JP6156521B2 - Organic electronics element, display device and lighting device - Google Patents

Description

The present invention relates to an organic electronics element, a display device including the organic electronics element, and a lighting device.
More specifically, the present invention relates to an organic electronic element having excellent luminous efficiency and luminous lifetime, low driving voltage, and small voltage change during low current driving, and a display device and lighting device including the element.

In recent years, there has been great interest in so-called organic electronics materials based on organic semiconductors, as well as organic electronics elements using them.
Examples of the organic electronics element include an organic electroluminescence element (hereinafter also referred to as “organic EL element”), an organic thin film solar cell, and an organic transistor. In general, organic electronics elements are light, thin, and flexible. In addition to dry (vacuum) processes such as vapor deposition, which have been widely used in inorganic semiconductors, they can be applied to wet processes such as printing and coating film formation. Because of the good matching, there is an expectation for large area and low price. On the other hand, there is a problem in the stability of materials compared to inorganic semiconductors, and development of new materials is awaited.

  For example, an organic EL element that has been attracting attention in recent years has a configuration in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and by injecting electrons and holes into the light emitting layer and recombining them. It is an element that generates excitons (excitons) and emits light using light emission (fluorescence / phosphorescence) when the excitons are deactivated. Light emission is possible at a voltage of several volts to several tens of volts, and since it is a self-luminous type, it has a wide viewing angle, and since it is a thin-film type completely solid element, it is very interesting from the viewpoint of space saving and portability. Collecting.

  As for development of organic EL elements for practical use, Princeton University has reported organic EL elements that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1). Research on the materials shown has been active (see, for example, Patent Document 1 and Non-Patent Document 2).

  In addition, organic EL elements that utilize phosphorescence emission, in principle, can achieve a luminous efficiency that is approximately four times that of elements that utilize previous fluorescence emission. Research and development of layer structure and electrodes are conducted all over the world. For example, many synthetic compounds have been studied focusing on heavy metal complexes such as iridium complexes (see Non-Patent Document 3, for example).

  As described above, the phosphorescence emission method is a method having a very high potential, but the organic EL device using phosphorescence emission is greatly different from the organic EL device using fluorescence emission, and a method of controlling the position of the emission center. In particular, how to stably perform light emission by recombination inside the light emitting layer is an important technical issue in terms of capturing the efficiency and lifetime of the device.

  Therefore, in recent years, a multi-layered element having a functional separation, in particular, a hole transport layer located on the anode side of the light emitting layer and an electron transport layer located on the cathode side of the light emitting layer in a form adjacent to the light emitting layer Is used (see, for example, Patent Document 2).

US Pat. No. 6,097,147 JP 2005-112765 A

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. 123, 4304 (2001)

  However, in the above prior art, from the viewpoints of charge injection / transport, voltage change during constant current driving, etc., the functionality of the organic electronics element is still not sufficient, and further improvement is required. ing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electronic element having excellent luminous efficiency and luminous lifetime, a low driving voltage, and a small voltage change during low voltage driving, and a display device and an illuminating device including the organic electronic element. That is.

In order to achieve the above object of the present invention, according to one aspect of the present invention,
Between the anode and the cathode, at least an electron injection layer, an electron transport layer, and a light emitting layer, in the organic electronics element laminated in order of the electron injection layer, the electron transport layer, the light emitting layer from the cathode side,
Between the electron transport layer and the light emitting layer, it has a buffer layer containing a compound represented by the following general formula ( 3 ),
The phosphorescent layer contains a phosphorescent organometallic complex,
An organic electronics element is provided, wherein the electron injection layer contains an alkali metal salt.

[In General Formula (3), X ₁ , X ₂ and X _{5 to} X ₈ each represent CR. Ar represents an unsubstituted phenyl group. Y represents O. R represents a hydrogen atom or a substituent, respectively. ]

According to another aspect of the invention,
A display device comprising the organic electronic element is provided.

According to still another aspect of the present invention,
Provided is a lighting device comprising the organic electronics element.

  According to the present invention, there are provided an organic electronic element having excellent luminous efficiency and luminous lifetime, a low driving voltage, and a small voltage change during low-voltage driving, and a display device and an illuminating device provided with the organic electronic element. Can do.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

  In order to solve the above-described object of the present invention, the present inventors have intensively studied, and as a result, an alkali metal salt used as a material for the electron injection layer (electron injection material), and between the electron transport layer and the light emitting layer. It discovered that the combination with the compound represented by General formula (1) used as a material of the provided buffer layer contributed greatly to the performance of an organic EL device. Further, in particular, potassium or cesium is used as the metal of the alkali metal salt, and the aromatic hydrocarbon ring is bonded to the α-position carbon atom of the N atom of the nitrogen-containing aromatic heterocyclic ring as the compound represented by the general formula (1). Or it discovered that organic EL device performance improved specifically by using what substituted the aromatic heterocyclic ring, and came to complete this invention.

