Laser-induced phase segregation of inorganic halide perovskite alloy nanowires for optical switch

Inorganic perovskite nanostructures have attracted considerable attention for their tunable band gaps and excellent optoelectronic properties. It is inevitable that phase segregation of halide perovskite usually occurs in mixed-halide perovskites under a focused laser illumination, which caused by photo-induced halide-ion segregation. Here, we reported an uniform perovskite alloy nanowires via a chemical vapor deposition (CVD) method. Microstructural characterization reveals that these perovskite nanowires have independent linear morphology with high-quality crystalline. Micro-photoluminescence (PL) spectra exhibit that these nanowire structures show a dual-wavelength emissions at 690 and 570 nm, respectively. Additionally, time-dependent PL intensity of the emission peak at 690 nm is increased by the decrease of the emission peak at 570 nm under a focused laser illumination, indicating the formation of phase segregation at the excited positions. Moreover, based on these as-grown halide perovskite CsPbBr_2.52I_0.48 nanowires, a reasonably optical switch is designed and constructed. This optical switch may have potential applications in timed blasting system and time-delay circuit in the future.