Abstract Polythiophene films were electrogenerated between −12 and 60°C by polarization at 1700 mV. The polymer films were studied at ambient temperature in the background electrolyte by cyclic voltammetry and potential steps techniques. From the polymer weight, the polymerization current efficiency and the charge storage efficiency were obtained. Both parameters increased in the temperature range studied, when the temperature decreased. The charge storage is related to a very strong nucleation process attributed to the formation of a polymer-perchlorate compound.