Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1998-11-03
2001-02-27
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S704000, C428S917000, C313S504000, C313S506000
Reexamination Certificate
active
06194090
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a luminescent material for a light emitting device (organic electroluminescence (EL) device) capable of converting an electric energy into light and emitting light and to a light emitting device having a high luminance, more specifically, the present invention relates to a light emitting device suitably used in the field of display device, display, back light, electrophotography, illumination light source, mark, billboard, interior decoration and the like.
BACKGROUND OF THE INVENTION
At the present time, development and study on various display devices are aggressively driven. In particular, organic EL devices can obtain highly bright luminescence at a low voltage and accordingly, are drawing an attention as a promising display device. For example, an EL device comprising an organic thin film formed by depositing an organic compound is known (see,
Applied Physics Letters
, Vol. 51, page 913 (1987)). The organic EL device described in this publication has a laminate structure comprising an electron transporting material and a hole transporting material and is greatly improved in the luminescence properties as compared with conventional single-layer devices.
As a means to improve the luminescence efficiency of the laminate-type EL device, a method of doping a fluorescent dye is known. For example, an organic EL device having doped therein a coumarin dye described in
Journal of Applied Physics
, Vol. 65, page 3,610 (1989) is greatly improved in the luminescence efficiency as compared with non-doped devices. In this case, by changing the kind of the fluorescent compound, light having a desired wavelength can be taken out but compounds capable of highly efficiently emitting blue light and having superior durability are small in number.
Examples of the blue light emissive material for organic EL devices include condensed polycyclic aromatic compounds such as anthracene, pyrene and perylene (compounds described, for example, in
J. Chem. Phys
., 44, 2902 (1966), and
Thin Solid Films
, 99, 171 (1982)), tetraphenylbutadiene-based compounds (compounds described, for example, in JP-A-59-194393 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)), distyrylbenzene-based compounds (compounds described, for example, in European Patents 281381, 319881 and 373582, U.S. Pat. Nos. 4,672,265, 4,725,531, 4,734,338, 4,741,976 and 4,776,320, JP-A-61-37890, JP-A-1-245087, JP-A-2-247277, JP-A-2-247278, JP-A-2-209988, JP-A-3-33184, JP-A-3-84089, JP-A-3-231970, JP-A-4-117485, JP-A-4-275268, JP-A-5-17765 and JP-A-140145), stilbene-based compounds (compounds described, for example, in JP-A-2-235983 and JP-A-3-47890), polyphenyl-based compounds (compounds described, for example, in JP-A-3-33183), polycarbonate-based compounds containing an aromatic tertiary amine skeleton as a repeating unit (compounds described, for example, in JP-A-5-247459), metal complexes having a tropolone skeleton (compounds described, for example, in JP-A-9-157642), and metal complexes having a 2-(o-hydroxyphenyl)benzoxazole derivative or 2-(o-hydroxyphenyl)-thiazole derivative as a ligand (compounds described, for example, in JP-A-7-133483, JP-A-8-113576, JP-A-8-301877 and JP-A-8-306489). However, these compounds are disadvantageous in that the luminescence efficiency is low, the durability has a problem and the color purity is bad, thus, cannot be used in practice.
Of organic EL devices, devices in which an organic substance is laminated by vacuum deposition can successfully achieve highly bright luminescence, however, in view of simplification of the production process, workability and the like or for obtaining a large area, the device is preferably fabricated by a coating method. The devices fabricated by the conventional coating method are, however, inferior in the luminance of light emitted and the luminescence efficiency to the devices fabricated by the deposition method. Thus, improvements are still in need for attaining high luminance and highly efficient luminescence.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an organic EL device material ensuring high color purity, being capable of achieving highly bright and highly efficient luminescence by the driving at a low voltage and having excellent stability on repeated use.
Another object of the present invention is to provide an organic EL device using the organic EL device material.
These objects have been attained by the following techniques.
(1) An organic electroluminescence device material which is a metal complex synthesized from a compound represented by the following formula (I) and a metal ion:
(wherein R
1
represents a hydrogen atom or a substituent, R
2
represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, Z represents an atomic group necessary for forming a 5- or 6-membered ring, and M represents a hydrogen atom or a cation).
(2) The organic electroluminescence device material as described in (1) above, wherein the metal ion of the metal complex is a divalent or trivalent cation.
(3) The organic electroluminescence element material as described in (1) or (2) above, wherein the metal ion of the metal complex is Be
2+
, Mg
2+
, Al
3+
, Ga
3+
or Zn
2+
.
(4) An organic electroluminescence device comprising a pair of electrodes having formed therebetween a light emitting layer or a plurality of organic compound thin films including a light emitting layer, wherein at least one layer comprises the organic electroluminescence device material described in (1) to (3) above.
(5) The organic electroluminescence device comprising a pair of electrodes having formed therebetween a light emitting layer or a plurality of organic compound thin films including a light emitting layer, wherein at least one layer comprises a polymer having dispersed therein the organic electroluminescence device material described in (1) to (3) above.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
Formula (1) is described below.
R
1
represents a hydrogen atom or a substituent. Examples of the substituent represented by R
1
include an alkyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, still more preferably from 1 to 8 carbon atoms, e.g., methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl), an alkenyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, still more preferably from 2 to 8 carbon atoms, e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), an alkynyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, still more preferably from 2 to 8 carbon atoms, e.g., propargyl, 3-pentynyl), an aryl group (preferably having from 6 to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, still more preferably from 6 to 12 carbon atoms, e.g., phenyl, p-methylphenyl, naphthyl), an amino group (preferably having from 0 to 20 carbon atoms, more preferably from 0 to 10 carbon atoms, still more preferably from 0 to 6 carbon atoms, e.g., amino, methylamino, dimethyl-amino, diethylamino, dibenzylamino), an alkoxy group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, still more preferably from 1 to 8 carbon atoms, e.g., methoxy, ethoxy, butoxy), an aryloxy group (preferably having from 6 to 20 carbon atoms, more preferably from 6 to 16 carbon atoms, still more preferably from 6 to 12 carbon atoms, e.g., phenyloxy, 2-naphthyloxy), an acyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., acetyl, benzoyl, formyl, pivaloyl), an alkoxycarbonyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 16 carbon atoms, still more preferably from 2 to 12 carbon atoms, e.g., methoxycarbonyl, ethoxycarbonyl), an aryloxycarbonyl group (
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Yamnitzky Marie
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