In hybrid perovskites, MAPbI<sub>3</sub> and MAPbBr<sub>3</sub> have been extensively studied for their optical and photovoltaic properties, but MAPbCl<sub>3</sub> is significantly less investigated for its optical and photovoltaic properties due to its low photoluminescence quantum yield (PL QY) and a large<br>band gap. However, the large band gap makes it a suitable host for doping transition metal ions to explore new optical properties. We synthesized nanocrystals (NCs) of MAPbCl<sub>3</sub> doped with Mn<sup>2+</sup> by simple ligand assisted reprecipitation method. The reaction temperature and Pb to Mn feed ratio were optimized by preparing a series of Mn<sup>2+</sup>-doped MAPbCl<sub>3</sub> NCs. The prepared NCs show bright Mn<sup>2+</sup> emission with ~13% PL QY suggesting an efficient energy transfer from host NCs to Mn<sup>2+</sup>. Since the large bandgap of MAPbCl3 precludes the possibility of investigating temperature dependent PL and lifetime measurements to understand the excited state dynamics, we carried out these experiments on Mn<sup>2+</sup> doped MAPbCl<sub>2.7</sub>Br<sub>0.3</sub> with the Br concentration adjusted to bring the bandgap of the alloyed system within the limits of the experimental technique. Our studies establish an anomalous behavior of Mn<sup>2+</sup> PL emission in this host. These results reveal the origin of a temperature mediated energy transfer from exciton to Mn<sup>2+</sup> and provides an understanding of the underlying mechanisms of PL properties of this new class of NCs.
<br>
Energy Transfer Mechanisms and Excited State Dynamics of Yb3+, Tm3+and Ho3+Doped Gd3Ga5O12Single Crystals