JPWO2011046165A1 - ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC ELECTROLUMINESCENT ELEMENT EMITTING WHITE, DISPLAY DEVICE AND LIGHTING DEVICE - Google Patents

Abstract

The present invention provides an organic electroluminescence device having a high emission luminance, a low driving voltage, and a low leak rate. The organic electroluminescence device of the present invention has at least an anode and a cathode on a support substrate, and has a light emitting layer containing at least an organic substance between the anode and the cathode, and between the cathode and the light emitting layer. At least an electron transport layer, and the cathode is formed by applying a solution containing silver, and the electron transport layer includes an electron transport material represented by the following general formula (1) The mass ratio of the metal or the metal salt to the electron transport material represented by the general formula (1) is 0.5: 1 to 1. The range is 99: 1. General formula (1) Ar1- (Ar2) n [wherein Ar1 represents a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocycle, and Ar2 derived from an aromatic heterocycle Represents a group. n represents an integer of 2 or more. ]

Description

  The present invention relates to an organic electroluminescence element having high luminous efficiency and high luminance, an organic electroluminescence element that emits white light, a display device, and an illumination device.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as “ELD”). As a component of ELD, an inorganic electroluminescence element and an organic electroluminescence element (hereinafter, also referred to as “organic EL element”) can be given.

  Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  An organic EL device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, injects electrons and holes into the light emitting layer, and recombines them to generate excitons (exciton). It is an element that emits light by using light emission (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts, and is also self-luminous. In addition, it is attracting attention from the viewpoints of space saving, portability and the like because it is a thin film type complete solid element with a wide viewing angle and high visibility.

  However, in organic EL elements for practical use in the future, development of organic EL elements that emit light efficiently and with high luminance with lower power consumption is desired.

  In Japanese Patent No. 3093796, a small amount of a phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to achieve an improvement in light emission luminance and a longer device lifetime.

  Further, an 8-hydroxyquinoline aluminum complex as a host compound, an element having an organic light emitting layer doped with a small amount of phosphor (for example, see Patent Document 1), and an 8-hydroxyquinoline aluminum complex as a host compound. A device having an organic light emitting layer doped with a quinacridone dye is known (for example, see Patent Document 2).

  In the technique disclosed in the above document, when the emission from the excited singlet is used, the generation ratio of the singlet exciton and the triplet exciton is 1: 3. Therefore, the generation probability of the luminescent excited species is 25%. In addition, since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (MA Baldo et al., Nature, 395, 151-154 (1998)), Research on materials that exhibit phosphorescence has become active.

  For example, M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), US Pat. No. 6,097,147, and the like.

  When the excited triplet is used, the upper limit of the internal quantum efficiency is 100%. In principle, the luminous efficiency is four times that of the excited singlet, and there is a possibility that almost the same performance as a cold cathode tube can be obtained. Therefore, it is attracting attention as a lighting application.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., many compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

  Further, the organic EL element is an all-solid element composed of an organic material film having a thickness of only about 0.1 μm between the electrodes, and the light emission can be achieved at a relatively low voltage of 2 to 20V. It is a technology that is expected as a next-generation flat display and illumination.

  However, the configuration of the organic EL element is simple, in which an organic layer is sandwiched between a transparent electrode and a counter electrode, and the manufacturing cost is also low because the number of parts is overwhelmingly smaller than that of a liquid crystal display that is a typical flat display. Although it should be kept low, this is not always the case at present, and a large amount of water is drained into the liquid crystal display in terms of performance and cost.

In particular, in terms of cost, poor productivity is considered as a factor. Most of the organic ELs currently commercialized are manufactured by a so-called vapor deposition method in which a low molecular material is deposited to form a film. In this vapor deposition method, a low-molecular compound that can be easily purified can be used as an organic EL material (high-purity material is easy to obtain), and a laminated structure can be easily formed. Although it is excellent, on the other hand, since vapor deposition is performed under a high vacuum condition of 10 ⁻⁴ Pa or less, restrictions are imposed on the film forming apparatus, and in practice it can only be applied to a substrate with a small area, and when a plurality of layers are stacked. The disadvantages are that the film formation takes time and the throughput is low. In particular, it becomes a problem when applied to lighting applications or large-area electronic displays, and organic EL is one of the causes that are not practically used in such applications.

  On the other hand, a coating method in which an organic layer is manufactured by a process such as spin coating, ink jet, printing, and spraying can produce a thin film at normal pressure, and is suitable for producing a uniform film over a large area.

  Moreover, since an organic EL element is an element in which an organic layer is sandwiched between ITO electrodes and metal electrodes such as Al and Ag, as it is, an injection barrier occurs at the interface between the organic layer and the metal electrode, and a voltage rise occurs. End up. In particular, on the cathode side, due to the difference between the LUMO of the organic layer material and the work function of the cathode metal such as Al or Ag, an electron injection barrier is generated and the driving voltage is greatly increased.

