JP5556929B2 - Organic electroluminescence element material - Google Patents

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, injects electrons and holes into the light emitting layer, and recombines them to generate excitons (exciton). It is 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 volts to several tens of volts, and is also self-luminous. In addition, it is attracting attention from the viewpoints of space saving, portability and the like because it is a thin film type complete solid element with a wide viewing angle and high visibility.

  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 a 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 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%. Since the efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (MA Baldo et al., Nature, 395, 151-154 (1998)), 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 the excited triplet is used, the upper limit of the internal quantum efficiency is 100%. In principle, the luminous efficiency is four times that of the excited singlet, and there is a possibility that almost the same performance as a cold cathode tube can be obtained. Therefore, it is attracting attention as a lighting application.

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

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, 403, 17, 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), for example, (ppy) ₂ Ir (acac) as a dopant, e. 0 g, Tetsuo Tsutsui, etc., again The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), the dopant as tris (2-(p-tolyl) pyridine) iridium (Ir (ptpy) _3), tris ( Studies using benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like are being conducted (note that these metal complexes are generally called orthometalated iridium complexes).

  The S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) and Japanese Patent Application Laid-Open No. 2001-247859, etc., attempts have been made to form devices using various iridium complexes.

  In order to obtain high luminous efficiency, in the 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), Ikai et al. Uses a hole transporting compound as a host of a phosphorescent compound.

  In addition, M.M. E. Thompson et al. Use various electron transporting materials as a host of phosphorescent compounds, doped with a novel iridium complex.

  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 are known in which ligands are characterized.

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

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

  In addition, regarding wavelength shortening, introduction of an electron withdrawing group such as a fluorine atom, a trifluoromethyl group, and a cyano group into phenylpyridine as a substituent, and picolinic acid and pyrazabole-based ligands as ligands However, with these ligands, the emission wavelength of the luminescent material is shortened to achieve a blue color, and a high-efficiency device can be achieved. There was a need to improve the trade-off.

  A metal complex having phenylpyrazole substituted with a phenyl group as a ligand is known (for example, see Patent Documents 1 and 2).

  However, although the phenyl radical substitution mode disclosed herein improves the light emitting device lifetime, it is still not sufficient, and there is still room for improvement from the viewpoint of light emission efficiency.

  On the other hand, the knowledge that a ligand having a sterically hindered substituent is good for improving the luminance of light emission has been obtained, and an example in which the ligand is applied to a phenylpyrazole mother nucleus is also seen (for example, see Patent Document 3). ).

  Examples of metal complexes in which phenylimidazole is used as a basic skeleton as a ligand and various substituents are introduced are disclosed (for example, see Patent Documents 4, 5 and 7). Here, although the emission wavelength, the drive characteristics of the device, the external quantum efficiency, and the chromaticity are shown, the lifetime of the light-emitting device is not particularly mentioned.

  Furthermore, an example of a light-emitting element including a metal complex having phenylimidazole, phenyltriazole, or phenyltetrazole as a basic skeleton is disclosed (for example, see Patent Document 6).

  Here, although the driving characteristics, external quantum efficiency, and chromaticity of the device are shown, the lifetime of the light emitting device is not particularly mentioned.

International Publication No. 04/085450 Pamphlet JP 2005-53912 A JP 2003-109758 A International Publication No. 05/007767 Pamphlet JP 2005-68110 A US Patent No. 2006-0008670 WO 06/009024 Pamphlet

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

The above object of the present invention has been achieved by the following configurations 1 to 18.
Specifically, according to the present invention, in Configuration 1, R represents a cycloalkyl group, an aromatic hydrocarbon ring group, or a heterocyclic group, and Y ₁ represents a —C (Ra) — group (Ra represents a hydrogen atom or An organic electroluminescent device material is provided in which Y ₂ represents N.

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

[Wherein, R represents an alkyl group, a cycloalkyl group, an aromatic hydrocarbon ring group or a heterocyclic group, and Y ₁ and Y ₂ each represent a —C (Ra) — group (Ra represents a hydrogen atom or a substituent Represents N) or N. Z ₁ , Z ₂ , Z ₃ , and Z _{4 each} represent —C (Rb) — group (Rb represents a hydrogen atom or a substituent) or N, and each of Z ₁ , Z ₂ , Z ₃ , and Z ₄ represents At least one represents N. X ₁ -L ₁ -X ₂ represents a bidentate ligand, and X ₁ and X ₂ each independently represent a carbon atom, a nitrogen atom or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table. ]
2. 2. The organic electroluminescence element material according to 1, wherein the general formula (1) is a metal complex represented by the following general formula (2).

[In the formula, Z represents an atomic group necessary for forming a hydrocarbon ring group or a heterocyclic group, R 1 represents a substituent, and the substituent is a hydrocarbon ring group formed by Z or The steric parameter value (Es value) bonded to the atom adjacent to the atom at the bonding site between the heterocyclic group and the nitrogen atom is -0.5 or less. Y _1, Y ₂ are each synonymous with Y _1, Y ₂ in the general formula (1). _{Z 1, Z 2, Z 3} , Z 4 are each the same meaning as _{Z 1, Z 2, Z 3} , Z 4 in the general formula (1). X ₁ -L1-X ₂ are each synonymous with X _1, L1, X ₂ in the general formula (1). m1, m2, and m1 + m2 are also synonymous with the general formula (1). M ₁ has the same meaning as M ₁ in the general formula (1). ]
3. 3. The organic electroluminescence element material according to 2, wherein the general formula (2) is a metal complex represented by the following general formula (3).

[Wherein R ₁ represents a substituent having a steric parameter value (Es value) of −0.5 or less. R ₂ and R ₃ each represent a hydrogen atom or a substituent, n1 represents an integer of 1 to 2, and n2 represents an integer of 1 to 4. _{Z 1, Z 2, Z 3} , Z 4 are each the same meaning as _{Z 1, Z 2, Z 3} , Z 4 in the general formula (1). X ₁ -L1-X ₂ has the same meaning as X _1, L1, X ₂ of each general formula (1). m1, m2, and m1 + m2 are also synonymous with the general formula (1). M ₁ has the same meaning as M ₁ in formula (1). ]
4). 4. The organic electroluminescence element material according to 3, wherein the general formula (3) is a metal complex represented by the following general formula (4).

