JP6098518B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence element.

An organic electroluminescence element (hereinafter also referred to as an organic EL element) has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and by applying an electric field, holes injected from the anode and This is a light emitting device utilizing the emission of light (fluorescence / phosphorescence) when electrons injected from the cathode are recombined in the light emitting layer to generate excitons (excitons) and the excitons are deactivated. Since it is an all-solid-state device composed of an organic material film having a thickness of only a submicron between electrodes, and can emit light with a voltage of several volts to several tens of volts, It is expected to be used for next generation flat display and lighting.
As for development of organic EL elements for practical use, Princeton University has reported organic EL elements that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1). Research on the materials shown has become active (see, for example, Patent Document 1 and Non-Patent Document 2).
In addition, recently discovered organic EL devices that use phosphorescence can realize a luminous efficiency that is approximately four times that of previous devices that use fluorescence. Research and development of light-emitting element layer configurations and electrodes are performed all over the world. For example, many compounds have been studied for synthesis centering on heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3).
Although this is a very high potential method, the organic EL device using phosphorescence emission is greatly different from the organic EL device using fluorescence emission, and the method for controlling the position of the emission center, particularly the emission layer, is particularly different. An important technical issue in capturing the efficiency and lifetime of the device is how to recombine inside to stably emit light.
Therefore, in recent years, multilayer multilayer devices having a hole transport layer (located on the anode side of the light emitting layer) and an electron transport layer (located on the cathode side of the light emitting layer) adjacent to the light emitting layer are well known. (For example, refer to Patent Document 2). In addition, a mixed layer using a host compound and a phosphorescent compound as dopants is often used for the light emitting layer.
On the other hand, from the viewpoint of materials, high carrier transportability and thermally and electrically stable materials are demanded. In particular, when using blue phosphorescence, since the blue phosphorescent compound itself has high triplet excitation energy (T1), it is possible to develop applicable peripheral materials and precisely control the emission center. There is a strong demand.
FIrpic is known as a typical blue phosphorescent compound, and a short wave is realized by substituting fluorine for the main ligand phenylpyridine and using picolinic acid as a secondary ligand. Yes. These dopants have achieved high-efficiency devices by combining carbazole derivatives and triarylsilanes as host compounds. However, since the light emission lifetime of the devices is greatly deteriorated, improvement of the trade-off has been demanded. .

  In recent years, as blue phosphorescent compounds having a high potential, metal complexes having specific ligands are disclosed in Patent Documents 3 to 5, and in these Patent Documents 3 to 5, the emission wavelength, It is improved in terms of luminous efficiency and phosphorescence lifetime.

US Pat. No. 6,097,147 JP 2005-112765 A US Patent Application Publication No. 2011/0057559 International Publication No. 2006/046980 US Patent Application Publication No. 2006/0251923

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

However, it is still not sufficient in terms of power efficiency, which is an index for practical use. In addition, when light is emitted continuously for a long time, or when light is emitted with high luminance, the carrier balance in the light emitting layer changes at high temperatures and high humidity, resulting in a decrease in light emission luminance. There is a concern about deterioration of device performance such as discoloration of emitted color over time. The above-mentioned Patent Document 3 does not describe the viewpoint of the stability of such chromaticity fluctuation, and has been found that research is insufficient and further improvement is necessary.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an organic electroluminescence element that is excellent in power efficiency, long life, aging, and excellent chromaticity stability during high luminance driving.

〔一般式（１）中、環Ａ及び環Ｂは５員または６員の芳香族炭化水素環または芳香族複素環を表し、
Ａｒは５員または６員の芳香族炭化水素環、芳香族複素環、非芳香族炭化水素環または非芳香族複素環を表し、
Ｒ_１及びＲ_２はそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表す。
Ｒａ、Ｒｂ及びＲｃはそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表し、ｎａ及びｎｃは１または２を表し、ｎｂは１〜４の整数を表す。〕
前記一般式（１）で表される部分構造とは異なる、下記一般式（２）で表される部分構造を有する配位子が配位した、有機金属錯体（Ｃ）を含むことを特徴とする有機エレクトロルミネッセンス素子が提供される。

〔一般式（２）中、環Ｃ、Ｄは５員または６員の芳香族炭化水素環または芳香族複素環を表し、
ｎｇは０または１を表し、ｎｇが０の場合は直接結合を表す。
Ｚ_１からＺ_５はそれぞれ独立に、ｐ炭素原子または窒素原子を表すが、Ｚ _１ からＺ _５ で形成される環はイミダゾール環またはトリアゾール環を表す。
Ｒｄ及びＲｅはそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表し、ｎｄは１または２を表し、ｎｅは１〜４の整数を表す。
Ｒｆは置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基を表し、ｎｆは１〜４の整数を表す。
環Ｃが有する置換基と環Ｄが有する置換基が結合して、これらに縮合する環を形成していても良い。〕 According to invention of Claim 1, in the organic electroluminescent element in which the organic layer which consists of one layer or multiple layers which has at least a light emitting layer between the anode and the cathode was sandwiched,
A phosphorescent organometallic complex (B) in which the light emitting layer is coordinated by a host material and a ligand having a partial structure represented by the following general formula (1);

[In general formula (1), ring A and ring B represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
Ar represents a 5- or 6-membered aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic hydrocarbon ring or non-aromatic heterocycle;
R ₁ and R ₂ are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, It represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
Ra, Rb and Rc are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, A heteroaryl group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group is represented, na and nc represent 1 or 2, and nb represents an integer of 1 to 4. ]
It includes an organometallic complex (C) coordinated by a ligand having a partial structure represented by the following general formula (2), which is different from the partial structure represented by the general formula (1). An organic electroluminescent device is provided.

