With the band structure and the relaxation times, we can calculate the electrical conductivity σ in dependency of the charge carrier concentration N (by varying the chemical potential The electrical conductivity is apparently anisotropic. Along the conjugated backbones (b-direction), σ b is five orders of magnitude larger than σ a along the π-π stacking axis of the thiophene backbones and σ c along the lamellar stacking (note the different scales on the y-axes in Fig. ). For a vanishing charge carrier concentration, we see that the intrinsic conductivity is zero in all cases, which is typical for semiconducting materials. Due to the system's band gap, no thermally excited charge carriers contribute to conduction. This