JP5499972B2 - ORGANIC ELECTROLUMINESCENT ELEMENT MATERIAL, ORGANIC ELECTROLUMINESCENT ELEMENT, DISPLAY DEVICE AND LIGHTING DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a novel organic electroluminescent element material, and an organic electroluminescent element, a display element, and a lighting device using the same.

  Conventionally, there is an electroluminescence display (hereinafter referred to as ELD) as a light-emitting electronic display device. Examples of the 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 high voltage is required to drive the light emitting elements. An organic electroluminescence device has a light-emitting layer containing a compound that emits light, and a structure in which a plurality of organic compound layers are sandwiched between a cathode and an anode as necessary. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when excitons (excitons) are generated by bonding, and the excitons are deactivated. Since it is capable of emitting light by voltage, and is self-luminous, it has a wide viewing angle, high visibility, and since it is a thin-film complete element solid, it has been attracting attention from the viewpoint of space saving and portability.

  However, in the organic electroluminescence device for practical use in the future, development of an organic electroluminescence device that emits light with higher efficiency and longer life is desired.

  In addition, it has become clear that not only fluorescent materials but also phosphorescent materials can be used as light-emitting materials for organic electroluminescence elements, and research and development has been conducted earnestly. The generation ratio of singlet excitons and triplet excitons is 1: 3. In the case of fluorescent materials, only excited singlets can be used, whereas in the case of phosphorescent materials, excitation is performed in addition to excited singlets. Since triplet can also be used, the upper limit of internal quantum efficiency can be made 100%. For this reason, when a phosphorescent material is used compared to a fluorescent material, the luminous efficiency is four times in principle, and there is a possibility of obtaining almost the same performance as a cold cathode tube. ing.

  On the other hand, as a means of improving the lifetime of organic electroluminescence devices, research focused on the structure of the compound contained has resulted in the discovery of some materials that could withstand practical use. Yes. However, introduction of substituents and small changes in the structure such as the introduction position have a great influence on various characteristics such as lifetime and light emission characteristics, and are difficult to predict.

  Structures similar to the compounds according to the invention have already been disclosed (see, for example, Patent Documents 1 to 4 and Non-Patent Document 1). However, since it is difficult to predict the structure and performance of the compound as described above, it was impossible to predict that the characteristics of the compound according to the present invention are very excellent.

Special table 2008-545630 gazette WO2009 / 136595 WO2009 / 148062 JP 2010-45281 A

The Journal of Organic Chemistry. 72, 5119-5128 (2007)

  An object of the present invention is to provide an organic electroluminescence element having a long life and a stable driving voltage, and a display device and a lighting device using the same.

The above object of the present invention can be achieved by the following configurations 1 to 8 .
Specifically, according to the present invention, the constitution 1 is represented by any one of the general formulas (1) to (3), and in the general formulas (1) to (3), X ₂ is O, S, S = O. , N—R ₁₁ , and in general formula (5), Ar ₁ and Ar ₂ are not bonded to each other to form a ring, thereby providing an organic electroluminescence device material.

  1. An organic electroluminescent element material represented by any one of the following general formulas (1) to (4).

(In the above general formulas (1) to (4), X ₁ represents O, S, S═O, N—R ₁₁ , and X ₂ represents O, S, S═O, N—R ₁₁ , C (R ₁₂ ) R ₁₃ may be the same as or different from each other, R ₁₁ represents an aromatic hydrocarbon ring group, R ₁₂ and R ₁₃ represent a hydrogen atom or a substituent, and may be the same It may be different.

R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a substituent, and at least one of R ₁ , R ₂ and R ₄ has a structure represented by the above general formula (5).

Y, Z ₁ , Z ₂ , Z ₃ and Z ₄ each represent a carbon atom or a nitrogen atom, and together with other constituent atoms of the ring form a 6-membered aromatic ring.

  Rb and Rc represent an arbitrary substituent, o is an integer of 0 to 2, and p is an integer of 0 to 4.

In the general formula (5), Ar ₁ and Ar _{2 each} represent an aromatic ring, which may have a substituent at an arbitrary position, but is further bonded to each other to form a nitrogen atom to which Ar ₁ and Ar ₂ are bonded. It does not form a five-membered ring. )
2. In the above general formulas (1) (4), an organic electroluminescence element material of the 1, wherein the one of X ₁ and X ₂ is an oxygen atom.

