WO2012002245A1 - Organic electroluminescent element - Google Patents

Abstract

Disclosed is an organic electroluminescent element having improved luminance half-life and voltage increase during drive time. The disclosed organic electroluminescent element comprises a substrate, an anode and a cathode which are on the substrate, and a plurality of organic functional layers which are sandwiched between the electrodes. The organic functional layers comprise at least a hole injection layer and a light emitting layer, and there is at least one intermediary layer containing fluorinated polymers, which is between two arbitrary organic functional layers amongst the plurality of organic functional layers.

Description

Organic electroluminescence device

The present invention relates to an organic electroluminescence device, and more particularly to an organic electroluminescence device that improves half-luminance life and suppresses a voltage increase in continuous driving.

Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

On the other hand, an organic EL element has a configuration in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoint of space saving and portability.

As the development of organic EL elements for practical application, since Princeton University has reported organic EL elements that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1), phosphorescence at room temperature. Research on materials exhibiting the above has become active (see, for example, Non-Patent Document 2 and Patent Document 1).

Furthermore, the recently discovered organic EL device using phosphorescence emission can in principle achieve light emission efficiency about 4 times that of the previous device using fluorescence emission. Research and development of light-emitting element layer configurations and electrodes are performed all over the world.

For example, many compounds have been studied focusing on heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3).

Although this is a very high potential method, the organic EL device using phosphorescence emission is greatly different from the organic EL device using fluorescence emission, and the method for controlling the position of the emission center, particularly the emission layer. How to recombine inside the element and stabilize the light emission is an important technical issue for grasping the efficiency and life of the device.

In recent years, multilayer stacked devices having a hole transport layer (located on the anode side of the light emitting layer) and an electron transport layer (located on the cathode side of the light emitting layer) adjacent to the light emitting layer are well known. It has been.

Especially when using blue phosphorescence, since the blue phosphorescent material itself has a high T1 (minimum excited triplet state), development of peripheral materials and precise control of the emission center are strongly demanded.

However, it is possible to improve the performance by separating the functions by making the layers multi-layered, but on the other hand, since multiple interfaces are generated by making the multi-layered stack of different materials, the possibility of causing an injection barrier also increases electrochemically. We believe that there is a possibility that the interaction between materials and the material in the excited state may react and decompose. In addition, there is a concern that the material between layers diffuses over time, resulting in a carrier trap. As a result, it is speculated that the luminance lifetime may decrease or the voltage may increase with time.

As a means for solving the above-mentioned problems, for example, a method of suppressing diffusion by treating the lower layer with an organic acid to produce a hardly soluble layer, or by devising that the surface is crosslinked / polymerized. (For example, refer to Patent Documents 2 and 3). However, since the impurities are introduced by the acid treatment, or the hardly soluble layer or the crosslinked layer works as an injection barrier or a trap component, sufficient performance has not been achieved. In addition, there have been contrivances such as reducing the injection barrier at the interface by providing an interface region containing a charge transfer complex at the interface (see, for example, Patent Document 4), but further measures for improving performance are required. .

US Pat. No. 6,097,147 JP 2010-80459 A JP 2009-152015 A JP 2008-251626 A

An object of the present invention is to provide an organic electroluminescence device having improved half-luminance life and voltage rise with time of driving, and more specifically, by using an intermediate layer having a critical surface tension of 10 mN / m to 30 mN / m, An organic electroluminescence device having improved voltage rise with time is provided.

The above object of the present invention can be achieved by the following configuration.

1. In an organic electroluminescence device having an anode and a cathode on a substrate, and a plurality of organic functional layers sandwiched between both electrodes, the plurality of organic functional layers include at least a hole injection layer, a hole transport layer, and An organic electroluminescence device comprising a light emitting layer and an intermediate layer containing at least one fluorinated polymer between any two organic functional layers of the plurality of organic functional layers.

2. 2. The organic electroluminescence device according to 1 above, wherein the intermediate layer has a thickness of 1 nm to 10 nm.

3. 3. The organic electroluminescence device as described in 1 or 2 above, wherein the intermediate layer contains a polymer material represented by the following general formula (a).

Wherein R ₁ and R ₂ are an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, a heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group , Alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or hetero At least one selected from arylsulfonyl group, amino group, halogen atom, fluorinated hydrocarbon group, cyano group, nitro group, hydroxy group, thiol group, silyl group, phosphono group, at least one of oxygen, nitrogen , A device containing one or more sulfur groups .n1 represents a group represents an integer from 10 to 10,000.)
4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein the intermediate layer contains a polymer material represented by the following general formula (b).

(Wherein X is at least one cyclic selected from cyclic ether, cyclic thioether, cyclic azaether, crown ether, thiacrown ether, and azacrown ether, which contains at least one of oxygen, nitrogen, and sulfur. Represents a partial structure, and n2 represents an integer of 10 to 10,000.)
5. 5. The organic electroluminescence device according to any one of 1 to 4, wherein the intermediate layer is located between the hole injection layer and the light emitting layer.

6. 6. The organic electroluminescence device according to any one of 1 to 5, wherein the intermediate layer is located between the hole injection layer and the hole transport layer.

According to the present invention, it was possible to provide an organic electroluminescence device having an improved emission lifetime.

The schematic of an organic EL element is shown. Sectional drawing of an organic EL element is shown.

Hereinafter, the best mode for carrying out the present invention will be described in detail.

In the organic EL device according to the present invention, by providing an intermediate layer containing at least one fluorinated polymer between the organic functional layers, it was possible to provide a device having an improved half-luminance lifetime.

Hereinafter, each component of the organic EL element of the present invention will be sequentially described.

《Middle layer》
The intermediate layer according to the present invention will be described.

