Highly Responsive, Polarization‐Sensitive, Flexible, and Stable Photodetectors Based on Highly Aligned CsCu2I3 Nanowires

Abstract As a new inorganic lead‐free perovskite, cesium copper iodide (CsCu 2 I 3 ) has attracted wide attention in the field of photodetectors due to its non‐toxicity, good air and thermal stability, and excellent optoelectronic properties. However, the random growth and disordered distribution of CsCu 2 I 3 crystals during their preparation results in poor crystal quality, seriously limiting their applications. Highly ordered CsCu 2 I 3 crystal formation with high crystal quality for high‐performance photodetectors remains a major challenge. Here, an ingenious nanoimprinting technology is utilized to obtain high‐performance photodetectors based on highly aligned CsCu 2 I 3 nanowires (NWs). Owing to the high crystal quality, the photodetector exhibits excellent responsivity of 12.35 A W −1 (310 nm) and 89.73 mA W −1 (365 nm), respectively, as well as good polarization light detection with a dichroism ratio of up to 2.28. Additionally, the device on a flexible substrate retains its initial level of performance even after being bent 2000 times. Remarkably, the device exhibits superior stability and maintains excellent performance after being placed in the natural environment for 1 month without any encapsulation.