Compositions – Organic luminescent material containing compositions
Patent
1995-10-02
1997-08-05
Bonner, Melissa
Compositions
Organic luminescent material containing compositions
25230135, 313509, 428690, H05B 3314
Patent
active
056539142
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to semiconductive conjugated polymers for use in blue light-emitting devices, particularly electroluminescent devices.
BACKGROUND TO THE INVENTION
In recent years there have been an increasing number of reports on the use of conjugated molecular materials as the emissive layers in electroluminescent (EL) devices; C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett. 1987, 51, 913; C. W. Tang, S. A. VanSlyke and C. H. Chen, J. Appl. Phys. 1989, 65, 3610; C. Adachi, S. Tokito, T. Tsutsui and S. Saito, Jpn. J. Appl. Phys. 1988, 27, 59; C. Adachi, T. Tsutsui and S. Saito, Appl. Phys. Lett. 1989, 55, 1489; C. Adachi, T. Tsutsui and S. Saito, Appl. Phys. Lent. 1989, 56, 799; M. Nohara, M. Hasegawa , C. Hosokawa, H. Tokailit and T. Kusomoto, Chem. Lett. 1990, 189. These materials have efficient light output and have been shown to be easily amenable to excellent colour variation.
A considerable number of blue light-emitting molecular compounds for electroluminescent devices have been investigated so far. C. Adachi, T. Tsutsui and S. Salvo report a set of examples consisting of anthracene, 9,10-diphenyianthracene, 1,1,4,4-tetraphenylbutadiene, substituted distyrylbenzenes, terphenyl, 1,8-naphthalimides, naphthalene-1,4,5,8,-tetracarboximide, 2,5-bis (5-tert-butylbenzoxazol-2-yl)thiophene, tetraphenylcyclopentadiene, pentaphenyicyciopentadiene and substituted stilbenes in "Blue light-emitting organic electroluminescent devices" published in Appl. Phys. Lett., 1990, 56, 799. Furthermore Eur. Pat. Appl. EP 319 881, EP 373 582, EP 388 768 (Idemitsu Kosan Co. Appl. EP 319 881, EP 373 582, EP 388 768 (Idemitsu Kosan Co. Ltd.) neach that distyrylbenzenes are useful organic compounds for molecular electroluminescent devices. Green, blue-green and blue light emission was observed after varying the substituents on the distyrylbenzene. Other blue light-emitting compounds are quaterphenyl, as mentioned in Eur. Pat. Appl. EP 387 715 (idemitsu Kosan Co. Ltd.), and oligothiophenes, as disclosed in Eur. Pat. Appl. EP 439 627 (Ideminsu Kosan Co. Ltd.). Recently 1,3,4-oxadiazole dimers have been shown to give rise to bright blue emission in molecular electroluminescent devices: Y. Hamada, C. Adachi, T. Tsunsui and S. Saito, Optoelectronics--Devices and Technologies, 1992, 7, 83 and Y. Hamada, C. Adachi, T. Tsutsui and S. Saino, Jpn. J. Appl. Phys., 1992, 31, 1812.
However, amorphous films, as obtained by sublimation and used in all these devices, tend to undergo changes in morphology due to the heat produced under the device operating conditions. This results in the breakdown of molecular electroluminescent devices after longterm storage or even earlier during continuous driving tests.
Working with electron-transporting layers in association with electroluminescent devices which have polymeric light-emitting layers the present applicants found that a uniform dispersion of tert-butyl-PBD (1) in poly(methyl methacrylate) (PMMA) could be formed. The results are reported in "Light-emitting diodes based on conjugated polymers: Control of colour and efficiency", P. L. Burn, A. B. Holmes, A. Kraft, A. R. Brown, D. D. C. Bradley and R. H. Friend in: Electrical, optical, and magnetic properties of organic solid state materials: symposium held Dec. 2-6, 1991, Boston, Mass., USA, L. Y. Chiang, A. F. Garito, D. J. Sandman (Eds.), Pittsburgh, 1992, Mat. Res. Soc. Proc. 1992, 247, 647. Films were obtained by spin-coating a solution of (1) and PMMA in chloroform and were found to be stable under the device operating conditions. ##STR1## Dispersion-type electroluminescent devices have been reported in Jpn. Kokai Tokkyo Koho JP 03/147,290 (Hitachi Chemical Co. Led.); Jpn. Kokai Koho-yo Koho JP 03/119,090 (NEC Corp.); Jpn. Kokai Tokkyo Koho JP 03/250,582 (Hitachi Maxell Ltd.); U.S. Pat. No. 5,075,172 (Cape Cod Research Inc.). "Molecularly doped polymers as a hole transpot: layer in organic electroluminescent devices" teaches the application of a dispersion of N, N'-diphenyt-N,N'-bis(3-methylphenyl)benzidin
REFERENCES:
patent: 3401152 (1968-09-01), Wessling et al.
patent: 3404132 (1968-10-01), Wessling et al.
patent: 3532643 (1970-10-01), Wessling et al.
patent: 3706677 (1972-12-01), Wessling et al.
patent: 4356429 (1982-10-01), Tang
patent: 5075172 (1991-12-01), Dixon et al.
patent: 5231329 (1993-07-01), Nishikitani et al.
patent: 5247190 (1993-09-01), Friend et al.
patent: 5389444 (1995-02-01), Hosokawa et al.
