Synthesis of large-area high quality 2D BiOI for highly sensitive ultraviolet photodetection

Abstract

In this study, we successfully synthesized high-quality 2D layered BiOI crystals using a novel space-confined molten salt method. These crystals exhibit a bandgap of 1.9 eV, closely aligning with theoretical expectations. The photodetectors fabricated from these BiOI nanosheets demonstrate exceptional ultraviolet (UV) detection capabilities. Key performance metrics include an ultrahigh photoresponsivity of 1048 mA W⁻¹, an impressive external quantum efficiency of 420%, and a significant detectivity of 4.7 × 10¹² Jones, coupled with a fast response time of 420/690 μs at 310 nm. This study not only highlights the potential of BiOI in UV photodetectors but also marks a substantial advancement in the development of high-performance bismuth-based semiconductor optoelectronic devices.