JP5569531B2 - ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC ELECTROLUMINESCENT ELEMENT MATERIAL, DISPLAY DEVICE AND LIGHTING DEVICE - Google Patents

Description

  The present invention relates to an organic electroluminescence element, an organic electroluminescence element material, a display device, and a lighting device.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements).

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

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

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

  Since Princeton University reported on organic EL devices using phosphorescence emission from excited triplets (MA Baldo et al., Nature, 395, 151-154 (1998)) Research on materials that exhibit light has become active.

  For example, M.M. A. Baldo et al. , Nature, 403, 17, 17, 750-753 (2000).

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

  Many compounds have been studied mainly for heavy metal complexes such as iridium complexes.

In addition, studies using tris (2-phenylpyridine) iridium as a dopant have been made. Other dopants include L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac), tris (2- (p-tolyl) pyridine) iridium (Ir (ptpy) ₃ ), tris (benzo [h] quinoline) Studies using iridium (Ir (bzq) ₃ ) and the like are being conducted (note that these metal complexes are generally called orthometalated iridium complexes).

  In addition, attempts have been made to form devices using various iridium complexes.

  Furthermore, in order to obtain high luminous efficiency, a hole transporting compound is used as a phosphorescent compound host, and various electron transporting materials are used as phosphorescent compound hosts, and these are doped with a novel iridium complex. The use is also disclosed.

  In either case, the light emission brightness and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. There was a problem that it was lower than the conventional element.

  As described above, it is difficult for phosphorescent highly efficient light-emitting materials to shorten the light emission wavelength and improve the light emission lifetime of the device, and the performance that can withstand practical use cannot be sufficiently achieved.

  Regarding wavelength shortening, introduction of electron-withdrawing groups such as fluorine atoms, trifluoromethyl groups, and cyano groups into phenylpyridine as substituents, and introduction of picolinic acid and pyrazabole-based ligands as ligands It is known.

  However, with these ligands, the emission wavelength of the light-emitting material is shortened to achieve blue, and a high-efficiency device can be achieved. On the other hand, the light-emitting lifetime of the device is greatly deteriorated, so an improvement in the trade-off is required. It was.

  It is disclosed that a metal complex having phenylpyrazole as a ligand is a light emitting material having a short emission wavelength.

  Furthermore, a metal complex formed from a ligand having a partial structure in which a 6-membered ring is condensed to a 5-membered ring of phenylpyrazole is disclosed.

  Moreover, it is already known that an iridium complex having a ligand having a phenylimidazole skeleton is useful as a light-emitting dopant in an organic EL device (see, for example, Patent Documents 1, 2, and 3).

  However, organic EL devices using conventionally disclosed light emitting dopants are still insufficient in terms of light emission efficiency, driving voltage, and lifetime. In the light emitting layer of the organic EL device, the light emitting dopant may be uniformly dispersed in the host compound due to problems such as carrier transportability, concentration quenching due to aggregation of the light emitting dopant, and quenching due to interaction between excitons. Although desirable, a material that solves the above-described problems and exhibits sufficient device performance has not yet been found.

  As described above, many light emitting materials have been studied for synthesis mainly on iridium complexes and platinum complexes. From the viewpoint of providing an organic EL device having high light emission efficiency, low driving voltage, and long life. It is still insufficient and further solutions are being sought.

  On the other hand, because of demands for large area, low cost, and high productivity, there is a great expectation for wet methods (also called wet processes, etc.), and film formation can be performed at a lower temperature than film formation by vacuum process. There is great expectation from the viewpoint of improving the light emission efficiency and the device lifetime because the damage of the lower organic layer can be reduced (see, for example, Patent Documents 4 and 5).

  In these documents, wet film formation using an ionic metal complex is realized.

  However, in order to realize wet film formation in an organic EL element using blue phosphorescence, from a practical point of view, currently known luminescent materials have solubility in solvents, solution stability, and driving voltage. It has been found that the device lifetime is still insufficient and further improvement techniques are indispensable.

US Patent Application Publication No. 2006/251923 International Publication No. 2007/097149 International Publication No. 2007/097153 JP 2002-302671 A International Publication No. 2007/006380

  An object of the present invention is to provide an organic EL element material that can emit light with a short wave, exhibits high luminous efficiency, has a long luminous lifetime, and is suitable for a wet process. An organic EL element material capable of providing an EL element, an organic EL element using the material, an illumination device, and a display device are provided.

The object of the present invention has been achieved by the following constitutions 1 to 11 .
Specifically, according to the present invention, there is provided an organic electroluminescence device material in which the number of carbon atoms of R ₁ and R ₂ is different from each other in the general formula (1) .