The intermediate layer according to the present invention is characterized by containing the fluorinated polymer (also referred to as a fluorine-substituted polymer) according to the present invention.

From the viewpoint of obtaining the effects described in the present invention (improved half-luminance lifetime and voltage increase), it is preferable that 90% by mass or more of the intermediate layer according to the present invention is a fluorinated polymer.

In addition, the intermediate layer according to the present invention may further contain a material known as a conventionally known organic EL element material.

The intermediate layer according to the present invention preferably has a critical surface tension in the range of 10 mN / m to 30 mN / m. However, the present invention can also be used as a material for obtaining the intermediate layer exhibiting the critical surface tension as described above. Such a fluorinated polymer can be preferably used.

Further, many of the fluorinated polymers according to the present invention can be formed by a wet process if a fluorine-substituted organic solvent is selected, and the productivity is higher than that by a dry process such as a vapor deposition method. preferable.

Furthermore, it is most preferable to use a fluorinated polymer as represented by the general formula (a) or (b) because the crystallinity is suppressed and a transparent amorphous film is easily formed.

The calculation of the critical surface tension and the measurement of the contact angle used for the calculation can be performed by the method described in, for example, Plastic Encyclopedia 1059 (Asakura Shoten (published March 1992)).

The reason why the layer satisfying the above conditions improves the half-luminance lifetime and the voltage rise over time is not clear, but when the organic material at the interface becomes an anion radical, a cation radical or an excited state, a reaction between the materials can occur However, it is speculated that the provision of the intermediate layer may have an effect of mitigating reactions and deterioration between organic materials, but details are not clear.

Also, in order to provide a film having a very low critical surface tension, a water-dispersed hole injection material such as polyethylenedioxythiophene-polysulfonic acid (hereinafter also referred to as PEDOT-PSS) generally used in coating is used. In this case, it is presumed that there is an effect on the diffusion of moisture remaining in the film, and even when the above water-dispersed hole injection material is used, it can be suitably used.

The thickness of the intermediate layer is not particularly limited, but is preferably adjusted to a range of 1 nm to 20 nm, more preferably from the viewpoint of the uniformity of the film to be formed and the prevention of unnecessary application of high voltage during light emission. The adjustment is made within the range of 1 nm to 10 nm.

<< Compounds Represented by General Formula (a) and General Formula (b) >>
In the general formula (a) and the general formula (b) according to the present invention, the fluorinated polymer has substituents R ₁ and R ₂ and a cyclic substituent X, respectively, and R ₁ , R It is preferable that any one of ₂ contains at least one oxygen, nitrogen, sulfur, or at least one oxygen, nitrogen, sulfur in the cyclic substituent X.

Any substituents may be introduced into the substituents R ₁ and R ₂ as long as the above characteristics are satisfied. Specific examples of the substituents R ₁ and R ₂ include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, Tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group, 1-propenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, isopropenyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), aromatic hydrocarbon group (aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group etc., for example , Phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, Azure Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group) A group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, a quinazolinyl group, a carbazolyl group, a carbolinyl group, a diazacarbazolyl group (in which one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom) ), Phthalazinyl group, etc.), heterocyclic group (eg pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group etc.), alkoxy group (eg methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group) , Octyloxy group, de Siloxy group etc.), cycloalkoxy group (eg cyclopentyloxy group, cyclohexyloxy group etc.), aryloxy group (eg phenoxy group, naphthyloxy group etc.), alkylthio group (eg methylthio group, ethylthio group, propylthio group, Pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyl Oxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group) , Naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group) Group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2- Ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, aceto Ruoxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, Propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, amino Carbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexyla Nocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group) Group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, Cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group Group), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenyl) Sulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino) Group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), fluorohydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl) Group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, thiol group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group, etc. Can be mentioned.

These substituents may be further substituted with the above substituents.

In the general formula (b) according to the present invention, the fluorinated polymer has a cyclic substituent X, and the cyclic substituent X contains at least one of oxygen, nitrogen, and sulfur.

The cyclic substituent X may be any substituent as long as the above conditions are satisfied. Specific examples of the cyclic substituent X include cyclic ether, cyclic thioether, cyclic azaether, crown ether, thiacrown ether, azacrown ether and the like.

Further, any number of hydrogen atoms in the above substituents may be substituted with fluorine atoms.

Specific examples of the compounds represented by the general formula (a) and the general formula (b) will be described below, but the present invention is not limited to these.

In the above specific examples, n represents a range of 10 to 10,000, but from the viewpoint of solubility in a solvent during film formation, a range of 10 to 1,000 is preferable.

Examples of the polymer material represented by the general formula (a) or (b) according to the present invention include, for example, US Pat. No. 3,418,302, US Pat. No. 3,978,030, Polymers described in JP-A-63-238111, JP-A-63-238115, JP-A-1-131214, JP-A-1-131215 and the like are preferably used.

<< Layer structure of organic EL element >>
Next, although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.

(I) Anode / hole injection layer / hole transport layer / intermediate layer / light emitting layer / electron transport layer / cathode (ii) Anode / hole injection layer / intermediate layer / hole transport layer / light emitting layer / electron transport layer / Cathode (iii) Anode / hole injection layer / intermediate layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode (iv) Anode / hole injection layer / intermediate layer / hole transport layer / Emission layer / electron transport layer / electron injection layer / cathode (v) anode / hole injection layer / hole transport layer / emission layer / electron transport layer / intermediate layer / electron injection layer / cathode Among these, anode, cathode, The layers excluding the intermediate layer are collectively referred to as an organic functional layer.

The following explains each layer.

<Light emitting layer>
The light-emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer. May be an interface between the light emitting layer and the adjacent layer, but is preferably within the layer of the light emitting layer because of deactivation of excitons between layers.

