Organic Single Crystal with High Mobility, Ultrahigh UV Sensitivity, and Fast Time Response

Abstract Organic semiconductor molecule is a highly promising material system for next‐generation photodetectors due to its tunable absorption, inherent flexibility, and solution and low‐temperature processibility. However, developing organic semiconductor materials for visible‐blind ultraviolet (UV) photodetectors with broad spectral response remains a big challenge. Herein, a novel triphenylamine‐functionalized donor–acceptor–donor (D–A–D) type isoindigo derivative, (E)‐6,6'‐bis(4‐(diphenylamino)phenyl)‐[3,3'‐biindolinylidene]‐2,2′‐dione (BDPBD), is successfully synthesized. The ultrasensitive visible‐blind UV single crystal organic phototransistors (SC‐OPTs) based on the BDPBD micro/nanometer‐sized single crystal using simple solution process for the detection of ultraviolet‐A (UV‐A), ultraviolet‐B (UV‐B), and ultraviolet‐C (UV‐C) UV light showed a highest hole mobility of 0.12 cm 2 V −1 s −1 , millisecond‐level response time (20 ms), and ultrahigh photoresponsivity, detectivity, and external quantum efficiency up to 2.62 × 10 6 A W −1 , 1.47 × 10 17 Jones, and 3.51 × 10 8 %, respectively.