"Analytical methods for Molecular Weight Determination of Poly(p-Xylylidene Dialkyl Sulfonium Halide): Degree of Polymerization of Poly(p-Phenylene Vinylene) Precursors", Machado, et al., J. Polym. Sci., Polmer Physics, 1989, vol. 27, pp. 199-203 No Month.
"Blue Electroluminescent Diodes Utilizing Blends of Poly(p-phenylphenylene vinylene) in Poly(9-vinylcarbazole", C. Zhang, et al., Polym. Prepr., 1993, 34, pp. 817-818 No Month.
"Side Change Liquid Crystalline Copolymers for NLO Response", A. Griffin, et al., Nonlinear Optical and Electroactive Polymers, Plenum Publ. Corp., 1988, pp. 375-377 No Month.
"A Light-Emitting Diode Using as Recombination Layer a Blend Containing a Poly-(Para-Phenylene Vinylene) Oligomer", W. Tachelet, et al., University of Antwerp, Department of Chemistry, International Conference on Science and Technology of Synthetic Metals, Gothenburg, Sweden, Aug. 12-18, 1992 No Month.
"A New Series of Electroluminescent Organic Compounds", M. Nohara, et al., The Chemical Society of Japan, Chemistry Letters, 1990, pp. 189-190 No Month.
"Organic Electroluminescent Devices with Bright Blue Emission", Y. Hamada, et al., Optoelectronics--Devices and Technologies, 1992, vol. 7, pp. 83-93, Jun.
"Blue-Light-Emitting Organic Electroluminescent Devices with Oxadiazole Dimer Dyes as an Emitter", Y. Hamada, et al., Jpn. J. Appl. Phys., 1992, vol. 31, pp. 1812-1816, Jun.
"Light-Emitting Diodes Based on Conjugated Polymers: Control of Colour and Efficiency", Paul L. Burn, et al., Mat. Res Soc. Symp. Proc., 1992, vol. 247, pp. 647-654 No Month.
"Molecularly Doped Polymers as a Hole Transport Layer in Organic Electroluminescent Devices", J. Kido, et al., Jpn. J. Appl. Phys., 1992, vol. 31, pp. L960-962, Jul.
"Synthesis of a Segmented Conjugated Polymer Chain Giving a Blue-shifted Electroluminescence and Improved Efficiency", Paul L. Burn, et al., J. Chem. Soc., Chem. Commun., 1992, pp. 32-34 No Month.
"Realization of a Blue-Light-Emitting Device using Poly(p-phenylen)", G. Grem, et al., Advanced Materials 4, 1992, pp. 36-37 No Month.
"Blue Electroluminescent Diodes Utilizing Poly(alkylfluorene)", Y. Ohmori, et al., Jpn. J. Appl. Phys., 1991, vol. 30, pp. L1941-1943, Nov.
"new Thermotropic Polyesters from Distyrylbenzene Bisphenols", T.E. Mates, et al., J. Polymer Science, Polymer Letters, 1990, vol. 28, pp. 331-339 No Month.
"Bright Blue Electroluminescence From Hole Transporting Polycarbonate", C. Hosokawa, et al., Appl. Phys. Lett., 1992, vol. 61 (21), 11/23, 2503-2505.
"Organic Electroluminescent Diodes", C.W. Tang, et al., Appl. Phys. Lett. 51, Sep. 1987, pp. 913-915.
"Electroluminescence of Doped Organic Thin Films", C.W. Tang, et al., J. Appl. Phys. 65, May 1989, pp. 3610-3616.
"Electroluminescence in Organic Films with Three-Layer Structure", C. Adachi, et al., Jpn. J. Appl. Phys. Feb. 1988, 27, pp. L269-271.
"Organic Electroluminescent Device Having a Hole Conductor as an Emitting Layer", C. Adachi, et al., Appl. Phys. Lett., Oct. 1989, 55, pp. 1489-1491.
"Blue Light-Emitting Organic Electroluminescent Devices", C. Adachi, et al., Appl. Phys. Lett., Feb. 1990, 56, pp. 799-801.
Hosokawa et al, "Bright Blue Electroluminescence from Hole Transporting Polycarbonate", Appl. Phys. Lett., vol. 61 (21), Nov. 23, 1992, pp. 2503-2505.
Bradley Donal Donat Conor
Brown Adam Richard
Burn Paul Leslie
Cacialli Franco
Friend Richard Henry
Bonner Melissa
Cambridge Display Technology Limited
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