JP2007180147A - Organic electroluminescence element, material thereof, display and illumination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence element material having controlled light-emitting wavelength, exhibiting high luminous efficiency and having long light-emitting lifetime, and to provide an organic electroluminescent element, an illumination apparatus, and a display. <P>SOLUTION: The organic electroluminescence element, sandwiched by an anode and a cathode and containing at least a light-emitting layer, contains a compound represented by general Formula (1). In the Formula; Ra, Rb, Rc and Rd each denote a hydrogen atom or its substituent, L denotes a mere bonding hand or a coupling group, and n, m each denotes a positive integer, and n and m will not be the same. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements. An organic EL device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer and recombines them to generate excitons. An element that emits light by using light emission (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several V to several tens V, and is self-luminous. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it has attracted attention from the viewpoints of space saving and portability.

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

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

  Further, an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a small amount of phosphor is doped thereto (for example, JP-A 63-264692), and an 8-hydroxyquinoline aluminum complex is used as a host compound. For example, an element having an organic light emitting layer doped with a quinacridone dye (for example, JP-A-3-255190) is known.

  As described above, when light emission from an excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, and thus the generation probability of luminescent excited species is 25%, and light extraction is performed. Since the efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University published a report on organic EL devices using phosphorescence emission from excited triplets (MA Baldo et al., Nature, 395, 151-154 (1998)), at room temperature. Research on materials that exhibit phosphorescence has become active.

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

  When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so that in principle the luminous efficiency is four times that of excited singlets, and there is a possibility that almost the same performance as cold cathode tubes can be obtained. Therefore, it is attracting attention as a lighting application.

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

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, Vol. 403, No. 17, pages 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

In addition, M.M. E. Thompson et al. In The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) used L ₂ Ir (acac) as a dopant, eg (ppy) ₂ Ir (acac), a. 0 g, Tetsuo Tsutsui, etc., again, The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) in, as a dopant tris (2-(p-tolyl) pyridine) iridium (Ir (ptpy) _3), Studies using tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like are being conducted. These metal complexes are generally called ortho-metalated iridium complexes.

  In addition, S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., attempts have been made to form devices using various iridium complexes.

  Orthometalated complexes in which the central metal is platinum instead of iridium are also attracting attention. With respect to this type of complex, many examples in which a ligand is characterized are known (for example, see Patent Documents 1 to 5).

As host compounds of these phosphorescent dopants, carbazole derivatives represented by CBP and m-CP are well known. However, m-CP and derivatives thereof are known as blue light-emitting hosts, but have not yet sufficiently satisfied efficiency and lifetime (see, for example, Patent Documents 6 and 7).
JP 2002-332291 A JP 2002-332292 A JP 2002-338588 A JP 2002-226495 A JP 2002-234894 A International Publication No. 03/080760 Pamphlet International Publication No. 04/074399 Pamphlet

  The present invention has been made in view of such problems, and an object of the present invention is to provide an organic electroluminescence element material, an organic electroluminescence element, and an illumination whose emission wavelength is controlled, high emission efficiency, and a long emission lifetime. An apparatus and a display device are provided.

  The above object of the present invention is achieved by the following configurations.

  1. An organic electroluminescent device comprising at least a light emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescent device contains a compound represented by the following general formula (1).

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, R ₁ represents a hydrogen atom or a substituent, and Z ₁ is necessary to form a 5- or 6-membered heterocyclic ring. Represents a residue, and a part of Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ can form a new ring.)
2. An organic electroluminescence device sandwiched between an anode and a cathode and containing at least a light emitting layer, comprising a compound represented by the following general formula (2):

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, Z 2 represents a residue necessary to form a 5-membered heterocyclic ring, Ar ₁ and Ar ₂ , Ar ₃ and A new ring can be formed with a part of Ar _4. )
3. An organic electroluminescence device comprising at least a light emitting layer sandwiched between an anode and a cathode, comprising an organic electroluminescence device comprising a compound represented by the following general formula (3).

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, Z 3 represents a residue necessary to form a 6-membered heterocyclic ring containing at least one nitrogen atom, and Ar ₁ And a part of Ar ₂ , Ar ₃ and Ar ₄ can form a new ring.)
4). An organic electroluminescence device comprising at least a light-emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescence device comprises a compound represented by the following general formula (4).

(Wherein R _{1 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 1 represents 5 Represents a residue necessary to form a 6-membered or 6-membered heterocyclic ring.)
5. An organic electroluminescence device comprising at least a light emitting layer sandwiched between an anode and a cathode, comprising an organic electroluminescence device comprising a compound represented by the following general formula (5).

(Wherein R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 2 represents 5 Represents the residues necessary to form a membered heterocyclic ring.)
6). An organic electroluminescent device comprising at least a light emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescent device comprises a compound represented by the following general formula (6).

(In the formula, R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 3 represents a complex. Represents a residue necessary to form a ring.)
7). 7. The organic electroluminescence according to 1, 4 or 6, wherein Z1 in the general formulas (1) and (4) and Z3 in the general formula (6) are residues necessary for forming a pyridine ring. element.

  8). 5. The organic electroluminescence device according to 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a thiophene ring.

  9. 5. The organic electroluminescence device according to 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a furan ring.

  10. 5. The organic electroluminescence device according to 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrazole ring.

  11. 5. The organic electroluminescence device according to 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyridazine ring.

  12 5. The organic electroluminescence device according to 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrimidine ring.

  13. 6. The organic electroluminescence device according to 2 or 5, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming an imidazole ring.

  14 6. The organic electroluminescence device according to 2 or 5, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming an oxazole ring.

