JP5045100B2 - Organic electroluminescence element material and organic electroluminescence element - Google Patents

Description

The present invention relates to an organic electroluminescence element material and organic electroluminescence element.

  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 compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer and recombines them to generate excitons. An element that emits light by using light emission (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several V to several tens V, and is self-luminous. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it has attracted attention from the viewpoints of space saving and portability.

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

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

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

  As described above, when light emission from 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)), at room temperature. Research on materials that exhibit phosphorescence has become active.

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

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

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

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

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

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

  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 a phosphorescent compound, doped with a novel iridium complex.

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

  In any case, the light emission luminance 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.

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 performance sufficient for practical use has not been achieved. Is the current situation. Regarding wavelength shortening, introduction of electron-withdrawing groups such as fluorine atoms, trifluoromethyl groups, and cyano groups into phenylpyridine as substituents, and introduction of picolinic acid and pyrazabole-based ligands as ligands (For example, refer to Patent Documents 6 to 10 and Non-Patent Documents 1 to 4.) With these ligands, the emission wavelength of the light-emitting material is shortened to achieve blue, and high efficiency. While the device can be achieved, the light emission lifetime of the device is greatly deteriorated, and thus improvement of the trade-off has been demanded.
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, Volume 79, 2082 (2001) Applied Physics Letters, 83, 3818 (2003) New Journal of Chemistry, 26, 1171 (2002)

An object of the present invention, the emission wavelength is controlled, it showed high luminous efficiency, and is to provide a long organic EL device emission lifetime.

To achieve the above object, one aspect of the present invention is an organic electroluminescence device material characterized by containing a metal complex represented by the following general formula (3 '').

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 above object of the present invention is achieved by the following configurations.
Configuration 1. An organic electroluminescence device material comprising a metal complex represented by the following general formula (3 ″) .
(In the formula, Rb, Rc, and Rd represent an alkyl group or an aryl group, Xb, Xc, and Xd represent an oxygen atom, a sulfur atom, or a nitrogen atom. Nb, nc, and nd represent 1 or 2. R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ represent a hydrogen atom, M represents iridium or platinum, and n represents 1 or 2.
Configuration 2 . An organic electroluminescence element comprising the organic electroluminescence element material according to Configuration 1 .
The following configuration is a preferred embodiment.
(1) An organic electroluminescence element material comprising a metal complex having a partial structure represented by the following general formula (1).

(In the formula, A, B and C represent a hydrogen atom or a substituent, at least two of which are represented by the following general formula (2) and may be different from each other. R ₁ , R ₂ , R ₃ , R ₄ and R ₅ represent a hydrogen atom or a substituent, and M ₁ represents an element of Group 8, 9 or 10 in the periodic table.
Formula (2) -Xa- (Ra) na
(In the formula, Ra represents a substituent. Xa represents an oxygen atom, a sulfur atom or a nitrogen atom. Na represents 1 or 2.)
(2) In the said General formula (2), Ra is an alkyl group, The organic electroluminescent element material as described in said (1) characterized by the above-mentioned.
(3) An organic electroluminescence element material comprising a metal complex having a partial structure represented by the general formula (3).

(In the formula, Rb, Rc and Rd represent a substituent, Xb, Xc and Xd represent an oxygen atom, a sulfur atom or a nitrogen atom. Nb, nc and nd represent 1 or 2. R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ represent a hydrogen atom or a substituent, and M ₂ represents an element of Group 8, 9 or 10 in the periodic table.
(4) The organic electroluminescent element material as described in (3) above, wherein in the general formula (3), Rb, Rc and Rd are alkyl groups.
(5) The organic electroluminescent element material as described in (3) or (4) above, wherein in the general formula (3), Xd is a nitrogen atom, and Xb and Xc are oxygen atoms.
(6) The organic electroluminescent element material as described in (3) or (4) above, wherein, in the general formula (3), Xd is a sulfur atom, and Xb and Xc are oxygen atoms.
(7) The organic electroluminescent element material as described in (3) or (4) above, wherein in the general formula (3), Xb, Xc and Xd are oxygen atoms.
(8) The organic electroluminescent device material according to (1) or (2) where M ₁ is characterized in that iridium or platinum.
(9) The electrolyte M ₂ is characterized in that iridium or platinum (3) The organic electroluminescence device material according to any one of (1) to (7).
(10) An organic electroluminescent element comprising the organic electroluminescent element material according to any one of (1) to (9).
(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 according to any one of (1) to (9).
(12) An organic material having a hole blocking layer as a constituent layer, wherein the hole blocking layer contains the organic electroluminescence element material according to any one of (1) to (9). Electroluminescence element.
(13) A display device comprising the organic electroluminescent element according to any one of (10) to (12).
(14) An illuminating device comprising the organic electroluminescent element according to any one of (10) to (12).

