Photo-induced phenomena in Organic Field-Effect Phototransistors based on Conjugated Polymer/Fullerene Blends and Organic Dielectric

Photo-induced phenomena were investigated in photoresposive organic field-effect transistors (photOFETs) based on conjugated polymer/fullerene solid-state mixtures as active semiconductor layer and divinyltetramethyldisiloxane-bis(benzocyclobutene) (BCB) as gate dielectrics. The devices were characterized both in under dark showing n-type transistor behaviour with linear and saturated mobility of 1.7 x 10-3 cm2/Vs and 2.7 x 10-2 cm2/Vs respectively, and under white light illumination condition, where large shifts in the threshold voltage in the transfer characteristics were obtained. A typical phototransistor behaviour in a wide range of illumination intensities are observed in these devices