  15. 6. The organic electroluminescence device according to 2 or 5, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming a thiazole ring.

  16. 7. The organic electroluminescence device according to 3 or 6, wherein Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrimidine ring.

  17. 7. The organic electroluminescence device according to 3 or 6, wherein Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrazine ring.

18. 18. The organic according to any one of 4 to 17, wherein L ₁ and L ₂ in the general formulas (4) to (6) are merely bonds, and X _{1 to} X ₁₆ are carbon atoms. Electroluminescence element.

19. L ₁ and L ₂ in the general formulas (4) to (6) are merely bonds, and at least one of X _{1 to} X ₁₆ is a nitrogen atom, The organic electroluminescent element of description.

  20. 20. The organic electroluminescent element according to any one of 1 to 19, wherein the light emitting layer has a phosphorescent dopant.

  21. 21. The organic electroluminescence device according to 20, wherein a phosphorescence wavelength (0-0 band) of the phosphorescent dopant is 485 nm or less.

  22. 22. The organic electroluminescence device according to 20 or 21, wherein the phosphorescent dopant has an ionization potential of 5.5 eV or less.

  23. 23. The organic electroluminescence device according to any one of 1 to 22, wherein the phosphorescent dopant is a compound represented by the following general formula (A).

(In the formula, X ₁ , X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 1 represents a 5-membered heterocyclic ring, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring. M Represents Ir or Pt.)
24. 24. The organic electroluminescence device according to 23, wherein the compound represented by the general formula (A) is represented by the following general formulas (B) to (E).

(In the general formula (B) ~ (E), X 2, X 3 represents a carbon atom or a nitrogen _{atom, Y 1, Y 5, Y} 9 represents a sulfur atom, a carbon atom or a nitrogen atom, Y _2, Y ₃ , Y ₄ , Y ₆ , Y ₇ , Y ₈ , Y ₁₀ , Y ₁₁ , Y _{12 each} represents a carbon atom or a nitrogen atom, and Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring. Represents Ir or Pt.)
25. 23. The organic electroluminescence device according to any one of 1 to 22, wherein the phosphorescent dopant is a compound represented by the following general formula (F).

(In the formula, X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring, R ₂ and R ₃ represent a hydrogen atom or a substituent, R ₄ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and M represents Ir or Pt.)
26. 26. The organic electroluminescence device according to any one of 1 to 25, wherein the compounds represented by the general formulas (1) to (6) are used as a host of the light emitting layer.

  27. 27. The organic electroluminescent device has an electron blocking layer, and the compounds represented by the general formulas (1) to (6) are used for the electron blocking layer. Organic electroluminescence element.

  28. 28. The organic electroluminescence device has a hole blocking layer, and the compounds represented by the general formulas (1) to (6) are used for the hole blocking layer. Organic electroluminescence element.

  29. 29. The organic electroluminescence device according to any one of 1 to 28, which emits white light.

  A display device comprising the organic electroluminescence element according to any one of 30.1 to 28.

  An illuminating device comprising the organic electroluminescent element according to any one of 31.1 to 28.

  32. A display device comprising the lighting device according to 32.31 and a liquid crystal element as display means.

  33. An organic electroluminescence element material, which is a compound represented by the general formulas (1) to (6).

  According to the present invention, it is possible to provide an organic electroluminescence element material, an organic electroluminescence element, an illuminating device, and a display device that have a controlled emission wavelength, exhibit high emission efficiency, and have a long emission lifetime.

  The organic EL device of the present invention is characterized in that in the organic EL device containing at least a light emitting layer sandwiched between an anode and a cathode, the organic EL device contains the compounds represented by the general formulas (1) to (6). .

[Compound represented by the general formula (1)]
In the general formula (1), Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, R ₁ represents a hydrogen atom or a substituent, and Z ₁ forms a 5-membered or 6-membered heterocyclic ring. A new ring can be formed by a part of Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ .

Examples of the aromatic group represented by Ar _{1 to} Ar ₄ include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, naphthyl group, m-chlorophenyl group, 4-dimethylaminophenyl group, o- Examples include a hexadecanoylaminophenyl group and a naphthyl group.

Examples of the aromatic heterocyclic group represented by Ar _{1 to} Ar ₄ include a furyl group, a thienyl group, a pyridyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, a quinazolinyl group, A phthalazinyl group etc. are mentioned.

Examples of the substituent represented by R ₁ 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.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), aryl group (eg , Phenyl group, naphthyl group, etc.), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, Phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imi Zolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxyl group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (for example, Cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group) Etc.), a cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), an arylthio group (eg, phenylthio group, naphthylthio group, etc.), an alkoxycarbonyl group (eg, methyloxycarbonyl group, Ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, Methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group Etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, Octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group) Group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2 -Ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc. Carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group) Group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenyl) Ureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butyl) Sulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group) Cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc., arylsulfonyl group (phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group etc.), amino group (for example, amino group, ethylamino group, dimethyl) Amino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, diphenylamino group, anilino group, ethyltolylamino group, naphthyl Mino group, 2-pyridylamino group, etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, mercapto group, silyl group (eg, Trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), fluorine atom and the like.

  These substituents may be further substituted with the above substituents. Further, these substituents may be bonded together to form a ring.

  Residues necessary for forming a 5-membered or 6-membered heterocyclic ring represented by Z1 include pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl Group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group.

[Compound represented by formula (2)]
In the general formula (2), Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, Z 2 represents a residue necessary to form a 5-membered heterocyclic ring, Y represents a nitrogen atom, It represents a sulfur atom or an oxygen atom, and a new ring can be formed by a part of Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ .

