Air-stable layered bismuth-based perovskite-like materials: Structures and semiconductor properties

Metal halide perovskites are newcomer optoelectronic materials that have attracted enormous attention and single crystal offers better stability and optical electronic performance. In this background, a lead-free, air-stable, effective material of bismuth halide perovskite is highly sought-after. Herein, millimeter-scale single-crystal A3Bi2I9 (A = Cs+ or methylammonium (MA+)) perovskites were synthesized via a facile hydrothermal approach and characterized by various means. Raman spectroscopy results in a layered cleavage distribution. Spin-coating of these compounds produced thin films with uniform surface morphologies, high carrier mobility and superior stabilities. Trivalent-bismuth-based materials were used as the photoactive layer in solution-processed heterojunction solar cell devices, which is a conceptual beneficial exploration and yield power conversion efficiencies of ~ 0.2%.