  Hereinafter, the present invention will be described in detail.

An organic EL device including an organic electroluminescence device material containing a metal complex represented by the general formula (3 ″), in which a substituent having an electronic property at a specific position of phenylpyridine is introduced, The light emission lifetime, which was a problem of organic EL devices manufactured using organic EL device materials whose emission wavelength is controlled to the short wavelength side only by electron-withdrawing groups, is greatly improved. Was found.

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

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

  As a result, it has been found that substitution positions effective for shortening the wavelength and increasing the wavelength are the 4th and 3p-6p positions. In particular, regarding the shortening of the wave length, when the substituent is an electron-donating group, introduction of the substituent at the 4-position, 4p-position, and 6p-position is effective, while when the substituent is an electron-withdrawing group, the 3p-position, 5p position is effective. It was found that introduction of a substituent at the position was 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.

  In response to this result, the present inventors have investigated and synthesized based on the above guidelines as a means for shortening the emission wavelength to blue, and found that the emission wavelength can be controlled almost satisfying the simulation result. It was.

  However, it has been found that when electron withdrawing groups are introduced at the 3p-position and the 5p-position, it is effective for improving the blue color purity, but the lifetime of the device tends to be remarkably deteriorated. On the other hand, when an electron donating group is introduced at the 4-position, 4p-position or 6p-position, high efficiency is realized, but it differs depending on whether the electron-donating property of the substituent is derived from σ or π. I understood that.

  When an electron donating group having a strong σ property such as a methyl group is a substituent, the effect of improving the lifetime is small, whereas an electron donating group having a strong π property such as an alkoxy group or an aryloxy group is a substituent. In this case, the effect of improving the lifetime was remarkably increased. Furthermore, substituents such as alkylthio groups and arylthio groups have a small electron donating property, but the effect of improving the lifetime is significantly increased. This is presumed to be due to the loan pair present in the substituents of the alkylthio group and the arylthio group, the electronic properties of these substituents have a function equivalent to that of a π-type electron donor group. Thus, it was found that the lifetime of the light emitting device can be improved even when an electron withdrawing group is introduced at the 3p-position and the 5p-position by having at least two electron donating groups having a strong π property in the molecule as substituents. .

Based on such knowledge, the molecular structure represented by claim 1 of the present invention has been reached and the present invention has been completed.

  For the calculation of the emission wavelength, Gaussian 98 (Revision A.11.4, MJ Frisch, GW Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, V. G. Zakrzewski, JA Montgomery, Jr., RE Stratmann, J. C. Burrant, 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, G. A. Petersson, P.A. 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. Y. Cioslowski, JV Ortiz, AG Baboul, BB Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin, D. J. Fox, T. Keith, MA Al-Laham, CY Peng, A. Nanayakara, M. Challacombe, PM GW Gill, B. Johnson, W. Chen, MW Wong, JL Andres, C.G. nzalez, M.Head-Gordon, E.S.Replogle, and J.A.Pople, Gaussian, Inc., Pittsburgh PA, 2002.) was used.

  The calculation was performed using the B3LYP method to optimize the structure, and then the phosphorescence wavelength was calculated by TD-DFT calculation to obtain the emission wavelength.

  The metal complex-containing layer is preferably a light-emitting layer and / or a hole blocking layer, and when contained in the light-emitting layer, it is an object of the present invention to be used as a light-emitting dopant in the light-emitting layer. In addition, it is possible to achieve a long emission life of the organic EL element.

