Near-Unity Red Mn2+ Photoluminescence Quantum Yield of Doped CsPbCl3 Nanocrystals with Cd Incorporation

Although Mn2+ doping in semiconductor nanocrystals (NCs) has been studied for nearly three decades, the near 100% photoluminescence (PL) quantum yield (QY) of Mn2+ emission has never been realized so far. Herein, greatly improved PL QYs of Mn2+ emissions are reported in Mn2+-doped CsPbCl3 NCs with various Mn2+ doping concentrations after CdCl2 post-treatment at room temperature. Specifically, the near-unity QY and near single-exponential decay of red Mn2+ emission peaking at 627 nm in doped CsPbCl3 NCs are obtained for the first time. The temperature dependence of steady-state and time-resolved PL spectra reveals that the CdCl2 post-treatment significantly reduces the nonradiative defect states and enhances the energy transfer from host to Mn2+ ions. Moreover, the Mn2+:CsPbCl3 NCs after CdCl2 post-treatment exhibit robust stability and high PL QYs after multipurification. The results will provide an effective route to obtain doped perovskite NCs with high performance for white lighting emitting diodes.