As a typical example, when Alq ₃ is used for the organic layer in contact with the cathode and Al or Ag is used as the cathode, the LUMO of Alq ₃ is 2.9 eV, and the work function of Al or Ag is 4.3 eV. A large electron injection barrier occurs.

Originally, in order to reduce the electron injection barrier, it is ideal to use a metal having a small work function such as an alkali metal as a cathode. However, since an alkali metal is unstable, the work function is stable such as Al and Ag. In many cases, an alkali metal salt (CsCO ₃ , LiF, etc.) is thinly deposited on a large cathode metal as an electron injection layer with a thickness of several nm or less (see, for example, Non-Patent Document 1).

  However, it is technically very difficult to form an electron injecting layer as thin as several nm or less by a coating method, and this is a big problem when an organic EL element is manufactured by a coating method.

  In addition, the organic EL element comprising 0.1 to 1000 ppm of a specific nitrogen-containing aromatic heterocyclic compound and a metal element with respect to the compound in a layer that is not in direct contact with the cathode, for example, a hole blocking layer An element is disclosed (for example, see Patent Document 3).

  However, when the content of the metal element in the layer is in the above range, it is difficult to reduce the electron injection barrier, and there is a demand for further improvement in order to obtain an element with a practically low driving voltage. .

Japanese Unexamined Patent Publication No. 63-264692 JP-A-3-255190 Japanese Patent Laid-Open No. 2006-120763

Device physics / material chemistry / device application of organic EL, CMC Publishing, 2007

  An object of the present invention is to provide an organic electroluminescence device having high luminous efficiency, a low driving voltage and a low leak rate, and an organic electroluminescence device that emits white light. Moreover, it is providing the illuminating device and display apparatus using this organic electroluminescent element or the organic electroluminescent element which light-emits white.

  The object of the present invention has been achieved by the following constitution.

1. Having at least an anode and a cathode on a support substrate, having a light emitting layer containing at least an organic substance between the anode and the cathode, and having at least an electron transport layer between the cathode and the light emitting layer; In the organic electroluminescence element formed by applying a solution containing silver, the cathode,
The electron transport layer is produced through a step of applying a solution containing an electron transport material represented by the following general formula (1) and a metal or a salt of the metal, and the metal or the metal salt is An organic electroluminescence device having a mass ratio with the electron transport material represented by the general formula (1) in the range of 0.5: 1 to 99: 1.

General formula (1)
Ar1- (Ar2) n
[Wherein, Ar1 represents a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocycle, and Ar2 represents a group derived from an aromatic heterocycle. n represents an integer of 2 or more. ]
2. 2. The organic electroluminescence device according to 1 above, wherein the metal contains an alkali metal or an alkaline earth metal.

  3. 3. The organic electroluminescence device as described in 1 or 2 above, wherein the metal salt is a salt of Li, Na, K or Cs.

  4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein the metal salt is an organic salt.

  5). 5. The organic electroluminescence device according to any one of 1 to 4, wherein the electron transport material is a compound having a carbazole derivative or a carboline derivative.

  6). 6. The organic electroluminescence device according to any one of 1 to 5, wherein the electron transport material contains a pyridine derivative, an imidazole derivative, a pyrazine derivative, a triazine derivative, an indole derivative or an indazole derivative.

  7). 7. The organic electroluminescence device according to any one of 1 to 6, wherein a diffusion prevention layer is provided between the light emitting layer and the electron transport layer.

  8). 8. The organic electroluminescence device according to 7, wherein the diffusion preventing layer contains an electron transport material.

  9. The organic electroluminescent element which has the organic electroluminescent element of any one of said 1-8, and light-emits white.

  10. 10. A display device comprising the organic electroluminescent element according to any one of 1 to 9 above.

  11. An illuminating device comprising the organic electroluminescent element according to any one of 1 to 9 above.

  According to the present invention, there are provided an organic electroluminescence element having a high light emission luminance and a low driving voltage, an organic electroluminescence element that emits white light, and an illumination device and a display using the organic electroluminescence element or an organic electroluminescence element that emits white light The equipment could be provided.

The schematic diagram which showed an example of the display apparatus comprised from an organic EL element. The schematic diagram of the display part A. FIG. The schematic diagram of a pixel. FIG. 3 is a schematic diagram of a passive matrix type full-color display device. Schematic of a lighting device. The schematic diagram of an illuminating device.

  In the organic electroluminescence device of the present invention, by adopting the configuration defined in any one of 1 to 9 above, the organic electroluminescence device having high luminous efficiency and high emission luminance, and organic electroluminescence that emits white light. An element was obtained.