[In general formula (2), rings C and D represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
ng represents 0 or 1, and when ng is 0, it represents a direct bond.
Z ₁ to Z ₅ each independently represent a p carbon atom or a nitrogen atom, but the ring formed from Z ₁ to Z ₅ represents an imidazole ring or a triazole ring .
Rd and Re are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl Represents a group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, nd represents 1 or 2, and ne represents an integer of 1 to 4.
Rf represents an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, and nf is The integer of 1-4 is represented.
The substituent which the ring C has and the substituent which the ring D has may combine, and the ring condensed to these may be formed. ]

According to the invention of claim 2, wherein the excited triplet energy of the organic metal complex (C) is, according to claim 1, wherein greater than excited triplet energy of the organic metal complex (B) The organic electroluminescence device is provided.

  According to the invention of claim 3, when the HOMO of the organometallic complex (B) and the organometallic complex (C) is HOMO (B) and HOMO (C), respectively, HOMO (B) -HOMO ( The organic electroluminescence device according to claim 1 or 2, wherein C) is in a range of <+0.2 eV.

  According to the invention of claim 4, when the HOMO of the organometallic complex (B) and the organometallic complex (C) is HOMO (B) and HOMO (C), respectively, -0.2 eV <HOMO ( The organic electroluminescence device according to any one of claims 1 to 3, wherein B) -HOMO (C) <+ 0.2 eV.

  According to invention of Claim 5, the density | concentration of the organometallic complex (B) in the said light emitting layer is 5 vol% or less, The organic electroluminescent element as described in any one of Claims 1-4 characterized by the above-mentioned. Is provided.

  According to invention of Claim 6, the density | concentration of the organometallic complex (C) in the said light emitting layer is 1-40 vol%, The organic electroluminescence as described in any one of Claims 1-5 characterized by the above-mentioned. An element is provided.

According to the invention of claim 7, the organic electroluminescent device according to any one of claims 1 to 6, wherein at least one of R ₁ and R ₂ is an alkyl group are provided.

According to an eighth aspect of the present invention, there is provided the organic electroluminescent device according to the seventh aspect, wherein at least one of R ₁ and R ₂ is an alkyl group having 2 or more carbon atoms.

According to the invention of claim 9, the organic electroluminescent device according to any one of claims 1-8, wherein R ₁ and R ₂ are both alkyl groups are provided.

According to the invention of claim 10, there is provided the organic electroluminescence device according to claim 9, wherein R ₁ and R ₂ are both alkyl groups having 2 or more carbon atoms.

  According to invention of Claim 11, the ring B is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-10 characterized by the above-mentioned is provided.

  According to invention of Claim 12, Ar is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-11 characterized by the above-mentioned is provided.

〔一般式（１−１）中、Ａｒ、Ｒ_１、Ｒ_２、Ｒａ、Ｒｂ、Ｒｃ、ｎａ、ｎｂ及びｎｃは前記一般式（１）と同義である。
ＬはＭに配位したモノアニオン性の二座配位子のうちの１つまたは複数であり、Ｍは原子番号４０以上且つ元素周期表における８〜１０族の遷移金属原子を表し、ｍ−ｎは０〜２の整数を表し、ｎは少なくとも１であり、ｍは２または３である。〕According to the invention of claim 13, the general formula (1) is represented by the following general formula (1-1). The organic electroluminescence element according to claim 1, Is provided.

[In the general formula (1-1), Ar, R ₁ , R ₂ , Ra, Rb, Rc, na, nb and nc have the same meanings as in the general formula (1).
L is one or more of monoanionic bidentate ligands coordinated to M, M represents a transition metal atom of atomic number 40 or more and 8-10 group in the periodic table, m − n represents an integer of 0 to 2, n is at least 1, and m is 2 or 3. ]

  According to the fourteenth aspect of the present invention, there is provided the organic electroluminescent element according to the thirteenth aspect, wherein M is Ir.

  According to invention of Claim 15, the ring C is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-14 characterized by the above-mentioned is provided.

〔一般式（４）中、ＸはＯ原子、Ｓ原子、ＮＲ_１基を表し、Ａ_１１〜Ａ_１８はＮ原子またはＣＲ_２ を表す。Ｒ_１及びＲ_２は結合手、水素原子または置換基を表し、ＣＲ_２が複数ある場合、各々のＣＲ_２は同じでも異なっていても良い。〕 According to invention of Claim 16, the said host compound is a host compound which has a partial structure represented by following General formula (4), It is described in any one of Claims 1-15 characterized by the above-mentioned. An organic electroluminescent device is provided.

In [general formula (4), X represents O atom, S atom, NR ₁ group, _A 11 _{to A 18} represents a N atom or CR _2. R ₁ and R ₂ is a bond, represents a hydrogen atom or a substituent, and when CR ₂ there are a plurality, each CR ₂ may be the same or different. ]

  According to the invention of claim 17, there is provided the organic electroluminescence device according to claim 16, wherein in the general formula (4), X is an oxygen atom.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element excellent in the chromaticity stability at the time of the high efficiency of power, long life, time, and high-intensity drive can be obtained.

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

Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.
As a result of intensive studies to achieve the above object, the present inventors have made a phosphorescent organometallic complex in which a ligand having a partial structure represented by the following general formula (1) is coordinated. (B) has a strong wrapping property with the carrier, and the recombination probability is small. Therefore, it is estimated that it leads to a decrease in efficiency, a decrease in life, and a change in chromaticity with time. Therefore, the excited triplet energy T1 is larger than that of the organometallic complex (B), does not emit light in the device, and HOMO is close to the organometallic complex (B), that is, the following general formula (2 When a phosphorescent organometallic complex (C) coordinated with a ligand having a partial structure represented by) is included in the light emitting layer, remarkable high efficiency and long life can be obtained. In addition, it was found that the chromaticity stability was excellent over time and during high-intensity driving.

