Theoretical Approach to the Study of Thiophene-Based Discotic Systems As Organic Semiconductors

The main parameters that control charge transport at the molecular level have been studied for a series of columnar mesophase, thiophene-based discotic systems at semiempirical and DFT levels using different approximations, i.e., the dimer model and isolated molecule calculations. Charge carrier mobility was estimated through the charge transfer constant evaluated according to the semiclassical Marcus theory and compared to that obtained for a reference compound, i.e., triphenylene derivative. A set of different density functionals has been essayed in order to search for general patterns for charge transport related properties. In summary, only the compound with four thiophene rings, RO-TetraT, shows a significant increase in p character in comparison to the triphenylene derivative.