The film thickness of the light emitting layer is not particularly limited, but it is 2 nm from the viewpoint of the uniformity of the film to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color with respect to the driving current. It is preferable to adjust to a range of ˜200 nm, and more preferably to a range of 5 nm to 100 nm.

Hereinafter, a host compound (also referred to as a light emitting host) and a light emitting dopant contained in the light emitting layer will be described.

《Host compound》
The host compound used in the present invention will be described.

Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is a compound having a phosphorescence quantum efficiency of less than 0.01.

As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient.

In addition, by using a plurality of light emitting dopants described later, it becomes possible to mix different light emission, thereby obtaining an arbitrary light emission color.

Specific examples of the host compound used in the present invention are shown below, but the present invention is not limited thereto.

The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (polymerizable light emission). Host).

As the host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents an increase in emission wavelength, and has a high Tg (glass transition temperature) is preferable. Specific examples of the host compound also include compounds described in the following documents.

JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002 -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

《Light emitting dopant》
The light emitting dopant according to the present invention will be described.

As the light-emitting dopant according to the present invention, a fluorescent dopant or a phosphorescent dopant can be used. From the viewpoint of obtaining an organic EL element with higher luminous efficiency, light emission used in the light-emitting layer or light-emitting unit of the organic EL element. As a dopant, it is preferable to contain a phosphorescent dopant simultaneously with the host compound.

The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL element.

The phosphorescent dopant according to the present invention is preferably a complex compound containing a transition metal element of group 8 to 10 in the periodic table of elements (also simply referred to as transition metal), more preferably an iridium compound or osmium. Compounds, platinum compounds (platinum complex compounds), and rare earth complexes, and most preferred are iridium compounds.

Specific examples of compounds used as phosphorescent dopants are shown below, but the present invention is not limited to these. These compounds are described, for example, in Inorg. Chem. It can be synthesized by referring to the method described in Vol. 40, 1704-1711.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists 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. May be.

An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes 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, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

In addition, it is generally often used to dope the polymer buffer layer with an acid such as polystyrene sulfonic acid (PSS) in order to improve conductivity.

The film thickness of the hole injection layer is not particularly limited, but is preferably adjusted in the range of 2 nm to 200 nm, more preferably in the range of 5 nm to 100 nm, from the viewpoint of the uniformity of the film to be formed.

The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. .

The buffer layer (injection layer) is preferably a very thin film, and although it depends on the material, the film thickness is preferably in the range of 0.1 nm to 5 μm.

<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 Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization (published by NTT Corporation on November 30, 1998)” on page 237. There is a hole blocking (hole blocking) layer.

The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

For the hole blocking layer, the compounds mentioned as the host compound can be preferably used.

In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode.

Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

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 that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

Moreover, the structure of the hole transport layer described later can be used as an electron blocking layer as necessary. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably in the range of 3 nm to 100 nm, and more preferably in the range of 5 nm to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, an electron blocking layer is 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 transport material has either hole injection or transport or electron barrier properties, and may be either organic or inorganic.

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 thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

The above-mentioned materials can be used as the hole transport material, 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 aromatic tertiary amine compounds and styrylamine compounds 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 ' Di (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-diphenylaminostilbenzene; N-phenylcarbazole, and also two described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

Further, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, 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. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light emitting element with high luminous 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 ink jet method, or an LB method. it can.

The thickness of the hole transport layer is not particularly limited, but is preferably in the range of 5 nm to 5 μm, and more preferably in the range of 5 nm to 200 nm.

Further, the hole transport layer may have a single layer structure composed of one or more of the above materials.

It is also possible to use a hole transport layer having a high p property doped with impurities.

Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and 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 as a single layer or a plurality of layers.

Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the 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 an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), 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, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.

In addition, the distyrylpyrazine derivative exemplified as the material for the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.

The film thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 nm to 200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

It is also possible to use an n-type electron transport layer doped with impurities as a guest material. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be produced.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used.

Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used.

For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (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 material that can be applied such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can be used.

When light emission is taken out from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less.

Furthermore, the film thickness is preferably in the range of 10 nm to 1000 nm, more preferably in the range of 10 nm to 200 nm, although it depends on the material.

"cathode"
As the cathode, a material having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound and a mixture thereof as an electrode material is used.

Specific examples of such electrode materials include 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 these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.

The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.

In addition, it is preferable that either one of the anode or the cathode of the organic EL element is transparent or semi-transparent from the viewpoint of transmitting the emitted light and improving the emission luminance.

In addition, a transparent or semi-transparent cathode can be produced by producing the conductive transparent material mentioned in the description of the anode on the cathode after producing the metal with a film thickness of 1 nm to 20 nm. By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

"substrate"
As a substrate (hereinafter also referred to as a support substrate) that can be used in the organic EL element of the present invention, there is no particular limitation on the type of glass, plastic and the like, and it may be transparent or opaque. When extracting light from the substrate side, the substrate is preferably transparent. Examples of the transparent substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable substrate is a resin film capable of giving flexibility to the organic EL element.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfone , Polyetherimide, polyether ketone imide, polyamide, fluorine resin, nylon, polymethyl methacrylate, acrylic or polyarylates, and cycloolefin resins such as ARTON (manufactured by JSR) or APEL (manufactured by Mitsui Chemicals).

An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and a barrier film having a water vapor permeability of 0.01 g / (m ² · 24 h) or less is preferable. Furthermore, the oxygen permeability is 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less (1 atm is 1.01325 × 10 ⁵ Pa), and the water vapor permeability is 10 ⁻⁵ cm ³ / (m ² · 24 h. -It is preferable that it is a high barrier film below atm).

The material for forming the barrier film may be any material that has a function of suppressing the intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

Examples of the opaque substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, ceramic substrates, and the like.

