JPWO2005097942A1 - ORGANIC ELECTROLUMINESCENT ELEMENT MATERIAL, ORGANIC ELECTROLUMINESCENT ELEMENT, DISPLAY DEVICE AND LIGHTING DEVICE - Google Patents

Abstract

It contains a platinum complex represented by the general formula (1) in which a nitrogen-containing group is introduced at the 4-position of phenylpyridine, which is a ligand of the platinum complex, and a specific substituent is introduced at a specific position. Organic electroluminescent element material characterized by the above. In the general formula (1) shown in the specification, R1, R2, R3, R4, R5, R6, and R7 each represent a hydrogen atom or a substituent, but at least one of R1, R2, R3, and R4 One is an electron donating group. It is possible to provide an organic EL element, a lighting device, and a display device using the organic electroluminescence element material.

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

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

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

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

  In addition, the aforementioned M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), tris (2-phenylpyridine) iridium is used 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 L2Ir (acac), for example (ppy) 2Ir (acac) as a dopant, and Yon-Je. 0g, Tetsuo Tsutsui, et al. Also used Tris (2- (p-tolyl) pyridine) iridium (I) as a dopant in The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu). Studies using tris (benzo [h] quinoline) iridium (Ir (bzq) 3) and the like have been conducted (note that these metal complexes are generally called orthometalated iridium complexes).

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

  In addition, in order to obtain high luminous efficiency, the 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) use Ikai et al. As a host of phosphorescent compounds. In addition, M.M. E. Thompson et al. Use various electron transporting materials as hosts for phosphorescent compounds doped with a novel iridium complex.

  On the other hand, compounds other than the Ir complex have been studied as light emitting dopants that emit phosphorescence. For example, it is disclosed that an orthometalated palladium complex is used as a light emitting dopant (see, for example, Patent Document 1), but in this case, the light emission luminance and the light emission efficiency are inferior to those of the Ir complex.

  Many examples of orthometalated complexes having platinum as the central metal are known in which ligands are characterized (for example, see Patent Documents 2 to 6 and Non-Patent Document 1). The light emission luminance and light emission efficiency of the device are greatly improved compared to the conventional device because the light emission is derived from phosphorescence. However, the light emission lifetime of the device is lower than that of the conventional device. It was.

  In addition, as a phosphorescent high-efficiency light-emitting material, a blue light-emitting material with good color purity is required, but it is difficult to shorten the emission wavelength, and the performance that can withstand practical use has not been sufficiently achieved. Is the current situation. Regarding wavelength shortening, introduction of electron withdrawing groups such as fluorine atoms, trifluoromethyl groups, and cyano groups as substituents on phenylpyridine, and picolinic acid and pyrazabole-based ligands as ligands (For example, see Patent Documents 7 to 11 and Non-Patent Documents 1 to 4) With these ligands, the emission wavelength of the light-emitting material is shortened to achieve blue, and a highly efficient device On the other hand, since the light emission lifetime of the device is greatly deteriorated, improvement of the trade-off has been demanded.

Although there is a statement about the relationship between the electronic properties of the substituents on the phenylpyridine of the ligand and the position of substitution, there is no disclosure of the structure of platinum complexes like iridium complexes, and mention of specific performance Has not been made (see Patent Document 11).
JP 2001-181616 A JP 2002-332291 A JP 2002-332292 A JP 2002-338588 A JP 2002-226495 A JP 2002-234894 A International Publication No. 02/15645 Pamphlet JP 2003-123982 A JP 2002-117978 A JP 2003-146996 A International Publication No. 04/016711 Pamphlet Inorganic Chemistry, Vol. 41, No. 12, pp. 3055-3066 (2002) Applied Physics Letters, 79, 2082 (2001) Applied Physics Letters, 83, 3818 (2003) New Journal of Chemistry, 26, 1171 (2002)

  The present invention has been made in view of such problems, and an object of the present invention is to design a compound whose emission wavelength is controlled by introducing a substituent into a specific position of phenylpyridine, which is a ligand of a platinum complex. It is an object to provide an organic EL element, an illuminating device, and a display device that exhibit high luminous efficiency and have a long light emission lifetime by using a phosphorescent blue light emitting element material.

  An object of the present invention is to provide an organic compound comprising a platinum complex in which a nitrogen-containing group is introduced into the 4-position of phenylpyridine, which is a ligand of a platinum complex, and a specific substituent is further introduced into a specific position. Achieved by electroluminescent device material.