〔一般式（１）中、環Ａ及び環Ｂは５員または６員の芳香族炭化水素環または芳香族複素環を表し、
Ａｒは５員または６員の芳香族炭化水素環、芳香族複素環、非芳香族炭化水素環または非芳香族複素環を表し、
Ｒ_１及びＲ_２はそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表す。
Ｒａ、Ｒｂ及びＲｃはそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表し、ｎａ及びｎｃは１または２を表し、ｎｂは１〜４の整数を表す。〕Hereinafter, the compound according to the present invention will be described.
[Phosphorescent organometallic complex (B) in which a ligand having a partial structure represented by the general formula (1) is coordinated to a metal atom]

[In general formula (1), ring A and ring B represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
Ar represents a 5- or 6-membered aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic hydrocarbon ring or non-aromatic heterocycle;
R ₁ and R ₂ are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, It represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
Ra, Rb and Rc are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, A heteroaryl group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group is represented, na and nc represent 1 or 2, and nb represents an integer of 1 to 4. ]

In the general formula (1), examples of the 5-membered or 6-membered aromatic hydrocarbon ring represented by the ring A and the ring B include a benzene ring.
In the general formula (1), examples of the 5-membered or 6-membered aromatic hydrocarbon ring represented by the ring A and the ring B include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, Examples include a pyrimidine ring, a pyrazine ring, a triazine ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, and a thiazole ring. More preferably, ring B is a benzene ring, and more preferably ring A is a benzene ring.

In the general formula (1), examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, and triphenylene. Ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene Ring, pyranthrene ring, anthraanthrene ring and the like.
In the general formula (1), examples of the aromatic heterocycle represented by Ar include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. Oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, aza A carbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), a dibenzosilole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzothiophene ring or a dibenzofuran ring. Any one Ring substituted with nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithia Gin ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene Ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.
In the general formula (1), examples of the non-aromatic hydrocarbon ring represented by Ar include a cycloalkane (eg, cyclopentane ring, cyclohexane ring, etc.), a cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.) ), A cycloalkylthio group (for example, a cyclopentylthio group, a cyclohexylthio group, etc.), a cyclohexylaminosulfonyl group, a tetrahydronaphthalene ring, a 9,10-dihydroanthracene ring, a biphenylene ring, and the like.
In the general formula (1), examples of the non-aromatic heterocycle represented by Ar include an epoxy ring, an aziridine ring, a thiirane ring, an oxetane ring, an azetidine ring, a thietane ring, a tetrahydrofuran ring, a dioxolane ring, a pyrrolidine ring, and a pyrazolidine. Ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran Ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2]- Octane ring, Fe Examples thereof include a noxazine ring, a phenothiazine ring, an oxanthrene ring, a thioxanthene ring, and a phenoxathiin ring.

These rings represented by Ar in the general formula (1) may further have the following substituents (hereinafter referred to as substituent Rx), and the substituents are bonded to each other to form a ring. It may be formed.
Examples of the substituent Rx include 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.), alkenyl group (eg vinyl group, aryl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), non-aromatic hydrocarbon ring group (eg cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.) Etc.), cycloalkoxy groups (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), cycloalkylthio groups (eg, cyclopentylthio group, cyclohexylthio group, etc.), tetrahydronaphthalene ring, 9,10-dihydroanthracene ring, biphenylene ring, etc. Monovalent group derived from Non-aromatic heterocyclic group (for example, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, Sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4- Dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane ring, phenoxazine ring, phenothiazine ring, oxane Monovalent groups derived from a lenne ring, a thioxanthene ring, a phenoxathiin ring, etc.), an aromatic hydrocarbon group (for example, a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring) , Chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring , Pentaphen ring, picene ring, pyrene ring, pyranthrene ring, monovalent group derived from anthraanthrene ring, etc.), aromatic heterocyclic group (for example, silole ring, furan ring, thiophene ring, oxazole ring, pyrrole ring) , Pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazo Ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (Represents any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), any of the carbon atoms constituting the dibenzosilole ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring Rings with one or more nitrogen atoms replaced, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidine ring, quinine Phosphorus ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthra Monovalent group derived from thiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring, etc.), alkoxy group (eg, methoxy group, ethoxy group) , Propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), aryloxy group (for example, phenoxy group, naphthyloxy group, etc.), alkylthio group (for example, methylthio group, ethylthio group, propylthio group) , Pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyl) Oxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butyl) Aminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group , Naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (eg, 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, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino) Cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc., carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethyl) Aminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group Group), 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, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecyl) Sulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridyl group) Sulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group) Etc.), halogen atoms (eg fluorine atom, chlorine atom, bromine atom, fluorinated hydrocarbon group (eg 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.
Preferably, Ar is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, more preferably an aromatic hydrocarbon ring, and still more preferably a benzene ring.

In the general formula (1), R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group Represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent, and at least one of R ₁ and R ₂ is an alkyl group having 2 or more carbon atoms Or a cycloalkyl group.
In the general formula (1), the aryl group and heteroaryl group represented by R ₁ and R ₂ are derived from the aromatic hydrocarbon ring and aromatic heterocycle represented by Ar in the general formula (1). And a monovalent group.
In the general formula (1), the non-aromatic hydrocarbon ring group and the non-aromatic heterocyclic group represented by R ₁ and R ₂ are the non-aromatic carbon groups represented by Ar in the general formula (1). And monovalent groups derived from a hydrogen ring and a non-aromatic heterocyclic ring.
Preferably, both R ₁ and R ₂ are alkyl groups or cycloalkyl groups having 2 or more carbon atoms, and it is also preferable that at least one of R ₁ and R ₂ is a branched alkyl group having 3 or more carbon atoms. . More preferably, both R ₁ and R ₂ are branched alkyl groups having 3 or more carbon atoms.