  1. An organic electroluminescence element material, which is a metal complex represented by the following general formula (1).

[Wherein, R ₁ and R ₂ each represent a substituent having 1 to 3 carbon atoms, and the total number of carbon atoms contained in R ₁ and R ₂ is 3 to 5. R represents a substituent, and n represents 0 or an integer of 1 to 4. ]
2. _2. The organic electroluminescent element material according to 1 above, wherein the total number of carbon atoms contained in R ₁ and R ₂ of the general formula (1) is 3 or 4.

3. _2. The organic electroluminescence device material according to 1, wherein the total number of carbon atoms contained in R ₁ and R ₂ of the general formula (1) is 4.

4). 4. The organic electroluminescence element material according to any one of 1 to 3, wherein the substituent represented by R ₁ and R ₂ in the general formula (1) is an alkyl group.

5. 5. The organic electroluminescent element material according to any one of 1 to 4, wherein R ₁ and R _{2 in} the general formula (1) each represent an ethyl group.

6). 6. n of said general formula (1) is 0, The organic electroluminescent element material of any one of said 1-5 characterized by the above-mentioned. In an organic electroluminescence device in which a plurality of organic compound layers including a light emitting layer are sandwiched between an anode and a cathode,
At least 1 layer of this organic compound layer contains the organic electroluminescent element material of any one of said 1-6, The organic electroluminescent element characterized by the above-mentioned.

  8). 8. The organic electroluminescence device as described in 7 above, wherein the organic compound layer is manufactured through a process of forming and forming a film by a wet process.

  9. 9. The organic electroluminescence device as described in 7 or 8 above, which emits white light.

  10. An illuminating device comprising the organic electroluminescent element according to any one of 7 to 9 above.

  11. A display device comprising the organic electroluminescence element according to any one of 7 to 9 above.

  According to the present invention, there is provided an organic EL element material that exhibits short-wave emission, exhibits high emission efficiency, has a long emission lifetime, and is suitable for a wet process, an organic EL element using the same, an illumination device, and a display device We were able to.

It is the schematic diagram which showed an example of the display apparatus of this invention. 4 is a schematic diagram of a display unit A. FIG. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device. The schematic block diagram of an organic electroluminescent full color display apparatus is shown.

  As a result of intensive research in order to achieve the above object, the present inventors obtained the following knowledge, designed a molecule based on the knowledge, and as a novel organic electroluminescence element material, the above general By finding a metal complex represented by the formula (1) and using the metal complex represented by the general formula (1) according to the present invention for an organic compound layer of an organic electroluminescence element (organic EL element), particularly a light emitting layer. The present inventors have found that organic EL elements, lighting devices, and display devices can be obtained in which short-wave light emission is observed, high light emission efficiency is exhibited, and the light emission lifetime is long.

  As described in Prior Patent Documents 1, 2, and 3, it is already known that an iridium complex having a ligand having a phenylimidazole skeleton is useful as a light-emitting dopant in an organic EL device.

  However, its performance is insufficient to solve the above problems.

Therefore, as a result of further studies by the present inventors, among metal complexes having a phenylimidazole skeleton ligand, they are represented by the general formula (1) and included in the substituents represented by R ₁ and R _2. It has been found that a metal complex having a total number of carbon atoms of 3 to 5 exhibits good performance as a light-emitting dopant for an organic EL device, particularly when used in a coating process.

  In the light emitting layer of the organic EL element, it is desirable that the light emitting dopant is uniformly dispersed in the host compound in view of the problem of concentration quenching due to carrier transportability, aggregation of the light emitting dopant, and quenching due to interaction between excitons. Therefore, it was found that a moderate interaction with the host compound is important.

However, when the total number of carbon atoms contained in the substituents represented by R ₁ and R ₂ is less than 3, the aggregating action between the dopants in the thin film tends to increase.

Further, when the total number of carbon atoms contained in the substituents represented by R ₁ and R ₂ is larger than 5, the interaction with the host is weak, and the dispersed state of the luminescent dopant in the host compound becomes non-uniform. It turns out that there is a tendency.

On the other hand, the metal complex of the present invention in which the total number of carbon atoms contained in the substituents represented by R ₁ and R ₂ is 3 to 5 has an appropriate interaction with the host compound and is uniform. It was found to give a distributed state.

  As a result, the present inventors are able to provide light-emitting dopants in which short-wave light emission is observed, the quantum yield of the light-emitting material is large, the light emission lifetime is long, and suitable for wet processes. The organic EL element, the illuminating device, and the display device can be provided.

