The role of sidechains in the luminescence of an electroactive polymer

Autor: H Dong, S Vaidyanathan, Mary E. Galvin
Rok vydání: 2004
Předmět:
Zdroj: Synthetic Metals. 142:1-6
ISSN: 0379-6779
DOI: 10.1016/s0379-6779(03)00420-x
Popis: We report here results of luminescence studies on a series of poly(2,5-dialkoxy-1,4-phenylene vinylene) derivatives incorporating an oxadiazole moiety in the conjugated backbone. While there is no difference in the photoluminescence (PL) quantum yield in solution, the photoluminescence intensity of thin films of the polymers shows a strong dependence on the length of the linear dialkoxy sidechains as it is varied from hexyloxy to dodecyloxy. We attribute this to differences in the packing of the chains and the interchain spacings in the polymers. The side group determines the spacing between the conjugated backbones and thereby, its luminescence efficiency. While there is a direct correlation between chain spacing and PL efficiency, the correlation with electroluminescence (EL) efficiency is subtler. A wider separation between the backbone chains, while suppressing formation of bound polaron pairs and thus aiding luminescence, may hinder interchain charge transport, carrier injection or carrier balance. Hence the actual dependence of EL efficiency on the sidechain is an interplay between these two opposing factors.
Databáze: OpenAIRE