High-Performance Deep Ultraviolet Photodetector Based on One-Dimensional Lead-Free Halide Perovskite CsCu2I3 Film with High Stability.

Lead halide perovskites have received much attention in recent years for fields of optoelectronic devices. However, the environment-unfriendly nature and intrinsic instability of these perovskites hamper their further commercial applications. In this work, one novel one-dimensional lead-free halide perovskite CsCu2I3 with high stability was prepared via an anti-solvent assisted crystallization method. The prepared CsCu2I3 bears a strong exciton binding energy of ~105 meV and bright yellow emission with high photoluminescence quantum yield (12.3%). We fabricated a deep ultraviolet photodetector device based on CsCu2I3 film, which exhibits nearly blind to 405 nm visible light but is apparently sensitive to 265 and 365 nm illumination. The device exhibits prominent device parameters with excellent reproducibility, and a high Ilight/Idark ratio of 22 under 265 nm illumination. Furthermore, the responsivity, specific detectivity and external quantum efficiency are as high as 22.1 mA/W, 1.2 ×1011 Jones and 10.3% under light density of 0.305 mW/cm2, respectively. These findings demonstrate that CsCu2I3 perovskites should have great potential for future optoelectronics.