FIG. 1 is a schematic view showing an example of a display device composed of organic EL elements. FIG. 2 is a schematic diagram of the display unit A. FIG. 3 is an equivalent circuit diagram of a drive circuit constituting a pixel. FIG. 4 is a schematic diagram of a passive matrix display device. FIG. 5 is a schematic diagram of a sealing structure of the organic EL element OLED1-1. FIG. 6 is a schematic diagram of a lighting device including an organic EL element.

The best mode for carrying out the present invention has the following configuration. However, the present invention is not limited to these.
(1) An organic electroluminescence element material comprising a platinum complex having a partial structure represented by the following general formula (1).

[Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ each represents a hydrogen atom or a substituent, but at least one of R ₁ , R ₂ , R ₃ , R _4] One is an electron donating group. Ra and Rb each represents a substituent. ]
(2) The organic electroluminescent element material as described in the above item 1, wherein at least two of R ₁ , R ₂ , R ₃ and R ₄ are electron donating groups.
(3) The organic electroluminescent element material as described in (1) above, wherein at least one σp of the electron donating group is −0.20 or less.
(4) The organic electroluminescent element material as described in (1) above, wherein the electron donating group is introduced into R ₂ or R ₄ of the general formula (1). More preferably, the organic electroluminescent element material according to the above item 1, wherein R ₂ and R ₄ are both the electron donating group.
(5) Ra and Rb are both alkyl groups, The organic electroluminescent element material of the said 1st term | claim characterized by the above-mentioned.
(6) An organic electroluminescence element material comprising a platinum complex having a partial structure represented by the following general formula (2).

[Wherein R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ each represents a hydrogen atom or a substituent, but at least one of R ₁₁ , R ₁₃ is an electron-withdrawing group It is. Rc and Rd represent a substituent. ]
(7) The organic electroluminescent element material according to the above item 6, wherein R ₁₁ and R ₁₃ are both electron-withdrawing groups.
(8) The organic electroluminescent element material as described in the above item 6, wherein σp of the electron withdrawing group is 0.10 or more.
(9) The organic electroluminescent element material according to item 6, wherein Rc and Rd are both alkyl groups.
(10) An organic electroluminescence device comprising the organic electroluminescence device material according to item 1 or 6.
(11) An organic electroluminescent device comprising a light emitting layer as a constituent layer, wherein the light emitting layer contains the organic electroluminescent device material described in item 1 or item 6.
(12) An organic electroluminescence device comprising a hole blocking layer as a constituent layer, wherein the hole blocking layer contains the organic electroluminescence device material according to item 1 or item 6.
(13) A display device comprising the organic electroluminescent element according to any one of items 10 to 12.
(14) An illuminating device comprising the organic electroluminescent element according to any one of items 10 to 12.

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

  The organic electroluminescent element material of the present invention is a metal complex in which a substituent having a specific electronic property is introduced into a specific position of phenylpyridine by adopting the configuration defined in any one of the above items. An organic EL element material could be obtained. By using the organic EL element material, it is possible to obtain an organic EL element having a high external extraction quantum efficiency and a long emission lifetime. Furthermore, by using the organic electroluminescence element, high luminance and high durability are exhibited. Furthermore, the display device described in the item and the illumination device described in the item were each obtained.

  As a result of studying various problems of the conventional platinum complex as described above, the present inventors have found that a specific electronic part of a phenylpyridine used as a ligand at the time of complex formation has a specific electronic property. By using an organic EL element that includes a metal complex having a substituent introduced with properties as an organic EL element material, a conventional blue metal complex, in particular, an organic substance whose emission wavelength is controlled to the short wavelength side only by an electron withdrawing group. It has been found that the short light emission lifetime, which has been a problem with organic EL devices fabricated using EL device materials, is greatly improved. Furthermore, it was found that an emission color with high color purity can be obtained by substituting an electron donating group or an electron withdrawing group at a specific position of the phenylpyridine.

In this examination, the substituent effect on phenylpyridine and the fluctuation of the emission wavelength were examined in detail by simulating the emission wavelength by molecular orbital calculation using the structure of the following general formula (3) as an example.

  As a result, it has been found that substitution positions effective for shortening and increasing the wavelength are the 4th and 3p-6p positions. In particular, regarding the shortening, when the substituent is an electron donating group (in the present invention, σp represents a group of less than 0), introduction of the substituent at the 4-position, 4p-position, and 6p-position is effective, In the case where the substituent is an electron-withdrawing group (in the present invention, σp represents a group exceeding 0), it has been found that introduction of substituents at the 3p position and the 5p position is effective.

  Moreover, it turned out that the 3, 5, 6 position becomes long wave regardless of the electronic property of a substituent.

  Furthermore, it was complementary with respect to the electronic properties of the substituents.