The external extraction quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

Here, external extraction quantum efficiency (%) = (number of photons emitted to the outside of the organic EL element) / (number of electrons passed through the organic EL element) × 100.

A hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means of the organic EL element of this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

The sealing member may be disposed so as to cover the display area of the organic EL element, and may be a concave plate shape or a flat plate shape. Further, transparency and 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 polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. 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 and a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. was measured by the method, the water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is preferably those of ^{1 × 10 -3 g / (m} 2 / 24h) or less .

For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned.

Also, hot melt type polyamides, polyesters and polyolefins can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

In addition, since an organic EL element may deteriorate by heat processing, what can be adhesively cured from room temperature to 80 ° C. is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

It is also possible to suitably form an inorganic or organic layer as a sealing film by covering the electrode and the organic layer on the outer side of the electrode facing the substrate with the organic layer interposed therebetween, and in contact with the substrate. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. 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 layers made of organic materials.

There are no particular limitations on the method of forming these films. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A combination 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 fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, 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 anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

<< Method for producing organic EL element >>
In the organic EL device manufacturing method of the present invention, the organic functional layer sandwiched between the anode and the cathode may be formed using either a dry process or a wet process, but from the viewpoint of productivity, a film is formed by a wet process. It is preferable. It is also preferable to form the entire organic laminate by a wet process. The wet process referred to in the present invention is to form a layer by supplying a layer forming material in the form of a solution when forming a layer.

As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably 10 nm to 200 nm. .

Next, organic compound thin films (organic layers) such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, are formed thereon.

Examples of methods for forming these layers include vapor deposition methods, wet processes (spin coating method, die coating method, casting method, ink jet method, spray method, printing method) and the like as described above.

Furthermore, in the present invention, a homogeneous film can be easily obtained and pinholes are not easily generated. In the present invention, a composition by a coating method such as a spin coating method, a die coating method, an ink jet method, a spray method, or a printing method is used. A membrane is preferred.

When the organic EL device of the present invention is produced by a wet process, examples of the liquid medium for dissolving or dispersing the material include ketones such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, ethyl acetate, butyl acetate, and the like. Fatty acid esters, halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, anisole, aliphatic hydrocarbons such as cyclohexane, decalin, dodecane, DMF, DMSO, etc. The organic solvent or water can be used.

After forming these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained.

It is also possible to reverse the production order to produce a cathode, an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, a hole injection layer, and an anode in this order.

When a DC voltage is applied to the multicolor display device obtained in this way, light emission can be observed by applying a voltage of about 2V to 40V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the substrate with the organic layer interposed therebetween or on the sealing film.

Particularly, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high. Therefore, it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is 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 (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

As a method of improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate and preventing total reflection at the transparent substrate and the air interface (US Pat. No. 4,774,435), A method for improving efficiency by providing light condensing property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an organic EL element (Japanese Patent Laid-Open No. 1-220394), a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (Japanese Patent Laid-Open No. 62-172691), and lowering the refractive index between the substrate and the light emitter than the substrate. A method of introducing a flat layer having a structure (Japanese Patent 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) No. 283751) That.

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 emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

In the present invention, by combining these means, it is possible to obtain an organic EL device having higher luminance or durability.

When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the efficiency of taking out the light from the transparent electrode to the outside increases as the refractive index of the medium decreases.

Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the 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, more preferably 1.35 or less.

Also, the thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses 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 and second-order diffraction. Introduce a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode) for light that cannot be emitted outside due to total internal reflection between layers. I want to take it 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 in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

However, by making the refractive index distribution a two-dimensional distribution, the 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 in any one of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of 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 gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Condensing sheet》
The organic EL device of the present invention can be processed to provide, for example, a microlens array-like structure on the light extraction side of the substrate, or combined with a so-called condensing sheet, for example, in a specific direction, for example, the device light emitting surface. On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

As an example of the microlens array, square pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate.

One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

As the condensing sheet, it is possible to use, for example, a sheet that has been put to practical use in an LED backlight of a liquid crystal display device. As such a sheet, for example, Sumitomo 3M brightness enhancement film (BEF) can be used. As the shape of the prism sheet, for example, a triangle stripe having a vertex angle of 90 degrees and a pitch of 50 μm may be formed on the substrate, the vertex angle may be rounded, and the pitch may be changed randomly. Other shapes may be used.

Further, in order to control the light emission angle from the light emitting element, a light diffusion 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.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

In the organic EL device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like during film formation, if necessary. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (manufactured by Konica Minolta Sensing) 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 CIE 1931 color system at 1000 cd / m ² is X = 0 when the 2 ° viewing angle front luminance is measured by the above method. .33 ± 0.07, Y = 0.33 ± 0.1. The light emitting layer of the organic EL device of the present invention preferably contains at least one of a light emitting host compound and a light emitting dopant as a guest material.

Hereinafter, although an example explains the present invention, the present invention is not limited to these.

The structures of the compounds used in the examples are shown below.

Example 1
<< Production of Organic EL Element 101 >>
After patterning a 100 mm × 100 mm × 1.1 mm glass substrate made of ITO (Indium Tin Oxide) 100 nm as an anode, the transparent support substrate provided with the ITO transparent electrode was superposed with normal propyl alcohol. Sonic cleaning, drying with dry nitrogen gas, and UV ozone cleaning were performed for 5 minutes.

This transparent support substrate was attached to a vacuum deposition apparatus, the vacuum layer was depressurized to 4 × 10 ⁻⁴ Pa, and the compound HI-1 was deposited by vapor deposition to form a 20 nm thick hole injection layer (HIL). .

Next, a film was formed by vapor deposition of the compound HT-1, and a hole transport layer (HTL) having a thickness of 20 nm was obtained. Further, Compound H-27 and Compound D-1 were co-evaporated so that Compound D-1 had a film thickness ratio of 16% to form a light emitting layer (EML) having a thickness of 40 nm.

