Self-powered, low-dark-current, high-detectivity CsPbBr3 nanowire photodetectors with excellent weak-light detection ability

Abstract

In recent years, all-inorganic CsPbBr₃ 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 CsPbBr₃ perovskites in polar solvents like DMSO limits the application of their polycrystalline film, which exhibits numerous pinholes and discontinuities. In this study, high-quality CsPbBr₃ perovskite nanowire films are explored by using the ionic liquid 1-octyl-3-methylimidazolium hydrogen sulfate (OMIMHSO₄) for surface passivation, and photodetectors with the structure of ITO/SnO₂/CsPbBr₃/carbon are constructed. Compared to the device without ionic liquid, devices treated with OMIMHSO₄ 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 × 10¹³ 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 CsPbBr₃ perovskite photodetectors towards potential commercial applications.