Hammett's σp value
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” The groups described in “Constants for Correlation Analysis in Chemistry and Biology” (C. Hansch and A. Leo, John Wiley & Sons, New York, 1979) can be cited.

  Based on this result, the present inventors have studied and synthesized based on the above guidelines as means for shortening the emission wavelength to blue, and found that the emission wavelength can be controlled almost satisfying the simulation result. It was. Furthermore, when various platinum complexes were synthesized and examined based on this knowledge and evaluated as an organic EL device, the following three findings were obtained when a substituted amino group was introduced at the 4-position.

  (1) When at least one of the 3p to 6p positions is an electron donating group, the device performance was improved in the light emission efficiency and the light emission lifetime.

  (2) In the case where at least one substituent at the 4p and 6p positions is electron donating, the blue color purity was improved in addition to the device performance of the light emission efficiency and the light emission lifetime.

  (3) When at least one substituent at the 3p and 5p positions is electron withdrawing, blue color purity was improved in addition to device performance such as luminous efficiency and luminous lifetime.

  Among the above three items, the following (1a), (2a) and (3a) are preferable.

(1a) When σp of at least one substituent at positions 3p to 6p is −0.20 or less (2a) Two substituents at positions 4p and 6p are electron donating, and most preferably σp is −0 (3a) The two substituents at the 3p and 5p positions are electron withdrawing, and most preferably the σp is 0.10 or more. Based on such findings, the above general formula (1 ) Or (2) has been molecularly designed to arrive at the present invention.

Here, Gaussian 98 (Revision A.11.4, MJ Frisch, GW Trucks, HB Schlegel, GE Scuseria, MA Robb, J R. Cheeseman, V. G. Zakrzewski, JA Montgomery, Jr., RE Stratmann, J. C. Burant, S. Daprich, J. M. Millam, AD Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomeri, C. Adamo, S. Clifford, J. Ochterski, GA Petersson , P. Y. Ayala, Q. Cui, K. Morokuma, N. Rega, P. Salvador, J. J. Dannenberg, D. K. Malick, A. D. Rabuck, K. Ragavachari, J. B. Forsman. , J. Cioslowski, J. V. Ortiz, AG Baboul, BB Stefanov, G. Liu, A. Liashenko,
P. Piskorz, I .; Komaromi, R.A. Gomperts, R.M. L. Martin, D.M. J. et al. Fox, T.M. Keith, M.C. A. Al-Laham, C.I. Y. Peng, A.M. Nanayakara, M .; Challacombe, P.M. M.M. W. Gill, B.M. Johnson, W.M. Chen, M.C. W. Wong, J. et al. L. Andres, C.I. Gonzalez, M .; Head-Gordon, E .; S. Replogle, and J.M. A. Pople, Gaussian, Inc. Pittsburgh PA, 2002. ) Was used.

  The calculation was carried out by optimizing the structure using the B3LYP method and then calculating the phosphorescence wavelength using the TD-DFT calculation to obtain the emission wavelength.

  The inclusion layer in the element of the platinum complex having the partial structure represented by the general formula (1) or (2) is preferably a light emitting layer and / or a hole blocking layer, and is contained in the light emitting layer. Was used as a light-emitting dopant in the light-emitting layer, thereby achieving an increase in the light-emitting lifetime of the organic EL device, which is the effect described in the present invention.

《Platinum complex》
The platinum complex according to the organic EL element material of the present invention will be described.

<< Platinum Complex Having Ligand Represented by General Formula (1) >>
The platinum complex which has the partial structure represented by General formula (1) based on this invention is demonstrated.

  The platinum complex represented by the general formula (1) according to the present invention will be described.

In the general formula (1), examples of the substituent represented by R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ include an alkyl group (for example, methyl group, ethyl group). Propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), Alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, propargyl group, etc.), aryl group (eg, phenyl group, tolyl group, xylyl group, naphthyl group, biphenylyl group, anthryl group, phenanthryl group, mesityl group) Group, fluorenyl group, etc.), heterocyclic group (for example, pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group) , Furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, carbazolyl group, etc.), alkoxyl group (for example, methoxy group, ethoxy group, propyloxy group) , Pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), Alkylthio group (for example, 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 (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (Eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octyl) Aminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), Id group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, Acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group ( For example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amino Group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group) Group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylamino) Carbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarb Nyl group, 2-pyridylaminocarbonyl group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group etc.), alkylsulfonyl group or arylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl) Group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentyl) Amino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), nitro group, cyano group, silyl group (trimethylsilyl group, t-butyldimethylsilyl group, dimethylphenylsilyl group) , Triphenylsilyl group, etc.).

