Monosolvent system for high-purity lead-free perovskite precursors scalable synthesis based on solubility differences

Metal halide perovskites (MHPs) are promising materials for various optoelectronic applications due to their unique properties. However, the presence of lead (Pb) in MHPs raises environmental and health concerns, prompting the search for lead-free alternatives. This study introduces a universal strategy for synthesizing high-purity lead-free perovskite precursors through a methanol monosolvent system that utilizes solubility differences. The synthesis method is scalable and universal, applicable to five lead-free perovskites such as Cs₂SnCl₆, Cs₂TeCl₆, Cs₃Sb₂Cl₉, Cs₂ZnCl₄, and Cs₂SnBr₆, all maintaining high structural and compositional integrity with purities exceeding 99.985 %. The Cs₂SnCl₆ perovskite precursors achieve a high yield of 91.7 %. The synthesized Cs₂SnCl₆ perovskite exhibits superior electron mobility and lower baseline resistance when incorporated into gas sensors, demonstrating a high response (1.98 at 20 ppm) for dimethyl carbonate (DMC) detection due to its high purity. The simplicity and effectiveness of this one-step synthesis method offer a significant advancement for the production of high-quality perovskite materials for commercial applications in sensors and optoelectronics.