Room-temperature synthesis of Mn2+-doped cesium lead halide perovskite nanocrystals via a transformation doping method

摘要： Currently, Mn2+-doped cesium lead halide perovskite nanocrystals have attracted research interests. Here, we report a novel room-temperature transformation doping method for the synthesis of Mn2+-doped CsPbCl3 and CsPb(Br/Cl)3 nanocrystals. Innovatively, the transformation of Cs4PbX6 (X=Cl, Br) phase which has no excitation emission to CsPbX3 phase which has strong luminescence was used in this mechanism. Simply injecting MnCl2 precursor into Cs4PbX6 solution could result in the full transformation of Cs4PbX6 phase to CsPbX3 phase and Mn2+-doped CsPbCl3 or CsPb(Br/Cl)3 were obtained. The basic idea for the transformation doping method is that MnCl2 can not only drive the transformation of the two structures but also Mn2+ can substitute Pb2+. In this reaction, the concentration of Mn precursor is a key influence factor. Moreover, instead of the ligand of OA, the acetic acid was used in our method. Through the adjustment of the ligand in precursor, not just the photoluminescence quantum yields of as-prepared Mn2+-doped CsPbCl3 nanocrystals were improved from 7.8 to 32.6% (Mn2+-doped CsPb(Br/Cl)3 nanocrystals even could reach to 42.7%), the nanocrystals also retained outstanding stability. We propose a combination of structure transformation and ion doping as a perovskite doping mechanism. Our doping method is a novel strategy for lead halide perovskite nanocrystals doping project and it could provide more possibilities in the future.