Organic Field-Effect Transistors Based on Oligo-p-Phenylenevinylene Derivatives

Organic field-effect transistors (OFETs) have been fabricated using thermally vacuum-evaporated films of two oligo- p -phenylenevinylenes, 1,4-bis(4-methylstyryl)benzene (4MSB), and 1,4-bis(2-methylstyryl)benzene (2MSB). From the electrical characteristics of the OFETs, a field-effect mobility of the 4MSB films was calculated to be 0.13 cm 2 V -1 s -1 , while the mobility of the 2MSB films was 1.0 ×10 -4 cm 2 V -1 s -1 . The mobility of 4MSB is comparable to that of widely studied organic semiconductors, such as oligothiophenes and pentacene. From atomic force microscopy and X-ray diffraction, densely-packed submicron-size grains with a high degree of molecular order were observed in a vacuum-sublimed 4MSB film.