Water-assisted synthesis of lead-free Cu based fluorescent halide perovskite nanostructures

Abstract

Lead halide perovskite nanocrystals (NCs) are eminent for their emission properties, but lead (Pb) toxicity and moisture instability have become an impediment to their commercial use. To resolve these obstacles and develop an environmentally friendly energy material at a low cost, we discuss the synthesis of lead-free Cs₂CuCl₄, Cs₂CuBr₄, and Cs₂CuBr₂Cl₂ perovskite nanostructures with non-toxic copper (Cu). In this work, we adopted a ligand assisted re-precipitation (LARP) synthesis route for material preparation at room temperature. Water is used as a polar solvent to dissolve the metal halide precursors rapidly. For the first time, we achieved a high PLQY of 38% in mixed halide perovskite Cs₂CuBr₂Cl₂NCs with blue luminescence in an aqueous medium. Cu-based perovskites Cs₂CuCl₄, Cs₂CuBr₄, and Cs₂CuBr₂Cl₂ demonstrated their morphology as square nanoplates, nanorods, and rectangular nanoplates, respectively. The long-term photoluminescence stability of these stored perovskites was also examined at different intervals for 45 days.