Novel Air Stable Organic Radical Semiconductor of Dimers of Dithienothiophene, Single Crystals, and Field-Effect Transistors.

Singly linked and vinyl-linked dimers of dithienothiophenes exhibit different electronic behaviors. Single crystals of the singly linked dimer show a high conductivity of 0.265 S cm(-1) , five orders of magnitude higher than that of the vinyl-linked dimer. The huge increase in the hole density of singly linked dimers results from the formation of radicals, which can be reversibly tuned by facile thermal de-doping.