In the general formula (1), Ra, Rb and Rc are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a silyl group, an arylalkyl group, an aryl group. Represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.
In the general formula (1), the aryl group and heteroaryl group represented by Ra, Rb and Rc are derived from the aromatic hydrocarbon ring and aromatic heterocycle represented by Ar in the general formula (1). And a monovalent group.
In the general formula (1), as the non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group represented by Ra, Rb and Rc, the non-aromatic carbon represented by Ar in the above-mentioned general formula (1) And monovalent groups derived from a hydrogen ring and a non-aromatic heterocyclic ring.
In general formula (1), na and nc represent 1 or 2, and nb represents an integer of 1 to 4.

一般式（１−１）において、Ａｒ、Ｒ_１、Ｒ_２、Ｒａ、Ｒｂ、Ｒｃ、ｎａ、ｎｂ及びｎｃは、上記一般式（１）のＡｒ、Ｒ_１、Ｒ_２、Ｒａ、Ｒｂ、Ｒｃ、ｎａ、ｎｂ及びｎｃと同義である。
一般式（１−１）において、ＬはＭに配位したモノアニオン性の二座配位子のうちの１つまたは複数であり、Ｌで表されるＭに配位したモノアニオン性の二座配位子の具体例としては、下記式の配位子等が挙げられる。

[Phosphorescent Organometallic Complex Represented by General Formula (1-1)]

In the general formula (1-1), Ar, R ₁ , R ₂ , Ra, Rb, Rc, na, nb and nc are Ar, R ₁ , R ₂ , Ra, Rb, Rc in the general formula (1). , Na, nb and nc.
In the general formula (1-1), L is one or more of monoanionic bidentate ligands coordinated to M, and the monoanionic divalent ligands coordinated to M represented by L Specific examples of the bidentate ligand include the following ligands.

In the formula, Rd ′, Rd ″ and Rd ′ ″ represent a hydrogen atom or a substituent, and the substituent represented by Rd ′, Rd ″ and Rd ′ ″ is represented by Ar in the above general formula (1). Examples thereof are the same as those of the substituent Rx.
In the general formula (1-1), M is an atomic number of 40 or more and a group 8-10 transition metal atom in the periodic table of elements. Among them, Os, Ir, and Pt are preferable, and Ir is more preferable.
In General Formula (1-1), mn represents an integer of 0 to 2, n is at least 1, and m is 2 or 3. Preferably n is 3 or 2, and mn is 0.

The compounds represented by the general formula (1) or (1-1) according to the present invention can be synthesized by referring to known methods described in International Publication No. 2006-121811, etc.
Although the specific example of the dopant compound which can be preferably used in this invention is given to the following, this invention is not limited to these.

〔一般式（２）中、環Ｃ、Ｄは５員または６員の芳香族炭化水素環または芳香族複素環を表し、
ｎｇは０または１を表し、ｎｇが０の場合は直接結合を表す。
Ｚ_１からＺ_５はそれぞれ独立に、ｐ炭素原子または窒素原子を表す。
Ｒｄ及びＲｅはそれぞれ独立に、置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基または非芳香族複素環基を表し、ｎｄは１または２を表し、ｎｅは１〜４の整数を表す。
Ｒｆは置換されていてもよい水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基を表し、ｎｆは１〜４の整数を表す。
環Ｃが有する置換基と環Ｄが有する置換基が結合して、これらに縮合する環を形成していても良い。〕[Organic metal complex (C) in which a ligand having a partial structure represented by the general formula (2) is coordinated]

[In general formula (2), rings C and D represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
ng represents 0 or 1, and when ng is 0, it represents a direct bond.
Z ₁ to Z ₅ each independently represents a p carbon atom or a nitrogen atom.
Rd and Re are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl Represents a group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, nd represents 1 or 2, and ne represents an integer of 1 to 4.
Rf represents an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, and nf is The integer of 1-4 is represented.
The substituent which the ring C has and the substituent which the ring D has may combine, and the ring condensed to these may be formed. ]

Specific examples of the general formula (2) are given below.

一般式（４）において、ＸはＯ原子、Ｓ原子、ＮＲ_１基、Ａ_１１〜Ａ_１８はＮ原子またはＣＲ_２である。Ｘは、特にＯ原子が好ましい。
一般式（４）において、上記Ｒ_１及びＲ_２は結合手、水素原子または置換基を表し、ＣＲ_２が複数ある場合、各々のＣＲ_２は同じでも異なっていても良い。[Host compound represented by general formula (4)]

In the general formula (4), X is an O atom, S atom, NR ₁ group, and A _{11 to} A ₁₈ are N atoms or CR ₂ . X is particularly preferably an O atom.
In the general formula (4), the R ₁ and R ₂ is a bond, represents a hydrogen atom or a substituent, and when CR ₂ there are a plurality, each CR ₂ may be the same or different.

Although the specific example of the host compound represented by General formula (4) below is given, it is not limited to these.

[Component layer of organic EL element]
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 When a plurality of light emitting layers are included, a non-light emitting intermediate layer may be provided between the light emitting layers. In addition, among the above layer structures, an organic layer including a light emitting layer excluding an anode and a cathode can be used as one light emitting unit, and a plurality of light emitting units can be stacked. The plurality of stacked light emitting units may have a non-light emitting intermediate layer between the light emitting units, and the intermediate layer may further include a charge generation layer.
The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.
Each layer which comprises the organic EL element of this invention is demonstrated.

