Giant phototransistor response in dithienyltetrathiafulvalene derivatives

Thienyl-substituted tetrathiafulvalene (DTh-TTF, 1a) and a t-butyl derivative (1b) are prepared, and the remarkable photoresponse and memory effect in the transistors are investigated. Upon irradiation of light with a wavelength shorter than the absorption edge (535 nm), the threshold voltage of 1b shifts by as large as 57 V, and the drain current increases by 103 times. The photo generated conducting state is maintained for several tens of minutes but erased by the application of a large negative gate voltage.