Fast Room-Temperature Cation Exchange Synthesis of Mn-Doped CsPbCl Nanocrystals Driven by Dynamic Halogen Exchange.

Currently, it is of great challenge to achieve cation exchange in CsPbX (X = Cl, Br, I) perovskite nanocrystals (NCs) on account of rigid Pb octahedral coordination protected by six halogen anions (PbX). Herein, we demonstrate that dynamic halogen exchange can effectively open up PbX octahedrons and enable fast Mn-to-Pb cation exchange at room temperature in a few seconds. Importantly, Cl concentration rather than Mn one is demonstrated to be a dominant factor for cation exchange, where different Mn/Cl salts can be adopted as Mn/Cl sources and Cl-to-Cl or Cl-to-Br anion exchange is the necessary prerequisite. Such a facile synthesizing method can lead to the feasibility of tuning emissive colors for the Mn-doped CsPb(Cl/Br) NCs by controlling both cation and anion exchanges and open a new way to replace Pb in CsPbX NCs by other nontoxic metal elements.