Postsynthetic, Reversible Cation Exchange between Pb²⁺ and Mn²⁺ in Cesium Lead Chloride Perovskite Nanocrystals

Abstract

CsPbX 3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are promising materials due to their excellent optoelectronic properties. In this work, we show a successful partial and reversible cation exchange reaction between Pb and Mn in both CsPbCl 3 NCs and CsMnCl 3 NCs systems to yield luminescent CsPb 1– x Mn x Cl 3 NCs. By adjusting the reaction time, the photoluminescence from the exciton emission of CsPbCl 3 and the electron transition of Mn 2+ can be tuned gradually. This work highlights the feasibility of a postsynthetic interconversion of Pb 2+ and Mn 2+ in cesium lead chloride perovskite nanocrystals, which enables a new strategy to reduce the toxicity and adjust the emissions of CsPbCl 3 NCs. In the end, we also discuss the plausible mechanisms for cation exchange in perovskite materials.