  In addition, a high-luminance display device and lighting device could be obtained by using an organic electroluminescence element or an organic electroluminescence element that emits white light, which exhibits the above characteristics.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  As a result of various studies on the above object, the present inventors applied an electron transport material represented by the general formula (1) and a solution containing a metal or a salt of the metal to form an electron transport layer. Thus, an electron transport layer having an electron injection function can be produced by a coating method, and the present invention has been achieved.

  In addition, the electron transport layer produced by the coating method according to the present invention improved the smoothness of the layer interface and reduced the leak rate of the device as compared with the electron transport layer produced by the conventional coating method.

  As a result, it has become possible to provide an organic electroluminescence element having higher emission luminance and lower driving voltage more stably.

  Moreover, in this invention, it became possible to produce all the layers other than an anode by application | coating by forming a cathode by application | coating using silver nanoparticle.

  The organic electroluminescence device of the present invention has at least an anode and a cathode on a support substrate, has a light emitting layer made of at least an organic material between the anode and the cathode, and has a space between the cathode and the light emitting layer. In an organic electroluminescence device having at least an electron transport layer and the cathode formed by applying a solution containing silver, the electron transport layer is an electron transport material represented by the general formula (1); An organic electroluminescence element formed by applying a solution containing a metal or a salt of the metal.

  This feature is a technical feature common to the inventions according to the above items 1 to 9.

《Electron transport layer》
The electron transport layer according to the present invention will be described.

  The electron transport layer that is a constituent layer of the organic electroluminescence device of the present invention is produced through a step of applying a solution containing the electron transport material represented by the general formula (1) and a metal or a metal salt. It is a feature.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, About 5 nm-5 micrometers are preferable, More preferably, it is adjusting so that it may become the range of 5 nm-200 nm.

  In addition, about the various structure layers provided between the cathode which comprises the organic electroluminescent element (organic EL element) of this invention, an anode, and this anode and this cathode, in the place of the structure of an organic electroluminescent element later Explained.

  In addition to the electron transport material, metal, or salt of the metal represented by the general formula (1), conventionally known electron transport materials (including organic materials and inorganic materials) can be used. The layer may have a single layer structure composed of one or more of the electronic materials represented by the general formula (1).

  The configuration of the element will be described in detail in the configuration layer of the organic electroluminescence element described later.

  Here, first, an electron transport material used for producing an electron transport layer will be described, and then a metal or a salt of the metal will be described.

<< Electron Transport Material Represented by Formula (1) >>
In the general formula (1), examples of the aromatic hydrocarbon ring used for forming the group derived from the aromatic hydrocarbon ring represented by Ar1 include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, Phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, Examples include a pentacene ring, a perylene ring, a pentaphen ring, a picene ring, a pyrene ring, a pyranthrene ring, and an anthraanthrene ring. Furthermore, the aromatic hydrocarbon ring may have a substituent described later.

  In the general formula (1), examples of the aromatic heterocycle used for forming the group derived from the aromatic heterocycle represented by Ar1 include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, Pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring Quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (one of the carbon atoms constituting the carboline ring is further substituted with a nitrogen atom) Shows the ring that is) It is.

  In the general formula (1), the aromatic heterocycle used for forming the group derived from the aromatic heterocycle represented by Ar2 includes the aromatic heterocycle represented by Ar1 in the general formula (1). It is synonymous with the aromatic heterocyclic ring used for formation of the group derived.

  In the general formula (1), a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocycle represented by Ar1, and a group derived from an aromatic heterocycle represented by Ar2 Examples of the substituent that may have an alkyl group (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 etc.), alkynyl group (eg ethynyl group, propargyl group etc.), aromatic hydrocarbon group (Also called aromatic carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group Naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group) , Pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, 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, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, , 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) Group), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), Aryloxycarbonyl groups (eg, phenyloxycarbonyl groups, naphthyloxycarbonyl groups, etc.), sulfamoyl groups (eg, aminosulfonyl groups, methylaminosulfonyl groups, dimethylaminos) Sulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl 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, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, Phenylcarbonyloxy group, etc.), amide groups (eg, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octyl) Carbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, Cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenyla Nocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group naphthyl) Ureido 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 etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl) Group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (phenylsulfonyl 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), fluoride Hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group) Group, triphenyl Group, phenyl diethyl silyl group and the like), a phosphono group, and the like.

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  In general formula (1), n represents an integer of 2 or more, preferably in the range of 2 to 20, more preferably in the range of 2 to 10.

  Specifically, the electron transport material represented by the general formula (1) according to the present invention is preferably a carbazole derivative or a carboline derivative, and more preferably the carbazole derivative or carboline derivative is a pyridine derivative, It is preferable to have an imidazole derivative, a pyrazine derivative, a triazine derivative, an indole derivative or an indazole derivative as a substituent or a partial structure.