  It should be noted that the organic EL element is composed of an anode, a cathode, and constituent layers sandwiched between the anode and the cathode (such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer). The organic layer) will be described in detail later.

  Hereinafter, the metal complex represented by the general formula (1) according to the present invention will be described.

In the general formula (1), R ₁ and R ₂ each represent a substituent having 1 to 3 carbon atoms, and the total number of carbon atoms contained in R ₁ and R ₂ is 3 to 5.

Examples of the substituent having 1 to 3 carbon atoms represented by R ₁ and R ₂ include an alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group), cycloalkyl group (eg, cyclopropyl group). An alkenyl group (for example, vinyl group, allyl group, etc.), an alkynyl group (for example, ethynyl group, propargyl group, etc.), an aromatic heterocyclic group (for example, triazyl group, triazolyl group, imidazolyl group, oxazolyl group, thiazolyl group, Oxadiazolyl group, thiadiazolyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, etc.), cycloalkoxy group (for example, cyclopropyloxy group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group) Etc.), a cycloalkylthio group (for example, a cyclopropylthio group), Lucoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, propyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, etc.), acyl group (for example, Acetyl group, ethylcarbonyl group, propylcarbonyl group etc.), acyloxy group (eg acetyloxy group, ethylcarbonyloxy group, propylcarbonyloxy group etc.), amide group (eg methylcarbonylamino group, ethylcarbonylamino group, dimethyl) Carbonylamino group, propylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, etc.), ureido group ( For example, methylureido group, ethylureido group, etc.), sulfinyl group (eg, methylsulfinyl group, ethylsulfinyl group, etc.), alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, etc.), amino group (eg, amino group) , Ethylamino group, dimethylamino group and the like), cyano group and the like.

  In addition, these substituents may be further substituted within a range not exceeding 1 to 3 carbon atoms.

Preferably the total number of carbon atoms contained in R ₁ and R ₂ is 3 or 4, more preferably 4.

Furthermore, the substituent represented by R ₁ and R ₂ is preferably an alkyl group, and more preferably R ₁ and R ₂ are ethyl groups.

  In the general formula (1), the substituent represented by R is an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group). , Tridecyl group, tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.) ), Aromatic hydrocarbon group (also called aromatic 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) Group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl Group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrazinyl group, pyrimidinyl group, triazinyl 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, carbazolyl group, azacarbazolyl group (any one or more of the carbon atoms constituting the carbazole ring of the carbazolyl group are nitrogen atoms) Indicates a replacement), quinoxari Group, pyridazinyl 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.), arylthio O 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 group (for example, Acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (For example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethyl group) Carbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octyl Rucarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group) Cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, Ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2 -Pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group) Group), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenyl) Sulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, Ruamino 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.), fluorinated carbonization Hydrogen group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group) , Triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group and the like.

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

  In the general formula (1), n represents 0 or an integer of 1 to 4, more preferably 0 or 1, and still more preferably 0.

  Hereinafter, although the specific example of a metal complex represented by General formula (1) based on this invention is shown, this invention is not limited to these.

  These metal complexes are described in, for example, Organic Letter, Vol. 3, no. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), Organic Letter, Vol. 8, no. 3, pages 415 to 418 (2006), International Application Publication No. 2007/097153, and further, by applying methods such as references described in these documents.

Below, the synthesis example of a typical compound is shown.
<< Synthesis of Exemplified Compound d-2 >>

  Under a nitrogen atmosphere, iridium chloride trihydrate, 8.1 g (0.023 mol) and 100 ml of water were added to a solution of 19 g (0.069 mol) of ligand A in 350 ml of 2-ethoxyethanol. The mixture was refluxed for 5 hours under a nitrogen atmosphere. The reaction solution was cooled, 500 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol and dried to obtain 15.3 g (yield: 85.2%) of Complex A.

Under a nitrogen atmosphere, 15.0 g (0.00966 mol) of complex A and 14.5 g of sodium carbonate were suspended in 350 ml of 2-ethoxyethanol. To this suspension, 3.9 g (0.0390 mol) of acetylacetone was added and refluxed for 2 hours under a nitrogen atmosphere. After cooling the reaction solution, sodium carbonate and inorganic salts were removed by filtration under reduced pressure. 1 L of water was added to the solid obtained after concentration of the solvent under reduced pressure to suspend it, and the solid was collected by filtration. The obtained crystals were further washed with a methanol / water = 1/1 mixed solution, and after drying, 15.0 g (yield 92.1%) of complex B was obtained.