[Wherein R ₁ and R ₄ each represent a substituent having a steric parameter value (Es value) of −0.5 or less. R ₂ and R ₃ each represent a hydrogen atom or a substituent, n1 represents 1 or 2, and n2 represents an integer of 1 to 3. _{Z 1, Z 2, Z 3} , Z 4 are each the same meaning as _{Z 1, Z 2, Z 3} , Z 4 in the general formula (1). X ₁ -L1-X ₂ has the same meaning as X _1, L1, X ₂ of each general formula (1). m1, m2, and m1 + m2 are also synonymous with the general formula (1). M ₁ has the same meaning as M ₁ in formula (1). ]
5. At least one Rb of the groups represented by —C (Rb) — in Z ₁ , Z ₂ , Z ₃ and Z ₄ represents a substituent having a steric parameter value (Es value) of −0.5 or less. 5. The organic electroluminescent element material according to any one of 1 to 4 above, wherein

6). 5. The organic electroluminescent element material according to any one of 1 to 4, wherein m2 in the general formulas (1) to (4) is 0.

7). 7. The organic electroluminescence device material according to any one of 2 to 6, wherein in any one of the metal complexes of the general formulas (2) to (4), R ₁ represents an electron donating group. .

8). 7. The organic electroluminescent element material according to any one of 4 to 6, wherein R ₁ and R _{4 in} the general formula (4) both represent an electron donating group.

9. 9. The organic electroluminescence element material according to any one of 1 to 8, wherein M ₁ is iridium.

10. 9. The organic electroluminescence element material according to any one of 1 to 8, wherein M ₁ is platinum.

11. 11. The organic electroluminescence element material according to any one of 1 to 10, wherein the first emission wavelength is in the range of 400 nm to 500 nm.

12 12. The organic electroluminescence device as described in any one of 1 to 11 above, comprising a polymer having a metal complex represented by any one of the general formulas (1) to (4) as a partial structure. material.

13. The organic electroluminescent element material of any one of said 1-12 is contained, The organic electroluminescent element characterized by the above-mentioned.

14 14. The organic electroluminescent device according to 13, wherein the organic electroluminescent device comprises a light emitting layer as a constituent layer, and the light emitting layer contains the organic electroluminescent device material described in any one of 1 to 12 above.

15. A light-emitting layer as a constituent layer, and the light-emitting layer contains a carboline derivative or a derivative having a ring structure in which at least one of carbon atoms of a hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom 15. The organic electroluminescence device as described in 13 or 14 above.

16. It has a hole blocking layer as a constituent layer, and the hole blocking layer has a ring structure in which at least one of carbon atoms of a carboline derivative or a hydrocarbon ring constituting a carboline ring of the carboline derivative is substituted with a nitrogen atom. 16. The organic electroluminescence device according to any one of 13 to 15, wherein the organic electroluminescence device comprises a derivative.

17. 17. A display device comprising the organic electroluminescence element according to any one of 13 to 16.

18. A lighting device comprising the organic electroluminescence element according to any one of 13 to 16.

  According to the present invention, an organic EL element material having a controlled emission wavelength, high emission efficiency, and a long emission lifetime, an organic EL element using the same, an illumination device, and a display device can be provided.

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

  In the organic EL element material of the present invention, the molecular design of the organic EL element material useful for the organic EL element has been successfully achieved by the constitution defined in any one of claims 1-12.

  In addition, by using the organic EL element material, it was possible to provide an organic EL element, an illumination device, and a display device that have a light emission wavelength controlled, a high light emission efficiency, and a long light emission lifetime.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  The metal complex which concerns on the organic EL element material of this invention is demonstrated.

  As a result of intensive studies on the above problems, the present inventors have used the metal complexes represented by the general formulas (1), (2), (3) or the general formula (4) as organic EL element materials. It has been found that the organic EL element contained greatly improves luminous efficiency and luminous lifetime.

  The present inventors took a phenyl imidazole derivative as an example, and the stability of the complex was greatly influenced by the substitution position and type of the substituent on the phenyl imidazole, which is the mother nucleus, and this greatly affected the emission lifetime. I found out that

The present inventors have a specific ring structure of the metal complex according to the present invention (having a 1,3-diazole skeleton because it has a nitrogen atom at positions 1 and 3 in the 5-membered ring structure, provided that A substituent having a specific steric parameter or electronic parameter in Y ₁ and Y ₂ of formula (1) can form an imidazole ring, a triazole ring, a tetrazole ring, or the like. Organic EL manufactured using conventional blue metal complexes, especially organic EL element materials whose emission wavelength is controlled to the short wave side only by electron-withdrawing groups, by introducing heterocyclic or aromatic hydrocarbon ring groups It has been found that the light emission lifetime which has been a problem of the device is greatly improved, and the light emission efficiency and the light emission lifetime can be achieved at the same time.

  In addition, it was found that by specifying the substitution position, size, and electronic properties of the aromatic cyclic substituent as in the present invention, the lifetime of a blue light emitting device with excellent color purity can be further extended. Succeeded in greatly improving the light emission life of EL elements.

  The concept of the present invention will be described by taking an example of introducing a 2-phenylimidazole ring and further introducing an aromatic hydrocarbon ring such as a phenyl group at the N-position of 2-phenylimidazole.

  That is, it is known that introduction of a phenyl group at the N-position of 2-phenylimidazole is difficult in terms of synthesis as compared with the case where a linear alkyl group is introduced at the N-position. In addition, the metal complex using this ligand has a characteristic that the emission wavelength is long and the waveform is broadened.

  This suggests that the conjugated system is not cleaved even though the phenyl group on the N-position is via a nitrogen atom, and the emission wavelength is broad, for example, the ligand of the N-methyl body It can be explained that the existence probability of the vibration level due to the rotation is remarkably increased even when compared with. This assumption is also supported by molecular orbital calculations by GAUSSIAN.

As a result of intensive studies, the inventors have introduced 1) a cyclic substituent having a bulky substituent at the ortho position at the N-position of phenylimidazole, 1) increasing the twist of the phenyl group, cutting the conjugated system, Shortening the wave 2) Decreasing the probability of vibration level by suppressing free rotation by bulky substituents 3) Significantly improving molecular stability by protecting the oxidizable N-position with bulky substituents 4) Combining the size of the substituted atom and the electronic effect makes it possible to achieve both shorter wave length and longer life. The present inventors have found the above effects and completed the present invention.

  Moreover, even if it is a ligand which has a mother nucleus based on this invention, the light emission wavelength of a metal complex is made into a desired area | region by introduce | transducing as a substituent the auxiliary | assistant ligand to combine and a substituent itself long wave. Can be controlled. Therefore, the molecular design for imparting the function of controlling the emission wavelength of the metal complex to a long wave region (green to red) is represented by the general formulas (1), (2), (3) or the general formula ( This is possible by using 4) as a starting point for basic skeleton design.

