Electrical and optical properties of poly(3-alkylthiophene)

Poly(3-alkylthiophene) has been found to be fusible at relatively low temperature. Films and fibers prepared by molding and melt-spinning methods, respectively, demonstrate also an insulator-metal transition upon doping. Reversible absorption spectrum change of poly(3-alkylthipphene) films with temperature and anomalous temperature dependence of luminescence have been also observed. By the application of hydrostatic pressure, the spectrum at high temperature turns into that of low temperature. Drastic change of electrical conductivity and optical properties have been also found at the melting point. These novel characteristics are tentatively explained in terms of the remarkable conformation change and its influence on the conjugation system.