  Among these, a compound having a pyridyl group or a phenylpyridyl group as a substituent in the carbazole derivative or carboline derivative is preferable.

  Although the specific example of the electron transport material represented by General formula (1) below is shown, this invention is not limited to these.

  Although the synthesis example of a typical compound is shown below, this invention is not limited to these.

  << Synthesis Example of Compound 5 >>

Step 1: (Synthesis of Intermediate 1)
Under a nitrogen atmosphere, 3,6-dibromodibenzofuran (1.0 mol), carbazole (2.0 mol), copper powder (3.0 mol), and potassium carbonate (1.5 mol) in 300 ml of DMAc (dimethylacetamide) And stirred at 130 ° C. for 24 hours. After cooling the reaction solution to room temperature, 1 l of toluene was added and washed 3 times with distilled water. The organic layer was evaporated under reduced pressure, and the residue was subjected to silica gel flash chromatography (n-heptane: toluene = 4: 1 to 1). 3: 1) to obtain Intermediate 1 in a yield of 85%.

Step 2: (Synthesis of Intermediate 2)
Intermediate 1 (0.5 mol) was dissolved in 100 ml of DMF at room temperature under air, NBS (2.0 mol) was added, and the mixture was stirred overnight at room temperature. The resulting precipitate was filtered and washed with methanol, yielding intermediate 2 in 92% yield.

Step 3: (Synthesis of Compound 5)
Under a nitrogen atmosphere, intermediate 2 (0.25 mol), 2-phenylpyridine (1.0 mol), ruthenium complex [(η ₆ -C ₆ H ₆ ) RuCl ₂ ] ₂ (0.05 mol), triphenyl Phosphine (0.2 mol) and potassium carbonate (12 mol) were mixed in 3 l of NMP (N-methyl-2-pyrrolidone) and stirred at 140 ° C. overnight.

After cooling the reaction solution to room temperature, 5 l of dichloromethane was added and the reaction solution was filtered. The filtrate was distilled off the solvent under reduced pressure (800 Pa, 80 ° C.), and the residue (N-methyl-2-pyrrolidone) was subjected to silica gel flash chromatography (CH ₂ Cl ₂ : Et ₃ N = 20: 1 to 10: 1). It refine | purified in.

  Each fraction was collected and the solvent was distilled off under reduced pressure. The residue was redissolved in dichloromethane and washed three times with water. The organic phase was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain Compound 5 in a yield of 68%.

<Metal or salt of the metal>
The metal or salt of the metal according to the present invention will be described.

  The metal according to the present invention or a salt of the metal is preferably used by being mixed with an electron transport material, and at least the metal according to the present invention or the salt of the metal is represented by the general formula (1) according to the present invention. The present inventors have found that an electron transport layer excellent in electron injectability can be provided by mixing with an electron transport material represented by

  Here, the metal or a salt of the metal may be an alkali metal (for example, Li, Na, K, Rb, Cs, Fr, etc.), an alkaline earth metal (Be, Mg, Ca, Sr, Ba, etc.) or its Although a salt is preferable, an alkali metal such as Li, Na, K or Cs or a salt thereof is preferable, and Cs, K or a salt thereof is particularly preferable.

Examples of the metal salt include an inorganic salt and an organic salt. Examples of the inorganic salt include NaF, KF, CsF, and CsCO _{3. When the} electron transport layer according to the present invention is formed by coating, From the viewpoint of improving the solubility in the solvent used for preparing the coating solution and improving the smoothness of the coating film to be produced, an organic salt is more preferably used.

  The organic salt according to the present invention is particularly an organic salt of Cs, preferably cesium acetate or cesium formate.

  Since the metal or salt of the metal contained in the electron transport layer according to the present invention has a small molecular weight, when the organic electroluminescence element is driven, it may diffuse to the light emitting layer described later. It is preferable to contain inclusion compounds such as calixarene compounds, thiacalixarene compounds, and crown ether compounds from the viewpoint of preventing light emission and improving luminous efficiency (external extraction quantum efficiency).

<Diffusion prevention layer>
The diffusion preventing layer according to the present invention will be described.

  From the viewpoint of efficiently preventing the metal or the metal salt from diffusing into the light emitting layer of the organic electroluminescence device and further improving the light emission efficiency (external extraction quantum efficiency), the light emitting layer, the electron transport layer, It is preferable to provide a diffusion preventing layer between them.

  The diffusion prevention layer according to the present invention is preferably a constituent layer that does not contain a metal or a salt of the metal in the electron transport layer but contains an electron transport material contained in the electron transport layer.

  Further, the diffusion preventing layer according to the present invention may contain an inclusion compound such as calixarene compound, thiacalixarene compound, and crown ether compound.

