Vertical Heterojunction Nanowire-Based Ambient-Stable γ-CsPbI3 Self-Powered Photodetectors with Enhanced Performance...

Photoactive γ-CsPbI3 perovskites hold great promise for high-performance optoelectronics, but their development is hindered by severe phase instability and undesired lateral photocarrier diffusion in conventional continuous thin-film architectures. Here, we integrate an electron transport layer, CsPbI3 active layer, and hole transport layer within vertically aligned anodic aluminum oxide nanochannels to form heterojunction nanowire arrays (HJNWs) that disrupt both lateral photocarrier diffusion and the propagation of phase transitions. This architecture stabilizes the photoactive γ-CsPbI3 in ambient air for more than 4 months. Self-powered photodetectors based on these HJNWs deliver competitive photodetection performance, simultaneously achieving a high external quantum efficiency of ∼85% and a short response time of 54 μs under zero bias. Our fabrication approach is also compatible with large-area (8 cm × 8 cm) rigid and flexible substrates. These results demonstrate that nanoconfined device architectures provide a promising route toward stable and high-performance self-powered perovskite optoelectronics.