<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.
The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (phosphorescent dopant, also referred to as phosphorescent dopant group) or fluorescent dopant) compound and a light emitting host compound, At least one light-emitting dopant is the blue phosphorescent organometallic complex (B) represented by the general formula (1) or (1-1), and at least one light-emitting dopant is the general formula (2) described above. It is a phosphorescence-emitting organometallic complex (C) represented by these. The host compound is preferably a compound represented by the aforementioned general formula (4).

(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 dopant compound, a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) is used. it can.

(Phosphorescent dopant (also called phosphorescent dopant compound))
The phosphorescent dopant according to the present invention will be described.
The phosphorescent dopant 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 is 25 ° C. The phosphorescence quantum yield is preferably 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 is to obtain light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant 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.
The phosphorescent dopant according to the present invention is a compound represented by the general formula (1) or the general formula (1-1) and the general formula (2) described above, and the compounds described in the following patent publications, etc. May be used in combination.
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))
Fluorescent dopants include 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.

Specific examples of known phosphorescent dopant compounds that can be preferably used in the present invention are given below. Of course, the present invention is not limited to these.

In the present invention, the excited triplet energy of the organometallic complex (C) is preferably larger than the excited triplet energy of the organometallic complex (B). By doing in this way, carrier transportability can be improved, without reducing the stability of an excited state.
Here, for the band gap between the ground state and the excited triplet state of the organometallic complex (B) and the organometallic complex (C), molecular orbital calculation using Gaussian 03 (B3LYP / 6-31G * is used as a basis function). Used) to determine the lowest excited triplet energy.

Further, when the HOMO of the organometallic complex (B) and the organometallic complex (C) is HOMO (B) and HOMO (C), respectively, HOMO (B) −HOMO (C) <+ 0.2 eV A range is preferable. More preferably, it is in the range of -0.2 eV <HOMO (B) -HOMO (C) <+ 0.2 eV. Carrier transportability can be improved by setting HOMO (B) -HOMO (C) in the above range.
The energy level of HOMO is Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002. Software for molecular orbital calculation manufactured by Gaussian, USA. ) And is defined as a value (eV unit converted value) calculated by performing structure optimization using B3LYP / 6-31G * as a keyword.

Moreover, it is preferable that the density | concentration of the organometallic complex (B) in a light emitting layer is 0.1-5 vol% or less. When the concentration of the organometallic complex (B) is less than 0.1 vol%, significant emission of the host material or organometallic complex (C) is observed to cause a reduction in efficiency. When the concentration exceeds 5 vol%, the carrier trap becomes strong. Transport is hindered, causing efficiency loss.
Moreover, it is preferable that the density | concentration of the organometallic complex (C) in a light emitting layer is 1-40 vol%. When the concentration of the organometallic complex (C) is less than 1 vol%, the transport of carriers is hindered and the efficiency is lowered. Stability is reduced.

(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.

Specifically, the host compound that can be used in the present invention is a compound represented by the general formula (4) described above.
Furthermore, as the host compound, a conventionally known compound may be used in combination with the compound represented by the general formula (4) described above.
The compound that may be used in combination typically has a basic skeleton such as a carbazole derivative, triarylamine derivative, aromatic derivative, nitrogen-containing heterocyclic compound, thiophene derivative, furan derivative, oligoarylene compound, or A carboline derivative or a diazacarbazole derivative (herein, a diazacarbazole derivative represents one in which at least one carbon atom of a hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom). Can be mentioned.
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. More preferably, Tg is 100 ° C. or higher.
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.

<< Injection layer: hole injection layer (anode buffer layer), electron injection layer (cathode buffer 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. Representative phthalocyanine buffer layer, oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using conductive polymer such as polyaniline (emeraldine) or polythiophene, tris (2-phenylpyridine) ) Orthometalated complex layers represented by iridium complexes and the like. Further, azatriphenylene derivatives such as those described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as the hole injection material.
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.

《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. Further, azatriphenylene derivatives such as those described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as the hole transport material.
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.
In addition, cyclometalated complexes and orthometalated complexes represented by copper phthalocyanine, tris (2-phenylpyridine) iridium complex, and the like can also be used as 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 injection layer of the organic EL element of this invention and a positive hole transport layer is given, this invention is not limited to these.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided 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 from any conventionally known compounds and used alone or in combination.
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.
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. The electron transport layer may have a single layer structure composed of one or more of the above materials, or may have a stacked structure in which a plurality of layers are stacked.
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.

<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.
The hole blocking layer contains carbazole derivatives, azacarbazole derivatives (where azacarbazole derivatives are those in which one or more carbon atoms constituting the carbazole ring are replaced by nitrogen atoms), pyridine derivatives, and the like. It is preferable to contain a nitrogen compound.
In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the 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, and more preferably 3 nm to 30 nm.

"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 substances 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, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method 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.
Furthermore, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.
In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.
In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. .
In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.
Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.
The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.
In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.
Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, etc.) and the like, and sulfates, metal halides and perchloric acids are preferably anhydrous salts.

