage before the high-temperature storage) was obtained.
The change amount of the drive voltage obtained above is applied to the following equation, and the relative value of the change amount of the drive voltage of each organic EL element to the change amount of the drive voltage of the organic EL element 3-1 is determined by the relative drive under high-temperature storage. It was obtained as a voltage change.
Relative drive voltage change rate (%) under high temperature storage = (drive voltage change amount of each organic EL element / drive voltage change amount of organic EL element 3-1) × 100
The smaller the obtained numerical value, the better the result.

[Example 4]
(Production of organic EL element)
<Preparation of Organic EL Element 4-1>
A 150 nm thick ITO (indium tin oxide) film was formed on a 50 mm × 50 mm glass substrate having a thickness of 0.7 mm as an anode. After patterning, the transparent substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Next, the substrate was dried with dry nitrogen gas and subjected to UV ozone cleaning for 5 minutes. Thereafter, the transparent substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus.

Each of the evaporation crucibles in the vacuum evaporation apparatus was filled with the constituent material of each layer in an amount optimal for producing each element. The crucible for vapor deposition used was made of a molybdenum or tungsten resistance heating material.
After the pressure was reduced to a degree of vacuum of 1 × 10 ⁻⁴ Pa, the deposition crucible containing HAT-CN (1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile) was energized and heated. And it vapor-deposited on the ITO transparent electrode at the vapor deposition rate of 0.1 nm / sec, and formed the 1st hole injection layer with a layer thickness of 20 nm.

Next, compound 4-A represented by the following structural formula was deposited on the first hole injection layer at a deposition rate of 0.1 nm / sec to form a first hole transport layer having a thickness of 50 nm.

{Circle around (4)} Further, compound 4-B represented by the following structural formula was deposited on the first hole transport layer at a deposition rate of 0.1 nm / sec to form an electron blocking layer having a thickness of 10 nm.

Compound 4-C represented by the following structural formula as a host compound of the first light-emitting layer, and compound 4-D as a blue fluorescent light-emitting dopant were formed at a deposition rate of 0.1 nm / sec so as to be 95% and 5% by volume, respectively. Co-evaporation was performed to form a first light-emitting layer having a thickness of 30 nm.

Thereafter, as a first electron transporting layer, a compound 4-E represented by the following structural formula was deposited at a deposition rate of 0.1 nm / sec to form a first electron transporting layer having a thickness of 30 nm.

Through the above steps, a first light emitting unit including a first hole transport layer, an electron blocking layer, a first light emitting layer, and a first electron transport layer was produced.

Next, the comparative compound 1 and Li were co-evaporated at a deposition rate of 0.1 nm / sec so as to be 95% and 5% by volume, respectively, to form a 20 nm-thick charge generation layer on the first electron transport layer. did. Note that the charge generation layer corresponds to the thin film in the present invention.

Then, HAT-CN (1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile) was deposited on the charge generation layer at a deposition rate of 0.1 nm / sec as in the case of the first hole transport layer. The second hole injection layer having a thickness of 20 nm was formed by vapor deposition. Next, compound 4-A was deposited on the second hole injection layer at a deposition rate of 0.1 nm / sec to form a second hole transport layer having a thickness of 60 nm.
The compound 4-F represented by the following structural formula as a host compound of the second light emitting layer, Ir (ppy) ₃ as a green phosphorescent dopant, and Ir (piq) ₃ (Tris [1-phenylisoquinoline-C ^2] as a red phosphorescent dopant , N] iridium (III)) were co-deposited at a deposition rate of 0.1 nm / sec to 79%, 20%, and 1% by volume, respectively, to form a second light emitting layer having a layer thickness of 20 nm.

Thereafter, similarly to the first electron transport layer, compound 4-E was deposited at an evaporation rate of 0.1 nm / sec to form a second electron transport layer having a thickness of 30 nm.
Furthermore, after depositing LiQ at a deposition rate of 0.1 nm / sec to form an electron injection layer having a thickness of 2 nm, aluminum was deposited at a deposition rate of 0.1 nm / sec to form a cathode having a thickness of 100 nm. Was covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and wiring for taking out electrodes was provided to produce an organic EL device 4-1.

<Production of organic EL elements 4-2 to 4-11>
Organic EL devices 4-2 to 4-11 were produced in the same manner as in the organic EL device 4-1 except that the compounds of the charge generation layer were changed as shown in Table IV.
In the organic EL elements 4-1 to 4-11, the charge generation layer contains 5% of Li, but notation of Li is omitted in Table IV.

