Optimizing Black Phosphorus/Halide Perovskite Compositions by Scanning Photoelectrochemical Microscopy

The incorporation of black phosphorus (BP) into methylammonium lead iodide (MAPbI₃) perovskites has been investigated and optimized by a high throughput screening method using scanning photoelectrochemical microscopy (SPECM) to determine how the addition of BP affects its photoelectrochemical and photovoltaic properties. An optimum ratio of 2.0 mole% BP/MAPbI₃ perovskite composite generates an increased photocurrent response compared to pristine MAPbI₃ for 2 mM benzoquinone (BQ) reduction at −0.6 V vs Ag/AgNO₃ on a spot array electrode under illumination. Due to the relatively high quantum yield of MAPbI₃, time-resolved photoluminescence measurements have been conducted to investigate photophysical behaviors of BP/MAPbI₃ composites. The optimal 2.0 mole% BP/MAPbI₃ exhibits an increased electron-hole diffusion lifetime compared to the pristine MAPbI₃ perovskite. Finally, we demonstrate the enhanced efficiency and stability of 2.0% BP/MAPbI₃-based perovskite solar cells arising from impeded Pb⁰-defect generation and suppressed charge-carrier recombination.