Alkyl chain length dependent mobility of organic field-effect transistors based on thienyl-furan oligomers determined by the transfer line method

Organic field-effect transistors are fabricated using oligomers composed of alternating connected thiophene and furan, and those having alkyl substituents at both ends of the molecules. The mobilities are determined by the transfer line method to correct for the effect of source/drain parasitic resistance. A mobility of 0.042cm2∕Vs is achieved for a thienyl-furan oligomer composed of five heterocycles and having hexyl groups at the terminal rings. The mobility of the oligomers strongly depends on the length of the π-conjugated chain and the alkyl chain substituent at both ends, attributable to the specific structural and morphological properties of the vacuum-deposited films.