Aromatic group represented by Ar ₁ to Ar _4, the aromatic heterocyclic group, an aromatic group represented by Ar ₁ to Ar ₄ in the general formula (1), be synonymous with an aromatic heterocyclic group , A residue necessary for forming a 5-membered heterocyclic ring represented by Z2 is synonymous with a residue necessary for forming a 5-membered heterocyclic ring represented by Z1 in the general formula (1). It is.

[Compound represented by formula (3)]
In the general formula (3), Ar _{1 to} Ar ₄ each represents an aromatic group or an aromatic heterocyclic group, and Z 3 represents a residue necessary for forming a 6-membered heterocyclic ring containing at least one nitrogen atom. And a new ring can be formed by a part of Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ .

Aromatic group represented by Ar ₁ to Ar _4, the aromatic heterocyclic group, an aromatic group represented by Ar ₁ to Ar ₄ in the general formula (1), be synonymous with an aromatic heterocyclic group Residues necessary for forming a 6-membered heterocyclic ring containing at least one nitrogen atom represented by Z3 include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, piperidinyl and pyrazolyl groups .

[Compound represented by formula (4)]
In the general formula (4), R _{1 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, and X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom. , Z1 represents a residue necessary for forming a 5-membered or 6-membered heterocyclic ring.

Examples of the substituent represented by R ₁ to R _5, the same meaning as the substituents represented by R ₁ in the general formula (1).

Examples of the linking group represented by L ₁ and L ₂ include an alkylene group and an arylene group. These groups may be further substituted with the substituents exemplified for R ₁ in the general formula (1).

  As a residue necessary for forming a 5-membered or 6-membered heterocyclic ring represented by Z1, to form a 5-membered or 6-membered heterocyclic ring represented by Z1 in the general formula (1), Synonymous with required residue.

[Compound represented by formula (5)]
In the general formula (5), R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, and X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom. , Z2 represents a residue necessary for forming a 5-membered heterocyclic ring.

As a substituent represented by R < ₂ > -R < ₅ >, it is synonymous with the substituent represented by R < ₁ > of the said General formula (1).

Examples of the linking group represented by L ₁ and L ₂ include an alkylene group and an arylene group. These groups may be further substituted with the substituents exemplified for R ₁ in the general formula (1).

  The residue necessary for forming the 5-membered heterocyclic ring represented by Z2 is synonymous with the residue necessary for forming the 5-membered heterocyclic ring represented by Z1 in the general formula (1). is there.

[Compound represented by the general formula (6)]
In the general formula (6), R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, and X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom. , Z3 represents a residue necessary for forming a 6-membered heterocyclic ring containing at least one nitrogen atom.

As a substituent represented by R < ₂ > -R < ₅ >, it is synonymous with the substituent represented by R < ₁ > of the said General formula (1).

Examples of the linking group represented by L ₁ and L ₂ include an alkylene group and an arylene group. These groups may be further substituted with the substituents exemplified for R ₁ in the general formula (1).

  Examples of the residue necessary for forming a 6-membered heterocyclic ring containing at least one nitrogen atom represented by Z3 include a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a piperidinyl group, and a pyrazolyl group.

In the general formula (1) ~ (6), Z1~Z3, for L ₁ and L _2, X ₁ ~X _16, specific structures and combinations such as the following is preferable.

  (1) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming pyridine.

  (2) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming a thiophene ring.

  (3) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming a furan ring.

  (4) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrazole ring.

  (5) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming a pyridazine ring.

  (6) It is preferable that Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrimidine ring.

  (7) It is preferable that Z2 in the general formula (2) or (5) is a residue necessary for forming an imidazole ring.

  (8) It is preferable that Z2 in the general formula (2) or (5) is a residue necessary for forming an oxazole ring.

  (9) It is preferable that Z2 in the general formula (2) or (5) is a residue necessary for forming a thiazole ring.

  (10) It is preferable that Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrimidine ring.

  (11) It is preferable that Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrazine ring.

(12) L ₁ and L ₂ in the general formulas (4) to (6) are simply bonds, and X _{1 to} X ₁₆ are preferably carbon atoms.

(13) Formula (4) ~ (6) L 1, L 2 are in a single bond, is preferably at least one of the nitrogen atom of X ₁ to X _16.

  Specific examples of the compounds represented by the general formulas (1) to (6) are shown below, but the present invention is not limited thereto.

(Synthesis example)
(Synthesis of Compound 1)
Compound 1 was synthesized according to the following scheme.

  A 300 ml three-necked flask was charged with 13.4 g (0.0801 mol) of carbazole, 9.0 g of the following compound A, 13.4 g of potassium carbonate, 6.2 g of Cu powder, and 90 ml of dimethylacetamito and refluxed for 5 hours (internal temperature 155 ° C. The reaction was completed. The reaction solution was filtered to remove inorganic substances, washed well with THF, about 500 ml of ethyl acetate was added to the filtrate, and it was sufficiently washed with brine, then dehydrated with magnesium sulfate and concentrated.

  The concentrated residue was separated and purified by silica gel chromatography using hexane: toluene = 4: 1 as a developing solvent to obtain 4.5 g of Compound 1.

  The structure of Compound 1 was confirmed by 1H-NMR and Mass.

  Other compounds can be synthesized in the same manner.

  These compounds are preferably used as a host for the light emitting layer described later, and for an electron blocking layer and a hole blocking layer.

  Next, 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 The hole blocking layer is also referred to as a hole blocking layer, and is substantially composed of an electron transporting material. May be configured in a single layer.