In the present invention, at least one of the groups represented by R ₁ , R ₂ , R ₃ and R ₄ is preferably an electron donating group, more preferably R ₁ , R ₂ , R ₃ , R _At least two of the groups represented by ₄ are electron donating groups, and at least one σp of the electron donating group is -0.20 or less, most preferably The electron donating group is introduced into R ₂ or R ₄ of the general formula (1), and it is more preferable that both R ₂ and R ₄ are the electron donating group.

<< electron donating group with σp of -0.20 or less >>
Here, as the electron donating group having σp of −0.20 or less, for example, cyclopropyl group (−0.21), cyclohexyl group (−0.22), tert-butyl group (−0.20) , —CH ₂ Si (CH ₃ ) ₃ (−0.21), amino group (−0.66), hydroxylamino group (−0.34), —NHNH ₂ (−0.55), —NHCONH ₂ ( _{-0.24), - NHCH 3 (-0.84} ), - NHC 2 H 5 (-0.61), - NHCONHC 2 H 5 (-0.26), - NHC 4 H 9 (-0.51 ), —NHC ₆ H ₅ (−0.40), —N═CHC ₆ H ₅ (−0.55), —OH (−0.37), —OCH ₃ (−0.27), —OCH ₂ COOH (−0.33), —OC ₂ H ₅ (−0.24), —OC ₃ H ₇ (−0. 25), —OCH (CH ₃ ) ₂ (−0.45), —OC ₅ H ₁₁ (−0.34), —OCH ₂ C ₆ H ₅ (−0.42) and the like. Is not limited to these.

In the general formula (1), the substituents represented by Ra and Rb are respectively R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ in the general formula (1). Although it is synonymous with the substituent represented, Preferably, Ra and Rb are the cases where both are alkyl groups.

<< Platinum Complex Having Ligand Represented by Formula (2) >>
The platinum complex which has the partial structure represented by General formula (2) based on this invention is demonstrated.

  The platinum complex represented by the general formula (2) according to the present invention will be described.

In the general formula (2), R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , and R ₁₇ are each a substituent represented by R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ have the same meanings as the substituents respectively represented. Provided _that at least one of R _{11, R 13} is an electron withdrawing _group, preferably R _{11, R 13} are both electron-withdrawing group, more preferably, .sigma.p of the electron withdrawing group is 0. 10 or more.

<< Electron withdrawing group with σp of 0.10 or more >>
Here, as an electron withdrawing group having σp of 0.10 or more, for example, —B (OH) ₂ (0.12), bromine atom (0.23), chlorine atom (0.23), iodine atom ( _{0.18), - CBr 3 (-0.29} ), - CCl 3 (0.33), - CF 3 (0.54), - CN (0.66), - CHO (0.42), - _{COOH (0.45), CONH 2 (} 0.36), - CH 2 SO 2 CF 3 (0.31), - COCH 3 (0.45), 3- Bareniru group (0.19), - CF ( _{CF 3) 2 (0.53),} - CO 2 C 2 H 5 (0.45), - CF 2 CF 2 CF 2 CF 3 (0.52), - C 6 F 5 (0.41), 2 - benzoxazolyl group (0.33), 2-benzothiadiazolyl no doubt Lil group _{(0.29), - C = O} (C 6 H 5) (0.43), _{-OCF 3 (0.35), - OSO} 2 CH 3 (0.36), - SO 2 (NH 2) (0.57), - SO 2 CH 3 (0.72), - COCH 2 CH 3 ( 0.48), —COCH (CH ₃ ) ₂ (0.47), —COC (CH ₃ ) ₃ (0.32) and the like, but the present invention is not limited thereto.

In the general formula (2), the substituents represented by Rc and Rd in the general formula (1) are R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ , respectively. Although it is synonymous with the substituent represented, Preferably, Rc and Rd are both a case where it is an alkyl group.

Although the specific example of the metal complex compound used as an organic EL element material of this invention is shown below, this invention is not limited to these.

  The platinum complex according to the organic EL device material of the present invention is described in, for example, Organic Letter, vol. 16, p2579-2581 (2001), Helvetica Chema Acta, 69, 1855 (1986), Inorganic Chemistry, 41, No. 12, 3055-3066 (2002), New Journal of Chemistry. Volume 26, page 1171 (2002), and further by applying methods such as references described in these documents.

<< Application of organic EL element material containing platinum complex to organic EL element >>
When producing an organic EL element using the organic EL element material of the present invention, it is preferably used for a light emitting layer or a hole blocking layer in the constituent layers (details will be described later) of the organic EL element. In the light emitting layer, as described above, it is preferably used as a light emitting dopant.

