Fast, Tunable and Reversible Anion-Exchange in CsPbBr3 Perovskite Nanocrystals with Hydrohalic Acids
Anion exchange in colloidal caesium-lead- halide perovskite nanocrystals (NCs) (CsPbX3, X = Cl, Br, I) is a highly efficient protocol to tune their chemical composition and optoelectronic properties. Here, we first report the use of hydrohalic acids (HX; X=Cl and Br) as a precursor for anion exchange which can be an efficient way to control the composition and optical properties of CsPbBr3 perovskite nanocrystals (NCs). In this work, it is demonstrated a facile and efficient approach of anion-exchange is implemented to tune the optical properties of CsPbX3 perovskite NCs via a simple post-synthetic modification with hydrohalic acids. To the Cl-exchanged NCs, a back exchange can be established in terms of variation in halide composition, to retain photoluminescence (PL) properties of parental CsPbBr3 perovskite NCs to a maximum extent. Along with hydrohalic acids, various other halide sources have been used to obtain tunable anion- exchange of CsPbBr3 NCs. Treatment with hydrohalic acid allows for a fast and feasible anion-exchange of CsPbX3 perovskite NCs which makes it stand out from the rest of halide sources. Importantly, this work presents a simple, feasible, reproducible synthetic route toward control halide exchange in metal halide perovskite NCs with various optoelectronic properties.