Anomalous Temperature Dependence of Electrical Conductivity in Polythiophene Derivatives Substituted with Long Alkyl Chain

Abstract

The electrical conductivity of poly(3-alkylthiophene)s such as poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-octylthiophene), poly(3-decylthiophene) and poly(3-dodecylthiophene) increases with increasing temperature. However, after attaining a maximum value, it decreases with further temperature increases. Hysteresis has also been observed in the temperature dependence of conductivity during heating and cooling cycles. This anomaly is interpreted in terms of the strong influence of molecular conformation change on carrier scattering.