Dual-Band, High-Performance Phototransistors from Hybrid Perovskite and Organic Crystal Array for Secure Communication Applications

High-performance phototransistors made from organic semiconductor single crystals (OSSCs) have attracted much attention due to the high responsivity and solution-processing capability of OSSCs. However, OSSC-based phototransistors capable of dual-band spectral response remain a difficult challenge to achieve because organic semiconductors usually possess only narrow single-band absorption. Here, we report the fabrication of high-performance, dual-band phototransistors from a hybrid structure of a 2,7-dioctyl[1]benzothieno[3,2- b ][1]benzothiophene (C8-BTBT) single-crystal array coated with CH 3 NH 3 PbI 3 nanoparticles (NPs) synthesized by a simple, one-step solution method. In contrast to C8-BTBT and CH 3 NH 3 PbI 3 NPs with respective absorption in the ultraviolet (UV) and visible (vis) region, their hybrid structure shows broad absorption covering the entire UV–vis range. The hybrid-based phototransistors exhibit an ultrahigh responsivity of >1.72 × 10 4 A/W in the 252–780 nm region, which represents the best performance for solution-processing, broadband photodetectors. Moreover, integrated phototransistor circuitries from the hybrid CH 3 NH 3 PbI 3 NPs/C8-BTBT single-crystal array show applications for high-security communication.