α,ω-Dihexylquaterthiophene:  A Second Thin Film Single-Crystal Organic Semiconductor

The thin film structure and hole mobility of 5,5'''-dihexylquaterthiophene are reported. Films sublimed onto Si/SiO2 or carbon grids held at 30−100 °C are single-crystal-like over tens of micrometers as shown by electron diffraction. The orientation has the long axis of the quaterthiophene core nearly perpendicular to the substrate. The mobility ranges from 0.05 to 0.23 cm2/Vs, depending on the deposition temperature, much higher than would be expected based on earlier thiophene oligomer data.