Phototransistors and Photoswitches From an Ultraclosely $\pi$ -Stacked Organic Semiconductor

In this letter, high-performance organic phototransistors and photoswitches based on an ultraclosely π-stacked organic semiconductor, i.e., titanyl phthalocyanine, are fabricated. The p-type transistor exhibited high performance with a hole mobility of ~ 4. 5 cm²·V^-1·s^-1 and an on/off ratio higher than 3.1 × 10⁷. Phototransistors exhibited high-photoresponse properties with a responsivity at 10.5 A/W and a photosensitivity up to 2.7 × 10⁵. The high performance of the devices showed their potential application in optoelectronic organic integrated circuits.