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

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

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not required (about 100 μm or more) ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. 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 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

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

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

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

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

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

  The details of the 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 lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

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

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

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

  For the hole blocking layer (hole blocking layer), it is preferable to use the compounds represented by the general formulas (1) to (6) according to the present invention.

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the layer. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

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

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

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

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  For the electron blocking layer, it is preferable to use the compounds represented by the general formulas (1) to (6) according to the present invention.

  Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

<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.

[Phosphorescent dopant]
The light emitting layer of the organic EL device of the present invention preferably contains a phosphorescent dopant. The phosphorescence wavelength (0-0 band) of the phosphorescent dopant is preferably 485 nm or less, and the ionization potential of the phosphorescent dopant is preferably 5.5 eV or less.

  By combining the phosphorescent dopant having these characteristics and the compounds represented by the general formulas (1) to (6) according to the present invention as a host of the light emitting layer, a good light emission efficiency and a long light emission lifetime can be obtained. Achieved.

  The 0-0 band of phosphorescence is obtained as follows.

  Phosphorescent dopant to be measured is dissolved in a well-deoxygenated ethanol / methanol = 4/1 (vol / vol) mixed solvent, put into a phosphorescence measurement cell, and then irradiated with excitation light at a liquid nitrogen temperature of 77K. The emission spectrum at 100 ms after the excitation light irradiation is measured. Since phosphorescence has a longer emission lifetime than fluorescence, it can be considered that light remaining after 100 ms is almost phosphorescence. For compounds with a phosphorescence lifetime shorter than 100 ms, measurement may be performed with a shorter delay time, but phosphorescence and fluorescence cannot be separated if the delay time is shortened so that it cannot be distinguished from fluorescence. Since this is a problem, it is necessary to select a delay time that can be separated. Moreover, about the compound which cannot be melt | dissolved in the said solvent type | system | group, you may use the arbitrary solvent which can melt | dissolve the compound. In practice, the above-described measurement method has no problem because the solvent effect of the phosphorescence wavelength is negligible.

  Next, the 0-0 band is determined. In the present invention, the emission maximum wavelength that appears on the shortest wavelength side in the phosphorescence spectrum chart obtained by the above measurement method is defined as the 0-0 band. Since the phosphorescence spectrum usually has a low intensity, when it is enlarged, it may be difficult to distinguish between noise and peak. In such a case, the emission spectrum immediately after the excitation light irradiation (for convenience, this is referred to as a steady light spectrum) is expanded, and the emission spectrum 100 ms after the excitation light irradiation (for convenience, this is referred to as a phosphorescence spectrum) is superimposed on the phosphorous. It can be determined by reading the peak wavelength from the stationary light spectrum part derived from the light spectrum.

  Further, by performing a smoothing process on the phosphorescence spectrum, it is possible to separate the noise and the peak and read the peak wavelength. As the smoothing process, a smoothing method of Savitzky & Golay can be applied.

  The ionization potential (Ip) of the phosphorescent dopant according to the present invention is preferably 5.5 eV or less, more preferably 4.5 to 5.5 eV.

  Here, the ionization potential according to the present invention is defined by the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level. Energy) required to extract electrons from the compound in the (state), which can be directly measured by photoelectron spectroscopy. In the present invention, a value measured with an ESCA 5600 UPS (ultraviolet photoemission spectroscopy) manufactured by ULVAC-PHI Co., Ltd. is used.

[Compound represented by formula (A)]
As a phosphorescent dopant used for this invention, the compound represented by the said general formula (A) is preferable.

In the general formula (A), X ₁ , X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 1 represents a 5-membered heterocyclic ring, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring. To express. M represents Ir or Pt, and Ir is preferable.

In the general formula (A), examples of the 5-membered heterocyclic ring represented by Z1 include an oxazole ring, an imidazole ring, a pyrazole ring, and a triazole ring. These rings may have the substituent described as the substituent represented by R ₁ in the general formula (1).

In the general formula (A), the 6-membered aromatic ring or 5- or 6-membered heterocycle represented by Z2 includes a benzene ring, an oxazole ring, a thiophene ring, a furan ring, a pyrrole ring, a pyridine ring, a pyridazine ring, and a pyrimidine. A ring, a pyrazine ring, a triazine ring, an imidazole ring, a pyrazole ring, a triazole ring, a thiazole ring, an isoxazole ring, an isothiazole ring, a tetrazole ring, and the like. These rings may have the substituent described as the substituent represented by R ₁ in the general formula (1).

[Compounds Represented by General Formulas (B) to (E)]
In the present invention, the compound represented by the general formula (A) is preferably a compound represented by the general formulas (B) to (E).

In the general formula (B) ~ (E), X 2, X 3 represents a carbon atom or a nitrogen _{atom, Y 1, Y 5, Y} 9 represents a sulfur atom, a carbon atom or a nitrogen atom, Y _2, Y ₃ , Y ₄ , Y ₆ , Y ₇ , Y ₈ , Y ₁₀ , Y ₁₁ , Y ₁₂ represent a carbon atom or a nitrogen atom, and Z 2 represents a 6-membered aromatic ring or a 5-, 6-membered heterocyclic ring. M represents Ir or Pt.

  In the general formulas (B) to (E), as the 6-membered aromatic ring represented by Z2 or the 5- or 6-membered heterocyclic ring, in the general formula (A), the 6-membered aromatic ring represented by Z2 or Synonymous with 5- or 6-membered heterocycle.

[Compound represented by formula (F)]
As a phosphorescent dopant used for this invention, the compound represented by the said general formula (F) is preferable.

In the general formula (F), X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring, and R ₂ and R ₃ represent a hydrogen atom or a substituent. R ₄ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. M represents Ir or Pt.