"Metal complexes"
The organic EL device material of the present invention for engaging Rukin metal complex will be described.
"General formula (3 '') is represented by Rukin metal complex"
According to the present invention, represented by general formula (3 '') will be described Rukin metal complex.
In the general formula (3 ″) , Rb, Rc, and Rd represent an alkyl group or an aryl group. The substituent for Rb, Rc and Rd is preferably an alkyl group. Examples of the alkyl group include a methyl group, isopropyl group, and tert-butyl group. Examples of the aryl group include a phenyl group, 2-naphthyl group, 9-phenanthryl group, 2-pyridyl group, 2-thienyl group, and 3-furyl group. Group, mesityl group, carbazolyl group, fluorenyl group and the like.
In the general formula (3 ″) , Xb, Xc and Xd represent an oxygen atom, a sulfur atom or a nitrogen atom. The combination of Xb, Xc, and Xd atoms includes (1) Xd is a nitrogen atom, Xb and Xc are oxygen atoms, (2) Xd is a sulfur atom, Xb and Xc are oxygen atoms, or (3) Xb Xc and Xd are preferably oxygen atoms.
In the general formula (3 ″) , nb, nc, and nd represent 1 or 2.
In the general formula (3 ″) , R6, R7, R8, R9, and R10 represent a hydrogen atom.
In the general formula (3 ″) , M represents iridium or platinum , and n represents 1 or 2.

<< Metal Complex Represented by General Formula (1) >>
The metal complex represented by the general formula (1), which is a preferred embodiment of the present invention, will be described.

  In the general formula (1), A, B and C are represented by hydrogen atoms or substituents, but at least two of them are represented by the general formula (2) and may be different from each other. The substituent represented by A, B, or C is not particularly limited, but is preferably an alkyl group (for example, a methyl group, an isopropyl group, a tert-butyl group), a cycloalkyl group (for example, a cyclohexyl group, a cyclopentyl group). , Cyclopropyl group, etc.), alkenyl group (eg, vinyl group, allyl group, 2-butenyl group, etc.), alkynyl group (eg, ethynyl group, propynyl group, etc.), aryl group (eg, phenyl group, 2-naphthyl group, etc.) 9-phenanthryl group, 2-pyridyl group, 2-thienyl group, 3-furyl group, mesityl group, carbazolyl group, fluorenyl group, etc.), heterocyclic group (N-morpholyl group, 2-tetrahydrofuranyl group, etc.), amino Group (eg, dimethylamino group, diphenylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom) , Iodine atom, etc.), alkoxy group (eg, methoxy group, ethoxy group, isopropoxy group, etc.), aryloxy group (eg, phenoxy group, perfluorophenoxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, Propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), cyano group, fluorinated hydrocarbon group (eg, trifluoromethyl group, pentafluorophenyl group) Etc.) and silyl groups (for example, triphenylsilyl group, trimethylsilyl group, etc.). Of these, amino groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, and aryl groups are particularly preferred. Most preferably, they are an amino group, an alkoxy group, and an alkylthio group.

In the general formula _{(1), R 1, R} 2, R 3, R 4, R 5 represents a hydrogen atom or a substituent. The substituents represented by R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ have the same meanings as those described as the substituents represented by A, B, and C. The substituent represented by R ₁ or R ₂ may be an electron-withdrawing group (in the present invention, σp represents a group exceeding 0).

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. Examples of electron withdrawing groups having σp of 0.10 or more are shown below.
<< 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 can be mentioned, but the present invention is not limited thereto.

In the general formula (1), M ₁ represents an element of Group 8, Group 9, or Group 10 in the periodic table. The element of Group 8, 9 or 10 is preferably ruthenium, rhodium, palladium, osmium, iridium or platinum, and most preferably iridium or platinum.

  In general formula (2), Ra represents a substituent. As a substituent represented by Ra, it is synonymous with what was demonstrated as a substituent represented by said A, B, and C. Of these, an alkyl group is particularly preferred.