  Further, the thickness of the diffusion preventing layer is preferably in the range of 5 nm to 5 μm, more preferably in the range of 5 nm to 200 nm.

  The constituent layers of the organic electroluminescence element of the present invention, such as the light emitting layer and the electron transport layer, will be described in detail later.

<Method of applying electron transport layer>
The coating method for the electron transport layer according to the present invention will be described.

  The electron transport layer according to the present invention is a step of applying a solution containing the electron transport material represented by the general formula (1) and a metal or a salt of the metal (the step of applying is separately a wet method, (It may also be referred to as a wet process).

  As a means (method) for applying the solution, it can be formed by thinning by a known method such as a spin coating method, a casting method, a printing method including an ink jet method, an LB method, or the like.

  Hereinafter, the constituent layers of the organic electroluminescence element of the present invention will be described.

<< Constituent layers of organic EL elements >>
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 transport layer / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / diffusion prevention layer / electron transport layer / cathode (iii) Anode / hole transport layer / Electron blocking layer / light emitting layer / diffusion preventing layer / electron transporting layer / cathode (iv) Anode / hole transporting layer / electron blocking layer / light emitting layer / diffusion preventing layer / electron transporting layer / cathode (v) Anode / hole transporting Layer / electron blocking layer / light emitting layer / diffusion preventing layer / electron transport layer / cathode buffer layer / cathode (vi) anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer / diffusion preventing layer / electron transport layer / Cathode buffer layer / cathode (vii) Anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer / diffusion prevention layer / electron transport layer / cathode buffer layer / cathode << electron transport layer >>
The characteristics of the electron transport layer according to the present invention, the electron transport material represented by the general formula (1) contained in the electron transport layer, the metal, or a salt of the metal have already been described. Here, various aspects of the electron transport layer according to the present invention (general layer configuration, function of the electron transport layer, etc.), and conventionally known electron transport materials that may be further contained in the electron transport layer, etc. Is also explained.

  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, when a single electron transport layer and a plurality of layers are used, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the cathode side with respect to the light emitting layer is injected from the cathode. However, in the present invention, the electron transport material represented by the above general formula (1) is preferable, and more specifically, a carbazole derivative or a carboline derivative. In particular, the carbazole derivative or carboline derivative preferably has a pyridine derivative, an imidazole derivative, a pyrazine derivative, a triazine derivative, an indole derivative, an indazole derivative, or the like as a substituent or a partial structure.

  Among these, a compound having a pyridyl group or a phenylpyridyl group as a substituent in the carbazole derivative or carboline derivative is preferable.

  In the electron transport layer according to the present invention, as a material that can be used in combination with the electron transport material represented by the general formula (1), any one of conventionally known compounds is selected and used. be able to.

  Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide 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.

  In addition, 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 of 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.

<Light emitting layer>
The light emitting layer according to the present invention 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, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 10 nm to 20 nm.

  For the production of the light emitting layer, a light emitting dopant and a host compound, which will be described later, are formed by differential film formation by applying a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, and an ink jet method. be able to.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting host compound and at least one kind of light emitting dopant (such as a phosphorescent dopant (also referred to as a phosphorescent dopant) or a fluorescent dopant).

(Host compound)
In the present invention, a “host compound (also referred to as“ light-emitting host ”or the like)” is defined as a compound having a phosphorescence quantum yield of phosphorescence of less than 0.1 at room temperature (25 ° C.). The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  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.

  Moreover, it becomes possible to mix different light emission by using multiple types of light emission dopants mentioned later, and, thereby, arbitrary luminescent colors can be obtained.

  Moreover, you may use together a conventionally well-known light emission dopant as shown below. It may be a conventionally known 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 (evaporation polymerizable light emitting host).

  As known host compounds that may be used in combination with the present invention, there are compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature). preferable.

  Specific examples of host compounds that can be used in combination with the present invention are shown below, but the present invention is not limited thereto.

  Specific examples of known host compounds further 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 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

(Luminescent dopant)
As the light-emitting dopant according to the present invention, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used. From the viewpoint of obtaining an organic EL device with high luminous efficiency, the light emitting dopant used in the light emitting layer or the light emitting unit of the organic EL device of the present invention (sometimes simply referred to as a light emitting material) contains the above host compound. At the same time, it is preferable to contain a phosphorescent dopant.

(Phosphorescent dopant)
The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescence at room temperature (25 ° C.) and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. The energy transfer type that obtains light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

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

  The phosphorescent dopant according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), Rare earth complexes, most preferably iridium compounds.

  Examples of the phosphorescent dopant according to the present invention include conventionally known light-emitting dopants as shown below.

(Fluorescent dopant)
Fluorescent dopants (also referred to as “photonic compounds”) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, Examples include pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Next, the charge transport layer used as a constituent layer of the organic EL device of the present invention, that is, an injection layer, a blocking layer, and the like will be described.