(Ligand)
For example, when the metal complex according to the present invention is described in the above general formula (1), when m1> m2, the partial structure shown in parentheses having m1 or a partial structure represented by a tautomer thereof is mainly used. A partial structure shown in parentheses having m2 or a partial structure represented by a tautomer thereof is called a sub-ligand.

  In the present invention, as represented by the general formula (1), the metal complex is composed of a combination of a main ligand or a tautomer thereof and a subligand or a tautomer thereof, As will be described later, in the case of m2 = 0, that is, all of the ligands of the metal complex may be composed only of a partial structure represented by the main ligand or a tautomer thereof.

  Furthermore, as a so-called ligand used for forming a conventionally known metal complex, the trader may have a well-known ligand (also referred to as a coordination compound) as a ligand as necessary.

  From the viewpoint of preferably obtaining the effects described in the present invention, the type of ligand in the complex is preferably composed of 1 to 2 types, and more preferably 1 type.

  There are various known ligands used in conventionally known metal complexes. For example, “Photochemistry and Photophysics of Coordination Compounds” Springer-Verlag H. Published by Yersin, 1987, “Organometallic Chemistry-Fundamentals and Applications-” Liu Huabosha, Akio Yamamoto, published by 1982, etc. (for example, halogen ligands (preferably chlorine ligands), Nitrogen heterocyclic ligands (for example, bipyridyl, phenanthroline, etc.) and diketone ligands).

(Transition metal element of group 8-10 of the periodic table)
As a metal used for formation of the metal complex represented by the general formulas (1), (2), (3) and the general formula (4) according to the present invention, a transition metal of group 8 to 10 of the periodic table Elements (also simply referred to as transition metals) are used, among which iridium and platinum are preferable transition metal elements.

  Furthermore, by using such an organic EL element material, it was possible to provide an organic EL element, an illuminating device, and a display device that have a light emission wavelength controlled, a high light emission efficiency, and a long light emission lifetime.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  The metal complex which is the organic EL element material of the present invention will be described.

  As the content layer of the metal complex represented by the general formula (1), (2), (3) or the general formula (4) according to the present invention, a light emitting layer and / or an electron blocking layer are preferable. In the case where it is contained in the organic EL device, it can be used as a light emitting dopant in the light emitting layer, so that the efficiency of the external extraction quantum efficiency of the organic EL device of the present invention can be increased (high luminance) and the light emission life can be extended.

  Here, the metal complex represented by the general formula (1), (2), (3) or the general formula (4) according to the present invention will be described.

<< Metal Complex Represented by General Formula (1) >>
The metal complex represented by the general formula (1) according to the present invention will be described.

  In the general formula (1), examples of the alkyl group represented by R include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, and a tridecyl group. , Tetradecyl group, pentadecyl group and the like.

  These groups may further have a substituent represented by Ra described later.

  In the general formula (1), examples of the cycloalkyl group represented by R include a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

  These groups may further have a substituent represented by Ra described later.

  In the general formula (1), examples of the aromatic hydrocarbon ring group represented by R (also referred to as aromatic hydrocarbon group, aromatic carbocyclic group, and aryl group) include a phenyl group, a p-chlorophenyl group, Examples include mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, and biphenylyl group.

  These groups may further have a substituent represented by Ra described later.

  In the general formula (1), examples of the heterocyclic group represented by R include a non-aromatic heterocyclic group and an aromatic heterocyclic group. Examples of the non-aromatic heterocyclic group include an epoxy ring and an aziridine group. Ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε- Caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine Ring, thiomorpholine-1,1-dioxide And groups derived from a ring, a pyranose ring, a diazabicyclo [2,2,2] -octane ring, and the like.

  These groups may further have a substituent represented by Ra described later.

  Examples of the aromatic heterocyclic group include pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl). Group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group , Benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), quinoxalinyl Group, pyridazinyl group, triazinyl group, key Zoriniru group, phthalazinyl group, and the like.

  These groups may further have a substituent represented by Ra described later.

In the general formula (1), examples of the substituent represented by Ra of Y ₁ and Y ₂ 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.), aromatic hydrocarbon ring group (also called aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl Group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group Biphenylyl group, etc.), aromatic heterocyclic groups (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazole- 1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, Dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (in which one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom) ), Quinoxalinyl group, pyridazinyl group, tria Dinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, Hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, Methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group) Naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, Naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, 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, ethylcarbo group) Group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy) Group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propyl) Carbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecyl Carbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group) Octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentyl) Ureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc. Sulfinyl group (eg, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl Group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group) , 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentyl) Mino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg. , Fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group) Group, phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents.

  A plurality of these substituents may be bonded to each other to form a ring, and when a plurality of C (Ra) are present, each Ra may be the same or different and are connected to each other. A ring may be formed.

In the general formula (1), the substituent represented by Rb of Z ₁ , Z ₂ , Z ₃ and Z _{4 has} the same meaning as the substituent represented by Ra of Y ₁ and Y _{2 in} the general formula (1). It is. When a plurality of C (Rb) are present, each Rb may be the same or different, and may be linked to each other to form a ring.

Specific examples of the bidentate ligand represented by X ₁ -L1-X ₂ in the general formula (1) include phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, acetylacetone, picoline An acid etc. are mentioned.

In the general formula (1), a transition metal element of group 8 to group 10 (also simply referred to as a transition metal) in the periodic table of elements is used as M ₁ , and among them, iridium and platinum are preferable transition metal elements.

  In the general formula (1), m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3, and m2 is preferably 0.

<< Metal Complex Represented by General Formula (2) >>
The metal complex represented by the general formula (2) according to the present invention will be described.

  In the general formula (2), examples of the hydrocarbon ring group formed by Z include a non-aromatic hydrocarbon ring group and an aromatic hydrocarbon ring group, and examples of the non-aromatic hydrocarbon ring group include a cyclopropyl group. , Cyclopentyl group, cyclohexyl group and the like. These groups may be unsubstituted or may have the above-described substituent.

  Examples of the aromatic hydrocarbon ring group (also referred to as aromatic hydrocarbon group, aryl group, etc.) include, for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like. These groups may be unsubstituted or may have the above-described substituent.

  In the general formula (2), examples of the heterocyclic group formed by Z include those having the same meaning as the heterocyclic group represented by R in the general formula (1).

  In the general formula (2), R 1 represents a substituent, and the substituent is bonded to an atom adjacent to the atom at the bonding site between the hydrocarbon ring group or heterocyclic group formed by Z and the nitrogen atom. The steric parameter value (Es value) is −0.5 or less, and among them, an electron donating group is preferable.