  In the general formula (1), Xa represents an oxygen atom, a sulfur atom or a nitrogen atom. na represents 1 or 2.

  In the general formula (1), it is most preferable that three of A, B, and C are represented by the general formula (2).

  In the general formula (1), when two of A, B and C are represented by the general formula (2), most preferably, when the general formula (2) is substituted at the 4-position and the 6p-position, preferably the general formula This is a case where (2) is substituted at positions 4 and 4p.

<< Metal Complex Represented by General Formula (3) >>
The metal complex represented by the general formula (3), which is a preferred embodiment of the present invention, will be described.

  In the general formula (3), Rb, Rc and Rd represent substituents, and the substituents represented by Rb, Rc and Rd include the substituents represented by A, B and C in the general formula (1). It is synonymous with what was demonstrated as. The substituent for Rb, Rc and Rd is preferably an alkyl group.

  In the general formula (3), Xb, Xc and Xd represent an oxygen atom, a sulfur atom or a nitrogen atom. The combination of Xb, Xc, and Xd atoms includes (1) Xd is a nitrogen atom, Xb and Xc are oxygen atoms, (2) Xd is a sulfur atom, Xb and Xc are oxygen atoms, or (3) Xb Xc and Xd are preferably oxygen atoms.

  In the general formula (3), nb, nc, and nd represent 1 or 2.

In General formula (3), R < ₆ >, R < ₇ >, R < ₈ >, R <_9> , R < ₁₀ > represents a hydrogen atom or a substituent. The substituents represented by R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ have the same meanings as those described as the substituents represented by A, B and C in the general formula (1).

In the general formula (3), M ₂ represents an element of Group 8, 9 or 10 in the periodic table. The element of Group 8, 9 or 10 is preferably ruthenium, rhodium, palladium, osmium, iridium or platinum, and most preferably iridium or platinum.

Below, it is represented by the general formula (3 '') Rukin metal complex of the general formula (1), the specific compound examples of the metal complex represented by the general formula (3), the present invention is, these It is not limited.

  These compounds are disclosed in, for example, Organic Letter, vol13, No. 16, p2579-2581 (2001), Inorganic Chemistry, vol. 8, p 1685-1687 (1991), J. MoI. Am. Chem. Soc. , Vol123, p4304 (2001), Inorganic Chemistry, vol41, No. 12, p13056-3066 (2002), New Journal of Chemistry, vol26, p1171 (2002), International Publication No. 04/045001 pamphlet, Journal of the Organic Chemistry, Vol. 67, No. 1, pages 238-241 (2002) Furthermore, it can be synthesized by applying methods such as references described in these documents.

  In the present invention, the organic EL element containing the organic EL element material means that an organic EL element material forms any organic layer constituting the organic EL element or an organic EL element contained in the organic layer. To express. The organic EL element material is preferably contained in the light emitting layer or the hole blocking layer.

(Luminescent dopant)
Next, a light-emitting dopant (also simply referred to as a dopant) and a light-emitting host (also simply referred to as a host) will be described.
In a layer constituting an organic EL element, when the layer is composed of two or more organic compounds, the main component is called a host, and the other components are called dopants, and the general formula (3 ″) according to the present invention is used. represented Rukin metal complex is used as a light emitting dopant.

  In that case, the mixing ratio of the dopant to the host compound as the main component is preferably less than 0.1 to 30% by mass.

  However, the light emitting dopant may be used by mixing a plurality of types of compounds, and the mixing partner may be a Group 8, 9 or 10 metal complex having a different structure, or other phosphorescent dopant, It may be a fluorescent dopant.

  The dopant that may be used in combination with the compounds of the present invention 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.

  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, rare earth complex phosphors, and other known fluorescent compounds.