The expression mechanism of the effect of the present invention is not necessarily elucidated, but the background situation and the background of the present invention related to the mechanism are as follows.
In general, alkali metals and alkaline earth metals typified by lithium fluoride having a small work function are well known as electron injection materials. When the present inventors examined in detail about the combination of such an electron injection material and the compound represented by General formula (1) mentioned later, it is an element which belongs to periodic table group 1 and is Mn ^<+>. / M system standard electrode potential is -3Vvs. It has been clarified that the performance of organic electronic devices can be specifically improved by using metal or metal compounds (including complexes and salts) of elements larger than SHE as electron injection materials.
This is because an element having a large oxidation-reduction potential is more likely to receive electrons than an element having a small oxidation-reduction potential, and thus is easily reduced to a metal state. Such an element is represented by the general formula (1) described later. This is considered to cause a specific interaction with the compound represented by the formula.
That is, as a material for the buffer layer, a material obtained by substituting an aromatic hydrocarbon ring or an aromatic heterocyclic ring for the carbon atom at the N-position of the N atom of the N-containing aromatic heterocyclic ring, and an alkali metal element having a large redox potential The combination is believed to significantly improve the performance of organic electronics elements, such as organic electroluminescent elements.

《Organic electronics device》
Although various aspects can be taken as an aspect of the organic electronics element of the present invention, an organic electroluminescence (EL) element, an organic thin film solar cell, an organic transistor, etc. are mentioned as preferred embodiments.

As an embodiment of the present invention, the organic electronics element is preferably an organic electroluminescence element that emits white light.
The organic electronic element of the present invention can be suitably included in a display device and a lighting device.

  In the following, an organic electroluminescence (EL) element will be described in detail as a representative example.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element according to the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (vi) anode // hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode Buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode

The light emitting layer may be a light emitting layer unit in which a plurality of light emitting layers form a unit.
Further, a non-light emitting intermediate layer may be provided between the plurality of light emitting layers, and the intermediate layer may include a charge generation layer.
The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  The organic electronic device of the present invention has an electron injection layer, an electron transport layer, and a light emitting layer between an anode and a cathode, and is configured by stacking an electron injection layer, an electron transport layer, and a light emitting layer in this order from the cathode side. A buffer layer (hole blocking layer) between the electron injection layer and the light-emitting layer, the buffer layer containing a compound represented by the general formula (1) described later, and the light-emitting layer phosphorescent The organometallic complex is contained, and the electron injection layer contains a salt of an alkali metal (elements belonging to Group 1 of the periodic table excluding hydrogen).

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<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 having a function of transporting electrons and a very small ability to transport holes. By blocking the holes, the probability of recombination of electrons and holes can be improved.
Moreover, the structure of the above-mentioned electron carrying layer can be used as a hole-blocking layer concerning this invention as needed.

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

  The hole blocking layer preferably contains the carbazole derivative, azacarbazole derivative, pyridine derivative, or the like mentioned as the host compound.

  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 layer.

  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 by 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.

  Here, in the organic electronic device of the present invention, the compound represented by the general formula (1) described below is contained in the hole blocking layer as described above.

(1) Compound represented by general formula (1)

In the general formula (1), X _{1 to} X ₄ each represent CR or N, _one of X _{1 to} X ₄ is N, and R represents a hydrogen atom or a substituent.
When X ₁ is N, X ₂ represents CR ₂ and R ₂ represents a substituted or unsubstituted aryl group or heteroaryl group.
When X ₂ is N, X ₁ represents CR ₁ , X ₃ represents CR ₃ , R ₁ and R ₃ each represent a hydrogen atom or a substituent, and at least one of R ₁ and R ₃ is substituted. Alternatively, it represents an unsubstituted aryl group or heteroaryl group.
When X ₃ is N, X ₂ represents CR ₂ , X ₄ represents CR ₄ , R ₂ and R ₄ each represent a hydrogen atom or a substituent, and at least one of R ₂ and R ₄ is substituted Alternatively, it represents an unsubstituted aryl group or heteroarylene group.
When X ₄ is N, X ₃ represents CR ₃ and R ₃ represents a substituted or unsubstituted aryl group or heteroaryl group.