Further, a film was formed by vapor deposition of the compound ET-1, and an electron transport layer (ETL) having a thickness of 20 nm was obtained. Thereafter, LiF was deposited as an electron injection layer with a thickness of 1 nm, and aluminum was deposited with a thickness of 110 nm to form a cathode.

Next, the non-light-emitting surface of the element was covered with a glass case, and an organic EL element 101 having the configuration shown in FIGS. 1 and 2 was produced.

FIG. 1 shows a schematic diagram of an organic EL element, and the organic EL element 101 is covered with a glass cover 102. The sealing operation with the glass cover was performed in a glove box (in an atmosphere of high purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. FIG. 2 shows a cross-sectional view of the organic EL element. In FIG. 2, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

<< Production of Organic EL Element 102 >>
In the production of the organic EL element 101, after forming the hole injection layer, the substrate was moved to a glove box under a nitrogen atmosphere, and a solution in which 60 mg of polyethylene (PE) was dissolved in 10 ml of chlorobenzene in the glove box was used. Then, an organic EL device 102 was produced in the same manner except that spin coating was performed at 5000 rpm for 60 seconds, and heating was performed at 150 ° C. for 30 minutes under nitrogen to form a 30 nm thick intermediate layer.

<< Production of Organic EL Elements 103 and 104 >>
In the production of the organic EL element 102, a film obtained by dissolving PE in 40 mg and 20 mg in 10 ml of chlorobenzene was spin-coated at 5000 rpm for 60 seconds, and heated at 150 ° C. for 30 minutes under nitrogen to form a film thickness. Organic EL elements 103 and 104 were produced in the same manner except that an intermediate layer of 20 nm and 10 nm was formed.

<< Production of Organic EL Element 105 >>
In the production of the organic EL device 101, before forming the hole injection layer, the substrate is moved to a glove box under a nitrogen atmosphere, and I-1 (20 mg) is transferred to 2, 2, 3, 3 in the glove box. , 3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether was spin-coated under a condition of 5000 rpm for 60 seconds and heated at 150 ° C. for 30 minutes under nitrogen. Then, an organic EL element 105 was produced in the same manner except that an intermediate layer having a thickness of 10 nm was formed.

<< Production of Organic EL Element 106 >>
In the production of the organic EL element 101, after forming the hole injection layer, the substrate was moved to a glove box under a nitrogen atmosphere, and 60 mg of polyvinylidene fluoride (PVDF) was added in 2, 2, 3, 3 in the glove box. , 3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether was spin-coated under a condition of 5000 rpm for 60 seconds and heated at 150 ° C. for 30 minutes under nitrogen. Then, an organic EL element 106 was produced in the same manner except that an intermediate layer having a thickness of 30 nm was formed.

<< Production of Organic EL Elements 107 and 108 >>
In the production of the organic EL element 106, using a solution in which 40 mg and 20 mg of PVDF were dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, respectively. Organic EL elements 107 and 108 were produced in the same manner except that spin coating was performed at 5000 rpm for 60 seconds and heating was performed at 150 ° C. for 30 minutes under nitrogen to form an intermediate layer having a thickness of 20 nm and 10 nm.

<< Production of Organic EL Element 109 >>
In the production of the organic EL element 101, after forming the hole injection layer, the substrate was moved to a glove box under a nitrogen atmosphere, and I-2 (60 mg) was transferred to 2, 2, 3, 3, in the glove box. Using a solution dissolved in 10 ml of 3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, spin-coated at 5000 rpm for 60 seconds, and heated at 150 ° C. for 30 minutes under nitrogen. An organic EL element 109 was produced in the same manner except that an intermediate layer having a thickness of 30 nm was formed.

<< Production of Organic EL Elements 110 and 111 >>
In the production of the organic EL element 109, a solution in which 40 mg and 20 mg of I-2 were dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, respectively. The organic EL elements 110 and 111 were prepared in the same manner except that an intermediate layer having a film thickness of 20 nm and 10 nm was formed by spin coating at 5000 rpm for 60 seconds and heating at 150 ° C. for 30 minutes under nitrogen. did.

<< Production of Organic EL Element 112 >>
In the production of the organic EL element 101, after forming the hole injection layer, the substrate was moved to a glove box under a nitrogen atmosphere, and I-1 (60 mg) was transferred to 2, 2, 3, 3, in the glove box. Using a solution dissolved in 10 ml of 3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, spin-coated at 5000 rpm for 60 seconds, and heated at 150 ° C. for 30 minutes under nitrogen. An organic EL element 112 was produced in the same manner except that an intermediate layer having a thickness of 30 nm was formed.

<< Production of Organic EL Elements 113 and 114 >>
In the production of the organic EL element 112, a solution in which 40 mg and 20 mg of I-1 were dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, respectively. The organic EL devices 113 and 114 were prepared in the same manner except that an intermediate layer having a thickness of 20 nm and 10 nm was formed by spin coating at 5000 rpm for 60 seconds and heating at 150 ° C. for 30 minutes under nitrogen. did.

<< Evaluation of organic EL elements 101 to 114 >>
The produced organic EL elements 101 to 114 were evaluated for the half life and voltage increase when the half luminance was reached as follows.

(Half life)
The manufactured organic EL element was continuously driven by applying a current that would give a front luminance of 1000 cd / m ² . The time required for the front luminance to reach the initial half value (500 cd / m ² ) is obtained as a half life, and the half lives of the organic EL elements 102 to 110 are 100 as measured values of the organic EL element 101 (comparative example). It was expressed as a relative value.