(Evaluation)
(1) Measurement of relative drive voltage For each organic EL element produced, the front luminance was measured on both the transparent electrode side (that is, the transparent substrate side) and the counter electrode side (that is, the cathode side) of each organic EL element. , And the voltage when the sum was 1000 cd / m ² was measured as the driving voltage (V). The luminance was measured using a spectroradiometer CS-1000 (manufactured by Konica Minolta).
The drive voltage obtained above was applied to the following equation to determine the relative drive voltage of each organic EL element with respect to the drive voltage of the organic EL element 4-1.
Relative drive voltage (%) = (drive voltage of each organic EL element / drive voltage of organic EL element 4-1) × 100
The smaller the obtained numerical value, the better the result.

(2) Measurement of change in relative drive voltage under high-temperature storage The organic EL device produced above was allowed to emit light at a temperature of 80 ° C. under a constant current of ^2.5 mA / cm ² , The driving voltage was measured 100 hours after the start.
By comparing the obtained driving voltages before and after the high-temperature storage, the amount of change in the driving voltage (a value obtained by subtracting the driving voltage after the high-temperature storage from the driving voltage before the high-temperature storage) was obtained.
The change amount of the drive voltage obtained above is applied to the following equation, and the relative value of the change amount of the drive voltage of each organic EL element with respect to the change amount of the drive voltage of the organic EL element 4-1 is determined by the relative drive under high-temperature storage. It was obtained as a voltage change.
Relative drive voltage change rate (%) under high-temperature storage = (drive voltage change amount of each organic EL element / drive voltage change amount of organic EL element 4-1) × 100
The smaller the obtained numerical value, the better the result.

As described above, the organic EL device of the present invention has a lower relative drive voltage than the organic EL device of the comparative example, and a small change in the relative drive voltage under high-temperature storage. It turned out to be excellent.

The present invention provides a thin film, an electronic device, an organic electroluminescence element, a material for organic electroluminescence, a display device, and a display device, which contribute to a reduction in driving voltage of the electronic device and an improvement in stability during storage for improving the performance of the electronic device. It can be used for lighting devices.

Reference Signs List 1 display 3 pixel 5 scanning line 6 data line 7 power supply line 10 organic EL element 11 switching transistor 12 drive transistor 13 capacitor 101 organic EL element 102 in lighting device glass cover 105 cathode 106 organic functional layer 107 glass substrate with transparent electrode 108 nitrogen Gas 109 Water collecting agent A Display unit B Control unit C Wiring unit L Emitted light

Claims

A thin film containing a compound having a structure represented by the following general formula (1).

(In the general formula (1), Ar 1 to Ar 3 each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline. Ar 4 to Ar 6 each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline ring. n represents an integer of 1 or more and 5 or less, and L independently represents an aromatic hydrocarbon ring or a heterocyclic ring.)
薄膜 The thin film according to claim 1, wherein in the general formula (1), when n = 2, at least one of L is a heterocyclic ring.
薄膜 The thin film according to claim 1, wherein in the general formula (1), n is 3 or more.
(4) The thin film according to any one of (1) to (3), wherein in the general formula (1), L independently represents a phenyl ring, a pyridine ring, a pyrazine ring, or a pyrimidine ring.
(5) The thin film according to any one of (1) to (4), further comprising an electron injection material.
An electrode, an organic electroluminescence device having a plurality of organic functional layers including a light emitting layer,
An organic electroluminescence device, wherein at least one of the organic functional layers is the thin film according to any one of claims 1 to 5.
7. The organic electroluminescence device according to claim 6, wherein the thin film, the electron injection layer, and the electrode are stacked in this order.
The electrode is mainly composed of silver,
The organic electroluminescence device according to claim 6, wherein the organic functional layer is provided adjacent to the electrode.
The organic electroluminescence device according to any one of claims 6 to 8, wherein the electrode has a thickness of 15 nm or less and is transparent.
An organic electroluminescent material comprising a compound having a structure represented by the following general formula (1).

(In the general formula (1), Ar 1 to Ar 3 each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline. Ar 4 to Ar 6 each independently represent a hydrogen atom, an aromatic hydrocarbon ring or a heterocyclic ring, and at least one of them represents a pyridine ring, a pyrazine ring, a pyrimidine ring, or a quinazoline ring. n represents an integer of 1 or more and 5 or less, and L independently represents an aromatic hydrocarbon ring or a heterocyclic ring.)
(10) A display device comprising the organic electroluminescence element according to any one of (6) to (9).
A lighting device comprising the organic electroluminescent element according to any one of claims 6 to 9.
An electronic device having an electrode and the thin film according to any one of claims 1 to 5.