Synthesis of conjugated copolymers containing phenothiazinylene vinylene moieties and their electrooptic properties

Abstract

Four different types of conjugated copolymers, consisting of alternating structures of phenothiazinylene vinylene and phenylene vinylene derivatives such as phenylene vinylene, 1,1'-biphenyl-4,4'-ylene vinylene, 2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene, and 9,10-anthrylene vinylene, were prepared by Horner-Emmons condensation between appropriate diphosphonates and dialdehydes. Single-layer and double-layer light-emitting diodes were fabricated with the synthesized conjugated polymers, and their electroluminescent properties were investigated. Poly(N-2-ethylhexyl-3,6-phenothiazinylene vinylene-alt-9,10-anthrylene vinylene), containing phenothiazinylene vinylene and anthrylene vinylene as repeat units, emitted a reddish-orange color with Commission Internationale de l'Eclairage coordinates of x = 0.6173 and y = 0.3814 that was very similar to the National Television System Committee standard red, and it showed a bipolar carrier-injection/transporting capability caused by electron-withdrawing anthracene and electron-donating amino groups. Poly[N-2-ethylhexyl-3,6-phenothiazinylene vinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], containing phenothiazinylene vinylene and dialkoxy phenylene vinylene moieties, showed excellent hole-injection/transporting capability. (C) 2003 Wiley Periodicals, Inc