  Hereinafter, the three-dimensional parameter value (Es value) will be described.

(3D parameter value (Es value))
In the present invention, the Es value is a steric parameter derived from chemical reactivity. The smaller this value, the more sterically bulky substituent can be said.

  In general, in ester hydrolysis under acidic conditions, it is known that the influence of substituents on the progress of the reaction may only be considered as steric hindrance. The Es value is obtained by quantifying the steric hindrance.

The Es value of the substituent X is expressed by the following chemical reaction formula: X—CH ₂ COORX + H ₂ O → X—CH ₂ COOH + RXOH
The reaction rate constant kX for hydrolyzing an α-monosubstituted acetic acid ester derived from α-monosubstituted acetic acid in which one hydrogen atom of the methyl group of acetic acid is substituted with the substituent X represented by the formula And the following chemical reaction formula CH ₃ COORY + H ₂ O → CH ₃ COOH + RYOH
(RX is the same as RY), which is obtained from the reaction rate constant kH when the acetate corresponding to the α-monosubstituted acetate described above is hydrolyzed under acidic conditions.

Es = log (kX / kH)
The reaction rate decreases due to the steric hindrance of the substituent X, and as a result, kX <kH, so the Es value is usually negative. When the Es value is actually obtained, the above two reaction rate constants kX and kH are obtained and calculated by the above formula.

  Specific examples of Es values are given by Unger, S. et al. H. Hansch, C .; , Prog. Phys. Org. Chem. 12, 91 (1976). The specific numerical values are also described in “Structure-activity relationship of drugs” (Regional Chemistry Special Issue 122, Nankodo) and “American Chemical Society Reference Book, 'Exploring QSAR' p.81 Table 3-3”. There is. Next, a part is shown in Table 1.

  Here, it should be noted that the Es value as defined in this specification is not defined by defining that of a methyl group as 0, but by assuming that a hydrogen atom is 0, and an Es value where a methyl group is 0. Minus 1.24.

  The Es value according to the present invention is −0.5 or less. Preferably it is -7.0--0.6. Most preferably, it is -7.0 to -1.0.

  Here, in the present invention, when a steric parameter value (Es value) is -0.5 or less, for example, a keto-enol tautomer may exist in Z, the keto moiety is regarded as an enol isomer. Es value is converted. Even when other tautomerism exists, the Es value is converted by the same conversion method. Furthermore, the substituent having an Es value of −0.5 or less is preferably an electron-donating substituent in terms of electronic effect.

(Electron donating group (electron donating substituent))
In the present invention, the electron-donating substituent is a substituent having a negative Hammett σp value as described below, and such a substituent has an electron on the bonding atom side compared to a hydrogen atom. Easy to give.

  Specific examples of the substituent exhibiting an electron donating property include a hydroxy group, an alkoxy group (for example, methoxy group), an acetyloxy group, an amino group, a dimethylamino group, an acetylamino group, and an alkyl group (for example, methyl group, ethyl group). Group, propyl group, t-butyl group and the like) and aryl group (for example, phenyl group, mesityl group and the like). For the Hammett σp value, for example, the following documents can be referred to.

The Hammett σp value according to the present invention refers to Hammett's substituent constant σp. Hammett's σp value is a substituent constant determined by Hammett et al. From the electronic effect of the substituent on the hydrolysis of ethyl benzoate. “Structure-activity relationship of drugs” (Nanedo: 1979), “Substituent” Constants for Correlation Analysis in Chemistry and Biology ”(C. Hansch a
nd A. Leo, John Wiley & Sons, New York, 1979) and the like can be cited.

<< Metal Complex Represented by General Formula (3) >>
The metal complex represented by the general formula (3) according to the present invention will be described.

In general formula (3), the substituent represented by R ₁ and having a steric parameter value (Es value) of −0.5 or less is synonymous with the substituent represented by R ₁ in general formula (2). .

In the general formula (3), the substituents represented by R ₂ and R ₃ have the same meaning as the substituents represented by Ra of Y ₁ and Y _{2 in} the general formula (1).

In addition, when several R < ₂ >, R < ₃ > exists, each R < ₂ >, R < ₃ > may be the same or different and may mutually connect and may form a ring.

<< Metal Complex Represented by Formula (4) >>
The metal complex represented by the general formula (4) according to the present invention will be described.

In the general formula (4), the steric parameter value (Es value) represented by each of R ₁ and R ₄ is −0.5 or less, and the substituent represented by R ₁ in the general formula (2) Each is synonymous.

Particularly preferred as R ₁ and R ₄ are both electron donating groups.

In the general formula (4), the substituents represented by R ₂ and R ₃ have the same meaning as the substituents represented by Ra of Y ₁ and Y _{2 in} the general formula (1).

In addition, when several R < ₂ >, R < ₃ > exists, each R < ₂ >, R < ₃ > may be the same or different and may mutually connect and may form a ring.

<< Emission wavelength of the metal complex represented by the general formulas (1) to (4) >>
The first emission wavelength of each metal complex represented by the general formulas (1) to (4) according to the present invention is preferably in the range of 400 nm to 500 nm.

  Here, the first emission wavelength refers to the shortest component of the emitted light that can be excited by the absorption wavelength of the metal complex, and the first emission wavelength is obtained by measurement using a fluorometer. I can do it.

<< Polymer containing any one of the general formulas (1) to (4) as a partial structure >>
In the present invention, a polymer (also referred to as a polymer) having a metal complex represented by any one of the above general formulas (1) to (4) as a partial structure is used as the organic EL element material of the present invention. Can do.

  Hereinafter, the metal complex represented by the general formula (1), (2), (3) or the general formula (4) according to the present invention, and the general formula (1), (2), (3) or the general formula Specific examples of the polymer having the metal complex represented by (4) as a partial structure are shown (metal complexes 3-2-25, 4-1-14, 4-2-22, 4-2-28, 4- 3-43, 4-3-55, and polymers 4, 5, and 6 are excluded.), The present invention is not limited to these compounds, such as these compounds may further have a substituent.

  These metal complexes are described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and synthesis by referring to methods such as references described in these documents. it can.

  Although the synthesis example of the metal complex based on this invention is shown below, this invention is not limited to these.

<< Synthesis of Exemplified Compound 4-4-64 >>

Step 1: Synthesis of Complex A 27.74 g (0.1 mol) of 5- (1-mesityl-1H-imidazol-2-yl) -2-methylpyridine and 14.1 g (0.04 mol) of iridium chloride. The trihydrate was refluxed for 18 hours in 500 ml of 2-ethoxyethanol and 170 ml of water with nitrogen bubbling.