3. In the above general formulas (1) to (4), any one of X ₁ and X ₂ is N—R ₁₁ (R ₁₁ represents an aromatic hydrocarbon ring group), 2. The material for an organic electroluminescence element according to 2.

  4). In said general formula (1) to (4), at least 1 substituent is a carbazolyl group or its derivative (s), The organic electroluminescent element material as described in any one of said 1-3 characterized by the above-mentioned.

  5. It has a layer containing the organic electroluminescent element material as described in any one of said 1-4, The organic electroluminescent element characterized by the above-mentioned.

  6). 6. The organic electroluminescence device as described in 5 above, wherein the layer containing the material for an organic electroluminescence device is formed by a wet method (wet process).

  7). A display device comprising the organic electroluminescence element as described in 5 or 6 above.

  8). An illumination device comprising the organic electroluminescence element as described in 5 or 6 above.

  According to the present invention, an organic electroluminescence element having a long life and a stable driving voltage, and a display device and a lighting device using the same can be provided.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

  In view of the above problems, the present inventors have focused on polycyclic compounds during intensive studies and have achieved the present invention by overcoming the problems.

Although details are omitted, past studies have shown that polycyclic compounds have excellent stability as compounds when made into devices, but compatibility with other materials is an issue for stability as devices. Also, it has been clarified that when the phosphorescence wavelength is long and the blue phosphorescence emitting dopant is used, the efficiency and the lifetime are practically insufficient. As a result of further intensive studies in view of these problems, the stability of the device is further improved by introducing a substituent having a specific structure represented by the general formula (5) into a specific site of the polycyclic compound. In addition, the present inventors have found that a stable organic electroluminescence device can be provided that has good compatibility with other organic electroluminescence device materials used in combination. Moreover, it discovered that an organic electroluminescent element which shows favorable element performance can be provided also when a blue light emission phosphorescent dopant is used. The reason for this is that when the substituent represented by the general formula (5) is introduced into a specific site of the polycyclic compound, the volume and angle occupied by Ar ₁ and Ar ₂ and the nitrogen atom are polycyclic compounds. Phosphorescence emission of polycyclic compounds by forming an appropriate twisted structure with respect to the mother nucleus, having a slightly rounded asymmetric shape as a whole molecule, and introducing a substituent at a specific site This is because it is possible to maintain the wavelength. Due to such factors, when the organic electroluminescent element organic layer of the present invention is used to form the organic layer of the organic electroluminescent element, the film quality is improved, the compatibility with other materials is improved, and the blue phosphorescent dopant is further improved. It is speculated that polycyclic compounds could be applied to the above, but the details are currently under investigation and are not clear.

  The material for an organic electroluminescence element of the present invention has a structure represented by any one of the general formulas (1) to (4).

In the above general formulas (1) to (4), X ₁ represents O, S, S═O or N—R ₁₁ , preferably O, S or N—R ₁₁ , more preferably O or N a -R _11, and most preferably even at O.

X ₂ represents O, S, S═O, N—R ₁₁ or C (R ₁₂ ) R ₁₃ , preferably O, S, N—R ₁₁ , C (R ₁₂ ) R ₁₃ , more preferably Is O, S, N—R ₁₁ , more preferably O, N—R ₁₁ , and most preferably O.

R ₁₁ is also referred to as an aromatic hydrocarbon ring group (aromatic carbocyclic group, aryl group, etc., for example, phenyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group. Which may further have a substituent, such as an alkyl group, a cycloalkyl group, an alkynyl group, an aromatic hydrocarbon ring group (aromatic carbocyclic group). Also referred to as an aryl group, for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, Biphenylyl group, etc.), aromatic heterocyclic groups (eg, pyridyl group, pyrimidyl group, furyl group) , Pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group)), 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, carbolinyl group A diazacarbolyl group (wherein one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), a quinoxalinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, etc.), a heterocyclic group (for example, a pyrrolidyl group, an imidazolidyl group) Group, morpho Nyl group, oxazolidyl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, Carbamoyl, ureido, sulfinyl, alkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, amino, halogen, fluorinated hydrocarbon, cyano, nitro, hydroxy, mercapto, silyl, phosphono Preferred examples include an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a phosphono group, and these substituents may be the same or different. Substituent is further substituted by the above substituent Reserve may be bonded to each other to form a ring. R ₁₁ is preferably a phenyl group.