  Complex B, 7.75 g (0.00921 mol) and ligand A, 6.3 g (0.0229 mol) were suspended in 400 ml of glycerol under a nitrogen atmosphere. The reaction was completed at a reaction temperature of 150 to 160 ° C. for 2 hours under a nitrogen atmosphere, and when the disappearance of the complex B was confirmed, the reaction was terminated. The reaction solution was cooled, 500 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol, and dried to obtain a crude product with a yield of 6.7 g (yield 71.7%). This crude product was dissolved in a small amount of methylene chloride and purified by silica gel column chromatography to obtain 6.3 g (yield 67.2%) of exemplary compound d-2.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of 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 form a unit to form a light emitting layer unit.
Further, a non-light emitting intermediate layer may be provided between the light emitting layers, and the intermediate layer may include a charge generation layer. The organic EL element of the present invention preferably emits white light and is preferably a lighting device using these.

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated.

《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 with a single layer or a plurality of layers.

  An electron transport material (including a hole blocking material and an electron injection material) used for the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. Can be selected and used from conventionally known compounds.

  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 azacarbazole derivatives including carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, carboline derivatives, and the like.

  Here, the azacarbazole derivative refers to one in which one or more carbon atoms constituting the carbazole ring are replaced with a nitrogen atom.

  Furthermore, 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.

  It is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

  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 the terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport 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 is made of an electron transport material such as a vacuum deposition method, a wet method (also referred to as a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, or a spraying method. It is preferable to form the film by a coating method, a curtain coating method, an LB method (such as Langmuir-Blodgett method)).

  The method for forming the constituent layers of the organic EL element will be described in detail in the section of the method for manufacturing the organic EL element.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 5 nm-5000 nm, Preferably it is 5 nm-200 nm. This electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also 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.

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

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 5 nm to 100 nm.

  For the production of the light emitting layer, a light emitting dopant or host compound described later is used, for example, a vacuum deposition method, a wet method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, An ink-jet method, a printing method, a spray coating method, a curtain coating method, an LB method (a Langmuir-Blodgett method and the like can be used)) and the like can be formed. When using the compound of this invention for a light emitting layer, producing by a wet process is preferable.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant, phosphorescent dopant group) or fluorescent dopant) compound and a light emitting host compound. Is preferred.

(Luminescent dopant compound)
A light-emitting dopant compound (also referred to as a light-emitting dopant) will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used.

(Phosphorescent dopant (also called phosphorescent dopant))
The phosphorescent dopant according to the present invention will be described.

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

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

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

  Particularly preferred as the light emitting dopant for the organic EL device of the present invention is a metal complex represented by the above general formula (1), and specific examples thereof include compounds d-1 to d-25.

  Moreover, you may use together the compound etc. which are described in the following patent gazettes in the light emitting layer which concerns on this invention.

  For example, International Publication No. 00/70655, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859 A, JP 2002-299060 A, JP 2001-313178 A, JP 2002-302671 A, JP 2001-345183 A, JP 2002-324679 A, International Publication. No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, Japanese Patent Application Laid-Open No. 2002-33858 JP, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002-173684. JP-A-2002-359082, JP-A-2002-175484, JP-A-2002-363552, JP-A-2002-184582, JP-A-2003-7469, JP-A-2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-2335076, JP 2002 No. 2411751, JP 2001-319779 A. JP, 2001-319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572, 2002-203678, etc. It is.

(Fluorescent dopant (also called fluorescent compound))
As fluorescent dopants, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes , Polythiophene dyes, rare earth complex phosphors, and the like, and compounds having a high fluorescence quantum yield such as laser dyes.

  In addition, the light-emitting dopant according to the present invention may be used in combination of a plurality of types of compounds, or may be a combination of phosphorescent dopants having different structures, or a combination of a phosphorescent dopant and a fluorescent dopant.

  Here, although the specific example of the conventionally well-known light emission dopant which may be used in combination with the metal complex represented by General formula (1) based on this invention as a light emission dopant is given, this invention is not limited to these.

(Luminescent host compound (also referred to as luminescent host))
In the present invention, the host compound has a mass ratio of 20% or more among the compounds contained in the light emitting layer, and a phosphorescence quantum yield of phosphorescence emission is 0 at room temperature (25 ° C.). Defined as less than 1 compound. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

There is no restriction | limiting in particular as a light emission host which can be used for this invention, The compound conventionally used with an organic EL element can be used. Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As the known light-emitting host that can be used in the present invention, 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.

  In the present invention, (the compound of the present invention and / or a known light-emitting host) may be used alone or in combination of two or more kinds as the light-emitting host.