<< 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.

  The details of the conventional cathode buffer layer (electron injection layer) are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Metal buffer layer typified by aluminum, etc., 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. Can be mentioned.

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

<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, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). 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.

  The hole blocking layer contains the carbazole derivative, carboline derivative, diazacarbazole derivative (one in which one of the carbon atoms constituting the carboline ring of the carboline derivative is replaced with a nitrogen atom) as the host compound described above. It is preferable to do.

  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.

  The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  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 positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 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, 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 transport material has any one of hole injection or transport and 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 ' − (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 of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  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. 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.

  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, these materials are preferably used because 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 ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, The range of 5 nm-5 micrometers is preferable, More preferably, it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. 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.

"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 of a desired shape may be formed by a photolithography method, or when pattern accuracy is not so necessary (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.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used.

  When light emission is extracted 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. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, conventionally, as a cathode, a metal having a small 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 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, silver, etc. have heretofore been preferred.

  However, these electrode materials are formed by vapor deposition or sputtering, and it is very difficult to form them by wet methods such as coating and ink jet which are excellent in cost.

  Therefore, in the present invention, the cathode was formed using a silver nanoparticle ink or a silver nanoparticle paste (for example, MDot-SL manufactured by Mitsuboshi Belting Co., Ltd.) that can be formed by a wet method such as coating or inkjet.

  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 order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque.

  When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film.

  A particularly preferable support 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, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry 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, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method described in JP 2004-68143 A is particularly preferable.

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

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

  In addition, 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. 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 used for 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.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. 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 element can be thinned.

Furthermore, the polymer film has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) 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 such as 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. Moreover, hot-melt type polyamide, polyester, and polyolefin 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 adhesive-hardened from room temperature to 80 degreeC 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.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. .

  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.

  The method for forming these films is not particularly limited. 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 is also possible. 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, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《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 support substrate with the organic layer interposed therebetween or the sealing film.

  In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus 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 within 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 that there is no.

  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 extracted outside 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 for 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 the air (US Pat. No. 4,774,435), A method for improving efficiency by giving light condensing property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method for forming a reflective surface on the 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 than the substrate between the substrate and the light emitter. 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 a substrate, a transparent electrode layer, and a light emitting layer (including between the substrate and the outside) No. 283751) .

  In the present invention, these methods can be used in combination with the organic EL device according to the present invention, or a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or the substrate, A method of forming a diffraction grating between any layers of the transparent 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 which is further excellent in 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 light extracted from the transparent electrode has a higher extraction efficiency to the outside 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 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. .

  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. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably 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, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in 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 grating is preferably two-dimensionally repeated such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device according to the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or in combination with a so-called condensing sheet, so that the organic EL device is directed to a specific direction, for example, the device light emitting surface By condensing 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 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, for example, a sheet that is put into practical use 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, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Method for producing organic EL element >>
The electron transport layer constituting the organic electroluminescent device of the present invention is produced through a step of applying a solution containing the electron transport material represented by the general formula (1) and a metal or a salt of the metal. When preparing other constituent layers of the organic electroluminescence element, any method such as a vapor deposition method can be applied even by a coating method (also referred to as a wet method).

  Here, as an example of a method for producing an organic EL element, a method for producing an element comprising an anode / hole injection layer / hole transport layer / light emitting layer / diffusion prevention layer / electron transport layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of a material for an anode is formed on a suitable substrate so as to have a thickness of 1 μm or less, preferably 10 nm to 200 nm, thereby producing 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 diffusion prevention layer, or an electron transport layer, which is an element material, is formed thereon.

  Here, as the wet method, there are 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, etc., but a precise thin film can be formed. In view of high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, or a spray coating method is preferable. Different film forming methods may be applied for each layer.

  After the formation of the electron transport layer, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a desired organic EL device can be obtained by providing a cathode. .

  Further, the order can be reversed, and the cathode, the electron transport layer, the diffusion preventing layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode can be formed in this order.

  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 V to 40 V with the anode as + and the cathode as-. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  The organic EL device of the present invention is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

<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 element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. 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 the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

Further, the white color of the organic EL white element according to the present invention means that the color temperature at 1000 cd / m ² is 7000 K to 2500 K (deviation Δuv from the black body locus) when the 2-degree viewing angle front luminance is measured by the above method. = ± 0.02).

<Display device>
The display device of the present invention comprises the organic EL element of the present invention.

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.

  Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  When a direct current voltage is applied to the obtained display device, light emission can be observed by applying a voltage of about 2 V to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with 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 alternating current waveform to be applied may be arbitrary.

  The display device can be used as a display device, a display, and various light emission sources.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. The present invention is not limited to these examples.