(Voltage increase at half brightness (Vt))
A current that gives a front luminance of 2000 cd / m ² is applied to the manufactured organic EL element, and the device is continuously driven until the front luminance reaches the initial half value (1000 cd / m ² ). Was obtained as a voltage increase at the time of reaching half luminance, and the results were classified into A to D.

A: Voltage increase when half luminance reached less than 0.5 V B: Voltage increase when half luminance reached 0.5 V or more and less than 1.0 V C: Voltage increase when half luminance reached 1.0 V or more and less than 2.0 V D: Half The voltage rise when the luminance reaches 2.0 V or more Note that a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used for measuring the luminance. In the present invention, ranks A and B are practical levels.

From the description in Table 1, compared with the comparative organic EL element, the organic EL element of the present invention has a half life by forming an intermediate layer containing a fluorinated polymer between the hole injection layer and the hole transport layer. It is apparent that the voltage increase when the half luminance is reached is suppressed.

Further, it is shown that the effect is further increased by forming the film to 10 nm, and the material I-1 which is a compound represented by the general formula (b) or the material I-2 represented by the general formula (a) It is also clear that the effects of the present invention are remarkably exhibited by using.

Example 2
<< Production of Organic EL Element 115 >>
In the production of the organic EL element 114 of Example 1, an intermediate layer was not provided between the hole injection layer (HIL) and the hole transport layer (HTL), but a hole transport layer (HTL) was formed. Later, the substrate was moved to a glove box under a nitrogen atmosphere, and spin-coated under a condition of 5000 rpm for 60 seconds using a solution in which I-1 (20 mg) was dissolved in 10 ml of chlorobenzene in the glove box, 150 An organic EL element 115 was produced in the same manner except that an intermediate layer having a film thickness of 10 nm was formed by heating under nitrogen at 30 ° C. for 30 minutes, and then a light emitting layer (EML) was formed.

<< Production of Organic EL Element 116 >>
In the production of the organic EL element 114 of Example 1, instead of providing an intermediate layer between the hole injection layer (HIL) and the hole transport layer (HTL), after forming the light emitting layer (EML), The substrate was moved to a glove box under a nitrogen atmosphere, and spin-coated under a condition of 5000 rpm for 60 seconds using a solution in which I-1 (20 mg) was dissolved in 10 ml of chlorobenzene in a glove box at 150 ° C., Organic EL element 116 was produced in the same manner except that it was heated under nitrogen for 30 minutes to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer (ETL) was formed.

<< Preparation of Organic EL Element 117 >>
In the production of the organic EL element 114 of Example 1, after forming a hole injection layer (HIL), an intermediate layer, and then a hole transport layer (HTL), the substrate was moved to a glove box under a nitrogen atmosphere. In a glove box, spin coating was performed on the hole transport layer (HTL) using a solution of I-1 (20 mg) dissolved in 10 ml of chlorobenzene at 5000 rpm for 60 seconds, An organic EL element 117 was produced in the same manner except that it was heated under nitrogen for 30 minutes to provide an intermediate layer having a thickness of 10 nm, and then a light emitting layer was formed.

<< Preparation of Organic EL Element 118 >>
In the production of the organic EL element 117, the intermediate layer is not provided between the hole transport layer (HTL) and the light emitting layer (EML), and after the light emitting layer is formed, the substrate is moved to a glove box in a nitrogen atmosphere. In a glove box, spin-coating was performed on the light-emitting layer (EML) using a solution obtained by dissolving I-1 (20 mg) in 10 ml of chlorobenzene at 5000 rpm for 60 seconds. An organic EL element 118 was produced in the same manner except that the film was heated under nitrogen for 10 minutes to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer (ETL) was formed.

<< Production of Organic EL Element 119 >>
In the production of the organic EL element 115, after forming the hole transport layer (HTL), the intermediate layer, and then the light emitting layer (EML), the substrate was moved to a glove box under a nitrogen atmosphere, and in the glove box, A film in which I-1 (20 mg) was dissolved in 10 ml of chlorobenzene was spin-coated on the light emitting layer (EML) at 5000 rpm for 60 seconds, and heated at 150 ° C. for 30 minutes under nitrogen. An organic EL element 119 was produced in the same manner except that an intermediate layer having a thickness of 10 nm was provided and then an electron transport layer (ETL) was formed.

<< Production of Organic EL Element 120 >>
In the production of the organic EL element 117, after forming a light emitting layer (EML), the substrate was moved to a glove box under a nitrogen atmosphere, and in the glove box, on the light emitting layer (EML), I-1 (20 mg) was dissolved in 10 ml of chlorobenzene, spin-coated at 5000 rpm for 60 seconds, heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 10 nm, and then electron transport An organic EL element 120 was produced in the same manner except that the layer (ETL) was formed.

<< Evaluation of organic EL elements >>
About the produced organic EL element, it carried out similarly to Example 1, and evaluated the voltage rise at the time of half-life and half-luminance arrival.

In addition, the value of half-life was shown by the relative value when the measured value of the organic EL element 101 of Example 1 was set to 100.

From Table 2, the organic EL device in which an intermediate layer is provided between the hole transport layer and the light emitting layer and the organic EL device in which an intermediate layer is provided between the light emitting layer and the electron transport layer are the same as in Example 1. It can be seen that the half-life is increased and the voltage rise when the half-luminance is reached is suppressed.

Furthermore, it can be seen that the half life (%) is further extended in the structure having a plurality of intermediate layers, such as the organic EL elements 117 to 120 of the present invention.

Example 3
<< Production of Organic EL Element 201 >>
As a positive electrode, patterning was performed on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) obtained by forming a 100 nm film of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate, and then this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a hole injection layer (HIL) having a thickness of 30 nm.

