Room Temperature Synthesis of All Inorganic Lead-Free Zero-Dimensional Cs₄SnBr₆ and Cs₃KSnBr₆ Perovskites

Lead halide perovskites are excellent candidates for photoelectronic and photovoltaic applications, but the toxicity from lead is extremely concerning. Recently, Sn-based zero-dimensional lead-free perovskites synthesized using solid-state reaction techniques have become a new focus in the field. Here, we report a simple room temperature antisolvent method for the synthesis of all inorganic lead-free green emissive Cs₄SnBr₆ (emission at 524 nm) and cyan emissive Cs₃KSnBr₆ (emission at 500 nm) zero-dimensional perovskites. Their photoluminescence quantum yields reach 20% and 35%, respectively. In addition, they maintain their emission for 46 and 55 h in the air, respectively, compared to only 5 min of CsSnBr₃. This method provides a convenient way to do the research and apply these highly emissive perovskites.