Large Photoresponsivity in High‐Mobility Single‐Crystal Organic Field‐Effect Phototransistors

Photons control number of mobile charge carriers: Organic field‐effect transistors based on dithiophene‐tetrathiafulvalene (DT‐TTF) and dibenzo‐tetrathiafulvalene (DB‐TTF) show enhanced conductivity under illumination (see figure). A very high ratio of photocurrent to dark current of the order of ≈10 4 was observed for DT‐TTF due to the photogeneration of mobile charge carriers (holes). These materials have the potential to be employed as light sensors or optoelectronic memory devices.