Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2001-08-28
2003-09-02
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C313S503000, C313S504000
Reexamination Certificate
active
06613457
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electroluminescent (EL) devices having diarylanthracene ladder polymers.
BACKGROUND OF THE INVENTION
Electroluminescent (EL) devices such as light emitting diode (LED) are opto-electronic devices which radiate light on the application of an electrical field. Organic materials including both polymers and small molecules have been used to fabricate LEDs. LEDs fabricated from these materials offer several advantages over other technologies, such as simpler manufacturing, low operating voltages, and the possibility of producing large area and full-color displays. Organic polymers generally offer significant processing advantages over small molecules especially for large area EL display because polymer films can be easily produced by casting from solutions.
Conjugated polymers are a class of polymers that possess an extended &pgr;-bond network along polymer main chain. Their electronic states can delocalize caused by the effect of the electron-lattice and electron-electron interactions. Conjugated polymers such as poly(p-phenylvinylene) (PPV) were first introduced as EL materials by Burroughes et al in 1990 (Burroughes, J. H.
Nature
1990, 347, 539-41). EL efficiency has been improved by balanced electron-hole injection, charge transport, and recombination of the charge carriers. Other conjugated polymers such as polydialkylfluorene (PF) (Ohmori, Y. et al
Jpn. J. Appl. Phys. Part
2 1991, 20, L1941), poly(p-phenylene) (PPP) (Grem, G. et al
Adv. Mater
. 1992, 4, 36), and poly(thiophene) (Ohmori, Y. et al
Solid State Commun
. 1991, 80, 605) have also been studied.
The light-emitting layer of an EL device comprises a highly luminescent material where electroluminescence is produced as a result of electron-hole pair recombination in this region. In order to achieve efficient light output, efficient and highly fluorescent materials are required. 9,10-Diaryl substituted anthracenes are well known for their high fluorescence efficiency. The highly efficient light output and high operational stability of EL devices have been disclosed in commonly assigned U.S. Pat. Nos. 5,935,721 and 5,972,247 by using substituted diarylanthracenes as light-emitting materials. Ladder polymers containing diarylanthracene moiety are interesting new EL materials. Ladder type &pgr;-conjugated polymers possess outstanding optoelectronic properties, thermal and chemical stability, low concentration of defects, and high intrachain order due to their planar structure (Huber et al.
Acta Polymer
, 1994, 45, 244)
SUMMARY OF THE INVENTION
It is an object of the present invention to provide new luminescent polymeric materials useful for polymer EL devices.
It is a further object of the present invention to provide various energy band gap luminescent polymers which emit broad range of color.
A new class of diarylanthracene-based ladder polymers has been discovered for use in electroluminescent devices.
These objects are achieved in an organic light emitting diode having an anode, a cathode and an emissive layer disposed between the anode and cathode, the emissive layer including the following repeating unit which is used to form a homopolymer or a copolymer comprising the structure:
wherein:
0≦x<1, 0<y≦1, and x+y=1;
S and T are each independently a chemical bond, an oxygen or sulfur atom, or C—R, or N—R wherein C is a carbon atom, N is a nitrogen atom, and R is a substituent including hydrogen, alkyl group of from 1 to 24 carbon atoms, or aryl or substituted aryl of from 6 to 28 carbon atoms, or heteroaryl or substituted heteroaryl of from 4 to 40 carbons, or a cyano group, a nitro group, a chlorine, bromine, or a fluorine atom;
In each ring, including D and E, if either D or E is a single bond, then the other group is not a single bond and is R—C—R, wherein C is a carbon atom and R is a substituent as defined above;
Ar
1
, Ar
2
, and Ar are each individually aryl or substituted aryl of from 6 to 40 carbon atoms; or
Ar
1
, Ar
2
, and Ar are each individually substituted heteroaryl or unsubstituted heteroaryl having 4 to 40 carbons.
The present invention provides light-emitting materials with a number of advantages that include good solubility, efficiency, and stability, low concentration of defects, and high intrachain order. The emitting color of the polymer can be easily tuned by the incorporation of desired Ar group. Furthermore, other electro-optical properties can also be tuned with Ar group. The materials from the present invention can also be used as host materials for other light emitting materials, or as dopants for other suitable light emitting materials.
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: 5935721 (1999-08-01), Shi et al.
patent: 5972247 (1999-10-01), Shi et al.
Burroughes et al, Light-emitting diodes based on conjugated polymers, Nature, vol. 347, 1990, pp. 539-541.
Ohmori et al, Blue Electroluminescent Diodes Utilizing Poly(alkylfluorene), Jap. Jour. of Applied Physics, vol. 30, No. 11B, 1991, pp. L1941-1943.
Grem et al, Realization of a Blue-Light-Emitting Device using Poly(p-phenylene), Advanced Materials, 4 (1992), No. 1, pp. 36-37.
Groenendaal et al, Poly(3,4-ethylenedioxythiophene) and Its Derivatives: Past, Present, and Future, Advanced Materials 2000, 12, No. 7, pp. 481-494.
Ohmori et al, Effects of Alkyl Chain Length and Carrier Confinement Layer on Characteristics of Poly(3-Alkylthiophene) Electroluminescent Diodes, Solid State Comm. vol. 80, No. 8, 1991, pp. 605-608.
Huber et al, Blue light-emitting diodes based on ladder polymer of the PPP type, Acta. Polymer, 45, pp. 244-247, 1994.
Scherf et al, A soluble ladder polymer via bridging of functionalized poly(p-phenylene)-precursors, Makromol. Chem, Rapid Commun. 12, 1991, pp. 489-497.
Shi Jianmin
Zheng Shiying
Garrett Dawn
Kelly Cynthia H.
Owens Raymond L.
LandOfFree
Electroluminescent devices having diarylanthracene ladder... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electroluminescent devices having diarylanthracene ladder..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electroluminescent devices having diarylanthracene ladder... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3063412