Theoretical calculations of band gaps in the aromatic structures of polythieno[3,4-b]benzene and polythieno[3,4-b] pyrazine

Band gaps in polythiophene (T) and the related polymers with a fused benzene ring or a fused pyrazine ring have been estimated using a variety of methods. In conclusion, the aromatic/quinoid character of the TB oligomer units is discussed and the extrapolation of DFT HOMO--LUMO energies also give reasonable band gap predictions.