  In the general formula (1), Y represents O, S, NR, CRR ′ or SiRR ′, and R and R ′ each represent a hydrogen atom or a substituent.

In the general formula (1), Z ₁ and Z ₂ each represent CR, and R represents a hydrogen atom or a substituent. In addition, CR represented by Z ₁ and Z ₂ may form a ring.

In the general formula (1), examples of the substituent represented by R _{1 to} R ₄ , R and R ′ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group). Pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl group, allyl group, etc.) Alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, p-chlorophenyl group, mesityl Group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phena Tolyl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, , 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, Thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, force rubazolyl group, force rubolinyl group, diaza force rubazolyl group (carbon atoms constituting the force rubolin ring of the force rubolinyl group) One of which is replaced by a nitrogen atom), Keno Xalinyl group, biridazinyl group, triazinyl 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 (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.) Alkylthio groups (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio groups (for example, cyclopentylthio group, cyclohexylthio group, etc.), Alkylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (Eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octyl) Aminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl (For example, acetyl group, ethyl group, propyl group, pentyl group, cyclohexyl group, octyl group, 2-ethylhexyl group, dodecyl group, phenyl group, naphthyl group) Carbonyl group, pyridyl group, etc.), acyloxy groups (eg, acetyloxy group, ethyl group sulfonyloxy group, butyl group carbonyloxy group, octyl group sulfonyloxy group, dodecyl group sulfonyloxy group, phenyl group carbonyloxy group) Amide groups (for example, methyl group sulfonylamino group, ethyl group sulfonylamino group, dimethyl group sulfonylamino group, propyl group sulfonylamino group, pentyl group sulfonylamino group, cyclohexyl group sulfonylamino group, 2-ethylhexyl group sulfonylamino group) , Octyl-strength sulfonylamino group, dodecyl-strength sulfonylamino group, phenyl-strength sulfonylamino group, naphthyl-strength carbonylamino group, etc. Propylamino group, pentylamino group, cyclohexylamino group, octylamino group, 2-ethylhexylamino group, dodecylamino group, phenylamino group, naphthylamino group, naphthylamino group 2-pyridylamino group, etc.), ureido groups (eg, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido) Group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group) 2-biridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroaryl Sulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino) Butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg fluorine atom, chlorine atom, bromine atom etc.), fluorine Hydrocarbon group (e.g., fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercatopto group, silyl group (e.g., trimethylsilyl group, Triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group and the like.
In addition, 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 the general formula (1), no examples of the substituent of the aryl group, the R ₁ to R 4, aromatic cited as substituents represented by _R and R 'hydrocarbon groups represented by R ₁ to R ₄ And the like.
In the general formula (1), the unsubstituted heteroaryl group represented by R ₁ to R _4, the R ₁ to R 4, _R and aromatic heterocyclic rings listed as the substituent represented by R ' Examples thereof are the same as those for groups.
In the general formula (1), as the substituted aryl group or heteroaryl group represented by R _{1 to} R ₄ , the unsubstituted aryl group or heteroaryl group may be the above R _{1 to} R ₄ , R and The thing substituted by the substituent etc. which are represented by R 'is mentioned.
In the general formula (1), the substituted or unsubstituted aryl group or heteroaryl group represented by R _{1 to} R ₄ also includes condensed rings such as carbazole, dibenzofuran, dibenzothiophene and the like.

  In addition, the said substituent, an aryl group, and heteroaryl group are representative examples, and are not restricted to these.

  As an embodiment of the present invention, the compound represented by the general formula (1) is preferably represented by the following general formula (2), from the viewpoint of manifesting the effects of the present invention, and represented by the general formula (2). It is more preferable that the compound to be represented by the following general formula (3). General formulas (2) and (3) will be described below.

(2) Compound represented by general formula (2) In the present invention, the compound represented by general formula (1) is preferably represented by the following general formula (2).

In the general formula (2), X ₁ and X ₂ each represent CR, and R represents a hydrogen atom or a substituent.

In the general formula (2), Ar represents a substituted or unsubstituted aryl group or heteroaryl group.
In the general formula (2), the substituted or unsubstituted aryl group or heteroaryl group represented by Ar is a substituted or unsubstituted aryl group represented by R _{1 to} R ₄ in the general formula (1) or The same thing as a heteroaryl group is mentioned.