  In the general formula (F), the 6-membered aromatic ring represented by Z2 or the 5- or 6-membered heterocyclic ring is a 6-membered aromatic ring represented by Z2 or the 5- or 6-membered heterocyclic ring in the general formula (A). It is synonymous with the heterocyclic ring.

The substituent represented by R ₂ and R ₃ has the same meaning as the substituent described as the substituent represented by R ₁ in the general formula (1).

Examples of the aliphatic group and aliphatic group represented by R ₄ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a tert-butyl group, an n-octyl group, an eicosyl group, a 2-chloroethyl group, Examples thereof include 2-cyanoethyl group, 2-ethylhexyl group, vinyl group, allyl group and the like, and examples of the aromatic group include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, naphthyl group, m- A chlorophenyl group, a 4-dimethylaminophenyl group, an o-hexadecanoylaminophenyl group, a naphthyl group, etc., and examples of the heterocyclic group include a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, a furyl group, a pyrrolyl group, Pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group Group, and the like.

  Although the specific example of the phosphorescence-emitting dopant represented with general formula (A)-(F) which concerns on this invention below is shown, this invention is not limited to these.

  These phosphorescent dopants are described in, for example, Organic Letter, vol. 16, p 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, pp. 1685-1687 (1991), J. MoI. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, pages 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, pages 3055-3066 (2002) , New Journal of Chemistry, Vol. 26, page 1171 (2002), and further by applying methods such as references described in these documents.

  As the host compound of the light emitting layer, it is preferable to use the compounds represented by the general formulas (1) to (6) according to the present invention, but they may be known host compounds or may be used in combination. .

  Here, in the present invention, the host compound is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more of the compound contained in the light emitting layer. Is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01.

  Furthermore, a plurality of known host compounds may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of the compounds represented by the general formulas (1) to (6) according to the present invention, whereby an arbitrary emission color can be obtained. White light emission is possible by adjusting the kind of the luminescent metal complex and the doping amount, and it can be applied to illumination and backlight.

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

  Specific examples of known host compounds include compounds described in the following documents.

  JP 2001-257076 A, JP 2002-308855 A, JP 2001-313179 A, 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.

  In the present invention, when having a plurality of light-emitting layers, it is preferable that 50% by mass or more of the host compound in each layer is the same compound because it is easy to obtain a uniform film property over the entire organic layer. It is more preferable that the phosphorescence emission energy of the compound is 2.9 eV or more because it is advantageous in efficiently suppressing energy transfer from the dopant and obtaining high luminance.

  The phosphorescence emission energy as used in the field of this invention means the peak energy of the 0-0 band of the phosphorescence emission which measures the photoluminescence of a 100 nm vapor deposition film | membrane on a board | substrate with a host compound.

  There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported, generating an excited state of the host compound, and this energy is phosphorescent. The energy transfer type is to obtain light emission from the phosphorescent luminescent dopant by transferring to the phosphorescent luminescent dopant, and the other is that the phosphorescent luminescent dopant becomes a carrier trap, and the carrier is trapped on the phosphorescent luminescent dopant. Although it is a carrier trap type in which recombination occurs and light emission from the phosphorescent luminescent dopant is obtained, in any case, the excited state energy of the phosphorescent luminescent dopant is higher than the excited state energy of the host compound. The condition is also low.

  In addition to the compounds represented by the general formulas (A) to (F) according to the present invention, a complex compound containing a group 8-10 metal in the periodic table of elements, preferably an iridium compound, an osmium compound, or A rare earth complex may be used in combination.

  These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent luminescent dopant is not particularly limited, and in principle, by selecting a central metal, a ligand, a substituent of the ligand, The emission wavelength obtained can be changed.

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

The white element referred to in the present invention means that when the front luminance at 2 ° C. viewing angle is measured by the above method, the chromaticity in the CIE 1931 color system at 1000 Cd / m ² is X = 0.33 ± 0.07, It is in the region of Y = 0.33 ± 0.07.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method.

  In the present invention, the light emitting layer includes layers having different emission spectra in which the emission maximum wavelengths are in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, or a layer in which these are laminated.

  There is no restriction | limiting in particular as a lamination order of a light emitting layer, You may have a nonluminous intermediate | middle layer between each light emitting layer. In the present invention, it is preferable that at least one blue light emitting layer is provided at a position closest to the anode in all the light emitting layers.

  When four or more light-emitting layers are provided, for example, blue / green / red / blue, blue / green / red / blue / green, blue / green / red / blue / green / red from the order close to the anode. In order to improve luminance stability, it is preferable to sequentially stack blue, green, and red.

  The total film thickness of the light emitting layer is not particularly limited, but is usually 2 nm to 5 μm, preferably 2 to 200 nm. In the present invention, it is preferably in the range of 10 to 20 nm. If it is too thin, it is difficult to obtain film uniformity. If it is thicker than this, a high voltage is required to obtain light emission, which is not preferable. A film thickness of 20 nm or less is preferable because it has the effect of improving the stability of the emission color with respect to the driving current as well as the voltage surface.

  The thickness of each light emitting layer is preferably selected in the range of 2 to 100 nm, and more preferably in the range of 2 to 20 nm. Although there is no restriction | limiting in particular about the film thickness relationship of each light emitting layer of blue, green, and red, It is preferable that the blue light emitting layer (the sum total when there are two or more layers) is the thickest among three light emitting layers.

  Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, the blue light emitting layer may be used by mixing a blue light emitting compound having a maximum wavelength of 430 to 480 nm and a green light emitting compound having the same wavelength of 510 to 550 nm.

