TEMPERATURE DEPENDENCE OF THE ELECTRICAL CONDUCTIVITY OF POLY(BENZO1,2-b:4,5-b' DITHIOPHENE-4,8-DIYL VINYLENE) AND POLY(DODECYLTHIOPHENE)

摘要

We present results for the electrical conductivity (a) of thin films of poly(benzo[1,2-b:4,5-b']dithiophene-4,8-diyl vinylene) (PBDV) and poly (dodecylthiophene) (PDDT) as a function of temperature in the range 15-295K. The polymers were doped with FeCl_3 and PF_6 which resulted in electrical conductivities differing by two orders of magnitude at room temperature. We examine three sets of σ(T)-data by using the variable-range hopping (VRH) model that predicts a linear relationship between ln(T~(1/2)σ) and T~(1/4). We observe a change in the slope of the ln(T~(1/2)σ) vs T~(1/4) relationship in all three samples at low temperatures. We also analyze the temperature dependence of the resistivity of PBDV by using the thermal fluctuation-induced tunneling model.