Mechanochemical synthesis of luminescent caesium copper iodide perovskite

Lead halide perovskites have shown impressive potential in the field of optoelectronics, but their toxicity has prompted exploration into alternative materials such as copper-based perovskites. The synthesis of these materials typically involves solution processing with hazardous chemicals, highlighting the necessity for more environmentally friendly methods. In this study, the mechanochemical synthesis of caesium copper iodide is introduced to produce powder-form perovskite and the optical characterisation such as absorption and photoluminescence is discussed. The findings demonstrate comparable optical properties with those reported for the solution-processed perovskites, with multiple photoluminescence peaks originating from recombination of free excitons (∼484 nm) and self-trapped excitons (∼421 nm). This suggests that mechanochemistry can serve as a potential method towards high-quality all-inorganic metal halide perovskites.