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 and benzylamine as passivating ligands and MnCl2·4H2O and MnBr2 as the Mn2+ dopant sources 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. A higher concentration of MnX2 favors PMSCs over PQDs as well as higher photoluminescence (PL) quantum yields (QYs) and PL stability. The large ratio between the characteristic Mn emission (∼590 nm) and the host band-edge emission shows efficient energy transfer from the host exciton to the Mn2+ dopant. PL excitation, electron paramagnetic resonance, and time-resolved PL results all support Mn2+ doping in CsPbBr3, which likely replaces Pb2+ ions. This study establishes a new method for synthesizing Mn-doped PMSCs with good PL stability, high PLQY and highly effective passivation.