All-inorganic lead-free NiO x /Cs 3 Bi 2 Br 9 perovskite heterojunction photodetectors for ultraviolet multispectral imaging

Bismuth-based perovskites are considered to be promising candidates to substitute the toxic lead-based perovskite in optoelectronics due to their excellent optoelectronic properties, high environmental friendliness, and (moisture, light, and heat) stability. However, there are still few reports about high performance bismuth-based perovskite ultraviolet photodetectors, and is more lacking in ultraviolet imaging demonstration. Herein, we reported a self-powered NiO x /Cs 3 Bi 2 Br 9 heterojunction photodetector with excellent photodetection performance by electrochemical depositing NiO x as the hole transport layer. The optimized NiO x /Cs 3 Bi 2 Br 9 heterojunction photodetector exhibits excellent ultraviolet detection performance with a fast response speed of 3.04/4.65 ms, wide linear dynamic range of 116.6 dB, decent responsivity of 4.33 mA·W −1 at 0 V bias, and high detectivity of 1.3 × 10 11 jones. The outstanding performance of the optimized NiO x /Cs 3 Bi 2 Br 9 heterojunction photodetector is enough to meet the high-quality ultraviolet imaging. Therefore, we further integrated the optimized NiO x /Cs 3 Bi 2 Br 9 heterojunction photodetector to the transmission mode ultraviolet multispectral imaging system, achieving admirable imaging results at weak light condition. This work will play a positive role in promoting the development of bismuth-based ultraviolet photodetection and ultraviolet multispectral imaging.