《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 preferably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.
However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.
As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.
At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.
The arrangement of the diffraction grating is preferably two-dimensionally repeated such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Condensing sheet》
The organic EL device 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 device light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.
As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.
As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.
As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.
Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<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). In FIG. 2, symbol L indicates light, and the same applies to FIGS. 5 and 6 described later.
The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)
When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.
Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

Next, the light emission process of the pixel will be described.
FIG. 3 is a schematic diagram of a pixel.
The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.
In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.
By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.
When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off.
However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues.
When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.
That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.
Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.
When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.
In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The 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, the combination of luminescent materials for obtaining multiple luminescent colors is a combination of multiple phosphorescent or fluorescent materials that emit light, fluorescent materials or phosphorescent materials, and light from the luminescent materials. Any combination with a dye material that emits light as light may be used, but in the white organic EL device according to the present invention, it is only necessary to mix and mix a plurality of light emitting dopants.
It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.
According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.
There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.
The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and an illumination device as shown in FIGS. Can be formed.
FIG. 5 shows a schematic diagram of a lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).
6 shows a cross-sectional view of the lighting device. In FIG. 6, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer including at least a light emitting layer, and 107 denotes a glass substrate with a transparent electrode (anode).
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.
<Dopant Compound (B) (Organic Metal Complex (B))>

<Dopant Compound (C) (Organic Metal Complex (C))>

<Host compound>

<Red light emitting dopant compound>

<Green light emitting dopant compound>

Example 1
[Production of organic EL element]
<< Production of Organic EL Element 101 >>
An organic EL element was produced as follows.
A transparent support provided with this ITO transparent electrode after patterning a substrate (NA45 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.
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of a hole injection material (HT-30) is put into a molybdenum resistance heating boat, and a hole transport material (HT) is put into another molybdenum resistance heating boat. -2) 200 mg, 200 mg host compound (host1) in another molybdenum resistance heating boat, 200 mg dopant compound (DP-57) in another molybdenum resistance heating boat, another molybdenum resistance heating boat 200 mg of an electron transporting material (ET-7) was put in and attached to a vacuum deposition apparatus.
Next, the pressure in the vacuum chamber is reduced to 4 × 10 ⁻⁴ Pa, and then the heating boat containing the hole injection material (HT-30) is energized and heated to form a transparent support substrate at a deposition rate of 0.1 nm / second. Evaporated to provide a 20 nm hole injection layer.
Further, the heating boat containing the hole transport material (HT-2) was heated by energization, and was deposited on the hole injection layer at a deposition rate of 0.1 nm / second to provide a 20 nm hole transport layer. .
Further, the heating boat containing the host compound (host1) and the dopant compound (DP-57) was heated by applying current to the hole transport layer at a deposition rate of 0.085 nm / second and 0.015 nm / second, respectively. Co-evaporated to provide a 20 nm light emitting layer.
Further, the heating boat containing the electron transporting material (ET-7) was heated by energization, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 20 nm electron transporting layer.
Subsequently, lithium fluoride 0.5 nm was vapor-deposited as a cathode buffer layer, and aluminum 110 nm was vapor-deposited to form a cathode, whereby an organic EL element 101 was produced.

<< Production of Organic EL Element 102 >>
In the production of the organic EL element 101, in addition to the material used in the organic EL element 101, a molybdenum resistance heating boat containing 200 mg of a dopant compound (dopantC1) is attached to a vacuum deposition apparatus, and the film formation of the light emitting layer is performed as a host compound (host1 ), A dopant compound (DP-57), and a dopant compound (dopantC1) containing the dopants (dopantC1) and heated to energize, and the deposition rate of 0.085 nm / second, 0.005 nm / second, and 0.010 nm / second, respectively. An organic EL device 102 was produced in the same manner except that a 20 nm light emitting layer was provided by co-evaporation on the hole transport layer.

<< Production of Organic EL Elements 103, 105, 106, 108 >>
Organic EL elements 103, 105, 106, and 108 were similarly manufactured except that the dopant compound and the host compound were changed to the compounds shown in Table 1A in the preparation of the organic EL element 101.

<< Production of Organic EL Elements 104, 107, 109 to 119 >>
Organic EL elements 104, 107, and 109 to 119 were similarly manufactured except that the dopant compound and the host compound were changed to the compounds shown in Table 1A in the preparation of the organic EL element 102.

  Table 1A shows the HOMO [eV] of the dopant compound (B) and dopant compound (C) used (represented as HOMO (B) and HOMO (C) in Table 1A), phosphorescence emission wavelength [nm] ( In Table 1A, phosphorescence emission wavelength (B), phosphorescence emission wavelength (C)), and HOMO difference [eV] (HOMO (B) −HOMO (C)) are shown. Moreover, the density | concentration [vol%] of the dopant compound (B) and the dopant compound (C) was also shown.

[Evaluation of organic EL elements]
The following evaluation was performed about the organic EL element produced as mentioned above, and the result was shown to Table 1A and Table 1B.
When evaluating the obtained organic EL element, the non-light-emitting surface of each organic EL element after production is covered with a glass cover, and the glass cover side periphery where the glass cover and the glass substrate on which the organic EL element is produced contacts An epoxy photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) was applied as a sealant to the cathode side, and this was adhered to the transparent support substrate to remove the organic EL element from the glass substrate side. The portions were irradiated with UV light, cured, sealed, and evaluated by forming an illumination device as shown in FIGS.

(External quantum efficiency (EQE))
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 100 as 100.

(Relative 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 100 to 100.

(Change in chromaticity over time)
The CIE 1931 table when the time (τ1 / 2) required to reach half of the chromaticity (x, y) and the initial luminance in the CIE 1931 color system at the initial driving time under a constant current condition of ^2.5 mA / cm ² is used. The chromaticity (x, y) in the color system was compared, and the difference between the x value and the y value was expressed in the form of (Δx, Δy), which was used as an index of chromaticity change over time. Smaller values of Δx and Δy are preferable.

(Change in chromaticity when driving at high brightness)
Comparing the chromaticity (x, y) in the chromaticity (x, y) and CIE1931 color system of 25mA / cm ² in the CIE1931 colorimetric system of the constant current condition of 2.5mA / cm ^2, x value, y value Is expressed in the form of (Δx, Δy) and used as an index of high luminance chromaticity change. Smaller values of Δx and Δy are preferable.