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

Specifically, it is a compound described in the following patent publications.
WO00 / 70655, JP 2002-280178, 2001-181616, 2002-280179, 2001-181617, 2002-280180, 2001-247859, 2002-299060, 2001 No. 313178, No. 2002-302671, No. 2001-345183, No. 2002-324679, WO02 / 15645, No. 2002-332291, No. 2002-50484, No. 2002-332292, No. 2002-83684, Special Table 2002-540572, 2002-117978, 2002-338588, 2002-170684, 2002-352960, WO01 / 93642, 2002-50483, 2002 No. 100476, No. 2002-173684, No. 2002-359082, No. 2002-175848, No. 2002-363552, No. 2002-184582, No. 2003-7469, No. 2002-525808, JP-A No. 2003 7471, Japanese translations of PCT publication No. 2002-525833, JP-A-2003-31366, 2002-226495, 2002-234894, 2002-2335076, 2002-241751, 2001-319779, 2001- 319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572, 2002-203678, and the like.

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.

  The light emitting host used in the present invention is preferably a compound having a wavelength shorter than the phosphorescence 0-0 band of the light emitting dopant used together, and the light emitting dopant has a blue light whose phosphorescence 0-0 band is 480 nm or less. 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 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 oligo A preferable compound is a compound having a basic skeleton such as an arylene compound and having the 0-0 band of 450 nm or less.

  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 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.
JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002 No. 141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453, No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 200 No. -255 934, the same 2002-260861 JP, same 2002-280183 JP, same 2002-299060 JP, same 2002-302516 JP, same 2002-305083 JP, same 2002-305084 JP, same 2002-308837 Patent, and the like.

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.

In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode << Anode >>
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such 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, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, 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.

  Next, an injection layer, a hole transport layer, an electron transport layer, etc. 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, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. .

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

  As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, JP-A-11-204258, JP-A-11-204359, and “Organic EL devices and their forefront of industrialization” (issued on November 30, 1998 by NTS, Inc.), page 237, etc. There is a hole blocking layer.

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

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

  The hole transport layer is made of 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.

  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.

<Light emitting layer>
In the present invention, the group VIII metal complex of the present invention is preferably used as a light emitting dopant, but other known light emitting hosts and light emitting dopants may be used in combination.

  Examples of known light-emitting hosts that may be used in combination include an electron transport material and a hole transport material, which will be described later, as a preferred example. When applied to blue or white light-emitting elements, display devices, and illumination devices, fluorescent materials are used. The maximum wavelength is preferably 415 nm or less, and the 0-0 band of phosphorescence is more preferably 450 nm or less.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although the film thickness as a light emitting layer does not have a restriction | limiting in particular, Usually, it selects in the range of 5 nm-5 micrometers. This light emitting layer may have a single layer structure composed of one or two or more of these light emitting materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

  Further, as described in JP-A-57-51781, this light emitting layer is prepared by dissolving the above light emitting material in a solvent together with a binder such as a resin, and then using a spin coat method or the like. It can be formed as a thin film. The film thickness of the light emitting layer thus formed is usually in the range of 5 nm to 5 μm as described above.

《Hole transport layer》
The hole transport layer is made of 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, 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 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) and the like.

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

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  In the present invention, the hole transport material of the hole transport layer preferably has a fluorescence maximum wavelength of 415 nm or less when applied to a blue or white light emitting element, a display device, and a lighting device. More preferably, the 0-0 band is 450 nm or less.

  The hole transport material is preferably a compound having a high Tg.

  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 5-5000 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 as a single layer or a plurality of layers.

  In the present invention, the group VIII metal complex of the present invention is preferably used for the hole blocking layer, but other than these, a known electron transporting material (also serving as a hole blocking material) may be used in combination.

  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 ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum. Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.

  The preferred compound used for the electron transport layer is preferably a fluorescent maximum wavelength of 415 nm or less and a phosphorescence 0-0 band of 450 nm when applied to a blue or white light emitting element, a display device and a lighting device. More preferably, it is as follows.

  The compound used for the electron transport layer is preferably a compound having a high Tg.

  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.

<< 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.

  The resin film is not particularly limited, and specifically, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate, and cellulose. Cellulose esters such as acetate phthalate and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone , Polysulfones, Polyetherketoneimide, Polyamide, Fluororesin, Nai , Polymethyl methacrylate, acrylic or polyarylates, norbornene (or cycloolefin) resins such as Arton (trade name: manufactured by JSR) or Apel (trade name: manufactured by Mitsui Chemicals), organic-inorganic hybrid Examples thereof include resins. Examples of the organic-inorganic hybrid resin include those obtained by combining an organic resin and an inorganic polymer (for example, silica, alumina, titania, zirconia, etc.) obtained by a sol-gel reaction.

