The effect of partial elimination of methoxy groups in a precursor polymer on the optical absorption and electrical properties of poly(thienylene vinylene).

Films of poly(thienylene vinylene) (PTV) were prepared by thermal elimination of methoxy groups in a precursor polymer in the presence of gaseous hydrochloric acid as a catalyst. The growth of the conjugation length of the polymer during elimination was studied by means of on-line UV-Vis spectroscopy under various conditions of reaction temperature, reaction time and HCl concentration. The optical absorption gap of the polymerś π-π* transition, determined from transmission and reflectivity data, was found to decrease with increasing conjugation length. Measurements of dc electrical conductivity on iodine-doped samples showed a direct connection between chain structure and charge carrier transport. From the temperature dependence of the electrical conductivity (90–300 K) we concluded that the electrical transport in the iodine-doped polymers can be described by a variable-range hopping model proposed by Schäfer-Siebert and Roth.