Multi-functional PbI2 enables self-driven perovskite nanowire photodetector with ultra-weak light detection ability

Abstract High-performance perovskite photodetectors with self-driven characteristic usually need electron/hole transport layers to extract carriers. However, these devices with transport layer structure are prone to result in a poor perovskite/transport layer interface, which restricts the performance and stability of the device. To solve this problem, this work reports a novel device structure in which perovskite nanowires are in-situ prepared on PbI 2 , which serves as both a reaction raw material and efficient carrier extraction layer. By optimizing the thickness of PbI 2 , nanowire growth time, and ion exchange time, a self-driven photodetector with an ITO/PbI 2 /CsPbBr 3 /carbon structure is constructed. The optimized device achieves excellent performance with the responsivity of 0.33 A/W, the detectivity of as high as 3.52 × 10 13 Jones. Furthermore, the device can detect the light with its optical power lowered to 0.1 nW/cm 2 . This research provides a new method for preparing perovskite nano/micro devices with simple structure but excellent performance.