(Light emitting host and light emitting dopant)
The mixing ratio of the light-emitting dopant to the light-emitting host, which is the host compound as 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 another metal complex having a different structure, or a phosphorescent dopant or a fluorescent dopant having another structure.

  Here, the dopant (phosphorescent dopant, fluorescent dopant, etc.) that may be used in combination with the platinum complex used as the light emitting dopant will be described.

  The light-emitting dopant is roughly classified into two types: a fluorescent dopant that emits fluorescence and a phosphorescent dopant that emits phosphorescence.

  Representative 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.

  Typical examples of the latter (phosphorescent dopant) are preferably complex compounds containing metals of Groups 8, 9, and 10 in the periodic table of elements, more preferably iridium compounds and osmium compounds. 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 examples are shown below.

(Light emitting host)
A light-emitting host (also simply referred to as a host) means a compound having the largest mixing ratio (mass) in a light-emitting layer composed of two or more compounds. For other compounds, “dopant compound ( Simply referred to as a dopant). " For example, if the light emitting layer is composed of two types of compound A and compound B and the mixing ratio is A: B = 10: 90, compound A is a dopant compound and compound B is a host compound. Furthermore, if a light emitting layer is comprised from 3 types of compound A, compound B, and compound C, and the mixing ratio is A: B: C = 5: 10: 85, compound A and compound B are dopant compounds, Compound C is a host compound.

  As the luminescent host used in the present invention, a compound having a wavelength shorter than the phosphorescence 0-0 band of the luminescent dopant used in combination is preferable, and the phosphorescent 0-0 band is 480 nm or less as the luminescent dopant. In the case of using a compound containing the above light emitting component, the phosphorescent 0-0 band is preferably 450 nm or less as the light emitting host.

  The light emitting host of the present invention is not particularly limited in terms of structure, but typically, a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound And the like, and the 0-0 band is 450 nm or less.

  The light emitting host of 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 having a hole transporting ability and an electron transporting ability, preventing emission light from being increased in wavelength, and having 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. .

  In the present invention, the host compound is preferably 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 substituted with a nitrogen atom.

Specific examples of preferred host compounds of the present invention will be given.

  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 the hole blocking layer, the electron blocking layer, etc., and particularly preferably used for the 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 metal complex according to any one of the configurations of the present invention is converted into the hole blocking layer or the electron blocking layer. It may be contained in a state of 100% by mass as a layer constituent component such as a layer, or may be mixed with another organic compound (for example, a compound used for a constituent layer of the organic EL device of the present invention).

  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 those disclosed in JP-A-11-204258, JP-A-11-204359, and “Organic EL device and its forefront of industrialization (issued by NTS, Inc. on November 30, 1998)”. The hole blocking (hole block) layer described in page 237 and the like 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.

《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 element 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 used for the hole blocking layer. Is preferred.

《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 an optical transmission material or a well-known material used for a hole injection layer or a hole transport layer of an EL element. Any one 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, stilbenes Derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, particularly thiophene oligomers, and the like can be given.

  As the hole transport material, those described above can be used, and 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 two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type (MTDATA).

  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.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, 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 multiple 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 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, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

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

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu Metal complexes replaced with Ca, Sn, Ga, or Pb can also be used as electron transport materials. 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 similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC. A semiconductor can also be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, 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 5-5000 nm. The 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 You may exist between a cathode, a light emitting layer, or an electron carrying layer.

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

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

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium or aluminum Metal buffer layer represented by lithium fluoride, alkali metal compound buffer layer represented by lithium fluoride, alkaline earth metal compound buffer layer represented by magnesium fluoride, oxide buffer layer represented by aluminum oxide, etc. It is done.

  The buffer layer (injection layer) is preferably a very thin film, and although it depends on the material, the film thickness is preferably in the range of 0.1 nm to 100 nm.

  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 5-5000 nm. This 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 an electrode substance include conductive transparent materials such as metals such as Au, CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not required (100 μm or more) Degree), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode 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, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, such as a magnesium / silver mixture, magnesium, from the viewpoint of electron injectability and durability against oxidation, etc. / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 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 to the type of glass, plastic, etc., and is not particularly limited as long as it is transparent. Examples of substrates that are preferably used include glass, quartz, A light transmissive resin film can be mentioned. 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 triacetate. Examples thereof include films made of (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 it should be a high barrier film having a water vapor transmission rate of 0.01 g / m ² · day · atm or less. preferable.