  An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film.

  Specific examples of the coating include a silica layer formed by a sol-gel method, an organic layer formed by application of a polymer, etc. (for example, an organic material film having a polymerizable group is subjected to post-treatment by means such as ultraviolet irradiation or heating). A DLC film, a metal oxide film, a metal nitride film, or the like. Metal oxide film, metal oxide constituting the metal nitride film, and metal nitride include metal oxides such as silicon oxide, titanium oxide, and aluminum oxide, metal nitrides such as silicon nitride, silicon oxynitride, and oxynitride Examples thereof include metal oxynitrides such as titanium.

The water vapor permeability of the resin film having an inorganic or organic coating or a hybrid coating of both on the surface is preferably a high barrier film of 0.01 g / m ² · day · atm or less.

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

As described above, there are spin coating methods, casting methods, ink jet methods, vapor deposition methods, printing methods, and the like as methods for thinning the organic compound thin films, but it is easy to obtain a uniform film and pinholes are not easily generated. In view of the above, the vacuum deposition method or the spin coating method 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 to 450 ° C., a vacuum degree of 10 ⁻⁶ Pa to 10 ⁻² Pa, a vapor deposition rate of 0. It is desirable to select appropriately within the range of 01 nm to 50 nm / second, substrate temperature of −50 ° C. to 300 ° C., and 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.

  In the display device of the present invention, a shadow mask is provided only when a light emitting layer is formed, and a film can be formed on one surface by a vapor deposition method, a cast 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.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order.

  When a DC voltage is applied to the 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 display device of the present invention can be used as a display device, a display, and various light emission sources. In a display device or a 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 emitting 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. Although a lighting apparatus is mentioned, it is not limited to this.

  Further, the organic EL element according to the present invention may be used as an organic EL element having a resonator structure.

  Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, and a light source of an optical sensor. Not. Moreover, you may use for the said use by making a laser oscillation.

<Display device>
The organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image. (Display) may be used. 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.

(Aspect of the Invention)
An example of a display device composed of the organic EL element of the present invention will be described below 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 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 light emission colors is a combination of a plurality of phosphorescent or fluorescent light emitting materials, a light emitting material that emits fluorescent light or phosphorescent light, and light from the light emitting material as excitation light. Any of those in combination with a dye material that emits light as described above may be used, but in the white organic EL device according to the present invention, it is only necessary to mix and mix a plurality of light emitting dopants. It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, or the like, and simply arrange them separately by 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.

  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 device of the present invention can be used as a light-emitting light source and a lighting device in addition to the display device and the 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.

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 reducing the pressure of the first vacuum tank to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was energized and heated, and the transparent support substrate was deposited at a deposition rate of 0.1 to 0.2 nm / sec. The film was deposited to a thickness of 25 nm to provide a 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-10 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.

Subsequently, the heating boat containing BCP was energized and heated to provide a hole blocking layer having a thickness of 10 nm at a deposition rate of 0.1 to 0.2 nm / second. 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 depressurizing the second vacuum tank to 2 × 10 ⁻⁴ Pa, a cathode buffer layer having a film thickness of 0.5 nm was provided at a deposition rate of 0.01 to 0.02 nm / second by energizing a boat containing lithium fluoride. Next, a boat containing aluminum was energized, and a cathode having a film thickness of 150 nm was attached at a deposition rate of 1 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 organic EL element OLED1-1 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 1-41 >>
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 1-41 was produced similarly.
(Manufacturing method of OLED1-42, 43)
In the production of OLED1-1, the organic light-emitting host was changed from CBP to AZ1, and the light-emitting dopant was used in the same manner as in OLED1-1 except that the metal complex of the present invention (shown as compound No. in the table) was used. EL elements 1-42 and 43 were produced.
(Method for producing OLED1-44 to 1-47)
In the production of OLED1-1, the organic light-emitting host was changed from CBP to CDBP, and the organic dopant was used in the same manner as in OLED1-1 except that the metal complex of the present invention (shown as compound No. in the table) was used. EL elements 1-44 to 47 were produced.