Next, the substrate was moved to a glove box under a nitrogen atmosphere, and spin coating (film thickness: about 20 nm) was performed at 1500 rpm for 30 seconds using a solution in which compound HT-2 (50 mg) was dissolved in 10 ml of monochlorobenzene. And dried under nitrogen at 160 ° C. for 30 minutes to form a hole transport layer (HTL).

Further, spin coating (film thickness of about 40 nm) was performed at 1500 rpm for 30 seconds using a solution in which compound H-27 (73 mg) and compound D-1 (14 mg) were dissolved in 10 ml of isopropyl acetate. It dried under nitrogen for 30 minutes and was set as the light emitting layer (EML).

Next, spin coating (film thickness: about 20 nm) was performed at 1500 rpm for 30 seconds using a solution in which compound ET-1 (50 mg) was dissolved in 10 ml of 2,2,3,3-tetrafluoropropanol. And dried for 30 minutes under nitrogen to obtain an electron transport layer (ETL).

The substrate is attached to a vacuum deposition apparatus, the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, LiF is deposited as an electron injection layer at 2 nm, then aluminum 110 nm is deposited to form a cathode, and the organic EL element 201 is formed. Produced.

<< Production of Organic EL Element 202 >>
In the production of the organic EL element 201, after forming a hole injection layer (HIL), a solution obtained by dissolving 60 mg of polyethylene (PE) in 10 ml of chlorobenzene was used on the hole injection layer at 5000 rpm for 60 seconds. The organic EL element 202 was formed in the same manner except that the film was spin-coated under the conditions of 150 ° C., heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 30 nm, and then a hole transport layer (HTL) was formed. Produced.

<< Production of Organic EL Elements 203 and 204 >>
In the production of the organic EL element 202, spin coating was performed at 5000 rpm for 60 seconds using a solution in which 40 mg and 20 mg of PE were dissolved in 10 ml of chlorobenzene, and the film was heated at 150 ° C. for 30 minutes under nitrogen. Organic EL elements 203 and 204 were produced in the same manner except that an intermediate layer of 20 nm and 10 nm was formed.

<< Production of Organic EL Element 205 >>
In the production of the organic EL element 201, before forming the hole injection layer, the substrate is moved to a glove box under a nitrogen atmosphere, and I-1 (20 mg) is transferred to 2, 2, 3, 3 in the glove box. , 3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether was spin-coated under a condition of 5000 rpm for 60 seconds and heated at 150 ° C. for 30 minutes under nitrogen. Then, an organic EL element 205 was produced in the same manner except that an intermediate layer having a thickness of 10 nm was formed.

<< Production of Organic EL Element 206 >>
In the production of the organic EL element 202, 60 mg of polyvinylidene fluoride (PVDF) was dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether instead of PE. The organic EL element 206 was fabricated in the same manner except that the solution was spin-coated at 5000 rpm for 60 seconds and heated under nitrogen at 150 ° C. for 30 minutes to form a 30 nm thick intermediate layer. did.

<< Production of Organic EL Elements 207 and 208 >>
In the production of the organic EL element 206, 40 mg and 20 mg of polyvinylidene fluoride (PVDF) were dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, respectively. The organic EL device 207 and the organic EL device 207 were prepared in the same manner as above except that an intermediate layer having a film thickness of 20 nm and 10 nm was formed by spin-coating using the prepared solution at 5000 rpm for 60 seconds and heating at 150 ° C. for 30 minutes under nitrogen. 208 was produced.

<< Production of Organic EL Element 209 >>
In the production of the organic EL element 206, I-2 (60 mg) was replaced with 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl instead of polyvinylidene fluoride (PVDF). Using a solution dissolved in 10 ml of ether, spin coating was performed at 5000 rpm for 60 seconds, and heating was performed at 150 ° C. for 30 minutes under nitrogen to form an intermediate layer having a thickness of 30 nm. An element 209 was manufactured.

<< Production of Organic EL Elements 210 and 211 >>
In the production of the organic EL element 209, a solution in which 40 mg and 20 mg of I-2 were dissolved in 10 ml of 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, respectively. The organic EL elements 210 and 211 were prepared in the same manner except that an intermediate layer having a thickness of 20 nm and 10 nm was formed by spin coating at 5000 rpm for 60 seconds and heating under nitrogen at 150 ° C. for 30 minutes. did.

<< Production of Organic EL Element 212 >>
In the production of the organic EL element 206, I-1 (60 mg) was replaced with 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl instead of polyvinylidene fluoride (PVDF). Using a solution dissolved in 10 ml of ether, spin coating was performed at 5000 rpm for 60 seconds, and heating was performed at 150 ° C. for 30 minutes under nitrogen to form an intermediate layer having a thickness of 30 nm. An element 212 was produced.

<< Production of Organic EL Elements 213 and 214 >>
In the production of the organic EL element 212, a solution in which I-1 was dissolved in 40 mg and 20 mg in 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether 10 ml, respectively. The organic EL elements 213 and 214 were prepared in the same manner except that an intermediate layer having a thickness of 20 nm and 10 nm was formed by spin coating at 5000 rpm for 60 seconds and heating at 150 ° C. for 30 minutes under nitrogen. did.

<< Evaluation of organic EL elements 201 to 214 >>
Each of the obtained organic EL elements 201 to 214 was evaluated in the same manner as in Example 1 for the half life and voltage increase when the half brightness was reached. In addition, the value of the half life is shown as a relative value when the measured value of the organic EL element 201 is 100.

From Table 3, an organic EL device in which a plurality of organic functional layers (for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, etc.) are produced by a wet process is also an intermediate containing a fluorinated polymer. It is clear that the organic EL element of the present invention provided with a layer has a longer half-life (%) than that of a comparative organic EL element that is not so, and suppresses an increase in voltage when the half-luminance is reached. is there.