  In the general formula (2), Y represents O, S, NR, CRR ′ or SiRR ′, and R and R ′ each represent a hydrogen atom or a substituent.

In the general formula (2), Z ₁ and Z ₂ each represent CR, and R represents a hydrogen atom or a substituent.

In the general formula (2), examples of the substituent represented by R and R ′ include the same substituents as those represented by R _{1 to} R ₄ , R and R ′ in the general formula (1).

(3) Compound Represented by General Formula (3) In the present invention, the compound represented by the general formula (2) is preferably represented by the following general formula (3).

In the general formula (3), X ₁ , X ₂ and X _{5 to} X ₈ each represent CR, and R represents a hydrogen atom or a substituent.

In the general formula (3), Ar represents a substituted or unsubstituted aryl group or heteroaryl group.
In the general formula (3), the substituted or unsubstituted aryl group or heteroaryl group represented by Ar is a substituted or unsubstituted aryl group represented by R _{1 to} R ₄ in the general formula (1) or The same thing as a heteroaryl group is mentioned.

  In the general formula (3), Y represents O, S, NR, CRR ′ or SiRR ′, and R and R ′ each represent a hydrogen atom or a substituent.

In the general formula (3), examples of the substituent represented by R and R ′ include the same substituents as those represented by R _{1 to} R ₄ , R and R ′ in the general formula (1).

(4) Specific Examples Hereinafter, specific examples of the compounds represented by the general formulas (1) to (3), which are the materials for organic electronics elements of the present invention, are shown, but the present invention is not limited thereto.
First, specific examples of the compound represented by the general formula (1) are shown below.

  Then, the specific example of a compound represented by General formula (2) is shown below.

  Specific examples of the compound represented by the general formula (3) are shown below.

(5) Synthesis Example Hereinafter, a method for synthesizing the compounds represented by the general formulas (1) to (3), which are the materials for organic electronics elements of the present invention, will be described. However, the present invention is not limited thereto. Absent. Of the specific examples described above, the synthesis method of HB-3-3 will be described as an example.

Under a nitrogen atmosphere, 30 mmol of compound A and 10 mmol of compound B were dissolved in dimethyl sulfoxide (DMSO; 100 ml), 2.5 mol of PdCl ₂ dppf and 40 mmol of K ₂ CO ₃ were added, and the mixture was stirred at 80 ° C. for 12 hours. Thereafter, the temperature was returned to room temperature, and 500 ml of ethyl acetate and 100 ml of pure water were added and stirred. The organic layer was washed with saturated brine and dried over magnesium sulfate. After completion of drying, the solvent was washed away under reduced pressure, washed with about 50 ml of toluene, further dissolved with 100 ml of toluene under heating, and allowed to stand overnight at room temperature for recrystallization. The target product ET-3-3 (6 mmol, 60% yield) was obtained as a white solid. The compound was identified by NMR and Mass, and the purity was measured by HPLC and confirmed to be> 99%.

  Other compounds represented by the general formulas (1) to (3) can be synthesized in the same manner as described above.

<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 not a layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total thickness of the light emitting layer is not particularly limited, but it prevents the uniformity of the film to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color against the drive current. From a viewpoint, it is preferable to adjust to the range of 2 nm-200 nm, More preferably, it adjusts to the range of 5 nm-100 nm.

  The light emitting layer of the organic EL device of the present invention preferably contains at least one of a host compound (also referred to as a light emitting host) and a light emitting dopant as a guest material, and contains a host compound and three or more kinds of light emitting dopants. Is more preferable. A host compound and a light emitting dopant (also referred to as a light emitting dopant compound) contained in the light emitting layer will be described below.

(1) Host Compound In the present invention, the “host compound” means that the content (mass%) in the layer of the compound contained in the light emitting layer is 20% or more, and room temperature (25 ° C.) Is defined as a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1. Preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the content rate (mass%) in the layer is 20% or more in the compound 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.

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

  Moreover, the compound represented by the said General formula (1) based on this invention is preferably used also as a host compound.

  As the known host compound that may be used in combination, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from becoming longer, and has a high Tg (glass transition temperature) is preferable.

Specific examples of known host compounds 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.

  Hereinafter, although the specific example of the conventionally well-known compound used as a host compound of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

(2) Luminescent dopant As the luminescent dopant, a fluorescent luminescent dopant (also referred to as “fluorescent compound”), a phosphorescent dopant (“phosphorescent substance”, “phosphorescent compound”, “phosphorescent dopant”). Or the like.) Can be used.