  By using a plurality of types of light-emitting hosts, the movement of charges can be adjusted, and the organic EL element can be made highly efficient.

  Moreover, it becomes possible to mix different light emission by using multiple types of well-known compounds used as the said phosphorescence dopant, and, thereby, arbitrary luminescent colors can be obtained.

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

  Specific examples of the known light-emitting host 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 light emission host of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

  Particularly preferred as the light emitting host of the light emitting layer of the organic EL device of the present invention is a compound represented by the following general formula (2).

[Wherein, X represents O or S, Y _{1 to} Y ₃ represent a hydrogen atom, a substituent, or a group represented by the following general formula (A), and at least one of Y _{1 to} Y ₃ is the following: Ar is a carbazolyl group represented by general formula (A) and at least one of the groups represented by general formula (A). ]

[Wherein, L represents a divalent linking group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. n represents 0 or an integer of 1 to 3, and when n is 2 or more, the plurality of L may be the same or different. * Represents a linking site with the general formula (1). Ar represents a group represented by the following general formula (A ′). ]

[Wherein, X ₀ represents N (R), O or S, E _{1 to} E ₈ represent C (R ₁ ) or N, and R and R ₁ represent a hydrogen atom, a substituent, or a linking site with L. Represents. * Represents a linking site with L. ]
In the compound represented by the general formula (2), preferably, Y ₁ to Y at least two of the _three is represented by the general formula (A), more preferably Y ₁ is the formula (A) And Ar in the general formula (A) represents a carbazolyl group which may have a substituent, and more preferably Y ₁ is represented by the general formula (A) and in the general formula (A). Ar represents a carbazolyl group linked to L at the N-position which may have a substituent.

Y ₂ is preferably represented by the general formula (A), and Y ₃ is preferably a hydrogen atom.

  Specific examples of the compound represented by the general formula (2) preferably used as a host compound (also referred to as a light emitting host) of the light emitting layer of the organic EL device of the present invention are shown below, but the present invention is not limited thereto.

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

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic.

  For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

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

  Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, 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 compound preferably 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.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the 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 of the present invention is preferably provided adjacent to the light emitting layer.

  For the hole blocking layer, the carbazole derivatives and azacarbazole derivatives mentioned above as the host compounds (where azacarbazole derivatives are those in which one or more carbon atoms constituting the carbazole ring are replaced by nitrogen atoms) Preferably).

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

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

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

  (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 As a value (eV unit converted value) calculated by performing structure 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 above-mentioned hole transport layer can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron blocking layer according to the present invention is preferably 3 nm to 100 nm, more preferably 3 nm to 30 nm.

<< Injection layer: electron injection layer (cathode buffer layer), hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166), and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by, alkali metal compound buffer layer typified by lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, and aluminum oxide And an oxide buffer layer. The buffer layer (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 anode buffer layer and the cathode buffer layer can be used in combination with other materials. For example, the materials can be mixed in the hole transport layer or the electron transport layer.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

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

  When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, 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.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.

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

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

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

  Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

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

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

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

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

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

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

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

<< 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.

  In the phosphorescent organic EL device of the present invention, at least the cathode and the electron transport layer adjacent to the cathode are applied and formed by a wet method.

  Wet methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but precise thin films can be formed. In view of high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, or a spray coating method is preferable. Different film forming methods may be applied for each layer.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used.

  Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, 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 nm to 200 nm, and a desired organic EL device is 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.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 V to 40 V with the anode as + and the cathode as-. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

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

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

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.

  Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has a oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² · 24 h · MPa) or less, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

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

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

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

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.

  Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

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

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as 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, etc.), among others, anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or 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, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

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

  As a method 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 of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (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) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

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

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the 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. Further, it is preferably 1.35 or less.

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

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the light emitting surface By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.

  As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

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

<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 device may be patterned. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (Konica Minolta Sensing Co., Ltd.) is applied to the CIE chromaticity coordinates.

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

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

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. 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 vapor deposition, casting, spin coating, ink jet, printing, 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 sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. The present invention is not limited to these examples.

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

  FIG. 1 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

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

  FIG. 2 is a schematic diagram of the display unit A.

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

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

  The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

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

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element.

  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, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied 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 light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning 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 as shown in FIG. 3 and FIG. Can be formed.

  FIG. 3 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  4 shows a cross-sectional view of the lighting device. In FIG. 6, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

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

  Moreover, the structure of the compound used for an Example is shown below.

Reference example 1
<< Production of Organic EL Element 1-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under conditions of 30 seconds and then dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.