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

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

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

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, as well as 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-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. It is also possible to use so-called p-type hole transport materials as described in the literature (Applied Physics Letters 80 (2002), p. 139). In the present invention, it is preferable to use these materials 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 5-200 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, JP-A-2001-102175, J.A. 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.

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

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum. Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.

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

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. Or 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. The surface of the resin film may be formed with an inorganic film, an organic film, or a hybrid film of both, and is preferably a barrier film having a water vapor permeability of 0.01 g / m ² / day · atm or less. Furthermore, a high barrier film having an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day 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 intrusion of elements such as moisture and oxygen, and silicon oxide, silicon dioxide, silicon nitride, and 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 method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, 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.

<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.

  The sealing member may be disposed so as to cover the display area of the organic EL element, and may be concave or flat. 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 preferably has an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less.

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

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

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

  In addition, it is also preferable to coat the electrode and the organic layer on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and form an inorganic or organic layer in contact with the support substrate to form a sealing film. it can. In this case, as a material for forming the film, any material may be used as long as it has a function of suppressing the intrusion of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil is injected in the gas phase and the liquid phase. Is preferred. A vacuum can also be used. 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), 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, barium perchlorate, Magnesium perchlorate), 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 outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, etc. used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light 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 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 side surface of the device.

  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 transparent substrate and the air interface (US Pat. No. 4,774,435), A method of improving efficiency by providing light condensing property (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on the side surface of the element (Japanese Patent Laid-Open No. 1-220394), and between the substrate and the light emitter A method of introducing an antireflection film by introducing a flat layer having an intermediate refractive index (Japanese Patent Laid-Open No. 62-172691), and a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter. (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer, and the light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951).

  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 low refractive index medium 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. Furthermore, it is preferable that it is 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 is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction. Of the light, light that cannot go out due to total reflection between layers, etc., is diffracted by introducing a diffraction grating in any layer or medium (in the transparent substrate or transparent electrode) It tries to take out light.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. 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 one of the layers or in the medium (in the transparent substrate or 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 to provide, for example, a microlens array-like structure on the light extraction side of the substrate, or is combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the light emitting surface By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 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, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may be used.

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

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

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

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

  As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. In the present invention, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is particularly preferable.

  In the present invention, in the formation of the light emitting layer, it is preferable to form a film by a coating method using a solution in which the compounds represented by the general formulas (1) to (6) according to the present invention are dissolved or dispersed. The method is preferably an ink jet method.

  Examples of the liquid medium for dissolving or dispersing the compounds represented by the general formulas (1) to (6) according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, and dichlorobenzene. Organic solvents such as halogenated hydrocarbons, DMF, DMSO and the like 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 forming these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably 50 to 200 nm, and by providing a cathode. A desired organic EL element is obtained.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. Examples of 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, and light sources for optical sensors. However, the present invention is not limited to this, but it can be effectively used particularly as a backlight of a liquid crystal display device and a light source for illumination.

  In the organic EL device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

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

Example 1
<Preparation of Organic EL Element 1-1>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm 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 α-NPD is put in a molybdenum resistance heating boat, and 200 mg of CBP as a host compound is put in another resistance heating boat made of molybdenum. 200 mg of HB-1 was put into a resistance heating boat made of molybdenum, 100 mg of D-1 was put into another resistance heating boat made of molybdenum, and 200 mg of Alq ₃ was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided. Further, the heating boat containing CBP and D-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.012 nm / sec, respectively, to obtain a film thickness of 40 nm. The light emitting layer was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature. Furthermore, the electron transport layer that also serves as a hole blocking function with a film thickness of 10 nm is formed by energizing and heating the heating boat containing HB-1 and vapor-depositing the light-emitting layer at a deposition rate of 0.1 nm / sec. Was provided. Further, the heating boat containing Alq ₃ was further energized and heated, and was deposited on the electron transport layer at a deposition rate of 0.1 nm / sec to further provide an electron injection layer having a thickness of 40 nm. . In addition, the substrate temperature at the time of vapor deposition was room temperature.

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

<Preparation of organic EL elements 1-2 to 1-20>
In the production of the organic EL element 1-1, organic EL elements 1-2 to 1-20 were produced in the same manner except that the light emitting host and the light emitting dopant were changed as shown in Table 1.

<Evaluation of organic EL element>
The non-light-emitting surface of each organic EL element after fabrication is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photo-curing adhesive (LUX Track 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, as shown in FIGS. Such a lighting device was formed and evaluated.

  FIG. 1 shows a schematic diagram of a lighting device, in which an organic EL element 101 is covered with a glass cover 102 (note that the sealing operation with the glass cover is performed without bringing the organic EL element 101 into contact with the atmosphere. (It was performed in a glove box under an atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more)). FIG. 2 shows a cross-sectional view of the lighting device. In FIG. 2, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(External extraction quantum efficiency)
About the produced organic EL element, the external extraction quantum efficiency (%) when a ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Minolta) was used.

  The measurement results of the external extraction quantum efficiency in Table 1 are shown as relative values when the measured value of the organic EL element 1-1 is 100.

(Luminescent life)
When driving at a constant current of ^2.5 mA / cm ² , the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, and this was calculated as the half-life time (τ _1/2 ) As an index of life. In addition, the spectral radiance meter CS-1000 (made by Minolta) was similarly used for the measurement. The measurement result of the light emission lifetime is shown as a relative value when the organic EL element 1-1 is 100.

  From Table 1, it was found that the organic EL device of the present invention has high luminous efficiency and a long lifetime.