(Luminescent color)
The color of light emitted when continuous light emission was performed under a constant current condition of ^2.5 mA / cm ² was visually evaluated.

  As is clear from Table 1A and Table 1B, the organic EL device using the dopant compound (B) and the dopant compound (C) of the present invention in combination is superior in power efficiency and emission life compared to the comparative organic EL device. It is clear that the chromaticity variation is stable over time and at high luminance.

Example 2
[Production of organic EL element]
<< Production of Organic EL Element 201 >>
A transparent support provided with this ITO transparent electrode after patterning a substrate (NA45 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, 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 a condition of 30 seconds and then dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 20 nm.
The substrate was transferred to a nitrogen atmosphere, and spin coating was performed on the hole injection layer using a solution of 50 mg of a hole transport material (HT-27) dissolved in 10 ml of toluene at 1500 rpm for 30 seconds. A thin film was formed. The substrate was heated to 80 ° C. and irradiated with ultraviolet light for 110 seconds to perform photopolymerization / crosslinking, and further vacuum dried at 60 ° C. for 1 hour to obtain a hole transport layer having a thickness of about 20 nm.
On this hole transport layer, a solution obtained by dissolving 85 mg of the host compound (host 4) and 15 mg of the dopant compound (DP-44) in 10 ml of butyl acetate was spin-coated under a condition of 1000 rpm for 30 seconds. A thin film was formed. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 45 nm.
Next, a thin film is formed on the light emitting layer by spin coating under a condition of 1000 rpm and 30 seconds using a solution in which 50 mg of an electron transport material (ET-15) is dissolved in 10 ml of hexafluoroisopropanol (HFIP). did. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 25 nm.
Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride is deposited as a cathode buffer layer, and further, 110 nm of aluminum is deposited. Thus, a cathode was formed, and an organic EL element 201 was produced.

<< Production of Organic EL Element 202 >>
In the production of the organic EL element 201, an organic EL element 202 was produced in the same manner except that the dopant compound and the host compound were changed to the compounds shown in Table 2A.

<< Production of organic EL element 203 >>
In the production of the organic EL element 201, a solution in which 85 mg of the host compound (host 4), 5 mg of the dopant compound (DP-44), and 10 mg of the dopant compound (dopantC6) are dissolved in 10 ml of butyl acetate on the hole transport layer. A thin film was formed by spin coating under conditions of 1000 rpm and 30 seconds. Further, an organic EL element 203 was produced in the same manner except that it was vacuum-dried at 60 ° C. for 1 hour to obtain a light emitting layer having a thickness of about 45 nm.

<< Production of organic EL element 204 >>
In the production of the organic EL element 203, an organic EL element 204 was produced in the same manner except that the dopant compound and the host compound were changed to the compounds shown in Table 2A.

  In Table 2A, HOMO [eV] of dopant compound (B) and dopant compound (C) used (represented as HOMO (B) and HOMO (C) in Table 2A), phosphorescence emission wavelength [nm] ( In Table 2A, phosphorescence emission wavelength (B), phosphorescence emission wavelength (C)), and HOMO difference [eV] (HOMO (B) −HOMO (C)) are shown. Moreover, the density | concentration [vol%] of the dopant compound (B) and the dopant compound (C) was also shown.

[Evaluation of organic EL elements]
Evaluation similar to Example 1 was performed about the organic EL element produced as mentioned above, and the result was shown to Table 2A and Table 2B.

  As is clear from Table 2A and Table 2B, the organic EL device using the dopant compound (B) and the dopant compound (C) of the present invention in combination is superior in power efficiency and emission life compared to the comparative organic EL device. It is clear that the chromaticity variation is stable over time and at high luminance.

Example 3
[Production of organic EL elements]
<< Production of organic EL element 301 >>
A transparent support provided with this ITO transparent electrode after patterning a substrate (NA45 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.
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of HT-31 is put into a molybdenum resistance heating boat, and 200 mg of HT-1 is put into another molybdenum resistance heating boat, and another molybdenum resistance is put. 200 mg of host compound (host3) is put into a heating boat, 200 mg of dopant compound (DP-1) is put into another molybdenum resistance heating boat, and 200 mg of green light emitting dopant compound (GD-2) is put into another molybdenum resistance heating boat. Then, 200 mg of the red light emitting dopant compound (RD-1) was put in another resistance heating boat made of molybdenum, and 200 mg of ET-2 was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.
The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the heating boat containing HT-31, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. An injection layer was provided.
Further, the heating boat containing HT-1 was energized and heated, and was deposited on the hole injection layer at a deposition rate of 0.1 nm / second to provide a 20 nm hole transport layer.
Further, the heating boat containing the host compound (host3), the dopant compound (DP-1), the green dopant compound (GD-2), and the red dopant compound (RD-1) was heated by supplying electricity, and the deposition rate was set to 0. A 60 nm light emitting layer was provided by co-evaporation on the hole transport layer at 1 nm / second, 0.0178 nm / second, 0.0007 nm / second, and 0.0002 nm / second.
Further, the heating boat containing ET-2 was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 20 nm electron transport layer.
Then, 0.5 nm of potassium fluoride was vapor-deposited as a cathode buffer layer, and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 301 was produced.

<< Production of Organic EL Element 302 >>
In the production of the organic EL element 301, a molybdenum resistance heating boat containing 200 mg of a dopant compound (dopantC4) in addition to the materials used in the organic EL element 101 is attached to a vacuum deposition apparatus, and the light-emitting layer is formed as a host 3 and DP- The heating boat containing 1 and dopantC4, GD-2 and RD-1 was energized and heated, and the deposition rates were 0.1 nm / second, 0.0058 nm / second, 0.012 nm / second and 0.0007 nm / second, respectively. The organic EL element 302 was produced in the same manner except that a light emitting layer having a thickness of 60 nm was formed by co-evaporation on the hole transport layer at 0.0002 nm / second.

