Broadband Ultraviolet Photodetectors Based on Cerium Doped Lead-Free Cs3MnBr5 Metal Halide Nanocrystals

Lead halide perovskites are widely used for optoelectronic devices because they possess a high charge carrier mobility, high photoconversion efficiency, low energy cost, etc. However, lead toxicity and instability of these perovskites prevent their wide-scale industrial applications. Herein, we successfully fabricated the lead-free Ce3+ doped Cs3MnBr5 metal halide nanocrystals (MHNCs), which displays a broad UV response and an efficient blue photoluminescence at 398 and 423 nm. The introduction of Ce3+ ions results in a broadband response to UV light, a highly improved photoluminescence quantum yield from 38% to 90%, and an improved longtime stability. The highly desirable broadband UV photodetector was fabricated based on the Ce3+ doped Cs3MnBr5 MHNCs film, which shows a broadband response to UV light ranging from 200 to 380 nm. The responsivity was 1.1 A/W with a millisecond rise/fall time response. This study demonstrates a strategy of fabricating the broadband UV photodetector for novel and advanced UV optoelectronic systems.