(2.1) Fluorescent luminescent dopant Examples of fluorescent luminescent dopants include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, Examples include pyrium-based dyes, perylene-based dyes, stilbene-based dyes, polythiophene-based dyes, rare-earth complex-based phosphors, and compounds having high fluorescence quantum yields such as laser dyes.

(2.2) Phosphorescent dopant The “phosphorescent dopant” according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, at room temperature (25 ° C.). It is a compound that emits phosphorescence, and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., but 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 emitting dopant according to the present invention achieves the above phosphorescence quantum yield (0.01 or more) in any solvent. It only has to be done.

  There are two types of light emission of the phosphorescent dopant in principle. One is that recombination of carriers occurs on the host compound to which carriers are transported, and an excited state of the host compound is generated. By transferring this energy to the phosphorescent dopant, light emission from the phosphorescent dopant is obtained. Energy transfer type. The other is a carrier trap type in which a phosphorescent dopant becomes a carrier trap, and carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. However, the condition is that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  The phosphorescent organometallic complex contained in the light emitting layer of the organic electronic device of the present invention is appropriately selected from known phosphorescent dopants used in the light emitting layer of conventional organic EL devices. Can do.

  The phosphorescent organometallic complex 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-based compounds) and rare earth complexes, most preferably iridium compounds.

  Hereinafter, although the specific example of the phosphorescence-emitting dopant which can be used preferably in this invention is shown, this invention is not limited to these.

《Electron transport layer》
The “electron transport layer” is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  As an electron transport material (also serving as a hole blocking material) used for the electron transport layer, it is sufficient if it has a function of transmitting electrons injected from the cathode to the light emitting layer. Any one can be selected and used.

Examples of conventionally known materials used for the electron transport layer (hereinafter referred to as “electron transport materials”) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, and the like. Products, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, carboline derivatives, and azacarbazole derivatives.
In the 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.
Further, similarly to the hole injection layer and the hole transport layer, inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as the electron transport material.

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

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

Alternatively, an electron transport layer with high n property doped with impurities as a guest material can be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.
In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

  Hereinafter, although the specific example of the conventionally well-known compound used for formation of the electron carrying layer of the organic EL element of this invention is given, this invention is not limited to these.

《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 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 is 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. Can do. About the film thickness of a positive hole transport layer, it is preferable that it is the range of 5 nm-5 micrometers, 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.

  Hereinafter, although the specific example of the conventionally well-known compound used for formation of the positive hole transport layer of the organic EL element of this invention is given, this invention is not limited to these.

<< Injection layer: hole injection layer (anode buffer layer), electron injection layer (cathode buffer layer) >>
The injection layer includes a hole injection layer and an electron injection layer.
The injection layer is provided as necessary 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.

  An “injection layer” is a layer provided between an electrode and an organic layer in order to reduce driving voltage or improve light emission luminance. “Organic EL element and its industrialization front line (NST 30, November 30, 1998) The details are described in the second volume, Chapter 2, “Electrode Materials” (pages 123 to 166) of

  The details of the 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, a phthalocyanine buffer represented by copper phthalocyanine And an oxide buffer layer typified 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 electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specifically, metals represented by strontium, aluminum and the like. Examples thereof include a buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide.

  The 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.

  In addition, the materials used for the hole injection layer and the electron injection layer can be used in combination with other materials. For example, the materials can be mixed and used in the hole transport layer or the electron transport layer. is there.

In the organic electronic device of the present invention, the electron injection layer contains an alkali metal salt. In the present invention, the alkali metal salt means a metal oxide or metal salt containing an alkali metal, and examples of the metal oxide include Li ₂ O, Na ₂ O, Rb ₂ O, and Cs ₂ O. Examples of the metal salt include, but are not limited to, LiF, NaF, KF, RbF, CsF, lithium acetate, sodium acetate, potassium acetate, potassium formate, cesium acetate, cesium formate, and the like. As the alkali metal contained in the alkali metal salt used in the present invention, sodium, potassium, or cesium is preferable.

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

For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.
In the case of using a coatable material such as an organic conductive compound, a wet film forming method such as a printing method or a coating method can be used.

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

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

"cathode"
As the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.
Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  In the present invention, these electrode substances (also referred to as conductive materials) are used as a conductive paste to form a thin film by a wet method to produce a cathode.

  The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is preferably in the range of 10 nm to 5 μm, more preferably in the range of 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 emission luminance is advantageously improved.
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.