<< Production of organic EL elements 303 to 305 >>
In the production of the organic EL element 302, organic EL elements 303 to 305 were similarly produced except that the dopant compound and the host compound were changed to the compounds shown in Table 3A.

  In Table 3A, HOMO [eV] of dopant compound (B) and dopant compound (C) used (represented as HOMO (B) and HOMO (C) in Table 3A), phosphorescence emission wavelength [nm] ( In Table 3A, phosphorescence emission wavelength (B), phosphorescence emission wavelength (C)), and HOMO difference [eV] (HOMO (B) -HOMO (C)) are shown. Moreover, the density | concentration [vol%] of the dopant compound (B) and the dopant compound (C) was also shown.

[Evaluation of organic EL elements]
Evaluation similar to Example 1 was performed about the organic EL element produced as mentioned above, and the result was shown to Table 3A and Table 3B.

  As is clear from Table 3A and Table 3B, the organic EL device using the dopant compound (B) and the dopant compound (C) of the present invention in combination is superior in power efficiency and emission life compared to the comparative organic EL device. It is clear that the chromaticity variation is stable over time and at high luminance.

  The organic electroluminescence element of the present invention has high power efficiency, long life, excellent chromaticity stability during aging and high luminance driving, and can be suitably used for lighting devices and display devices.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (17)

In an organic electroluminescence element in which an organic layer composed of one or more layers having at least a light emitting layer is sandwiched between an anode and a cathode,
A phosphorescent organometallic complex (B) in which the light emitting layer is coordinated by a host material and a ligand having a partial structure represented by the following general formula (1);

[In general formula (1), ring A and ring B represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
Ar represents a 5- or 6-membered aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic hydrocarbon ring or non-aromatic heterocycle;
R ₁ and R ₂ are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, It represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
Ra, Rb and Rc are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, A heteroaryl group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group is represented, na and nc represent 1 or 2, and nb represents an integer of 1 to 4. ]
It includes an organometallic complex (C) coordinated by a ligand having a partial structure represented by the following general formula (2), which is different from the partial structure represented by the general formula (1). Organic electroluminescence device.

[In general formula (2), rings C and D represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle,
ng represents 0 or 1, and when ng is 0, it represents a direct bond.
Z ₁ to Z ₅ each independently represent a p carbon atom or a nitrogen atom, but the ring formed from Z ₁ to Z ₅ represents an imidazole ring or a triazole ring .
Rd and Re are each independently an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl Represents a group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, nd represents 1 or 2, and ne represents an integer of 1 to 4.
Rf represents an optionally substituted hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, and nf is The integer of 1-4 is represented.
The substituent which the ring C has and the substituent which the ring D has may combine, and the ring condensed to these may be formed. ] 2. The organic electroluminescence device according to claim 1, wherein the excited triplet energy of the organometallic complex (C) is larger than the excited triplet energy of the organometallic complex (B).   When the HOMO of the organometallic complex (B) and the organometallic complex (C) is HOMO (B) and HOMO (C), respectively, in the range of HOMO (B) −HOMO (C) <+ 0.2 eV. The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device is provided.   When the HOMO of the organometallic complex (B) and the organometallic complex (C) is HOMO (B) and HOMO (C), respectively, -0.2 eV <HOMO (B) -HOMO (C) <+ 0 The organic electroluminescence device according to any one of claims 1 to 3, wherein the organic electroluminescence device is in a range of 0.2 eV.   The organic electroluminescent element according to claim 1, wherein the concentration of the organometallic complex (B) in the light emitting layer is 5 vol% or less.   The organic electroluminescent element according to claim 1, wherein the concentration of the organometallic complex (C) in the light emitting layer is 1 to 40 vol%. The organic electroluminescent device according to any one of claims 1 to 6, at least one of R ₁ and R _2, characterized in that an alkyl group. The organic electroluminescent device according to claim 7 wherein at least one of R ₁ and R _2, characterized in that an alkyl group having 2 or more carbon atoms. The organic electroluminescent device according to any one of claims 1-8, wherein R ₁ and R ₂ are both alkyl groups. The organic electroluminescence device according to claim 9, wherein R ₁ and R ₂ are both alkyl groups having 2 or more carbon atoms.   Ring B is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-10 characterized by the above-mentioned.   Ar is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-11 characterized by the above-mentioned. The said general formula (1) is represented by the following general formula (1-1), The organic electroluminescent element as described in any one of Claims 1-12 characterized by the above-mentioned.

[In the general formula (1-1), Ar, R ₁ , R ₂ , Ra, Rb, Rc, na, nb and nc have the same meanings as in the general formula (1).
L is one or more of monoanionic bidentate ligands coordinated to M, M represents a transition metal atom of atomic number 40 or more and 8-10 group in the periodic table, m − n represents an integer of 0 to 2, n is at least 1, and m is 2 or 3. ]   14. The organic electroluminescence device according to claim 13, wherein M is Ir.   Ring C is a benzene ring, The organic electroluminescent element as described in any one of Claims 1-14 characterized by the above-mentioned. The organic electroluminescence device according to claim 1, wherein the host compound is a host compound having a partial structure represented by the following general formula (4).

In [general formula (4), X represents O atom, S atom, NR ₁ group, _A 11 _{to A 18} represents a N atom or CR _2. R ₁ and R ₂ is a bond, represents a hydrogen atom or a substituent, and when CR ₂ there are a plurality, each CR ₂ may be the same or different. ]   In the said General formula (4), X is an oxygen atom, The organic electroluminescent element of Claim 16 characterized by the above-mentioned.

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