Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1999-10-01
2001-07-31
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C428S704000, C428S446000, C428S448000, C313S504000, C313S506000
Reexamination Certificate
active
06268072
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electroluminescent (EL) devices. More specifically, phenylanthracenie-based polymers used as luminescent materials in polymer EL devices.
BACKGROUND OF THE INVENTION
Electroluminescent devices are opto-electronic devices where light emission is produced in response to an electrical current through the device. The physical model for EL is the radiative recombination of electrons and holes. The term light emitting diode (LED) is commonly used to describe an EL device where the current-voltage behavior is non-linear, meaning that the current through the EL device is dependent on the polarity of the voltage applied to the EL device. Both organic and inorganic materials have been used for the fabrication of LEDs. Inorganic materials such as ZnS/Sn, Ga/Bs, Ga/As have been used in semiconductor lasers, small area displays, LED lamps, etc. However, the drawbacks of inorganic materials include difficulties to process and to obtain large surface areas and efficient blue light.
Organic polymers and small organic molecules used as light-emitting materials in EL devices offer several advantages over inorganic materials, such as simpler manufacturing, low operating voltages, the possibility of producing large area and full-color displays. An efficient multilayer organic LED was first discovered by Tang et al (Tang, C. et al
Appl. Phys. Lett
. 1987, 51, 913-15). Conjugated polymers such as poly(phenylvinylene) (PPV) were first introduced as EL materials by Burroughes et al in 1990 (Burroughes, J. H.
Nature
1990, 347, 539-41). Considerable progress has been made since then to improve the stability, efficiency, and durability of polymeric LEDs (Sheats, J. R. et al
Science
1996, 273, 884-888; Cacialli, F. et al
Synth. Met
. 1994, 67, 157-60; Berggren, M. et al
Nature
1994, 372, 444-6; Spreitzer, H. et al WO 98/27136 (1998); Holmes, A. B. et al WO 94/29883 (1994); and Heinrich B. et al,
Adv. Mater
. 1998, 10(16), 1340). Polymers with wide energy bandgap to emit blue light are important materials because stable, efficient blue-light-emitting materials with high brightness, are desirable for full color EL display applications. With these primary materials, it is possible to produce other colors by a downhill energy transfer process. For instance, a green or red EL emission can be obtained by doping a blue host EL material with a small amount of green or red luminescent material. The first report of blue-emission from a conjugated polymeric LED was for polydialkylfluorene (PF) (Olhmori, Y. et al
Jpn. J. Appl. Phys. Part
2 1991, 20, L1941-L1943), followed by poly(p-phenylene) (PPP) (Grem, G. et al
Adv. Mater
. 1992, 4, 36-7). Incorporating non-conjugated spacer groups into a conjugated polymer backbone is an effective approach to break conjugation, thus increases the energy bandgap in order to emit blue light. These spacer groups usually prevent the extended conjugation and contribute to the solubility and film-forming properties of the polymer. Blue-light-emitting PPV (Aguiar, M et al
Macromolecules
1995, 28, 4598-602), polythiophene (Andersson, M. R. et al
Macromolecules
1995, 28, 7525-9), poly(oxadiazoles) (Pei, Q. et al
Adv. Mater
. 1995, 7, 559-61) and PPP (Hilberer, A et al
Macromolecules
1995, 28, 4525-9) have been prepared by this approach. However, the incorporation of flexible nonconjugated spacer groups into a rigid conjugated polymer backbone reduces the stiffness of the backbone thus affecting the microscopic molecular order of the polymer (Remmers, M. et al
Macromolecules
1996, 29, 7432-7445). Such groups can also act as a barrier to the injection and mobility of the charge carriers which leads to high threshold voltages and operating voltages. Thus, it is desirable to develop processable new blue-light-emitting polymers with low driving voltages for full color displays.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide wide energy bandgap luminescent polymeric materials useful for polymer EL devices.
It is a further object of the present invention to provide wide energy bandgap luminescent polymers which emit blue light.
