Self‐Purification Affecting the Optical Performance of Mn‐Doped Halide Perovskite Nanocrystals

Abstract Component doping is the fundamental topic for modulating the properties of semiconductor materials. The introduction of doping ions into lead halide perovskites (LHPs) can not only maintain the excellent photoelectric properties but also enhance the stability of LHPs in open air and thermal environments. However, due to the “self‐purification” effect in crystallography, there is an inherent trend to pop doping ions out of LHPs lattice. In this work, it is confirmed that in Mn 2+ doped LHPs nanocrystals (NCs) the discharge of Mn 2+ will be accelerated at higher temperatures. It is also proved that even at room temperature, the dopants in LHPs NCs will also actively “migrate”, resulting in declined optical performance. Therefore, for cation alloying/doping LHPs NCs, the migration of doping ions in the material should be considered in addition to the intrinsic halide migration characteristics. This work will provide a benign reference for application of doped LHPs NCs.