Example 4
<< Production of Organic EL Element 215 >>
In the production of the organic EL element 214, after forming the hole transport layer without providing an intermediate layer between the hole injection layer (HIL) and the hole transport layer (HTL), the substrate was placed under a nitrogen atmosphere. Move to the glove box, spin on the hole transport layer (HTL) in the glove box using a solution of I-1 (20 mg) dissolved in 10 ml of chlorobenzene at 5000 rpm for 60 seconds. An organic EL element 215 was produced in the same manner as described above except that the coating was heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 10 nm, and then the light emitting layer (EML) was formed.

<< Production of Organic EL Element 216 >>
In the production of the organic EL element 215, after forming the light emitting layer without providing an intermediate layer between the hole transport layer (HTL) and the light emitting layer (EML), the substrate is transferred to a glove box under a nitrogen atmosphere. In a glove box, spin-coat the solution on a light emitting layer (EML) on a light emitting layer (EML) using a solution of I-1 (20 mg) in 10 ml of chlorobenzene at 5000 rpm for 60 seconds, An organic EL element 216 was produced in the same manner except that it was heated under nitrogen for 30 minutes to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer (ETL) was formed.

<< Production of Organic EL Element 217 >>
In the production of the organic EL element 214, after forming the hole transport layer, the substrate is moved to a glove box under a nitrogen atmosphere, and in the glove box, on the hole transport layer (HTL), I-1 (20 mg) was dissolved in 10 ml of chlorobenzene, spin-coated at 5000 rpm for 60 seconds, and heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 10 nm. An organic EL element 217 was produced in the same manner except that (EML) was formed.

<< Production of Organic EL Element 218 >>
In the production of the organic EL element 217, after forming the light emitting layer without providing an intermediate layer between the hole transport layer (HTL) and the light emitting layer (EML), the substrate is transferred to a glove box under a nitrogen atmosphere. In a glove box, spin-coat the solution on a light emitting layer (EML) on a light emitting layer (EML) using a solution of I-1 (20 mg) in 10 ml of chlorobenzene at 5000 rpm for 60 seconds, An organic EL element 218 was produced in the same manner except that it was heated under nitrogen for 30 minutes to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer (ETL) was formed.

<< Production of Organic EL Element 219 >>
In the production of the organic EL element 215, after forming a light emitting layer (EML), the substrate was moved to a glove box under a nitrogen atmosphere, and I-1 (20 mg) was placed on the light emitting layer (EML) in the glove box. ) In a solution of 10 ml of chlorobenzene, spin-coated at 5000 rpm for 60 seconds, heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer ( An organic EL element 219 was produced in the same manner except that ETL) was formed.

<< Production of Organic EL Element 220 >>
In the production of the organic EL element 217, after forming the light emitting layer (EML), the substrate was moved to a glove box under a nitrogen atmosphere, and I-1 (20 mg) was placed on the light emitting layer (EML) in the glove box. ) In a solution of 10 ml of chlorobenzene, spin-coated at 5000 rpm for 60 seconds, heated at 150 ° C. for 30 minutes under nitrogen to provide an intermediate layer having a thickness of 10 nm, and then an electron transport layer ( An organic EL element 220 was produced in the same manner except that ETL) was formed.

<< Evaluation of organic EL elements 215 to 220 >>
The produced organic EL elements 215 to 220 were evaluated in the same manner as in Example 1 for the half life and voltage increase when the half luminance was reached. In addition, the value of the half life is shown as a relative value when the measured value of the organic EL element 201 is 100.

From Table 4, even in an element in which a plurality of organic functional layers (for example, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, etc.) are produced by a wet process, the positive hole transport layer (HTL) It can be seen that the effect of the present invention is obtained even when an intermediate layer is inserted other than between the hole injection layer (HIL).

Furthermore, it can be seen that an example in which the effect is more remarkable is that an intermediate layer is provided between the hole injection layer and the light emitting layer. It has also been clarified that an effect can be obtained even in a configuration having a plurality of intermediate layers.

DESCRIPTION OF SYMBOLS 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (6)

1. In an organic electroluminescence device having an anode and a cathode on a substrate, and a plurality of organic functional layers sandwiched between both electrodes, the plurality of organic functional layers include at least a hole injection layer, a hole transport layer, and An organic electroluminescence device comprising a light emitting layer and an intermediate layer containing at least one fluorinated polymer between any two organic functional layers of the plurality of organic functional layers.
2. 2. The organic electroluminescence device according to claim 1, wherein the thickness of the intermediate layer is 1 nm to 10 nm.
3. The organic electroluminescent element according to claim 1, wherein the intermediate layer contains a polymer material represented by the following general formula (a).
   

   

   
   Wherein R ₁ and R ₂ are an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, a heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group , Alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or hetero At least one selected from arylsulfonyl group, amino group, halogen atom, fluorinated hydrocarbon group, cyano group, nitro group, hydroxy group, thiol group, silyl group, phosphono group, at least one of oxygen, nitrogen , A place containing at least one of sulfur .n1 represents a group represents an integer from 10 to 10,000.)
4. 4. The organic electroluminescence device according to claim 1, wherein the intermediate layer contains a polymer material represented by the following general formula (b).
   

   

   
   (Wherein X is at least one cyclic selected from cyclic ether, cyclic thioether, cyclic azaether, crown ether, thiacrown ether, and azacrown ether, which contains at least one of oxygen, nitrogen, and sulfur. Represents a partial structure, and n2 represents an integer of 10 to 10,000.)
5. The organic electroluminescence device according to any one of claims 1 to 4, wherein the intermediate layer is located between the hole injection layer and the light emitting layer.
6. The organic electroluminescence device according to any one of claims 1 to 5, wherein the intermediate layer is located between the hole injection layer and the hole transport layer.

Images