Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2002-04-22
2004-10-19
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S704000, C428S917000, C313S504000, C313S506000, C252S301160, C252S301310, C252S301320, C252S301350, C548S110000, C548S405000
Reexamination Certificate
active
06805978
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pyrromethene metal complexes for use as fluorescent dye and to light emitting devices (LEDs) using the same.
2. Description of the Related Art
Organic thin-film LEDs, from which light is emitted when electrons injected from a cathode are recombined with holes injected from an anode in an organic fluorescent material between the cathode and the anode, have recently been studied with great interest. These devices are of interest because they can be formed in a thin structure, can emit light with high luminance under a low driving voltage, and can emit multicolored light depending on the fluorescent materials used.
Many research organizations have studied these elements since C. W. Tang et al of Kodak disclosed that an organic thin-film LED emits light with high luminance (Appl. Phys. Lett. 51 (12) 21, p. 913, 1987). A typical organic thin-film LED developed by Kodak comprises a hole transporting diamine compound, 8-hydroxyquinoline aluminum serving as a emissive layer, and a Mg—Ag cathode, in that order, on an ITO glass substrate. This LED was able to emit green light with a luminance of 1000 cd/m
2
under a driving voltage of about 10 V. Some existing organic thin-film LEDs are have undergone certain modifications. For example, an electron transporting layer may be additionally disposed in a device.
Research in green emissive materials is the most advanced for multicolored emission. Red and blue emissive materials are still required to be more durable and to have high luminance and chromatic purity, and have been studied more intensely.
Exemplary red emissive materials include perylenes such as bis(diisopropylphenyl)perylene, perynone, porphyrin, and Eu complexes (Chem. Lett., 1267(1991)).
Also, a method has been studied in which a host material is doped with a red fluorescent material to generate red emission. Exemplary host materials include quinolinol metal complexes such as tris(8-quinolinolato)aluminum, bis(10-benzoquinolinate)beryllium, diarylbutadienes, stilbenes, and benzothiazoles. These host materials are doped with 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran, metal phthalocyanine complexes such as MgPc and AlPcCl, squaliriums, and violanthrones to generate red luminescence.
Unfortunately, some of the known emissive materials including host materials and dopants have low luminance efficiency and thus have a high power consumption, and others are not durable and thus result in a short lifetime of the LED. Also, concentration quenching and exciplex and excimer formations often lower the fluorescence intensity when the materials are in a thin-film state although the materials have high fluorescence when they are in a solution. Thus, many of the materials cannot provide high luminance suitable for LEDs. It is a big problem that particularly most of the red emissive materials including host materials and dopants cannot provide both high chromatic purity and high luminance, simultaneously.
In Japanese Unexamined Patent Application Publication No. 2000-208270, a diketopyrrolo[3,4-c]pyrrole derivative and an organic fluorescent material having a peak fluorescent wavelength of 580 to 720 nm are used to generate a red emission, but cannot lead to high luminance.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to solve the above-described problem and to provide a new pyrromethene metal complex capable of resulting in an LED having high luminance efficiency and high chromatic purity and an LED using the same.
The present invention is directed to a pyrromethene metal complex.
The present invention is also directed to an LED material comprising the pyrromethene metal complex.
The present invention is also directed to an LED generating a emission having an emission peak wavelength in the range of 580 to 720 nm by electrical energy. The device comprises at least one of: an LED material comprising a diketopyrrolo[3,4-c]pyrrole derivative and an organic fluorescent material having a fluorescent peak wavelength of 580 to 720 nm; and an LED material comprising a pyrromethene metal complex.
According to the present invention, the pyrromethene metal complex has highly fluorescent properties and therefore can be used for LEDs. By using the pyrromethene metal complex, an LED having a high energy efficiency, a high luminance, and a high chromatic purity can be achieved.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Pyrromethene metal complexes represented by the chemical formula (1) will now be described in detail.
R
1
, R
2
, and L are each a substituent selected from the group consisting of hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, aryl ether, aryl thioether, aryl, heterocyclic, halogen, haloalkane, haloalkene, haloalkyne, cyano, aldehyde, carbonyl, carboxyl, ester, carbamoyl, amino, nitro, silyl, siloxanyl, and a fused aromatic ring and an alicyclic ring formed with adjacent substituents. R
1
, R
2
, and L may be the same as or different from one another. M represents a metal having a valence of m and is selected from the group consisting of boron, beryllium, magnesium, chromium, iron, nickel, copper, zinc, and platinum. Ar
1
to Ar
5
represent aryl.
In these substituents, alkyl means saturated aliphatic hydrocarbon substituents such as methyl, ethyl, propyl, and butyl. Cycloalkyl means saturated alicyclic ring substituents such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl. Aralkyl means substituents formed with aromatic hydrocarbons having an aliphatic hydrocarbon therebetween, such as benzyl and phenylethyl. Alkenyl means unsaturated aliphatic hydrocarbon substituents having a double bond, such as vinyl, allyl, and butadienyl. Cycloalkenyl means unsaturated alicyclic ring substituents having a double bond, such as cyclopentenyl, cyclopentadienyl, and cyclohexene. Alkynyl means unsaturated aliphatic hydrocarbon substituents having a triple bond, such as acetylenyl. Alkoxy means substituents formed with aliphatic hydrocarbons having an ether linkage therebetween, such as methoxy. Alkylthio means substituents in which sulfur is substituted for oxygen in the ether linkage of alkoxy. Aryl ethers mean substituents formed with aromatic hydrocarbons having an ether linkage therebetween, such as phenoxy. Aryl thioethers mean substituents in which sulfur is substituted for oxygen in the ether linkage of aryl ethers. Aryl means aromatic hydrocarbon substituents, such as phenyl, naphthyl, biphenyl, phenanthryl, terphenyl, and pyrenyl. Heterocyclic means cyclic substituents having an atom other than carbon, such as furyl, thienyl, oxazolyl, pyridyl, quinolyl, and carbazolyl. Halogens mean fluorine, chlorine, bromine, and iodine. Haloalkane, haloalkene, and haloalkyne mean substituents in which halogens are substituted for part or entirety of the above-described alkyl, alkenyl, or alkynyl. Aldehyde, carbonyl, ester, carbamoyl, and amino includes substituents having an aliphatic hydrocarbon, an alicyclic ring, an aromatic hydrocarbon, a heterocycle, and the like therein. Silyl means silicon compounds such as trimethylsilyl. Each above-described substituent may have a substituent therein or not. The fused aromatic ring and the alicyclic ring may have a substituent or not.
Boron complexes represented by the following chemical formula (2) have higher fluorescence quantum yield in the metal complexes represented by the chemical formula (1).
R
3
to R
6
may be the same as or different from one another, and are each a substituent selected from the group consisting of hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, aryl ethers, aryl thioethers, aryl, heterocyclic, halogens, haloalkane, haloalkene, haloalkyne, cyano, aldehyde, carbonyl, carboxyl, esters, carbamoyl, amino, nitro, silyl, siloxanyl, and a fused aromatic ring and an alicyclic ring formed with adjacent substituents. Ar
6
to Ar
10
represent aryl groups. These s
Kohama Akira
Murase Seiichiro
Tominaga Tsuyoshi
Jones Deborah
Morrison & Foerster / LLP
Toray Industries Inc.
Xu Ling
LandOfFree
Pyrromethene metal complex and light emitting device... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pyrromethene metal complex and light emitting device..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pyrromethene metal complex and light emitting device... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3296546