  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 organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays 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, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside, and the pixels for each scanning line respond to the image data signal by the scanning signal. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A. The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning line 5 and the plurality of data lines 6 in 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 pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). 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 according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram 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. A 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.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. 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, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects 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 moved 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 if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by 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 light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels. 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 light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic view of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by 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.

《Lighting device》
The illuminating device of this invention has the said organic EL element, It is characterized by the above-mentioned. The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However, It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  The organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display).

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied as an illumination device to an organic EL element that emits substantially white light. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two of the complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, a plurality of light emitting dopants may be mixed and mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning such as a mask is unnecessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also 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 are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and an illumination device as shown in FIGS. Can be formed.

  FIG. 5 shows a schematic diagram of a lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  FIG. 6 shows a cross-sectional view of the lighting device. In FIG. 6, 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

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

Example 1
<< Production of Organic EL Element 1 >>
After patterning on a substrate (NH-Techno Glass NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, 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. Then, the film was formed by spin coating and then dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole transport layer.

  On this hole transport layer, a solution in which 15 mg of H-32 and 3 mg of Ir-12 were dissolved in 2.5 ml of dehydrated butyl acetate was formed by spin coating at 1500 rpm for 30 seconds. Heat-dried at 120 ° C. for 1 hour to provide a light-emitting layer having a thickness of 50 nm.

  On this light emitting layer, a solution obtained by dissolving (or dispersing) 15 mg of ET-1 in 2 ml of dehydrated 1,1,1-3,3,3-hexafluoroisopropanol was spin-coated under a condition of 1500 rpm for 30 seconds. Was formed. Heat-dried at 120 ° C. for 1 hour to provide an electron transport layer having a thickness of 20 nm.

  Further, 20 ml of silver nanoparticle paste dispersion (MDot-SL, manufactured by Mitsuboshi Belting Co., Ltd.) was ejected and patterned using an inkjet head (manufactured by Epson; MJ800C), then baked at 120 ° C. for 5 minutes under nitrogen, A 110 nm silver cathode was formed, and the organic EL element 1 was manufactured.

<< Organic EL element 2 >>
In the production of the organic EL element 1, the organic EL element 2 was produced in the same manner except that the electron transport layer was changed as follows.

Specifically, a solution obtained by dissolving (or dispersing) 10 mg of ET-1 and 5 mg of zinc chloride (ZnCl ₂ ) in 2 ml of dehydrated 1,1,1-3,3,3-hexafluoroisopropanol on the light emitting layer. Was formed by spin coating under conditions of 1500 rpm and 30 seconds, followed by heat drying at 120 ° C. for 1 hour to provide an electron transport layer having a thickness of 20 nm.

<< Organic EL element 3 >>
An organic EL element 3 was produced in the same manner except that zinc chloride was changed to calcium (Ca) in the production of the organic EL element 2.

<< Organic EL element 4 >>
Organic EL element 4 was prepared in the same manner except that zinc chloride was changed to potassium fluoride (KF) in the production of organic EL element 2.

<< Organic EL element 5 >>
In the production of the organic EL element 2, the organic EL element 5 was produced in the same manner except that zinc chloride was changed to cesium fluoride (CsF).

<< Organic EL element 6 >>
Organic EL element 6 was similarly manufactured except that zinc chloride was changed to cesium acetate (AcOCs) in preparation of organic EL element 2.

<< Organic EL element 7 >>
In the production of the organic EL element 6, an organic EL element 7 was produced in the same manner except that ET-1 was changed to ET-2.

<< Organic EL element 8 >>
In the production of the organic EL element 6, an organic EL element 8 was produced in the same manner except that ET-1 was changed to ET-3.

<< Organic EL element 9 >>
In the production of the organic EL element 8, the organic EL element 9 was produced in the same manner except that a diffusion preventing layer was provided between the light emitting layer and the electron transport layer.

(Preparation of diffusion prevention layer)
A solution obtained by dissolving (or dispersing) 10 mg of ET-3 in 2 ml of dehydrated 1,1,1-3,3,3-hexafluoroisopropanol on the light emitting layer by spin coating under conditions of 1500 rpm and 30 seconds. A film was formed and heat-dried at 120 ° C. for 1 hour to prepare a diffusion prevention layer having a thickness of 10 nm.

<< Organic EL Element 10 >>: Comparative Example In the preparation of the organic EL element 6, the organic EL element 6 was organic except that the ratio of cesium acetate (AcOCs), which is a metal salt, to ET-1 was changed to 0.0011: 1. An EL element 10 (comparative example) was produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 1 to 9, the non-light emitting surface of each organic EL element after production is covered with a glass case, and a glass substrate having a thickness of 300 μm is used as a sealing substrate. As an epoxy-based photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.), this is superimposed on the cathode and brought into close contact with the transparent support substrate, and cured by irradiation with UV light from the glass substrate side. Then, it was sealed and a lighting device as shown in FIGS. 5 and 6 was produced and evaluated.

