Self-powered, low-dark-current, high-detectivity CsPbBr nanowire photodetectors with excellent weak-light detection ability

In recent years, all-inorganic CsPbBr 3 perovskite materials have shown significant progress in photonic device research due to their straightforward fabrication, cost-effectiveness, efficient photoelectric conversion and stability. However, the low solubility of CsPbBr 3 perovskites in polar solvents like DMSO limits the application of their polycrystalline film, which exhibits numerous pinholes and discontinuities. In this study, high-quality CsPbBr 3 perovskite nanowire films are explored by using the ionic liquid 1-octyl-3-methylimidazolium hydrogen sulfate (OMIMHSO 4 ) for surface passivation, and photodetectors with the structure of ITO/SnO 2 /CsPbBr 3 /carbon are constructed. Compared to the device without ionic liquid, devices treated with OMIMHSO 4 exhibit reduced dark current (down to 3.68 × 10 −12 A), and achieve a linear detection range of up to 215 dB, a responsivity of 0.385 A W −1 and a high detectivity of 7.09 × 10 13 Jones. Additionally, the devices can show good response under weak light (0.114 nW cm −2 ), indicating superior weak-light detection capabilities due to ultra-low dark current and reduced defect density. These results lay a foundational framework for advancing CsPbBr 3 perovskite photodetectors towards potential commercial applications. 1-octyl-3-methylimidazolium hydrogen sulfate (OMIMHSO 4 ) is introduced into CsPbBr 3 nanowires for defect passivation, resulting in the corresponding nanowire photodetector with a minimum response light intensity as low as 1.14 × 10 −10 W cm −2 .