  The reaction solution was concentrated, and the precipitated solid was collected with a 100 ml solution of water / methanol = 1/1. The solid was washed with water / methanol = 1/2 solution and dried to obtain 23.8 g (76.2 g) of complex A. %)Obtained.

The obtained complex A was a mixture of compounds ortho-metalated at the 2-position and 4-position of the pyridine ring. The structure of complex A was identified using ¹ H-NMR, ¹³ C-NMR, and the like.

Step 2: Synthesis of Complex B 20 g (0.01281 mol) of Complex A and 5.25 g (0.05190 mol) of acetylacetone and 20 g of sodium carbonate obtained in Step 1 were added to nitrogen in 400 ml of 2-ethoxyethanol. The mixture was refluxed for 3 hours while bubbling.

  After cooling the reaction solution, the salt is filtered off, the filtrate is concentrated, the solid precipitated with a 100 ml solution of water / methanol = 1/1 is collected by filtration, and the solid is washed and dried with a solution of water / methanol = 1/1. As a result, 14.8 g (68.5%) of complex B was obtained.

  The resulting complex B was a mixture of compounds ortho-metalated at the 2-position and 4-position of the pyridine ring.

Step 3: Synthesis of Exemplified Compound 4-4-64 10.0 g (0.01185 mol) of Complex B obtained in Step 2 and 8.22 g (0.02962 mol) of 5- (1-mesityl-1H) -Imidazol-2-yl) -2-methylpyridine was reacted in 350 ml of glycerol at an internal temperature of 150 ° C. to 170 ° C. for 5 hours while performing nitrogen bubbling.

  After cooling the reaction solution, 800 ml of methanol was added, and the precipitated solid was collected by filtration and dried to obtain 10.6 g of a solid.

  The obtained solid was a mixture of exemplified compounds 4-4-64 and 4-2-22, and a trisated complex ortho-metalated at the 2-position of some amount of the pyridine ring.

  This solid was separated and produced by silica gel column chromatography (hexane / tetrahydrofuran / triethylamine) to give 2.18 g (18.0%) of Exemplified Compound 4-4-64 and 4.52 g of Exemplified Compound 4-2-32 ( 37.3%).

In addition, the emission wavelength in the solution of exemplary compound 4-232 was 447 nm (the emission wavelength was measured in 2-methyltetrahydrofuran).
In the present invention, the emission wavelength of the exemplified compound was measured as follows. First, an absorption spectrum of the exemplary compound is measured, and an absorption maximum wavelength in the range of 300 nm to 350 nm is set as excitation light.

  Using the set excitation light, the emission wavelength is measured with a fluorometer F-4500 (manufactured by Hitachi, Ltd.) while performing nitrogen bubbling.

  In addition, although there is no restriction | limiting in the solvent which can be used, 2-methyltetrahydrofuran, a dichloromethane, etc. are used preferably from a soluble viewpoint of a compound.

The concentration at the time of measurement is preferably sufficiently diluted, and specifically, it is preferably measured in the range of 10 ⁻⁶ mol / l to 10 ⁻⁴ mol / l.

  Moreover, there is no restriction | limiting in particular as temperature at the time of measurement, However, Generally, it is preferable that temperature setting of the range of room temperature-77K is performed.

<< Application of organic EL element materials to organic EL elements >>
When producing the organic EL element of the present invention using the organic EL element material of the present invention, the organic EL element of the present invention is formed on the light emitting layer or the electron blocking layer in the constituent layers (details will be described later) of the organic EL element. It is preferable to use a material. Moreover, it is preferably used as the following light emitting dopant in the light emitting layer.

(Light emitting host and light emitting dopant)
The mixing ratio of the light-emitting dopant to the light-emitting host that is the host compound that is the main component in the light-emitting layer is preferably adjusted to a range of 0.1% by mass to less than 30% by mass.

  However, the light-emitting dopant may be a mixture of a plurality of types of compounds, and the partner to be mixed may be a phosphorescent dopant or a fluorescent dopant having a different structure, other metal complexes or other structures.

  Here, the dopant (phosphorescent dopant, fluorescent dopant, etc.) that may be used in combination with the metal complex used as the light emitting dopant will be described. Luminescent dopants are roughly classified into two types: fluorescent dopants that emit fluorescence and phosphorescent dopants that emit phosphorescence.

  Typical examples of the former (fluorescent dopant) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, Examples include perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  A typical example of the latter (phosphorescent dopant) is preferably a complex compound containing a transition metal element of Group 8, 9, or 10 in the periodic table, and more preferably an iridium compound or an osmium compound. Of these, iridium compounds are most preferred.

  Specifically, it is a compound described in the following patent publications.

  WO 00/70655 pamphlet, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859, JP 2002-299060, JP 2001-313178, JP 2002-302671, JP 2001-345183, JP 2002-324679, International Publication No. 02/15645 pamphlet, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, JP 20 JP-A-2-338588, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002. No. -173744, JP-A No. 2002-359082, JP-A No. 2002-17584, JP-A No. 2002-363552, JP-A No. 2002-184582, JP-A No. 2003-7469, JP-T-2002-525808. Gazette, JP2003-7471, JP2002-525833, JP2003-31366, JP2002-226495, JP2002-234894, JP2002-2335076 JP 2002-241751 A JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, JP 2002-343572, JP 2002-203678 gazette etc.

  Some specific examples are shown below.

(Light emitting host)
The host compound used in the present invention represents a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.01 at room temperature (25 ° C.) among compounds contained in the light emitting layer.

  The light-emitting host used in the present invention is not particularly limited in terms of structure, but is typically a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene. Examples thereof include compounds having a basic skeleton such as compounds, or carboline derivatives and derivatives having a ring structure in which at least one carbon atom of a hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom. Among these, carbazole derivatives, carboline derivatives, and derivatives having a ring structure in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom are preferably used.

  Specific examples are given below, but the present invention is not limited thereto. These compounds are also preferably used as hole blocking materials.

  In the light emitting layer according to the present invention, a plurality of known host compounds may be used in combination as a host compound. 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. As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are preferable.

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

  As the light-emitting host, a compound that has a hole transporting ability and an electron transporting ability, prevents an increase in the wavelength of light emission, and has a high Tg (glass transition temperature) is preferable.

