Organic Phototransistor with n-Type Semiconductor Channel and Polymeric Gate Dielectric

We report the fabrication of a photoresponsive organic field-effect transistor (OFET) based on a stable, n-type organic semiconductor (F 16 CuPc) and low-temperature processable polymer gate dielectric. The device exhibited a photoswitching speed of much less than 10 ms and a photosensitivity of 1.5 mA/W at low optical power. Under illumination, the device produced a current gain ( I light / I dark ) of 22 at V G = 4 V. The drain current increased gradually with an increase in the illumination intensity, resulting in typical output FET characteristics. The multifunctions (photodetection, photoswitching, signal amplification) achieved by the single device can ensure very promising material for future optoelectronic applications.