This substrate was transferred to a nitrogen atmosphere, and on the hole transport layer, a solution of 3 mg of the hole transport material 1 and 40 mg of the hole transport material 2 dissolved in 10 ml of toluene was added at 1500 rpm for 30 seconds. A thin film was formed by spin coating on the transport layer. Further, ultraviolet light was irradiated for 180 seconds to carry out photopolymerization and crosslinking, thereby forming a second hole transport layer having a thickness of about 20 nm.
A thin film was formed on the second hole transport layer by spin coating using a solution of 100 mg Host-14 and 10 mg d-2 dissolved in 10 ml of toluene at 600 rpm for 30 seconds. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 70 nm.

  Next, a thin film was formed on the light emitting layer by a spin coating method using a solution of 50 mg of ET-40 dissolved in 10 ml of hexafluoroisopropanol (HFIP) at 1000 rpm for 30 seconds. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 30 nm.

Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, lithium fluoride was deposited to 0.4 nm and aluminum was deposited to 110 nm as a cathode buffer layer. A cathode was formed, and an organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-5 >>
In the production of the organic EL element 1-1, organic EL elements 1-2 to 1-5 were produced in the same manner except that Host-14, d-2 and ET-40 were changed to the compounds shown in Table 1. .

<< Evaluation of Organic EL Elements 1-1 to 1-5 >>
When evaluating the obtained organic EL elements 1-1 to 1-5, the specific light emitting surface of each organic EL element after production is covered with a glass cover, and the glass cover and the glass substrate on which the organic EL element is produced are prepared. An epoxy-based photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the glass cover side that comes into contact with the transparent support substrate so as to overlap the cathode side, and the glass substrate side. Then, it was cured by irradiating with UV light and sealed, and the lighting device as shown in FIGS. 3 and 4 was formed and evaluated.

  Subsequently, the following evaluation was performed.

(External quantum 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. The external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 as 100.

(Luminescent life)
The organic EL device continuously emitted light 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 organic EL element 1-1 to 100.

(Voltage increase rate)
When driving at a constant current of 6 mA / cm ² , the initial voltage and the voltage after 150 hours were measured. The relative value of the voltage after 100 hours with respect to the initial voltage was defined as the voltage increase rate.

  The obtained results are shown in Table 1.

From Table 1, it is clear that the organic EL element of the reference example is superior in all characteristics of the external extraction quantum efficiency, the light emission lifetime, and the voltage increase rate as compared with the comparative element.

Example 2
<< Preparation of Organic EL Element 2-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under conditions of 30 seconds and then dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.

  The substrate was transferred to a nitrogen atmosphere, and a solution prepared by dissolving 50 mg of the hole transport material 2 in 10 ml of toluene was spin-coated on the hole transport layer at 1500 rpm for 30 seconds on the hole transport layer. Formed. Further, ultraviolet light was irradiated for 180 seconds to carry out photopolymerization and crosslinking, thereby forming a second hole transport layer having a thickness of about 20 nm.

  On this second hole transport layer, a thin film was formed by spin coating using a solution of 100 mg Host-25 and 13 mg of comparative dopant 2 dissolved in 10 ml of toluene at 200 rpm for 30 seconds. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 35 nm.

  Next, a thin film was formed on this light emitting layer by spin coating using a solution obtained by dissolving 50 mg of ET-10 in 10 ml of hexafluoroisopropanol (HFIP) at 2000 rpm for 30 seconds. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 20 nm.

Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, potassium fluoride was deposited at 0.4 nm as a cathode buffer layer, and aluminum was deposited at 110 nm as a cathode. Thus, a cathode was formed, and an organic EL element 2-1 was produced.

<< Production of Organic EL Element 2-2 >>
In the production of the organic EL element 2-1, the organic EL element 2-2 was produced in the same manner except that the rotation speed of the spin coat at the time of forming the light emitting layer was changed to a light emitting layer having a film thickness of about 60 nm.

<< Production of Organic EL Elements 2-3, 2-5, and 2-7 >>
In the production of the organic EL element 2-1, the organic EL elements 2-3 and 2-5 having a light-emitting layer thickness of about 35 nm and the organic EL element were similarly obtained except that the comparative dopant 2 was changed to the dopant shown in Table 2. 2-7 was produced.

<< Production of Organic EL Elements 2-4, 2-6, and 2-8 >>
In the production of the organic EL element 2-2, except that the comparative dopant 2 was changed to the dopant shown in Table 2, the organic EL elements 2-4 and 2-6 having an emission layer thickness of about 60 nm and the organic EL element were similarly obtained. 2-8 was produced.