R ₁₂ and R ₁₃ each represent a hydrogen atom or a substituent, and examples of the substituent include the substituents indicated by the substituent that R ₁₁ may have.

R ₁ , R ₂ , R _3, and R ₄ represent a hydrogen atom or a substituent, and examples of the substituent include the substituents indicated by the substituent that R ₁₁ may have, more preferably aromatic. It is a hydrocarbon group or an aromatic heterocyclic group, and these may be the same or different.

In addition, it is a feature common to the present invention that at least one of R ₁ , R ₂ and R ₄ is a structure represented by the general formula (5). At this time, any of R ₁ , R ₂ and R ₄ is preferably used as a substitution position of the structure represented by the general formula (5), but preferably present as a substituent of any of R ₁ and R ₄ Most preferably, it is a substituent of R ₁ , and in this case, the above-mentioned effect is most greatly obtained.

Y and Z ₁ , Z ₂ , Z ₃ and Z ₄ represent a carbon atom or a nitrogen atom, and together with other constituent atoms of the ring form a 6-membered aromatic ring. When any of Z ₁ , Z ₂ , Z ₃ and Z ₄ represents a nitrogen atom, it is more preferable that either Z ₁ or Z ₃ is a nitrogen atom.

  Rb and Rc each represents a substituent, and examples of the substituent include the same substituents as those described above, preferably an aromatic hydrocarbon ring or an aromatic heterocyclic group, and at least one substituent is an aromatic heterocyclic group. It is preferably a cyclic group, and more preferably an aromatic heterocyclic group, a quinolyl group, a benzoimidazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a carbolinyl group, a diazacarbazolyl group, Preferred are a carbazolyl group and derivatives thereof (here, carbolinyl group and diazacarbazolyl group are shown), and more preferred are a dibenzofuranyl group and a carbazolyl group. The carbazolyl group and derivatives thereof can be bonded by a carbon-carbon bond or a nitrogen-carbon bond, and more preferably a substituent bonded by a carbon-carbon bond.

  o represents an integer of 0 to 2, more preferably 0. p represents an integer of 0 to 4, more preferably 1 or 2, and still more preferably 1.

In the general formula (5), Ar ₁ and Ar ₂ are aromatic rings (aromatic hydrocarbon rings (eg, phenyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group). And biphenylyl groups) and aromatic heterocycles (eg, pyridyl group, pyrimidyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group, etc.)), substituted at any position Although it may have a group, the substituents on Ar ₁ and Ar ₂ are not further bonded to each other to form a 5-membered ring containing a nitrogen atom to which Ar ₁ and Ar ₂ are bonded.

  In addition, the general formulas (1) to (4) can be a multimer such as a dimer or a trimer through an n-valent linking group L. Examples of such a linking group L include a group formed by removing n-1 hydrogen atoms from the above substituent. Preferred examples of the substituent used as the linking group L include an amino group, an aromatic hydrocarbon group, an aromatic heterocyclic group, and a phosphono group. n represents an integer, preferably an integer of 2 to 4, and when n is 2, the linking group L may be a single bond.

  Of the above general formulas (1) to (4), it is more preferably represented by the general formula (1), (2), (3), and more preferably in the general formula (1) or (2). It is more preferable that the structure represented by the general formula (1) is taken.

  Hereinafter, although the compound concerning this invention is mentioned, it is not limited to these. In addition, the compound based on this invention is The Journal of Organic Chemistry. 72, 5119-5128 (2007), Japanese translations of PCT publication No. 2008-545630, and WO2009 / 148062.

  The compound according to the present invention may be contained in any organic layer in the organic electroluminescence device, but is preferably used as a host compound, a hole transport material, or an electron transport material, more preferably a host. It is used as a material and a hole transport material. At this time, each organic layer may be composed of the compound according to the present invention alone, or may be used by mixing with other materials.

