Stable and Sensitive Ultraviolet Photodetectors Based on High-Quality CsCu2I3 Films

In recent years, cesium copper(I) halides have emerged as a promising candidate for photodetection applications due to their non-toxicity, high quantum efficiency, and remarkable stability in open air. In this study, the fabrication process was optimized with an annealing treatment to achieve high-quality, pinhole-free CsCu2I3 films with excellent crystallinity. The CsCu2I3 photodetector (PD) exhibits an optimized UV detection performance with high responsivity, specific detectivity, and external quantum efficiency of 42 mA W–1, 1.1 × 1011 jones, and 12.26%, respectively. Moreover, the Ilight/Idark ratio can reach 7.5 × 105, and the rise/fall times were found to be 1.49/1.33 ms. In addition, the CsCu2I3 PD demonstrated excellent working stability and retained its photoresponsivity even after two months of storage in ambient air. The fabricated device is also capable of performing UV imaging. These findings highlight the great potential of lead-free CsCu2I3 PD for next-generation UV optoelectronic systems.