  As specific examples of the light-emitting host, compounds described in the following documents are suitable. For example, Japanese Patent Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, JP2002-8860, JP2002-334787, JP2002-15871, JP2002-334788, JP2002-43056, JP2002-334789, JP JP 2002-75645 A, JP 2002-338579 A, JP 2002-105445 A, JP 2002-343568 A, JP 2002-141173 A, JP 2002-352957 A, JP 2002-2002 A. No. 203683, JP-A-2002-3632 7, JP 2002-231453, JP 2003-3165, JP 2002-234888, JP 2003-27048, JP 2002-255934, JP 2002-286061. JP, JP-A-2002-280183, JP-A-2002-299060, JP-A-2002-302516, JP-A-2002-305083, JP-A-2002-305084, JP-A-2002-308837, etc. .

  The light emitting layer may further contain a host compound having a fluorescence maximum wavelength as a host compound. In this case, the energy transfer from the other host compound and the phosphorescent compound to the fluorescent compound allows electroluminescence as an organic EL element to be emitted from the other host compound having a fluorescence maximum wavelength. A host compound having a fluorescence maximum wavelength is preferably a compound having a high fluorescence quantum yield in a solution state.

  Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific host compounds having a maximum fluorescence wavelength include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Perylene dyes, stilbene dyes, polythiophene dyes, and the like. The fluorescence quantum yield can be measured by the method described in 362 (1992, Maruzen) of Spectroscopic II of the Fourth Edition Experimental Chemistry Course 7.

  Next, a configuration of a typical organic EL element will be described.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described.

  Although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.

(I) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode (ii) Anode / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode (iii) anode / Hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode (iv) anode / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode ( v) Anode / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vi) anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer / Hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode 《Blocking layer (electron blocking layer, hole blocking layer)》
The blocking layer (for example, electron blocking layer, hole blocking layer) according to the present invention will be described.

  In the present invention, the organic EL device material of the present invention is preferably used for a hole blocking layer, an electron blocking layer, and the like, and particularly preferably used for a hole blocking layer.

  When the organic EL device material of the present invention is contained in the hole blocking layer and the electron blocking layer, the organic EL device material of the present invention described in any one of claims 1 to 7 is added to the hole blocking layer or It may be contained in a state of 100% by mass as a layer constituent component such as an electron blocking layer, or may be mixed with other organic compounds.

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

《Hole blocking layer》
The hole blocking layer has the function of an electron transport layer in a broad sense, and is made of a material that has a function of transporting electrons but has a very small ability to transport holes, and blocks holes while transporting electrons. Thus, the probability of recombination of electrons and holes can be improved.

  Examples of the hole blocking layer include, for example, JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization thereof (issued by NTT Corporation on November 30, 1998)” Can be applied as the hole blocking layer according to the present invention. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The organic EL device of the present invention has a hole blocking layer as a constituent layer, and at least one of the carbon atoms of the hydrocarbon ring constituting the carboline derivative or the carboline ring of the carboline derivative is a nitrogen atom. It is preferable to contain a derivative having a substituted ring structure.

《Electron blocking layer》
On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  In the present invention, the organic EL device material of the present invention is preferably used for the adjacent layer adjacent to the light emitting layer, that is, the hole blocking layer and the electron blocking layer, and particularly preferably used for the electron blocking layer.

《Hole transport layer》
The hole transport layer includes a 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 is not particularly limited, and is conventionally used as a hole charge injection / transport material in a photoconductive material, or used for a hole injection layer or a hole transport layer of an organic EL device. Any one of known ones can be selected and used.

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

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

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

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

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

  This 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, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, it is about 5 nm-5000 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

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

  Conventionally, in the case of a single-layer electron transport layer and a plurality of layers, the following materials are used as the electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the cathode side with respect to the light emitting layer. Are known.

  Further, the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any material can be selected and used from conventionally known compounds.

  Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, carbodiimides, Fluorenylidenemethane derivative, anthraquinodimethane and anthrone derivative, oxadiazole derivative, carboline derivative, or a ring in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom Examples thereof include derivatives having a structure. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or 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.

  Also, 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), etc., and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga, or Pb can also be used as an 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 transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  This 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, 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, it is about 5 nm-5000 nm. This electron transport layer may have a single layer structure composed of one or more of the above materials.

  Next, an injection layer 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, between the anode and the light emitting layer or the hole transport layer, and the cathode. You may exist between a light emitting layer or an electron carrying layer.

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

  Details of the anode buffer layer (hole injection layer) are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like, and a specific example is represented by copper phthalocyanine. Phthalocyanine buffer layers, oxide buffer layers typified by vanadium oxide, amorphous carbon buffer layers, polymer buffer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene, and the like.

  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. Examples include a metal buffer layer represented by an alkali metal compound buffer layer represented by lithium fluoride, an alkaline earth metal compound buffer layer represented by magnesium fluoride, and an oxide buffer layer represented by aluminum oxide.

  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 100 nm, although it depends on the material.

  This injection layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an injection | pouring layer, Usually, it is about 5 nm-5000 nm. The injection layer may have a single layer structure composed of one or more of the above materials.

"anode"
As the anode according to the organic EL device of the present invention, an electrode having a work function (4 eV or more) metal, alloy, electrically conductive compound and a mixture thereof as an electrode material is preferably used. Specific examples of such electrode substances include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode according to the present invention, a cathode having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof 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 1000 nm, preferably 50 nm to 200 nm. In order to transmit light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

<< Substrate (also referred to as substrate, substrate, support, etc.) >>
The substrate of the organic EL device of the present invention is not particularly limited as to the type of glass, plastic and the like, and is not particularly limited as long as it is transparent. Examples of the substrate preferably used include glass and quartz. And a light transmissive resin film. A particularly preferable substrate is a resin film that can give flexibility to the organic EL element.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose. Examples include films made of triacetate (TAC), cellulose acetate propionate (CAP), and the like.

An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , And a relative humidity (90 ± 2)% RH) of 0.01 g / (m ² · 24 h) or less is preferable.

  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 2% 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.

  Further, a hue improving filter such as a color filter may be used in combination.

  When used in lighting applications, a film (such as an antiglare film) that has been roughened to reduce unevenness in light emission can be used in combination.

  When used as a multicolor display device, it is composed of at least two types of organic EL elements having different light emission maximum wavelengths. A suitable example for producing an organic EL element will be described.

<< 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 / hole blocking layer / electron transport layer / cathode buffer layer / cathode. Will be described.

  First, a thin film made of a desired electrode material, for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm, thereby producing an anode. . Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, or an electron transport layer, which is an element material, is formed thereon.