<< Evaluation of Organic EL Elements 2-1 to 2-8 >>
When evaluating the obtained organic EL elements 2-1 to 2-8, they were sealed in the same manner as the organic EL elements 1-1 to 1-5 of Reference Example 1 , and illumination as shown in FIGS. A device was formed and evaluated.

  Subsequently, the following evaluation was performed.

(Driving rate of drive voltage)
The voltage when each organic EL element was driven at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² was measured. Next, for each of the set of organic EL elements 2-1 and 2-2, the set of 2-3 and 2-4, the set of 2-5 and 2-6, and the set of 2-7 and 2-8, the light emitting layer The increase rate of the driving voltage when the film thickness was increased was determined according to the following equation.

Increase rate of drive voltage between each set element = drive voltage of an element having a film thickness of about 60 nm / drive voltage of an element having a film thickness of 35 nm × 100
The obtained evaluation results are shown in Table 2.

  From Table 2, when the compound represented by the general formula (1) according to the present invention is used as a light emitting dopant, even if the film thickness of the light emitting layer is changed, the organic EL element of the present invention is uniformly dispersed. It is apparent that the driving voltage does not increase greatly even when the thickness of the light emitting layer is increased compared to the comparative organic EL element.

  From the above, it was found that the organic EL element of the present invention can provide a thick element that can be driven at a low voltage.

Example 3
<< Production of Organic EL Element 3-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under conditions of 30 seconds and then dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.
The substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was spin-coated on the hole transport layer at 2500 rpm for 30 seconds to form a thin film. Formed. It vacuum-dried at 60 degreeC for 1 hour, and formed the 2nd positive hole transport layer.

  On this second hole transport layer, 100 mg of Host-36 and 12 mg of comparative dopant 4 were dissolved in 10 ml of butyl acetate and stored at room temperature (23-25 ° C.) for 24 hours. A thin film was formed by spin coating under the condition of 30 seconds. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 50 nm.

  Next, a thin film was formed on the light emitting layer by spin coating using a solution of 50 mg of ET-13 dissolved in 10 ml of hexafluoroisopropanol (HFIP) at 1500 rpm for 30 seconds. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 20 nm.

Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, lithium fluoride was deposited at 0.4 nm as a cathode buffer layer, and aluminum was deposited at 110 nm as a cathode. Thus, a cathode was formed, and an organic EL element 3-1 was produced.

<< Production of Organic EL Elements 3-2 to 3-5 >>
In the production of the organic EL element 3-1 , organic EL elements 3-2 to 3-5 were produced in the same manner except that the host 36 and the comparative dopant 4 were changed to the compounds shown in Table 3.

<< Evaluation of Organic EL Elements 3-1 to 3-5 >>
When evaluating the obtained organic EL elements 3-1 to 3-5, the organic EL elements 1-1 to 1-5 of Reference Example 1 were sealed in the same manner as shown in FIGS. 3 and 4. A device was formed and evaluated.

  Subsequently, the following evaluation was performed.

(Power efficiency)
Using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.), the front luminance and luminance angle dependency of the central portion of each organic EL element were measured, and the power efficiency at a front luminance of 1000 cd / m ² was obtained. The power efficiency is expressed as a relative value that sets the power efficiency of the organic EL element 3-1 to 100.

(Luminescent life)
The light emission lifetime was evaluated in the same manner as in Reference Example 1 . In addition, it represented with the relative value which sets the light emission lifetime of the organic EL element 3-1 to 100.

(Light emission unevenness)
For the organic EL element, the emission luminance when a constant current of ^2.5 mA / cm ² was applied at room temperature in a dry nitrogen gas atmosphere was measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing).

  Ten arbitrary points on the light emitting surface were measured, and from the measured values at this time, light emission unevenness = in-plane minimum luminance / maximum luminance was calculated, and the three-level rank evaluation was performed as follows.

○: Light emission unevenness of 0.96 or more Δ: Light emission unevenness of 0.86 or more and less than 0.96 ×: Light emission unevenness of less than 0.86 Table 3 shows the results obtained.

  From Table 3, it is clear that the organic EL device of the present invention is superior in all the characteristics of power efficiency, light emission lifetime, and light emission unevenness as compared with the comparative device.

Example 4
<< Production of organic EL full-color display device >>
FIG. 5 shows a schematic configuration diagram of an organic EL full-color display device. After patterning at a pitch of 100 μm on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) having a 100 nm thick ITO transparent electrode (202) formed on a glass substrate 201 as an anode, non-between the ITO transparent electrodes on this glass substrate. A photosensitive polyimide partition 203 (width 20 μm, thickness 2.0 μm) was formed by photolithography.