  The external extraction efficiency at room temperature for light emission of the organic electroluminescence 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 organic EL elements having at least two 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. To do. 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 described above, there are spin coating method, casting method, ink jet method, vapor deposition method, printing method and the like as a method for thinning the thin film containing the organic compound, but it is easy to obtain a uniform film and has pinholes. From the viewpoint of difficulty in formation, vacuum deposition or spin coating is particularly preferable. Further, different film forming methods 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 to 50 nm / second, a substrate temperature of −50 ° C. to 300 ° C., and a film thickness of 0.1 nm 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 film 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 element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is 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 may be single color or multicolor, but here, the multicolor display device will be described. 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 a vapor deposition method, a casting method, a spin coating method, an ink jet method, a printing method, 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 the display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in a car. 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 emitting sources include household 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, but not limited to.

《Lighting device》
The lighting device of the present invention will be described.

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The use of the organic EL element having such a resonator structure is as a light source for an optical storage medium, an electrophotographic copying machine, and the like. Light sources, optical communication processor light sources, optical sensor light sources, and the like. 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 type for directly viewing a still image or a moving image. It may be used as a display device (display). When used as a display device for reproducing moving images, the driving method 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 diagram illustrating an example of a display device including 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 the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display 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 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 (details are shown in FIG. Not shown).

  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 that emit light 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 organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.

  The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

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

  FIG. 4 is a schematic view 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 according to the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of three primary colors of blue, green, and blue, or two using a complementary color relationship 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 that emit light, and a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material. Any combination with a dye material that emits light as excitation light may be used. However, in the white organic electroluminescence device according to the present invention, it is only necessary to mix and combine a plurality of light-emitting dopants. It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, or the like, and simply arrange them separately by coating with the mask. 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.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is known so as to be suitable for the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.

  As described above, the white light-emitting organic EL element of the present invention can be used as a light-emitting light source and lighting device in addition to the display device and display, as a kind of lamp such as home lighting, interior lighting, and exposure light source. 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.

Here, the light-emitting host material used in any of Examples 1-6, the light-emitting dopant, the raw material used for formation of a hole-blocking layer, etc. are shown.

Example 1
<< Production of Organic EL Element OLED1-1 >>
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.

The transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while α-NPD, CBP, Ir-12, BCP, and Alq ₃ are placed in five tantalum resistance heating boats, respectively. It was attached to the (first 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 the vacuum of the first vacuum chamber to 4 × ^10- 4 Pa, and heated by supplying an electric current to the boat containing alpha-NPD, transparent at a deposition rate of 0.1 nm / sec to 0.2 nm / sec It vapor-deposited so that it might become a film thickness of 25 nm on the support substrate, and provided the positive hole injection / transport layer.

  Further, the heating boat containing CBP and the boat containing Ir-12 are energized independently to adjust the deposition rate of CBP as a light emitting host and Ir-12 as a light emitting dopant to 100: 7. A light emitting layer was provided by vapor deposition so as to have a thickness of 30 nm.

Then, 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 40 nm at a deposition rate of 0.1 to 0.2 nm / second.

  Next, after the element formed up to the electron transport layer as described above is transferred to the second vacuum chamber in a vacuum state, a stainless steel rectangular perforated mask is disposed on the electron transport layer from the outside of the apparatus. Installed with remote control.

After decompression of the second vacuum chamber up to 2 × ^10- 4 Pa, a cathode buffer layer deposition rate 0.01 nm / sec ～0.02Nm / sec to a film thickness 0.5nm by energizing the boat lithium fluoride containing the Then, a boat containing aluminum was energized to attach a cathode having a film thickness of 150 nm at a deposition rate of 1 nm / second to 2 nm / second. Further, the organic EL element was transferred to a glove box under nitrogen atmosphere (a glove box substituted with high-purity nitrogen gas with a purity of 99.999% or more) without being brought into contact with the atmosphere, and the interior as shown in FIG. An OLED 1-1 was produced with a substituted sealing structure. In addition, barium oxide 105 which is a water trapping agent is a glass-sealed can 104 made of high-purity barium oxide powder manufactured by Aldrich with a fluororesin-based semipermeable membrane (Microtex S-NTF8031Q made by Nitto Denko) with an adhesive. The material pasted on was prepared and used in advance. An ultraviolet curable adhesive 107 was used for bonding the sealing can and the organic EL element, and both were bonded to each other by irradiation with an ultraviolet lamp to produce a sealing element. In FIG. 5, 101 is a glass substrate provided with a transparent electrode, 102 is an organic EL layer composed of the hole injection / transport layer, light emitting layer, hole blocking layer, electron transport layer, and the like, and 103 is a cathode.

<< Production of Organic EL Elements OLED1-2 to 1-27 >>
In preparation of said organic EL element OLED1-1, as described in Table 1, except having changed the light emission dopant, organic EL element OLED1-2 to 1-27 was produced similarly.

