Effects of Sulfur Oxidation on the Electronic and Charge Transport Properties of Fused Oligothiophene Derivatives

Comparative studies of a series of oligothiophenes and their oxidized compounds are carried out by means of quantum chemical calculations. Taking aim at the effects of chemical oxidation of thienyl sulfur on the modulation of electronic structures and charge transport properties of oligothiophenes, the geometrical structures, molecular reorganization energies upon gaining or losing electrons, molecular ionization potentials (IPs) and electron affinities (EAs), molecular aromaticities, frontier molecular orbitals, and charge mobilities are analyzed in detail to determine the structure–property relationships for the investigated oligothiophenes and their corresponding oxidized counterparts. The calculated results show that the oxidation of thienyl sulfur into the corresponding S,S-dioxide could possibly change the charge transport characteristics of fused oligothiophene from hole transporting materials to bipolar or electron transporting materials, shedding light on the exploration of n-type thiophene-based semiconductors.