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

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, 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 measured by a method in accordance with JIS K 7129-1992 (25 ± 0.5 ° C., It is preferably a barrier film having a relative humidity (90 ± 2)% RH) of 0.01 g / (m ² · 24 h) or less, and further, oxygen permeation measured by a method according to JIS K 7126-1987. The film is preferably a high barrier film having a degree of 10 ⁻³ ml / (m ² · 24 h · MPa) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less.

  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, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma weighting. A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used. However, an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque substrate include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, a ceramic substrate, and the like.

  The external extraction efficiency at room temperature of light emission of the organic EL device according to 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 may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Method for Manufacturing Organic EL Element >>
As an example of a method for producing an organic EL device, a device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection 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 hole blocking layer, an electron transport layer, or a cathode buffer layer, which is an element material, is formed thereon.

  The thin film formation method is roughly classified into a dry method and a wet method. Examples of the dry method include a vacuum deposition method and a sputtering method. Examples of the wet method include a spin coating method, a casting method, a die coating method, and a blade. There are coating method, roll coating method, ink jet method, printing method, spray coating method, curtain coating method, LB method, etc., but it is possible to form a precise thin film and from the point of high productivity, vacuum deposition method and die coating A method having high suitability for a roll-to-roll method such as a 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 these layers, 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, cathode buffer layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed in this order.

  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.

<Sealing>
In the organic EL device of the present invention, the anode, the cathode, and each layer provided between the anode and the cathode are preferably sealed off from the outside air by a sealing member.

  As a sealing means of the organic EL element 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 organic EL element can be thinned.
Furthermore, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² / 24h) or less, and is measured by a method according to JIS K 7129-1992. is water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is preferably that of ^{1 × 10 -3 ml / (m} 2 / 24h) or less.

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

Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups 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 possible to suitably form an inorganic or organic layer as a sealing film by covering the electrode and the organic layer on the outer side of the electrode facing the substrate with the organic layer interposed therebetween, and in contact with the substrate. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.
Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

  The method for forming these sealing films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure A plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as 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 substrate with the organic layer interposed therebetween or on 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, etc. 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 taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method 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. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, 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 having further high 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.

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

As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 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.

<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, when the organic EL element according to the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is measured when the front luminance at 2 ° viewing angle is measured by the above method. , X = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device according to the present invention includes the organic EL element of the present invention. The display device according to the present invention may be single color or multicolor, but here, the multicolor display device will be described.

In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by a vapor deposition method, a casting method, a spin coating method, an ink jet method, a printing method, or the like.
In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

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.

  In the case of applying a DC voltage to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V with the positive polarity of the anode and the negative polarity of the cathode. 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 multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  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 emitting 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. However, the present invention is not limited to these.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram illustrating an example of a display device including 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 shown in FIG. 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.
FIG. 2 shows a case where 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 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. The power supply line 7 connects the organic EL element 10 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, since the capacitor 13 holds the charged potential of the image data signal even when the driving of the switching transistor 11 is turned off, 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 organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL elements 10 of the plurality of pixels, and the organic EL elements 10 of the plurality of pixels 3 emit light. 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 lighting device of the present invention will be described. The illumination device of the present invention has the organic EL element of the present invention.

  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.

  Further, 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, it is possible to produce a full-color display device 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 to an organic EL element that emits substantially white light as a lighting device. 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 using the relationship of 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 excitation of light from the light emitting materials. Any combination with a dye material that emits light as light may be used, but in the white organic EL device according to the present invention, it is only necessary to mix and mix a plurality of light emitting dopants.

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 of the mask or the like is not necessary. 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 to be in 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 addition, the sealing operation with the glass cover is to bring the organic EL element 101 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, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Moreover, the structure of each compound used in the following Examples is represented by the following formula.

<< Production of Organic EL Element 1-1 >>

  After patterning a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide: tin-doped indium oxide) as an anode on a glass substrate of 100 mm × 100 mm × 1.1 mm, this ITO transparent The transparent support substrate provided with the electrodes was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by HC Starck Co., Ltd., CLEVIO P VP AI 4083) with pure water on this transparent support substrate to 70%. After forming a thin film by spin coating at 3000 rpm for 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 20 nm.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, 100 mg of α-NPD is put into a molybdenum resistance heating boat, 100 mg of CBP is put into another resistance heating boat made of molybdenum, and another molybdenum resistance heating boat 100 mg of Ir (ppy) ₃ was put in, 100 mg of BAlq was put in another resistance heating boat made of molybdenum, and Alq ₃ was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after reducing the pressure of the vacuum tank to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated to deposit α-NPD on the transparent support substrate at a deposition rate of 0.1 nm / sec. A second hole transport layer having a thickness of 20 nm was provided.

