Effect of structural fluctuations on charge carrier mobility in thiophene, thiazole and thiazolothiazole based oligomers

Charge transport properties of thiophene, thiazole and thiazolothiazole based oligomers have been studied using electronic structure calculations. The charge transport parameters such as charge transfer integral and site energy are calculated through matrix elements of Kohn-Sham Hamiltonian. The reorganization energy for the presence of excess positive and negative charges and rate of charge transfer calculated from Marcus theory are used to find the mobility of charge carriers. The effect of structural fluctuations on charge transport was studied through the polaron hopping model. Theoretical results show that for the studied oligomers, the charge transfer kinetics follows the static non-Condon effect and the charge transfer decay at particular site is exponential, non-dispersive and the rate coefficient is time independent. It has been observed that the thiazole derivatives have good hole and electron mobility.