  A hole injection layer composition having the following composition is ejected and injected between polyimide partition walls on the ITO electrode using an inkjet head (manufactured by Epson Corporation; MJ800C), irradiated with ultraviolet light for 200 seconds, and dried at 60 ° C. for 10 minutes. A hole injection layer 204 having a thickness of 40 nm was produced by the treatment.

  The following blue light-emitting layer composition, green light-emitting layer composition, and red light-emitting layer composition are similarly discharged and injected onto the hole injection layer using an inkjet head and dried at 60 ° C. for 10 minutes. Each light emitting layer (205B, 205G, 205R) was formed.

  Next, ET-41 was vapor-deposited to a thickness of 20 nm so as to cover the light-emitting layer, and lithium fluoride was 0.6 nm, and Al was vapor-deposited as a cathode at a thickness of 130 nm to produce an organic EL device.

  It was found that the produced organic EL element showed blue, green, and red light emission by applying a voltage to each electrode, and could be used as a full-color display device.

(Hole injection layer composition)
Hole transport material 3 20 parts by mass Cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass (blue light emitting layer composition)
Compound Example 54 0.7 parts by mass d-2 0.04 parts by mass Cyclohexylbenzene 50 parts by mass Isopropyl biphenyl 50 parts by mass (green light emitting layer composition)
Compound Example 54 0.7 parts by mass
d-1 0.04 parts by mass Cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass (red light emitting layer composition)
Compound Example 54 0.7 parts by mass
d-10 0.04 parts by mass Cyclohexylbenzene 50 parts by mass Isopropyl biphenyl 50 parts by mass Example 5
<< Preparation of white organic EL element 5 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

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

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was spin-coated on the hole transport layer at 2500 rpm for 30 seconds, and a thin film was formed. Formed. It vacuum-dried at 60 degreeC for 1 hour, and formed the 2nd positive hole transport layer.

Next, a film obtained by dissolving Compound Example 1 (100 mg), d-6 (0.5 mg), and d-2 (16 mg) in 10 ml of butyl acetate was formed by spin coating at 1000 rpm for 30 seconds. did. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer.

  Further, using a solution obtained by dissolving ET-11 (25 mg) in 5 ml of hexafluoroisopropanol (HFIP), a film was formed by spin coating at 2000 rpm for 30 seconds, and then vacuum-dried at 60 ° C. for 1 hour. It was set as the electron carrying layer.

Subsequently, this substrate was fixed to a substrate holder of a vacuum vapor deposition apparatus, 200 mg of ET-7 was placed in a molybdenum resistance heating boat, and was attached to the vacuum vapor deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, heating by energizing the heating boat containing ET-7, vapor deposition on the electron transport layer at a deposition rate of 0.1 nm / second, A second electron transport layer having a thickness of 20 nm was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 9-1 was produced.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent 201 Glass substrate 202 ITO transparent electrode 203 Partition 204 Hole injection layer 205B, 205G, 205R Light emitting layer

Claims (10)

An organic electroluminescence element material, which is a metal complex represented by the following general formula (1).
[Wherein, R ₁ and R ₂ each represent a substituent having 1 to 3 carbon atoms, and the number of carbon atoms in R ₁ and R ₂ is different from each other. The total number of carbon atoms contained in R ₁ and R ₂ is 3-5. R represents a substituent, and n represents 0 or an integer of 1 to 4. ] _2. The organic electroluminescent element material according to claim 1, wherein the total number of carbon atoms contained in R ₁ and R ₂ of the general formula (1) is 3 or 4. 3. _2. The organic electroluminescent element material according to claim 1, wherein the total number of carbon atoms contained in R ₁ and R ₂ of the general formula (1) is 4. 3. The organic electroluminescence element material according to claim 1, wherein the substituent represented by R ₁ and R ₂ in the general formula (1) is an alkyl group. The organic electroluminescence element materials according to any one of claims 1 to 4, n is characterized in that it is a 0 in the general formula (1). In an organic electroluminescence device in which a plurality of organic compound layers including a light emitting layer are sandwiched between an anode and a cathode,
At least 1 layer of this organic compound layer contains the organic electroluminescent element material of any one of Claims 1-5 , The organic electroluminescent element characterized by the above-mentioned. The organic electroluminescence element according to claim 6 , wherein the organic compound layer is manufactured through a process in which the organic compound layer is formed and formed by a wet process. The organic electroluminescence device according to claim 6, which emits white light. The illuminating device provided with the organic electroluminescent element of any one of Claims 6-8 . A display device comprising the organic electroluminescence element according to claim 6 .