Browsing by Author "Chen, Chien-Kai"

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Highly substituted poly(2,3-diphenyl-1,4-phenylenevinylene) derivatives having bulky phenyl and fluorenyl pendant groups: Synthesis, characterization, and electro-optical properties
(2006-12-01)
Yang, Sheng-Hsiung
;
Li, Hsing-Chuan
;
Chen, Chien-Kai
;
Hsu, Chain-Shu
;
應用化學系
Two series of poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) derivatives containing multiple bulky substituents were synthesized. In the first series, two different groups were incorporated on C-5,6 positions of the phenylene moiety to increase steric hindrance and to obtain blue-shifted emissions. In the second series, bulky fluorenyl groups with two hexyl chains on the C-9 position were introduced on two phenyl pendants to increase the solubility as well as steric hindrance to prevent close packing of the main chain. Polymers with high molecular weights and fine-tuned electro-optical properties were obtained by controlling the feed ratio of different monomers during polymerization. The maximum photoluminescent emissions of the thin films are located between 384 and 541 nm. Cyclic voltammetric analysis reveals that the band gaps of these light-emitting materials are in the range from 2.4 to 3.3 eV A double-layer EL device with the configuration of ITO/PEDOT/P4/Ca/Al emitted pure green light with CIE ' 1931 at (0.24, 0.5). Using copolymer P6 as the emissive layer, the maximum luminescence and current efficiency were both improved when compared with the homopolymer P4. (c) 2006 Wiley Periodicals, Inc.
Synthesis of novel poly(2,3-diphenylphenylene vinylene) derivatives and their application for polymer light emitting diodes
(2005)
Chen, Chien-Kai
;
Yang, Sheng-Hsiung
;
Hsu, Chain-Shu
;
應用化學系
;
Department of Applied Chemistry
Nine kinds of poly(2,3-diphenylphenylene vinylene) (DP-PPV) derivatives, P1-P9, were synthesized via Gilch route using potassium t-butoxide (t-BuOK) as the base. Their glass transition temperatures (Tg) are in the range from 136 to 184 degrees C. The polymers emit blue-green to yellow-green light. The photoluminescence (PL) emissions are located in the range from 496 to 550 nm. Introducing the rigid fluorenyl substituents onto DP-PPV main chains can shift the yellow-green color to pure green one. Most polymers exhibit very high electroluminescence (EL) efficiency. Two-layer light emitting device with ITO/PEDOT/polymer/Ca/Al configurationw ere also fabricated and characterized.