Example 2
<Preparation of organic EL element 2-1>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm 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 α-NPD is put in a molybdenum resistance heating boat, and 200 mg of CBP as a host compound is put in another resistance heating boat made of molybdenum. 200 mg of HB-1 was put into a resistance heating boat made of molybdenum, 100 mg of D-1 was put into another resistance heating boat made of molybdenum, and 200 mg of Alq ₃ was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided. Further, the heating boat containing CBP was energized and heated, and vapor deposition was performed so that the film thickness was 10 nm at a vapor deposition rate of 0.1 nm / second to 0.2 nm / second, and an electron blocking layer was provided.

Further, the heating boat containing CBP and D-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.012 nm / sec, respectively, to obtain a film thickness of 40 nm. The light emitting layer was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature. Furthermore, the electron transport layer that also serves as a hole blocking function with a film thickness of 10 nm is formed by energizing and heating the heating boat containing HB-1 and vapor-depositing the light-emitting layer at a deposition rate of 0.1 nm / sec. Was provided. Further, the heating boat containing Alq ₃ was further energized and heated, and was deposited on the electron transport layer at a deposition rate of 0.1 nm / sec to further provide an electron injection layer having a thickness of 40 nm. . In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 2-1 was produced.

  This organic EL element was sealed using a sealing can having the same method and the same structure as in Example 1 to produce a flat lamp.

<Preparation of organic EL elements 2-2 to 2-32>
In the production of the organic EL element 2-1, the organic EL elements 2-2 to 2-32 were produced in the same manner except that the materials of the light emitting host, the light emitting dopant, and the electron blocking layer were changed as shown in Table 2. .

<Evaluation of organic EL element>
The produced organic EL element was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 2. External extraction quantum efficiency and light emission lifetime are relative values with the organic EL element 2-1 as 100 respectively.

  From Table 2, it is clear that the organic EL device produced using the metal complex according to the present invention can achieve higher luminous efficiency and longer lifetime than the organic EL device of the comparative example.

Example 3
<Preparation of organic EL element 3-1>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD is put in a molybdenum resistance heating boat, and 200 mg of CBP as a host compound is put in another resistance heating boat made of molybdenum. 200 mg of HB-1 was put into a resistance heating boat made of molybdenum, 100 mg of D-1 was put into another resistance heating boat made of molybdenum, and 200 mg of Alq ₃ was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided. Further, the heating boat containing CBP and D-1 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / sec and 0.012 nm / sec, respectively, to obtain a film thickness of 40 nm. The light emitting layer was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature. Furthermore, the electron transport layer that also serves as a hole blocking function with a film thickness of 10 nm is formed by energizing and heating the heating boat containing HB-1 and vapor-depositing the light-emitting layer at a deposition rate of 0.1 nm / sec. Was provided. Further, the heating boat containing Alq ₃ was further energized and heated, and was deposited on the electron transport layer at a deposition rate of 0.1 nm / sec to further provide an electron injection layer having a thickness of 40 nm. . In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 3-1 was produced.

<Preparation of organic EL elements 3-2 to 3-20>
In the production of the organic EL element 3-1, organic EL elements 3-2 to 3-20 were produced in the same manner except that the light emitting host, the light emitting dopant, and the hole block layer material were changed as shown in Table 3.

<Evaluation of organic EL element>
The produced organic EL element was evaluated in the same manner as in Example 1, and the obtained results are shown in Table 3. The external extraction quantum efficiency and the light emission lifetime are expressed as relative values with the organic EL element 3-1 as 100, respectively.

  From Table 3, it is clear that the organic EL device produced using the metal complex according to the present invention can achieve higher light emission efficiency and longer life than the organic EL device of the comparative example.

Example 4
The electrode of the transparent electrode substrate of Example 1 was patterned to 20 mm × 20 mm, and α-NPD was formed as a hole injection / transport layer with a thickness of 50 nm thereon as in Example 1, and The heated boat, the boat containing D-1 and the boat containing Btp ₂ Ir (acac) were energized independently, respectively, and the compound 16 as the light emitting host and the light emitting dopants D-1 and Btp ₂ Ir The vapor deposition rate of (acac) was adjusted to 100: 5: 0.6, and the light emitting layer was provided by vapor deposition to a thickness of 30 nm.

Next, HB-1 was deposited to a thickness of 10 nm to provide an electron transport layer. Furthermore, Alq ₃ was deposited at 40 nm to provide an electron injection layer.

  Next, the vacuum chamber is opened, and a square perforated mask having the same shape as the transparent electrode made of stainless steel is placed on the electron injection layer, and 0.5 nm of lithium fluoride is deposited as a cathode buffer layer and 110 nm of aluminum is deposited as a cathode. A film was formed.

  This organic EL element was sealed using a sealing can having the same method and the same structure as in Example 1 to produce a flat lamp.

  When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device. It has been found that white light emission can be obtained in the same manner even when the light emitting host is replaced with another compound of the present invention.

It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Organic EL element 102 Glass cover 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 108 Nitrogen gas 109 Water catching agent

Claims (33)

An organic electroluminescent device comprising at least a light emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescent device contains a compound represented by the following general formula (1).

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, R ₁ represents a hydrogen atom or a substituent, and Z ₁ is necessary to form a 5- or 6-membered heterocyclic ring. Represents a residue, and a part of Ar ₁ and Ar ₂ , Ar ₃ and Ar ₄ can form a new ring.) An organic electroluminescence device sandwiched between an anode and a cathode and containing at least a light emitting layer, comprising a compound represented by the following general formula (2):

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, Z 2 represents a residue necessary to form a 5-membered heterocyclic ring, Ar ₁ and Ar ₂ , Ar ₃ and A new ring can be formed with a part of Ar _4. ) An organic electroluminescence device comprising at least a light emitting layer sandwiched between an anode and a cathode, comprising an organic electroluminescence device comprising a compound represented by the following general formula (3).

