Self-Powered Dual-Color UV–Green Photodetectors Based on SnO₂ Millimeter Wire and Microwires/CsPbBr₃ Particle Heterojunctions

Multiband detection has always been a challenge and has drawn much attention in the development of photodetectors (PDs). Herein, we present controllable synthesis of SnO 2 wires with different sizes via chemical vapor deposition and formed composites with CsPbBr 3 particles to realize dual spectral response. We constructed PDs based on a single SnO 2 millimeter wire decorated with CsPbBr 3 particles (SnO 2 MMW/CsPbBr 3 ), which showed a stepped spectrum, fast response speed, and self-powered function. Meanwhile, SnO 2 microwires/CsPbBr 3 composites (SnO 2 MWs/CsPbBr 3 ) were also utilized to fabricate PDs. It is noteworthy that detection occurred in two different wavelength bands (320 and 520 nm) with equivalent intensity at a bias of 0 V. The self-powered feature of this device comes from the built-in electric field at the interface of SnO 2 /CsPbBr 3, and the dual-color response originates from asymmetric junction barriers between conduction bands of SnO 2 and CsPbBr 3 . This work demonstrated promising self-powered PDs that are capable of multiband detection.