First Synthesis of Mn-Doped Cesium Lead Bromide Perovskite Magic Sized Clusters at Room Temperature

Mn-doped CsPbBr3 perovskite magic sized clusters (PMSCs) are synthesized for the first time using benzoic acid (BA) and benzylamine (BZA) as passivating ligands and MnCl24H2O and MnBr2 as the Mn2+ dopant source at room temperature. The same approach is used to prepare Mn-doped CsPbBr3 perovskite quantum dots (PQDs). The concentration of MnX2 (X=Cl or Br) affects the excitonic absorption of the PMSCs and PQDs. Higher concentration of MnX2 favors PMSCs over PQDs, and higher photoluminescent (PL) quantum yields (QYs) and PL stability. The large ratio between the characteristic Mn emission (~ 590 nm) and host band-edge emission shows efficient energy transfer from the host exciton to the Mn dopant. PL excitation, electron paramagnetic resonance, and time-resolved PL results all support Mn2+ doping in CsPbBr3, which likely replace Pb2+ ions. This study establishes a new method for synthesizing Mn-doped PMSCs with high stability and PLQY and highly effective passivation.