Environmentally-friendly synthesis of highly luminescent cesium lead halide perovskite nanocrystals using Sn-based halide precursors

Abstract

In the last several years, cesium lead halide perovskite (CsPbX3, X=Cl, Br, I) nanocrystals (NCs) have attracted much attention as promising kinds of optoelectronic and photonic materials. Via anion exchange reactions, the photoluminescence spectra of the CsPbX3 NCs can be tuned over nearly the entire visible spectral region. However, the preparation of the anion-exchange sources, mainly Pb-based halide precursors or oleylammonium halide precursors, would use large amounts of PbX2 (X=Cl, Br, I), trioetylphosphine (TOP) and HX (X=Cl, Br, I). These chemicals are toxic and environmentally-hazardous. To solve this problem, we report the synthesis of CsPbX3 (X=Cl, Br, I or mixed halides) NCs through modified anion exchange reactions. Using two kinds of Sn-based halide precursors as the anion-exchange sources, we can finely tune the chemical compositions and optical properties of pre-synthesized CsPbX3 NCs. Considering no PbX2, TOP and HX have been used in the preparation of the Sn-based halide precursors, we can determine this two-pot synthetic scheme asa step toward a green-chemistry approach for synthesizing high quality CsPbX3 NCs.