The following evaluation was performed about each of obtained organic EL element OLED1-1 to 1-27.
<< Production of Organic EL Elements OLED1-36 and 1-37 >>
Organic EL elements OLED1-36 and 1-37 were respectively produced in the same manner as OLED1-7 and OLED1-16 except that the light emitting host was changed from CPB to AZ1 in the production of OLED1-7 and OLED1-16. .

The following evaluation was performed about each of obtained organic EL element OLED1-1 to 1-27, 1-36, and 1-37.

<< External quantum efficiency >>
Each of the obtained organic EL elements OLED1-1 to 1-27, 1-36, and 1-37 is turned on under a constant current condition of room temperature (about 23 ° C to 25 ° C) and ^2.5 mA / cm ^2. The external extraction quantum efficiency (η) was calculated by measuring the emission luminance (L) [cd / m ² ] immediately after the start of lighting. Here, CS-1000 (manufactured by Minolta) was used for measurement of light emission luminance.

  The external extraction quantum efficiency was expressed as a relative value when the organic EL element OLED1-1 was 100.

<Luminescent life>
Each of the organic EL elements OLED1-1 to 1-27, 1-36, and 1-37 is continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature, so that the luminance is half of the initial luminance. The time required to become (τ1 / 2) was measured. Moreover, the light emission lifetime was represented by the relative value when the organic EL element OLED1-1 was set to 100, respectively.

《Chromaticity difference》
Each of the organic EL elements OLED1-1 to 1-27, 1-36, and 1-37 is turned on under constant current conditions of room temperature (about 23 ° C to 25 ° C) and ^2.5 mA / cm ² The CIE chromaticity ((x, y) = (a, b)) of the emission color of the element immediately after the start was measured, and NTSC (modern) blue ((x, y) = (0.155, 0.07) ) Was calculated as Δ.

  Here, (DELTA) was calculated | required according to the following formula | equation, and the measurement of CIE chromaticity used CS-1000 (made by Minolta).

Δ = (| 0.155−a | ² + | 0.07−b | ² ) ^1/2
The obtained results are shown in Table 1.

  From Table 1, when the structure of the platinum complex used for the organic EL device material is compared with the above general formula (3), it has at least one electron donating group in 4p and 6p, or in 3p and 5p. It is clear that an organic EL element produced using a platinum complex having at least one electron-withdrawing group as an organic EL element material has achieved higher emission efficiency and longer emission lifetime than the comparative element. It is. It was also found that the color purity was improved as compared with the conventional device.

<< Production of Organic EL Elements OLED1-28 to 1-35 >>
In preparation of said organic EL element OLED1-1, as described in Table 2, except having changed the light emission dopant, organic EL element OLED1-28-1-35 was produced respectively.

  For each of the obtained organic EL elements OLED1-28 to 1-35, the light emission efficiency and the light emission lifetime were measured in the same manner. The external extraction quantum efficiency and the light emission lifetime are expressed as relative values when the organic EL element OLED1-1 is 100. The obtained results are shown in Table 2.

  From Table 2, the organic EL element produced using a platinum complex containing at least one electron donating group in 3p to 6p as the organic EL element material has higher luminous efficiency and longer emission lifetime than the comparative element. It is clear that the lifetime has been achieved.

Example 2
<< Production of Organic EL Elements OLED2-1 to 2-25 >>
In the production of the organic EL element OLED1-1 of Example 1, the light emitting dopant was changed from Ir-12 to Ir-1, and a hole blocking material was used as shown in Table 3 in the same manner. Elements OLED2-1 to 2-25 were produced.

  The obtained organic EL elements OLED2-1 to 2-25 were measured for the external extraction quantum efficiency and the light emission lifetime using the method described in Example 1.

  In showing an evaluation result, it represented with each relative value of each sample of organic EL element when the value of organic EL element OLED2-1 was set to 100. The obtained results are shown in Table 3.

  From Table 3, it was found that the device of the present invention has higher light emission efficiency and light emission lifetime than the comparative device. In addition, all the luminescent colors of the organic EL element of this invention were green.

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element OLED1-7 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
In the organic EL element OLED1-7 of Example 1, a green light emitting element was produced in the same manner as OLED1-7 except that the light emitting dopant was changed from 1 to Ir-1.

(Production of red light emitting element)
In the organic EL element OLED1-7 of Example 1, a red light emitting element was produced in the same manner as OLED1-7 except that the light emitting dopant was changed from 1 to Ir-9.