  The following evaluation was performed about obtained organic EL element OLED1-1 to 1-47.

<< External quantum efficiency >>
The organic EL elements OLED1-1 to 1-47 are turned on at room temperature (about 23 to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and light emission luminance (L) [cd / m ² immediately after the start of lighting] The external extraction quantum efficiency (η) was calculated. 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 set to 100.

<Luminescent life>
The organic EL elements OLED1-1 to 1-47 are continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature, and the time (τ _1/2 ) required to obtain half the initial luminance is obtained. It was measured. Moreover, the light emission lifetime was represented by the relative value when the organic EL element OLED1-1 was set to 100.

《Chromaticity difference》
The organic EL elements OLED1-1 to 1-47 are turned on at room temperature (about 23 to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the CIE chromaticity (( x, y) = (a, b)) was measured, and the difference between NTSC (modern) and blue ((x, y) = (0.155, 0.07)) was calculated as Δ. CIE chromaticity was measured using CS-1000 (Minolta). Δ was determined according to the following equation.

Δ = ((0.155−a) ² + (0.07−b) ² ) ^1/2
The external extraction quantum efficiency was expressed as a relative value when the organic EL element OLED1-1 was set to 100.

  The obtained results are shown in Table 1.

  From Table 1, 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 emission lifetime than the comparative organic EL device. Moreover, it turned out that color purity is also improved compared with the conventional element.

Example 2
<< Production of Organic EL Elements OLED2-1 to 2-22 >>
In the production of the organic EL element OLED1-1 of Example 1, the organic EL element was similarly changed except that the emission dopant was changed from Ir-12 to Ir-1 and the hole blocking material was changed as shown in Table 2. Elements OLED2-1 to 2-22 were produced.

  The obtained organic EL elements OLED2-1 to 2-22 were measured for the external extraction quantum efficiency and the light emission lifetime using the method described in Example 1. Evaluation was represented by the relative value of each sample of the organic EL element when the value of the organic EL element OLED2-1 was 100. The obtained results are shown in Table 2.

  From Table 2, it was found that the organic EL device of the present invention has higher light emission efficiency and light emission lifetime than the comparative organic EL device. The emission color of the organic EL element of the present invention was all green.

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element OLED1-11 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
The organic EL element OLED2-7 of Example 2 was used as a green light emitting element.

(Production of red light emitting element)
In the production of the organic EL element OLED1-11 of Example 1, an organic EL element produced in the same manner except that the light emitting dopant was changed from I-1 to Ir-9 was used as a red light emitting element.

  The red, green, and blue light-emitting organic EL elements are juxtaposed on the same substrate to produce an active matrix type full-color display device having a configuration as shown in FIG. 1, and FIG. Only a schematic diagram of the display unit A 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 (light 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 the 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, a full color display device was produced by appropriately juxtaposing the red, green, and blue pixels.

  It has been found that by driving a 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 The heated boat containing, the boat containing the compound P-9 of the present invention, and the boat containing Ir-9 are energized independently, respectively, CBP as the luminescent host and compounds P-9 and Ir- of the present invention as the luminescent dopant. The vapor deposition rate of 9 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 transport 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, it is possible to provide an organic EL element, a lighting device, and a display device that have a light emission wavelength controlled, exhibit high light emission efficiency, and have a long light emission lifetime.

Claims (2)

An organic electroluminescence device material comprising a metal complex represented by the following general formula (3 ″) .
(In the formula, Rb, Rc, and Rd represent an alkyl group or an aryl group, Xb, Xc, and Xd represent an oxygen atom, a sulfur atom, or a nitrogen atom. Nb, nc, and nd represent 1 or 2. R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ represent a hydrogen atom, M represents iridium or platinum, and n represents 1 or 2. An organic electroluminescent element comprising the organic electroluminescent element material according to claim 1 .