(In the formula, Ar _{1 to} Ar ₄ represent an aromatic group or an aromatic heterocyclic group, Z 3 represents a residue necessary to form a 6-membered heterocyclic ring containing at least one nitrogen atom, and Ar ₁ And a part of Ar ₂ , Ar ₃ and Ar ₄ can form a new ring.) An organic electroluminescence device comprising at least a light-emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescence device comprises a compound represented by the following general formula (4).

(Wherein R _{1 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 1 represents 5 Represents a residue necessary to form a 6-membered or 6-membered heterocyclic ring.) An organic electroluminescence device comprising at least a light emitting layer sandwiched between an anode and a cathode, comprising an organic electroluminescence device comprising a compound represented by the following general formula (5).

(Wherein R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 2 represents 5 Represents the residues necessary to form a membered heterocyclic ring.) An organic electroluminescent device comprising at least a light emitting layer sandwiched between an anode and a cathode, wherein the organic electroluminescent device comprises a compound represented by the following general formula (6).

(In the formula, R _{2 to} R ₅ represent a hydrogen atom or a substituent, L ₁ and L ₂ represent a simple bond or a linking group, X _{1 to} X ₁₆ represent a carbon atom or a nitrogen atom, and Z 3 represents a complex. Represents a residue necessary to form a ring.) 7. The organic according to claim 1, 4 or 6, wherein Z1 in the general formulas (1) and (4) and Z3 in the general formula (6) are residues necessary for forming a pyridine ring. Electroluminescence element. The organic electroluminescence device according to claim 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a thiophene ring. The organic electroluminescence device according to claim 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a furan ring. The organic electroluminescence device according to claim 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrazole ring. 5. The organic electroluminescence device according to claim 1, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyridazine ring. The organic electroluminescent device according to claim 1 or 4, wherein Z1 in the general formula (1) or (4) is a residue necessary for forming a pyrimidine ring. 6. The organic electroluminescence device according to claim 2, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming an imidazole ring. 6. The organic electroluminescent device according to claim 2, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming an oxazole ring. 6. The organic electroluminescence device according to claim 2, wherein Z2 in the general formula (2) or (5) is a residue necessary for forming a thiazole ring. The organic electroluminescence device according to claim 3 or 6, wherein Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrimidine ring. 7. The organic electroluminescence device according to claim 3, wherein Z3 in the general formula (3) or (6) is a residue necessary for forming a pyrazine ring. 18. The L ₁ and L ₂ in the general formulas (4) to (6) are merely bonds, and X _{1 to} X ₁₆ are carbon atoms. Organic electroluminescence element. L ₁ and L ₂ in the general formulas (4) to (6) are merely bonds, and at least one of X _{1 to} X ₁₆ is a nitrogen atom. 2. The organic electroluminescence device according to item 1. The organic light-emitting device according to claim 1, wherein the light-emitting layer has a phosphorescent dopant. 21. The organic electroluminescence device according to claim 20, wherein a phosphorescence wavelength (0-0 band) of the phosphorescent dopant is 485 nm or less. The organic electroluminescence device according to claim 20 or 21, wherein an ionization potential of the phosphorescent dopant is 5.5 eV or less. 23. The organic electroluminescent element according to claim 1, wherein the phosphorescent dopant is a compound represented by the following general formula (A).

(In the formula, X ₁ , X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 1 represents a 5-membered heterocyclic ring, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring. M Represents Ir or Pt.) 24. The organic electroluminescence device according to claim 23, wherein the compound represented by the general formula (A) is represented by the following general formulas (B) to (E).

(In the general formula (B) ~ (E), X 2, X 3 represents a carbon atom or a nitrogen _{atom, Y 1, Y 5, Y} 9 represents a sulfur atom, a carbon atom or a nitrogen atom, Y _2, Y ₃ , Y ₄ , Y ₆ , Y ₇ , Y ₈ , Y ₁₀ , Y ₁₁ , Y _{12 each} represents a carbon atom or a nitrogen atom, and Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring. Represents Ir or Pt.) 23. The organic electroluminescent element according to claim 1, wherein the phosphorescent dopant is a compound represented by the following general formula (F).

(In the formula, X ₂ and X ₃ represent a carbon atom or a nitrogen atom, Z 2 represents a 6-membered aromatic ring or a 5- or 6-membered heterocyclic ring, R ₂ and R ₃ represent a hydrogen atom or a substituent, R ₄ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and M represents Ir or Pt.) 26. The organic electroluminescence device according to claim 1, wherein the compounds represented by the general formulas (1) to (6) are used as a host of the light emitting layer. 27. The organic electroluminescence device has an electron blocking layer, and the compounds represented by the general formulas (1) to (6) are used for the electron blocking layer. The organic electroluminescent element of description. The organic electroluminescence device has a hole blocking layer, and the compounds represented by the general formulas (1) to (6) are used for the hole blocking layer. The organic electroluminescent element of description. The organic electroluminescence device according to any one of claims 1 to 28, which emits white light. A display device comprising the organic electroluminescence element according to claim 1. It has an organic electroluminescent element of any one of Claims 1-28, The illuminating device characterized by the above-mentioned. 32. A display device comprising the lighting device according to claim 31 and a liquid crystal element as display means. An organic electroluminescence element material, which is a compound represented by the general formulas (1) to (6).

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