Ambipolar organic field-effect transistors based on a low band gap semiconductor with balanced hole and electron mobilities

The authors have demonstrated the thin-film properties and the ambipolar transport of a delocalized singlet biradical hydrocarbon with two phenalenyl radical moieties (Ph-2-IDPL). The organic field-effect transistors (OFETs) based on Ph-2-IDPL exhibit ambipolar transport with balanced hole and electron mobilities in the order of 10(-3) cm(2)/V s. The Ph-2-IDPL film is an organic semiconductor with a low band gap of 0.8 eV and has small injection barriers from gold electrodes to both the highest occupied molecular orbital and the lowest unoccupied molecular orbital. A complementary metal-oxide-semiconductor-like inverter using two identical Ph-2-IDPL based ambipolar OFETs shows a sharp inversion of the input voltage with high gain. (C) 2007 American Institute of Physics.