  Each of the red, green, and blue light emitting organic EL elements produced above was juxtaposed on the same substrate to produce an active matrix type full-color display device having the form shown in FIG. 1, and FIG. Only the schematic diagram of the display section A of the display device is shown. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) 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 orthogonal positions ( Details are 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. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, full-color display devices were fabricated by appropriately juxtaposing the red, green, and blue pixels.

  It has been found that by driving the full-color display device, a clear full-color moving image display having high luminance, high durability, and clearness 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 was patterned to 20 mm × 20 mm, and α-NPD was formed as a hole injection / transport layer with a thickness of 25 nm thereon as in Example 1, and further, CBP Vapor deposition rates of CBP as a luminescent host and compounds 2 and Ir-9 as luminescent dopants by energizing the heated boat, the boat containing the present compound 2 and the boat containing Ir-9 independently, respectively. Was adjusted to be 100: 5: 0.6, and vapor deposition was performed so as to have a thickness of 30 nm to provide a light emitting layer.

Next, a hole blocking layer was provided by depositing BCP to a thickness of 10 nm. Furthermore, providing the film with an electron transporting layer Alq ₃ in 40 nm.

  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, lithium fluoride 0.5 nm as the cathode buffer layer and aluminum 150 nm as the cathode. Was deposited.

  This element was provided with a sealing can having the same method and the same structure as in Example 1 to produce a flat lamp. FIG. 6 shows a schematic diagram of a flat lamp. FIG. 6A shows a schematic plan view, and FIG. 6B shows a schematic cross-sectional view.

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

  According to the present invention, high luminous efficiency is achieved by using a compound-designed phosphorescent blue light-emitting element material whose emission wavelength is controlled by introducing a substituent at a specific position of phenylpyridine, which is a ligand of a platinum complex. In addition, an organic EL element, a lighting device, and a display device having a long light emission lifetime can be provided.

Claims (27)

An organic electroluminescent element material comprising a platinum complex having a partial structure represented by the following general formula (1).

[Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ each represents a hydrogen atom or a substituent, but at least one of R ₁ , R ₂ , R ₃ , R _4] One is an electron donating group. Ra and Rb each represents a substituent. ] The organic electroluminescent element material according to claim ₁ , wherein at least two of R ₁ , R ₂ , R ₃ and R ₄ are electron donating groups. 2. The organic electroluminescent element material according to claim 1, wherein at least one σp of the electron donating group is −0.20 or less. The organic electroluminescent element material according to claim 1, wherein the electron donating group is introduced into R ₂ or R ₄ of the general formula (1). 2. The organic electroluminescent element material according to claim 1, wherein Ra and Rb are both alkyl groups. An organic electroluminescent element material comprising a platinum complex having a partial structure represented by the following general formula (2).

[Wherein R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ each represents a hydrogen atom or a substituent, but at least one of R ₁₁ , R ₁₃ is an electron-withdrawing group It is. Rc and Rd represent a substituent. ] 7. The organic electroluminescence element material according to claim 6, wherein R ₁₁ and R ₁₃ are both electron withdrawing groups. The organic electroluminescent element material according to claim 6, wherein σp of the electron withdrawing group is 0.10 or more. The organic electroluminescent element material according to claim 6, wherein Rc and Rd are both alkyl groups. An organic electroluminescence element comprising the organic electroluminescence element material according to claim 1. An organic electroluminescent element comprising the organic electroluminescent element material according to claim 6. An organic electroluminescent device comprising a light emitting layer as a constituent layer, the light emitting layer containing the organic electroluminescent device material according to claim 1. An organic electroluminescent device comprising a light emitting layer as a constituent layer, and the light emitting layer containing the organic electroluminescent device material according to claim 6. An organic electroluminescence device comprising a hole blocking layer as a constituent layer, wherein the hole blocking layer contains the organic electroluminescence device material according to claim 1. An organic electroluminescence device comprising a hole blocking layer as a constituent layer, the hole blocking layer containing the organic electroluminescence device material according to claim 6. A display device comprising the organic electroluminescence element according to claim 10. A display device comprising the organic electroluminescence element according to claim 11. A display device comprising the organic electroluminescence element according to claim 12. A display device comprising the organic electroluminescence element according to claim 13. A display device comprising the organic electroluminescence element according to claim 14. A display device comprising the organic electroluminescence element according to claim 15. An illuminating device comprising the organic electroluminescence element according to claim 10. An illuminating device comprising the organic electroluminescence element according to claim 11. An illuminating device comprising the organic electroluminescent element according to claim 12. An illuminating device comprising the organic electroluminescent element according to claim 13. An illuminating device comprising the organic electroluminescent element according to claim 14. An illuminating device comprising the organic electroluminescent element according to claim 15.