Carrier modulation of one-dimensional MAPb _x Sr _{1− x} (I _y Cl _{1− y} ) ₃ core–shell perovskite nanowires

Low dimensional hybrid organic-inorganic perovskites (HOIPs) have become one of the most promising materials in solar cells, photodetectors, and lasers due to their low exciton binding energy, high bipolar carrier mobility, and long carrier lifetime. The effective separation and collection of photo-generated electrons and holes have always been crucial for a perovskite as a working medium for optoelectronic devices. However, the surface state of pristine perovskite nanowires causes recombination of electrons and holes at the edge of the energy band, leading to deactivation of charge carriers. In this work, we constructed MAPb_xSr_1-xI₃ core-shell nanowires, which adjust the band gap and control the spatial distribution of charge carriers by changing the Pb composition ratio, achieving spontaneous separation of electron-hole pairs to avoid surface recombination. In addition, MAPb_xSr_1-x(I_yCl_1-y)₃ core-shell nanowires with different component ratios (x, y) can be constructed by further doping the Cl element, and the spatial distribution of charge carriers in the nanowires can be flexibly manipulated to achieve exchange between type-I and type-II band alignment orders. This study provides a feasible method for enhancing the carrier separation of organic-inorganic hybrid perovskites and improving the performance of optoelectronic devices.