≪Component layer of organic EL element≫
The constituent layers of the organic EL element of the present invention will be described. In the present invention, preferred specific examples of the layer structure of the organic EL element are shown below, but the present invention is not limited thereto.

(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 In the organic EL device of the present invention, the blue light emitting layer preferably has a light emission maximum wavelength of 430 to 480 nm, and the green light emitting layer has a light emission maximum wavelength of 510 to 550 nm, The red light emitting layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 600 to 640 nm, and is preferably a display element using these. Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

≪Luminescent 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 also be the interface between the light emitting layer and the adjacent layer.

  There is no particular limitation on the total thickness of the light emitting layer, but from the viewpoint of preventing the application of unnecessary high voltage during film homogeneity and light emission, and improving the stability of the light emission color with respect to the drive current It is preferable to adjust to the range of 5 micrometers, More preferably, it adjusts to the range of 2-200 nm, Especially preferably, it is the range of 10-40 nm.

  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 group) or fluorescent dopant) compound and a host compound.

(Luminescent dopant compound)
The luminescent dopant compound will be described.
As the luminescent dopant compound, a fluorescent dopant compound or a phosphorescent dopant compound can be used.

(Phosphorescent dopant compound)
The phosphorescent dopant compound 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 a phosphorescence quantum yield of 25 ° C. The phosphorescence quantum yield is preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectra II, page 398 (1992 version, 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 compound according to the present invention can be measured in any solvent if the phosphorescence yield of 0.01 or more is achieved. good.

  There are two types of emission principles of the phosphorescent dopant compound. One is the recombination of carriers on the host compound to which carriers are transported, and the excited state of the luminescent host compound is generated. Energy transfer type that obtains light emission from phosphorescent dopant by moving to optical dopant. The other is a carrier trap type in which the phosphorescent dopant compound itself becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound is obtained. It is a condition for obtaining favorable light emission that the excited state energy of the phosphorescent dopant compound is lower than the excited state energy of the host compound.

  Although the specific example of the well-known compound used as a phosphorescence dopant below is shown, this invention is not limited to these. These compounds are described in, for example, Inorg. Chem. 40, pages 1704 to 1711, and the like.

  Although the example of a light emission dopant is given to the following, it is not limited to these.

(Fluorescent dopant compound)
As fluorescent dopant compounds, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squarylium dyes, oxobenzoanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, Examples include stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

(Luminescent host compound (also referred to as luminescent host))
As the light-emitting host compound used in the light-emitting layer and the light-emitting unit of the organic EL device of the present invention, among the compounds contained in the light-emitting layer, the mass ratio in the layer is 20% or more and room temperature (25 ° C) is defined as a compound having a phosphorescence quantum yield of less than 0.1, preferably a phosphorescence quantum yield of less than 0.01. Moreover, it is preferable that the mass ratio in a layer is 20% or more among the compounds contained in a light emitting layer.

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

  The light emitting host used in the present invention may be a low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). Alternatively, one or a plurality of such compounds may be used.

  Known light-emitting host compounds typically include those having a basic skeleton such as carbazole derivatives, triarylamine derivatives, aromatic derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, carboline derivatives, And diazacarbazole derivatives.

  A known host compound that may be used in combination is preferably a compound that has a hole transporting ability and an electron transporting ability, prevents a long wavelength of light emission, and has a high Tg (glass transition temperature).

  Specific examples of known host compounds include, but are not limited to, 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.

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

≪Injection layer: electron injection layer, hole transport layer≫
The injection layer is provided as necessary, and has an electron injection layer and a hole injection layer, and is present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above. May be.

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

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45579, JP-A-9-260062, JP-A-8-288069, and the like, and representative examples thereof include copper phthalocyanine. Phthalocyanine buffer layers, oxide buffer layers typified by vanadium oxide, amorphous carbon buffer layers, polymer buffer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene, and the like.

  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 or aluminum Metal buffer layer represented by lithium fluoride, alkali metal compound buffer layer represented by lithium fluoride, alkaline earth metal compound buffer layer represented by magnesium fluoride, oxide buffer layer represented by aluminum oxide, etc. It is done.

  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.

