Luminescence properties of PPV derivatives bearing substituted carbazole pendants

A series of PPV derivatives bearing substituted and unsubstituted carbazole and 2-ethylhexyloxy pendants were prepared and their photo- (PL) and electroluminescence (EL) properties were studied. Substituted carbazole structures were N-phenylcarbazole and 3,6-dimethoxycarbazole. The substituents on the carbazole pendants caused little change in UV-vis absorption, PL, and EL when compared with the polymer bearing the unsubstituted carbazole pendants. The presence of the benzene ring between the main chain and the carbazole pendant increased the threshold electric field in EL. We could obtain maximum brightness of ca. 17,000 - 30,000 cd/m² for the polymers carrying the unsubstituted and dimethoxy substituted carbazole pendants.