Further, the heating boat containing the light emitting host CBP and Ir (ppy) ₃ is energized and heated, and the positive and negative CBP and Ir (ppy) ₃ are deposited at the deposition rates of 0.1 nm / sec and 0.006 nm / sec, respectively. A 40 nm-thick luminescent layer was provided by co-evaporation on the hole transport layer.

  Next, the heating boat containing BAlq was energized and heated, and BAlq was deposited on the light emitting layer at a deposition rate of 0.1 nm / sec to provide a hole blocking layer having a thickness of 5 nm.

Further, the heating boat containing Alq ₃ was heated by energization, and Alq ₃ was deposited on the hole blocking layer at a deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 30 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, lithium fluoride (LiF) was vapor-deposited to provide an electron injection layer with a thickness of 0.5 nm, and aluminum was further vapor-deposited to provide a cathode with a thickness of 110 nm to produce an organic EL element 1-1.

<< Production of Organic EL Elements 1-2 to 1-32 >>
In the production of the organic EL element 1-1, the hole blocking layer material and the electron injection layer material were changed to the materials shown in Table 1. Other than that produced the organic EL element 1-2 to 1-32 similarly.
The structure of the hole blocking layer material used in the production of the organic EL elements 1-5 to 1-16 is represented by the following formula.

<< Evaluation of Organic EL Elements 1-1 to 1-32 >>
When evaluating the produced organic EL elements 1-1 to 1-32, the non-light-emitting surface of each produced organic EL element is covered with a glass cover, and the glass cover and the glass plate on which the organic EL element is produced are in contact with each other. An epoxy photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material around the glass cover side, and this is placed on the cathode side so as to be in close contact with the transparent support substrate. It was cured by irradiation with UV light, sealed, and the lighting device as shown in FIGS. 5 and 6 was manufactured, and the lighting device was evaluated as a sample.
The following evaluation was performed for each sample thus prepared. The evaluation results are shown in Table 1.

(1) External extraction quantum efficiency (luminescence efficiency)
By causing the organic EL device to emit light at room temperature (about 23 ° C. to 25 ° C.) and a constant current of ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of light emission, The external extraction quantum efficiency (η) was calculated. Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance.
In addition, the external extraction quantum efficiency was represented by the relative value which sets the measured value of the organic EL element 1-1 of a comparative example to 100.

(2) Drive voltage The voltage when the organic EL element was driven under a constant current condition of room temperature (about 23 ° C. to 25 ° C.) and ^2.5 mA / cm ² was measured.
In addition, the drive voltage was represented by the relative value which sets the measured value of the organic EL element 1-1 of a comparative example to 100.

(3) Luminous Lifetime The organic EL element was continuously emitted at room temperature under a constant current condition of ^2.5 mA / cm ² , and the time (τ1 / 2) required to obtain half the initial luminance was measured.
In addition, the light emission lifetime was represented by the relative value which sets the measured value of the organic EL element 1-1 of a comparative example to 100.

(4) Voltage change under constant voltage The time required for the organic EL device to continuously emit light under a constant current condition of ^2.5 mA / cm ² at room temperature to obtain half the initial luminance (τ1 / 2 ) Was compared with the initial voltage, and the amount of change (increased value) was expressed as a relative value with the measured value of the organic EL element 1-1 being 100.

(5) Summary As shown in Table 1, an organic EL element 1-17 using an alkali metal salt as the material of the electron injection layer and a compound represented by the general formula (1) as the material of the hole blocking layer. 1-32 is superior in luminous efficiency and driving voltage, has a long lifetime, and has a small voltage change under a constant voltage as compared with the organic EL elements 1-1 to 1-16 of the comparative example. I understand.
Moreover, the organic EL element 1-21-1- using the compound represented by General formula (2) rather than the organic EL element 1-17-1-20 using the compound represented by General formula (1). 24 shows that each performance is improved. Furthermore, rather than the organic EL elements 1-21 to 1-24 using the compound represented by the general formula (2), the organic EL elements 1-25 to 1- 1 using the compound represented by the general formula (3) are used. It can be seen that the performance of 32 is improved.
Further, it can be seen that an organic EL element using cesium has the highest performance as the material of the electron injection layer, and then the performance of the organic EL element is higher in the order of potassium, sodium, and lithium.