≪Blocking layer: hole blocking layer, electron blocking layer≫
As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, described in JP-A Nos. 11-204158 and 11-204359, and “Organic EL devices and the forefront of industrialization (November 30, 1998, issued by NTS Corporation)” on page 237, etc. There is a hole blocking layer (hole blocking layer).

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

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

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

  Moreover, when it has several light emitting layers from which luminescent color differs, it is preferable that the light emitting layer with the shortest light emission maximum wavelength is the closest to an anode among all the light emitting layers. In such a case, it is preferable to additionally provide a hole blocking layer between the shortest wave light emitting layer and the light emitting layer next to the anode next to the light emitting layer. Further, it is preferable that 50% by mass or more of the compound of the hole blocking layer provided at the position is 0.3 eV or more larger than the ionization potential of the host compound of the shortest wave emitting layer.

  The ionization potential is defined as the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained 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 The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) It can also be determined by a method of direct measurement by photoelectron spectroscopy. Yes. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material having a function of transporting holes and a very small ability to transport electrons, and transporting electrons while transporting holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  The film thickness of the hole blocking layer and the electron blocking layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

≪Hole transport layer≫
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, the hole transport layer and the electron blocking layer can be regarded as being included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers and conductive polymers (polymers and 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. In addition, the organic EL device material of the present invention can be preferably used in the same manner.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4 '. -Diamine (TPD), 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ', 4 "-tris [N- (3-methylphenyl) ) -N-phenylamino] triphenylamine (MTDATA).

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or a polymer main chain can also be used. Inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole transport material. JP-A-11-251067, J. Org. Huang et al. A p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used.

  The hole transport layer is formed by thinning the hole transport material as described above by, for example, 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. be able to. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-5 micrometers, Preferably it is 5-200 nm. Further, the hole transport material may have a single layer structure composed of a plurality of types of materials.

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

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

  An electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the cathode side with respect to the light emitting layer may have a function of transmitting electrons injected from the cathode to the light emitting layer. As the material, any of conventionally known compounds can be selected and used. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthra Examples include quinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, phthalocyanine materials and derivatives thereof can also be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and hole transport layer Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The 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.

"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, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern may be formed through a photolithography method or a mask. 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 in the range of 10 to 1000 nm, preferably in the range of 10 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 the 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 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 with a film thickness of 1-20 nm on a cathode, a 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》
The 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 is not particularly limited in the type of glass, plastic, etc., and 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, cellulose esters (cellulose acetate propionate (CAP), cellulose acetate phthalate (TAC), and cellulose nitrate. Etc.) or derivatives thereof, polyvinylidene chloride, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyether Imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic Alternatively polyarylates, and cycloolefin resins such as ARTON (manufactured by JSR) or APEL (manufactured by Mitsui Chemicals).

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. Preferably, the film is a high barrier film having a permeability of 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻³ g / (m ² · 24 h) or less, and moreover, a water vapor transmission rate. The degree is more preferably 10 ⁻⁵ g / (m ² · 24 h) or less.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of moisture or oxygen that causes deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is preferably used. it can. 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, or the like can be used, and an atmospheric pressure plasma polymerization method 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 quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, 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 with a phosphor may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means 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 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. Further, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. The water permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the method is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  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, when using a thermosetting adhesive, since an organic EL element may deteriorate with heat processing, what can be adhesively cured 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, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, etc.), metal halides. Perchloric acids and the like, and anhydrous salts are preferably used.

《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 sealing is performed by the sealing film, it is preferable to provide a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, etc. used for the sealing can be used. It is preferable to use a film.

《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 or second-order diffraction, and light generated from the light-emitting layer. The light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating in any layer or medium (in the transparent substrate or transparent electrode). It is intended to be taken 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 can be processed to provide, for example, a microlens array-like structure on the light extraction side of the substrate or combined with a so-called condensing sheet, for example, in a specific direction, for example, the device light emitting surface On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

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

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

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

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

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

  Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, is formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, in the present invention, a wet process is preferable, and film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is particularly preferable.

  Examples of the liquid medium for dissolving or dispersing the organic EL device material of 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 by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 50 to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode 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 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<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 the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the 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.