These objects are achieved in an electroluminescent device comprises an anode, a cathode, and polymer luminescent materials disposed between the anode and cathode, the polymeric luminescent materials includes 9-(4-adamantanyl)phenyl)-10-phenylanthracene-based polymers of the following formula:
wherein:
substituents R, R
1
, R
2
, R
3
, R
4
and R
5
are each individually hydrogen, or alkyl or alkoxy of from 1 to 24 carbon atoms; aryl or substituted aryl of from 6 to 28 carbon atoms; or heteroaryl or substituted heteroaryl of from 4 to 40 carbons; or F, Cl, Br; or a cyano group; or a nitro group; wherein
the ratio of n/(m+n) is between 0 to 1 wherein m and n are integers but m cannot be 0; and Y are divalent linking groups.
In the formula, Y can be one or the combination of a number of different groups all of which satisfy the above formula.
The present invention provides polymeric luminescent materials with a number of advantages that include good solubility, reduced crystallinity, and better thermal stability. With the primary wide energy bandgap chromophore, 9-(4-adamantanyl)phenyl-10-phenylanthracene, other color emitting luminescent copolymers can be easily designed and produced by introducing the narrow energy bandgap chromophores into the polymeric chain.
REFERENCES:
patent: 4356429 (1982-10-01), Tang
patent: 4769292 (1988-09-01), Tang et al.
patent: 5429884 (1995-07-01), Namiki et al.
patent: 5776622 (1998-07-01), Hung et al.
patent: 5777070 (1998-07-01), Inbasekaran et al.
patent: 94/29883 (1994-12-01), None
patent: 98/27136 (1998-06-01), None
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Burroughes et al, Light-emitting diodes based on conjugated polymers, Nature, vol.347, Oct. 11, 1990, pp. 539-541.
Sheats et al, Organic Electroluminescent Devices, Science, vol. 273, Aug. 16, 1996, pp. 884-888.
Cacialli, et al, Characterization of properties of polymeric light-emitting diodes over extended periods, Synthetic Metals 67 (1994) pp. 157-160 (no month).
Berggren et al, Light-emitting diodes with variable colours from polymer blends, Nature, vol. 372, Dec. 1, 1994, pp. 444-446.
Spreitzer et al, Soluble Phenyl-Substituted PPVs-New Materials for Highly Efficient Polymer LEDs, Advanced Materials, 1998, 10, No. 16, pp. 1340-1343 (no month).
Ohmori et al, Blue Electroluminescent Diodes Utilizing Poly(alkylfluorene), Japanese Journal of Appl. Phys. vol. 30, No. 11B, 11/91, pp. L1941-L1943.
Aguiar et al, Light-Emitting Polymers with Pendant Chromophoric Groups, Macromolecules 1995, 28, pp. 4598-4602 (no month).
Andersson et al, Electroluminescene from Substituted Poly(thiophenes): From Blue to Near Infrared, Macromolecules 1995, 28, pp. 7525-7529 (no month).
Pei et al, Bright Blue Electroluminescence From an Oxadiazole-containing Copolymer, Adv. Mater. 1995, 7, No. 6, pp. 559-561 (no month).
Hilberer et al, Synthesis and Characterization of a New Efficient Blue-Light-Emitting Copolymer, Macromolecules 1995, 28, pp. 4525-4529 (no month).
Remmers et al, The Optical, Electronic and Electroluminescent Properties of Novel Poly(p-phenylene)-Related Polymers, Macromolecules, 1996, 29, pp. 7432-7445 (no month).
Pixton et al, Gas transport properties of adamantane-based polysulfones, Polymer, vol. 36, No. 16, 1995, pp. 3165-3172 (no month).
Chern et al, Low Dielectric Constants of Soluble Polyimides Based on Adamantane, Macromolecules, 1997, 30, pp. 4646-4651 (no month).
Hsiano et al, Synthesis and Characterization of New Adamantane-Based Polyimides, Macromolecules 1998, 31, pp. 7213-7217, (no month).
Miyaura et al, Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds, Chem. Rev. 95, 1995, pp. 2457-2483 (no month).
Miyaura et al, The Palladium-Catalyzed Cross-Coupling Reaction of Phenylboronic Acid with Haloarenes in the Presence of Bases, Synthetic Communications, 11(7), 1981, pp. 513-519 (no mont
Klubek Kevin P.
Shi Jianmin
Zheng Shiying
Eastman Kodak Company
Owens Raymond L.
Xu Ling
Yamnitzky Marie
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