Efficient energy transfer from self-trapped excitons to Mn2+ dopants in CsCdCl3:Mn2+ perovskite nanocrystals

Mn 2+ doping has been adopted as an efficient approach to regulating the luminescence properties of halide perovskite nanocrystals (NCs). However, it is still difficult to understand the interplay of Mn 2+ luminescence and the matrix self-trapped exciton (STE) emission therein. In this study, Mn 2+ -doped CsCdCl 3 NCs are prepared by hot injection, in which CsCdCl 3 is selected because of its unique crystal structure suitable for STE emission. The blue emission at 441 nm of undoped CsCdCl 3 NCs originates from the defect states in the NCs. Mn 2+ doping promotes lattice distortion of CsCdCl 3 and generates bright orange-red light emission at 656 nm. The energy transfer from the STEs of CsCdCl 3 to the excited levels of the Mn 2+ ion is confirmed to be a significant factor in achieving efficient luminescence in CsCdCl 3 :Mn 2+ NCs. This work highlights the crucial role of energy transfer from STEs to Mn 2+ dopants in Mn 2+ -doped halide NCs and lays the groundwork for modifying the luminescence of other metal halide perovskite NCs.