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

  In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented. Moreover, the compound used in an Example and a comparative compound are shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
Each organic layer was laminated | stacked on the glass substrate with ITO patterned as an anode using the commercially available vacuum evaporation apparatus with the vacuum degree of 4.0 * 10 <^-4> Pa. First, α-NPD is formed to a thickness of 20 nm as a hole transport / injection layer, and further, as a light emitting layer, compound (2) and D-2 (blue phosphorescent dopant) have a D-2 concentration of 6%. A film having a thickness of 40 nm was formed. Further, Alq ₃ was formed to a thickness of 40 nm as an electron transport layer. Subsequently, lithium fluoride was formed to a thickness of 0.5 nm as an electron injection layer, and then 150 nm of aluminum was formed as a cathode to prepare an organic EL element 1-1.

<< Production of Organic EL Elements 1-2 to 1-18 >>
Organic EL elements 1-2 to 1-18 were prepared in the same manner as in the preparation of organic EL element 1-1 except that compound (2) was changed to the compounds shown in Table 1. Each organic EL element after production was evaluated by covering the non-light emitting surface with a glass case and sealing with an epoxy adhesive.

<< Evaluation of Organic EL Elements 1-1 to 1-18 >>
The efficiency and stability of the organic EL elements 1-1 to 1-18 were evaluated by the following methods. The results are shown in Table 1.

(efficiency)
The produced organic EL elements 1-1 to 1-18 were measured for external extraction quantum efficiency when a constant current of ^2.5 mA / cm ² was applied. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used. The efficiency values in Table 1 are expressed as relative values when the measured value of the organic EL element 1-1 is 100.

(Stability)
About the produced organic EL elements 1-1 to 1-18, a constant current drive was performed with a current that gave an initial luminance of 10000 cd / m ² , and a time that was ½ (5000 cd / m ² ) of the initial luminance was measured. A measure of stability. As in the evaluation of efficiency, the stability value is shown in Table 1 as a relative value when the measured value of the organic EL element 1-1 is 100.

  From the above, it has been clarified that by using the organic EL element material of the present invention, an organic EL element having excellent efficiency and stability can be provided.

(Example 2)
<< Production of Organic EL Elements 2-1 and 2-2 >>
In preparation of the organic EL element 1-1, except that α-NPD was formed to a thickness of 10 nm as a first hole transport / injection layer and a compound (93) was formed to a thickness of 15 nm as a second hole transport / injection layer. Similarly, the organic EL element 2-1 was produced. Similarly, a comparative organic EL device 2-2 was prepared in the same manner as the organic EL device 1-1 except that the comparative compound (M-4) was used as the second hole transport / injection layer. When the produced organic EL elements 2-1 and 2-2 were evaluated in the same manner as in Example 1, the efficiency of the organic EL element 2-1 was 114 and the stability was 127. In addition, the efficiency of the comparative organic EL element 2-2 was 47, and the stability was 51. The efficiency and stability are expressed as relative values when the measured value of the organic EL element 1-1 is 100.

  From the above, it became clear that the organic EL device material of the present invention can also be used as a hole transport / injection layer material. Moreover, it became clear that the organic EL element material which was further excellent in efficiency and stability can be provided by using the organic EL element material of this invention also for a positive hole transport layer with a light emitting layer.

(Example 3)
<< Production of Organic EL Elements 3-1 and 3-2 >>
In the production of the organic EL device 1-1, α-NPD was formed to a thickness of 10 nm as the first hole transport / injection layer, and the compound (8) was formed to a thickness of 15 nm as the second hole transport / injection layer. Organic EL element 3-1 was produced in the same manner except that compound (134) was used instead of Alq ₃ as the transport layer. Further, the organic EL element except that the compound (8) is formed to a thickness of 15 nm as the second hole transport / injection layer, and the comparative compound (M-2) is used instead of Alq ₃ as the electron transport layer. A comparative organic EL element 3-2 was produced in the same manner as in 1-1. When the same evaluation as Example 1 was implemented about produced organic EL element 3-1 and 3-2, when the measured value of organic EL element 1-1 was set to 100, the efficiency of organic EL element 3-1 136, and the stability was 159, but the efficiency of the comparative organic EL element 3-2 was 94, and the stability was 63. From the above, the organic EL device material of the present invention can be used as an electron transport material, and further, the organic EL device material of the present invention can be used for a hole transport / injection layer and an electron transport layer together with a light emitting layer. Furthermore, it became clear that an organic EL element excellent in efficiency and stability can be provided.