  From the above, for the improvement of the light emission efficiency and light emission lifetime of the organic EL element and the suppression of the drive voltage and voltage change, the alkali metal salt is used as the material of the electron injection layer and the general formula (1) is used as the material of the hole blocking layer. It can be seen that it is effective to use a compound represented by Furthermore, it is particularly effective to use a cesium salt as a material for the electron injection layer, and it is particularly effective to use a compound represented by the general formula (3) as a material for the hole injection layer. I understand.

(1) Blue Light-Emitting Organic EL Element As a blue light-emitting organic EL element, a blue light-emitting organic EL element was produced in the same manner except that Ir (ppy) ₃ was changed to D-26 in the production of the organic EL element 1-20 of Example 1. An EL element 2-1B was produced.

(2) Green light emitting organic EL element The organic EL element 1-20 produced in Example 1 was used as a green light emitting organic EL element.

(3) Red light emitting organic EL element As a red light emitting organic EL element, red light emitting organic EL element was prepared in the same manner except that Ir (ppy) ₃ was changed to D-10 in the production of the organic EL element 1-20 of Example 1. An EL element 3-1R was produced.

(4) Production of display device The above red, green and blue light emitting organic EL elements are juxtaposed on the same substrate to produce an active matrix type full color display device having the form shown in FIG. Only the schematic view of the display part A of the display device is shown. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) 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 ( Details are not shown.) The plurality of pixels 3 are driven by an active matrix system in which an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor are provided, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. Thus, a full color display device was produced by juxtaposing the red, green, and blue pixels appropriately.
It was confirmed that by driving the full-color display device, a full-color moving image display with high light emission efficiency and a long light emission life can be obtained.

《Preparation of white light emitting lighting device》
In the preparation of the organic EL element 1-20 produced in Example 1, the Ir _{(ppy) 3,} was changed to 3-component mixture of _{Ir (ppy) 3, D-} 10, D-26 in the same manner, white A light-emitting organic EL element 4-1W was produced. The obtained organic EL device 4-1W was covered with a glass case on the non-light-emitting surface in the same manner as in the above example to obtain a lighting device. The illuminating device could be used as a thin illuminating device that emits white light with high luminous efficiency and long emission life.

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 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate 108 with a transparent electrode Nitrogen gas 109 Water capturing Agent 201 Glass substrate 202 ITO transparent electrode 203 Partition wall 204 Hole injection layer 205B, 205G, 205R Light emitting layer A Display part B Control part

Claims (9)

Between the anode and the cathode, at least an electron injection layer, an electron transport layer, and a light emitting layer, in the organic electronics element laminated in order of the electron injection layer, the electron transport layer, the light emitting layer from the cathode side,
Between the electron transport layer and the light emitting layer, it has a buffer layer containing a compound represented by the following general formula (3),
The phosphorescent layer contains a phosphorescent organometallic complex,
An organic electronic element comprising an alkali metal salt in the electron injection layer.

[In General Formula (3), X ₁ , X ₂ and X _{5 to} X ₈ each represent CR. Ar represents an unsubstituted phenyl group. Y represents O. R represents a hydrogen atom or a substituent, respectively. ] In the general formula (3), X ₅ represents CR ₅ , X ₆ represents CR ₆ , X ₇ represents CR ₇ , X ₈ represents CR ₈ , R _{5 to} R ₈ each represent a hydrogen atom or a substituent, R _5. The organic electronic device according to claim 1, wherein ₅ and R ₆ and / or R ₇ and R ₈ are bonded to each other to form a ring .   In the general formula (3), R ₅ ~ R ₈ Each represents a substituent and R ₅ And R ₆ And R ₇ And R ₈ The organic electronic device according to claim 2, wherein the are bonded to each other to form a ring. The organic electronic device according to any one of claims 1 to 3, wherein the compound represented by the general formula (3) is contained in a hole blocking layer. The organic electronic element according to any one of claims 1 to 4 , wherein the alkali metal salt is a potassium salt or a cesium salt. The organic electronic device according to any one of claims 1 to 5, wherein the phosphorescent organometallic complex is characterized in that an iridium complex. The organic electronic device according to any one of claims 1 to 6 , wherein the emission color is white. Display apparatus characterized by comprising an organic electronic device according to any one of claims 1 to 7. Lighting apparatus characterized by comprising an organic electronic device according to any one of claims 1 to 7.

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