Bulk mobility of polycrystalline thin films of quaterthiophene derivatives

Abstract

Although polycrystalline thin films of organic materials are applied for organic field effect transistors, their bulk electrical properties have not been characterized. In this study, we investigated hole transport properties in the polycrystalline thin films of a series of quaterthiophene derivatives by both time-of-flight experiments and field effect measurements. The time-of-flight bulk mobility was almost same or smaller than field effect mobility. Both mobilities showed a similar trend as a function of side chain length. We discussed these results from the view point of the intrinsic nature of quaterthiophenes, which gave a fundamental knowledge of charge transport properties in the organic polycrystalline thin films.