As a method for thinning a thin film containing an organic compound, there are a spin coating method, a casting method, an ink jet method, a vapor deposition method, a printing method, and the like, but a homogeneous film is easily obtained and pinholes are not easily generated. In view of the above, the vacuum deposition method or the spin coating method is particularly preferable. Further, a different film forming method may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C., a vacuum degree of 10 ⁻⁶ Pa to 10 ⁻² Pa, and a vapor deposition rate of 0 It is desirable to select appropriately within a range of 0.01 nm / second to 50 nm / second, a substrate temperature of −50 ° C. to 300 ° C., and a film thickness of 0.1 μm to 5 μm.

  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 in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL device is preferably manufactured from the hole injection layer to the cathode consistently by a single vacuum, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

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

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  When patterning is performed only on the light-emitting layer, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  Moreover, it is also possible to reverse the production order to produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport 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. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. For example, it is not limited to this.

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

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However, It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display). The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

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

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

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

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

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

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

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

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

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

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

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be maintained until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.

  In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

  The organic EL material of the present invention can be applied as an illumination device to an organic EL element that emits substantially white light. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed. It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved. According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

  As described above, the white light emitting organic EL element according to the present invention is used as a kind of lamp such as household illumination, interior lighting, and exposure light source as various light emitting light sources and lighting devices in addition to the display device and display. It is also useful for display devices such as backlights for liquid crystal display devices.

  Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. In addition, the structure of the compound used for an Example is shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
After patterning on a substrate (made by NH Techno Glass Co., Ltd .: NA-45) having a 150 nm ITO film formed on glass as an anode, the transparent support substrate provided with this ITO transparent electrode was ultrasonically cleaned with iso-propyl alcohol. Then, it was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while α-NPD, H4, Ir-12, BCP, and Alq ₃ are placed in five tantalum resistance heating boats, respectively. (Vacuum chamber).

  Further, lithium fluoride was placed in a resistance heating boat made of tantalum, and aluminum was placed in a resistance heating boat made of tungsten, and attached to the second vacuum tank of the vacuum evaporation apparatus.

First, after reducing the pressure in the first vacuum tank to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD is energized and heated, and transparent at a deposition rate of 0.1 nm / second to 0.2 nm / second. It vapor-deposited so that it might become a film thickness of 20 nm on the support substrate, and provided the positive hole injection / transport layer.

  Further, the heating boat containing H4 and the boat containing Ir-12 are energized independently to adjust the deposition rate of H4 as a light emitting host and Ir-12 as a light emitting dopant to 100: 6. And it vapor-deposited so that it might become a film thickness of 30 nm, and provided the light emitting layer.

  Next, the heating boat containing BCP was energized and heated to provide a 10 nm thick hole blocking layer at a deposition rate of 0.1 nm / sec to 0.2 nm / sec.

Further, the heating boat containing Alq ₃ was energized and heated to provide an electron transport layer having a film thickness of 20 nm at a deposition rate of 0.1 nm / second to 0.2 nm / second.

  Next, after the element deposited up to the electron transport layer was transferred to the second vacuum chamber while being vacuumed, it was remotely controlled from the outside of the apparatus so that a stainless steel rectangular perforated mask was placed on the electron transport layer. Installed.

After reducing the pressure in the second vacuum chamber to 2 × 10 ⁻⁴ Pa, a cathode buffer layer having a film thickness of 0.5 nm was formed at a deposition rate of 0.01 nm / second to 0.02 nm / second by energizing a boat containing lithium fluoride. Then, a boat containing aluminum was energized, a cathode having a film thickness of 150 nm was attached at a deposition rate of 1 nm / second to 2 nm / second, and an organic EL device 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-40 >>
In the production of the organic EL element 1-1, organic EL elements 1-2 to 1-40 were produced in the same manner except that the light emitting host, the light emitting dopant, and the hole blocking material were changed as shown in Table 2.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 1-1 to 1-40, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 5 and 6 was formed and evaluated.

  FIG. 5 is a schematic view of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more). 6 shows a cross-sectional view of the lighting device. In FIG. 6, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, 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 quantum efficiency)
The organic EL element is turned on at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of 2.5 mA / cm 2, and the emission luminance (L) [cd / m 2] immediately after the start of lighting is measured. The extraction quantum efficiency (η) was calculated. Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance. The external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 as 100.

(Luminescent life)
The organic EL element was continuously lit at a constant current of ^2.5 mA / cm ² at room temperature, and the time (τ ^1/2 ) required to achieve half the initial luminance was measured. The light emission lifetime was expressed as a relative value at which the organic EL element 1-1 was set to 100.

(Luminescent color)
The organic EL element was visually evaluated for the color of light emitted when the organic EL element was continuously lit at a constant current of ^2.5 mA / cm ² at room temperature.

  The obtained results are shown in Table 2.

  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.

  In addition, it can be seen that the blue purity is higher than that of the organic EL element of the comparative example and is useful as a blue light emitting element. Furthermore, by using a carboline derivative or a derivative having a ring structure in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is further substituted with a nitrogen atom in the light emitting layer or the hole blocking layer. Furthermore, the effect of the present invention was improved.

  Further, when the elements 1-1 and 1-40 are manufactured, when the elements 1-1 and 1-40 are once exposed to the atmosphere for 24 hours before sealing and then sealed again under deaeration and nitrogen conditions, the elements 1-1 are externally taken out. While the efficiency and the light emission lifetime were 50% or less as compared with the results shown in Table 1, the element 1-40 showed no significant change.

  Therefore, it turned out that the organic EL element produced using the metal complex which concerns on this invention has very high oxidation deterioration tolerance compared with the organic EL element of a comparative example.

Example 2
<< Preparation of Organic EL Element 2-1 >>
An anode of indium tin oxide (ITO, indium / tin = 95/5 molar ratio) was formed on a glass support substrate of 25 mm × 25 mm × 0.5 mm by a sputtering method using a direct current power (thickness: 200 nm). The surface resistance of this anode was 10Ω / □.

  Polyvinylcarbazole (hole transporting binder polymer) / Ir-13 (blue light-emitting orthometalated complex) / 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4 -Oxadiazole (electron transport material) = A dichloroethane solution in which a mass ratio of 200/2/50 was dissolved was applied by a spin coater to obtain a light-emitting layer having a thickness of 100 nm.

  A patterned mask (a mask with a light emission area of 5 mm × 5 mm) is placed on the organic compound layer, and lithium fluoride 0.5 nm is deposited as a cathode buffer layer and aluminum 150 nm is deposited as a cathode in a deposition apparatus to form a cathode. A blue light-emitting organic EL device 2-1 was prepared.