(External quantum efficiency)
By lighting the organic EL element under a constant current condition of room temperature (about 23 ° C. to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting. The external extraction quantum efficiency (η) was calculated.

  Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance. The external extraction quantum efficiency was expressed as a relative value with the organic EL element 1 (comparative example) as 100.

(Drive voltage)
Each voltage was measured when the organic EL element was driven at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the measurement results are shown below. Comparative example) is taken as 100, and each is shown as a relative value.

Drive voltage = (drive voltage of each element / drive voltage of the organic EL element 1) × 100
A smaller value indicates a lower drive voltage for comparison.

(Leakage rate)
The organic EL device at room temperature (about 23 ℃ ~25 ℃), + 2.5mA / cm 2 and subjected to constant current of -2.5mA / cm ^2, the voltage ratio when the absolute value is 1,000 or less The leak generation rate was calculated, and 100 device samples were made with the same device configuration, and the leak generation rate was calculated. The obtained results are shown in Table 1.

  From Table 1, compared with the organic EL elements 1 and 10 which are comparative examples, in the organic EL element of the present invention, the electron transport layer is composed of an electron transport material represented by the general formula (1) and a metal or the metal It is clear that the organic EL element produced by applying a solution containing salt exhibits high luminous efficiency, has a low driving voltage, and can effectively prevent the leak occurrence rate.

Example 2
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element 9 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
In the production of the organic EL element 9 of Example 1, a green light emitting element was produced in the same manner except that Ir-12 was changed to Ir-1, and this was used as a green light emitting element.

(Production of red light emitting element)
In the production of the organic EL element 9 of Example 1, a red light emitting element was produced in the same manner except that Ir-12 was changed to Ir-9, and this was used as a red light emitting element.

  The red, green, and blue light-emitting organic EL elements produced above were juxtaposed on the same substrate to produce an active matrix type full-color display device having a configuration as shown in FIG. In FIG. 2, only the schematic diagram of the display part A of the produced display device is shown.

  That is, a plurality of pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) juxtaposed with a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate. The scanning lines 5 and the plurality of data lines 6 in 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 lattice shape and are connected to the pixels 3 at the orthogonal positions (for details, see FIG. Not shown).

  The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. The image data signal is received from the data line 6 and light is emitted according to the received image data.

  In this way, a full color display device was produced by appropriately juxtaposing red, green, and blue pixels.

  It has been found that when this full-color display device is driven, high brightness, high durability, and clear full-color moving image display can be obtained.

Example 3
<< Preparation of white light emitting element and white lighting device >>
In the organic EL element 5 of Example 1, Ir-12 was changed to Ir-1, Ir-9, and Ir-12, and an organic electroluminescence element that emitted white light was produced. Used as a light emitting element.

  This element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 5 and 6 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 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 (11)

Having at least an anode and a cathode on a support substrate, having a light emitting layer containing at least an organic substance between the anode and the cathode, and having at least an electron transport layer between the cathode and the light emitting layer; In the organic electroluminescence element formed by applying a solution containing silver, the cathode,
The electron transport layer is produced through a step of applying a solution containing an electron transport material represented by the following general formula (1) and a metal or a salt of the metal, and the metal or the metal salt is An organic electroluminescence device having a mass ratio with the electron transport material represented by the general formula (1) in the range of 0.5: 1 to 99: 1.
General formula (1)
Ar1- (Ar2) n
[Wherein, Ar1 represents a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocycle, and Ar2 represents a group derived from an aromatic heterocycle. n represents an integer of 2 or more. ]   The organic electroluminescence device according to claim 1, wherein the metal includes an alkali metal or an alkaline earth metal.   3. The organic electroluminescence device according to claim 1, wherein the metal salt is a salt of Li, Na, K, or Cs.   The organic electroluminescent element according to claim 1, wherein the metal salt is an organic salt.   The organic electroluminescent device according to claim 1, wherein the electron transport material is a compound having a carbazole derivative or a carboline derivative.   The organic electroluminescence device according to any one of claims 1 to 5, wherein the electron transport material contains a pyridine derivative, an imidazole derivative, a pyrazine derivative, a triazine derivative, an indole derivative or an indazole derivative.   The organic electroluminescence device according to claim 1, further comprising a diffusion prevention layer between the light emitting layer and the electron transport layer.   The organic electroluminescence device according to claim 7, wherein the diffusion prevention layer contains an electron transport material.   It has the organic electroluminescent element of any one of Claims 1-8, The organic electroluminescent element which light-emits white characterized by the above-mentioned.   A display device comprising the organic electroluminescence element according to claim 1.   An illuminating device comprising the organic electroluminescence element according to claim 1.