( Reference Example 4 )
<< Production of White Light Emitting Element and White Lighting Device-1 >>
On the glass substrate with ITO patterned to 20 mm × 20 mm as the anode, α-NPD was formed to a thickness of 25 nm as the hole injection / transport layer in the same manner as in Example 1, and further compound (105) and D-34 and D-39 were adjusted such that the deposition rate was 100: 0.5: 6, and a 40 nm-thick luminescent layer was provided. Next, 10 nm of BAlq was formed as a hole blocking layer, and then 40 nm of Alq ₃ was formed to provide an electron transport layer. Subsequently, lithium fluoride was formed to a thickness of 0.5 nm as an electron injection layer, and then 150 nm of aluminum was formed as a cathode. The non-light emitting surface was covered with a glass case and sealed with an epoxy adhesive.

  The flat lamp shown in FIGS. 3 and 4 was produced using this element. When this flat lamp was energized, it was found that almost white light was obtained and it could be used as a lighting device.

(Example 5)
<< Production of White Light Emitting Element and White Lighting Device-2 >>
Poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) is purely 70% on the same substrate as the white light emitting element and white illumination device 1 described above. The diluted solution was spin-coated at 3000 rpm for 30 seconds, and then dried to provide a 30 nm-thick hole transport layer.

Furthermore, this board | substrate with a positive hole transport layer was moved under nitrogen atmosphere, 1000 rpm, the solution which melt | dissolved the compound (88) (80 mg), D-34 (3.5 mg), and D-7 (3.0 mg) in toluene 8 ml, After spin coating for 30 seconds, it was dried to obtain a light emitting layer. Subsequently, this substrate was transferred to a vacuum deposition apparatus, and Alq ₃ was formed to a thickness of 40 nm as an electron transport layer at a degree of vacuum of 4.0 × 10 ⁻⁴ Pa, and subsequently, lithium fluoride was set to a thickness of 0.04 as an electron injection layer. After forming to a thickness of 5 nm, aluminum 150 nm was formed as a cathode, the non-light emitting surface was covered with a glass case, and sealed with an epoxy adhesive.

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

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scanning line 6 Data line A Display part B Control part 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water catching agent

Claims (8)

An organic electroluminescent element material represented by any one of the following general formulas (1) to (3) .

(In the above general formulas (1) to (3) , X ₁ represents O, S, S═O, N—R ₁₁ , X ₂ represents O, S, S═O, N—R ₁₁ , and may be different even in the same .R ₁₁ is to display the aromatic hydrocarbon ring group.
R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a substituent, and at least one of R ₁ , R ₂ and R ₄ has a structure represented by the above general formula (5).
Y, Z ₁ , Z ₂ , Z ₃ and Z ₄ each represent a carbon atom or a nitrogen atom, and together with other constituent atoms of the ring form a 6-membered aromatic ring.
Rb and Rc represent an arbitrary substituent, o is an integer of 0 to 2, and p is an integer of 0 to 4.
In the general formula (5), Ar ₁ and Ar _{2 each} represent an aromatic ring and may have a substituent at an arbitrary position, but they are not bonded to each other to form a ring. ) In the above general formulas (1) (3), an organic electroluminescence device material according to claim 1, wherein the one of X ₁ and X ₂ is an oxygen atom. In the above general formulas (1) (3), according to claim 1, any one of _{X 1} and _{X 2 N-R 11 (R} 11 represents. An aromatic hydrocarbon ring group), characterized in that it is Or the material for organic electroluminescent elements of 2. In said general formula (1) to (3) , at least 1 substituent is a carbazolyl group or its derivative (s), The organic electroluminescent element material as described in any one of Claims 1-3 characterized by the above-mentioned.   It has a layer containing the organic electroluminescent element material as described in any one of Claims 1-4, The organic electroluminescent element characterized by the above-mentioned.   6. The organic electroluminescent element according to claim 5, wherein the layer containing the material for an organic electroluminescent element is formed by a wet method (wet process).   A display device comprising the organic electroluminescence element according to claim 5.   An illuminating device comprising the organic electroluminescent element according to claim 5.

Images