<< Production of Organic EL Elements 2-2 to 2-11 >>
In the production of the organic EL element 2-1, organic EL elements 2-2 to 2-11 were produced in the same manner except that the luminescent dopant was changed as shown in Table 3.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 2-1 to 2-11, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 5 and 6 was formed and evaluated.

  Subsequently, the luminance and luminous efficiency were measured as follows.

(Luminance, luminous efficiency)
Using Toyo Technica source measure unit type 2400, a direct current voltage is applied to the organic EL element to emit light, and a light emission luminance (cd / m ² ) and ^2.5 mA / cm ² when a direct current voltage of 10 V is applied. Luminous efficiency (lm / W) when passing current was measured. The obtained results are shown in Table 3.

  From Table 3, it is clear that the organic EL element produced using the metal complex described in this table can achieve high luminous efficiency and high luminance as compared with the organic EL element of the comparative example.

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element 1-40 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
A green light emitting device was produced in the same manner as in the organic EL device 1-2 of Example 1 except that Ir-13 was changed to Ir-1, and this was used as a green light emitting device.

(Production of red light emitting element)
A red light emitting device was produced in the same manner as in the organic EL device 1-2 of Example 1 except that Ir-13 was changed to Ir-9, and this was used as a red light emitting device.

  The red, green, and blue light-emitting organic EL elements produced above were juxtaposed on the same substrate to produce an active matrix type full-color display device having a configuration as shown in FIG. In FIG. 2, only the schematic diagram of the display part A of the produced display device is shown.

  That is, a plurality of pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) juxtaposed with a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate. The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions (for details, see FIG. Not shown).

  The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. The image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was produced by appropriately juxtaposing red, green, and blue pixels.

  It has been found that when this full-color display device is driven, a high-brightness, high durability, and clear full-color moving image display can be obtained.

Example 4
<< Preparation of white light emitting element and white lighting device >>
The electrode of the transparent electrode substrate of Example 1 is patterned to 20 mm × 20 mm, and α-NPD is formed as a hole injection / transport layer with a thickness of 25 nm thereon, as in Example 1, and further contains H4. The heated boat, the boat containing the exemplified compound (4-4-64) and the boat containing Ir-9 were energized independently, and the CBP as the luminescent host and the exemplified compound as the luminescent dopant (4-4) -64) and Ir-9 were adjusted to have a deposition rate of 100: 5: 0.6, and were deposited to a thickness of 30 nm to provide a light emitting layer.

Next, BCP was deposited to a thickness of 10 nm to provide a hole blocking layer. Further, Alq ₃ was formed at 40 nm to provide an electron transport layer.

  Next, as in Example 1, a square perforated mask having the same shape as the transparent electrode made of stainless steel was placed on the electron injection layer, and lithium fluoride 0.5 nm was used as the cathode buffer layer and aluminum 150 nm was used as the cathode. Evaporated film was formed.

  This element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 5 and 6 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 5
<< Preparation of Organic EL Element 5-1 >>: On a substrate (NA-45 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 of the present invention. After patterning, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

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

  On this hole injecting / transporting layer, a solution prepared by dissolving 30 mg of Exemplified Compound 1 (Polymer-1) in 3 ml of toluene was formed by spin coating under conditions of 1000 rpm and 30 seconds, and then at 60 ° C. for 1 hour. It vacuum-dried and it was set as the light emitting layer with a film thickness of 80 nm.

This was attached to a vacuum deposition apparatus, and then the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, calcium 10 nm as a cathode buffer layer and aluminum 110 nm as a cathode were deposited to form a cathode, and the organic EL element 5-1 was formed. Produced.

<< Preparation of Organic EL Elements 5-2 to 5-17 >>: Present Invention In the preparation of the organic EL element 5-1, Example Compound 1 used for the preparation of the light emitting layer was used as 1, 2, 7, 8, 10, 11 , 13, 15, 17, 19, 20, 22, 24, 25, 29, 30 Except that they were respectively changed to organic EL elements 5-2 to 5-17.

<< Preparation of Organic EL Element 5-18 >>: Comparative Example Organic EL element 5-1 was prepared in the same manner as in the preparation of organic EL element 5-1, except that 3 ml of the solution of Exemplary Compound 1 was replaced with the solution described in [A] below. EL element 5-18 was produced.

[A]: A solution in which 30 mg of polyvinylcarbazole and 1.5 mg of Ir-13 (blue light-emitting orthometalated complex) are dissolved in 3 ml of toluene << Evaluation of Organic EL Elements 5-1 to 5-18 >>
When evaluating the obtained organic EL elements 5-1 to 5-18, the non-light-emitting surface of each organic EL element after fabrication was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 5 and 6 was formed and evaluated.

  Next, external extraction quantum efficiency and emission lifetime were measured as follows.

《External extraction quantum efficiency》
The organic EL device was measured for external extraction quantum efficiency (%) when a constant current of ^2.5 mA / cm ² was applied at 23 ° C. in a dry nitrogen gas atmosphere. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Co., Ltd.) was used.

<Luminescent life>
When driving at a constant current of ^2.5 mA / cm ^{2 in} a dry nitrogen gas atmosphere at 23 ° C., the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured. Was used as an index of life as half-life time (τ ^1/2 ).

  Similarly, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Co., Ltd.) was used for the measurement.

  The measurement results of the external extraction quantum efficiency and the light emission lifetime of the organic EL elements 5-1 to 5-18 were subjected to relative evaluation with the organic EL element 5-18 as 100.

  The results obtained are shown in Table 4 below.

  From Table 4, it was found that by using the polymer compound described in this table for the light emitting layer, the external extraction quantum efficiency was significantly improved and the power consumption was suppressed. It was also found that the light emission life was improved.

  In addition, green light emission was obtained from the element (5-16) using the compound 29, and red light emission was obtained from the element (5-17) using the compound 30. All other organic EL elements emitted blue or blue-green light.

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

Claims (1)

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

[Wherein, R represents a cycloalkyl group, an aromatic hydrocarbon ring group or a heterocyclic group, Y ₁ is -C (Ra) - group (Ra represents a hydrogen atom or a substituent.) Represents the , Y ₂ represents N. Z ₁ , Z ₂ , Z ₃ , and Z _{4 each} represent —C (Rb) — group (Rb represents a hydrogen atom or a substituent) or N, and each of Z ₁ , Z ₂ , Z ₃ , and Z ₄ represents At least one represents N. X ₁ -L ₁ -X ₂ represents a bidentate ligand, and X ₁ and X ₂ each independently represent a carbon atom, a nitrogen atom or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table. ]

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