Flexible and Self-Powered Lateral Photodetector Based on Inorganic Perovskite CsPbI3-CsPbBr3 Heterojunction Nanowire Array

Self-powered perovskite photodetectors mainly adopt the vertical heterojunction structure composed of active layer, electron-hole transfer layers, and electrodes, which results in the loss of incident light and interfacial accumulation of defects. To address these issues, a self-powered lateral photodetector based on CsPbI3-CsPbBr3 heterojunction nanowire arrays is designed on both a rigid glass and a flexible polyethylene naphthalate substrate using an in situ conversion and mask-assisted electrode fabrication method. Through adding the polyvinyl pyrrolidone and optimizing the concentration of precursors under the pressure-assisted moulding process, both the crystallinity and stability of perovskite nanowire array are improved. The nanowire array-based lateral device shows a high responsivity of 125 mA W-1 and a fast rise and decay time of 0.7 and 0.8 ms under a self-powered operation condition. This work provides a new strategy to fabricate perovskite heterojunction nanoarrays towards self-powered photodetection.