Unveiling the Excited-State Dynamics of Mn in 0D CsPbCl Perovskite Nanocrystals.

Doping is an effective strategy for tailoring the optical properties of 0D CsPbX (X = Cl, Br, and I) perovskite nanocrystals (NCs) and expanding their applications. Herein, a unique approach is reported for the controlled synthesis of pure-phase Mn-doped CsPbCl perovskite NCs and the excited-state dynamics of Mn is unveiled through temperature-dependent steady-state and transient photoluminescence (PL) spectroscopy. Because of the spatially confined 0D structure of CsPbCl perovskite, the NCs exhibit drastically different PL properties of Mn in comparison with their 3D CsPbCl analogues, including significantly improved PL quantum yield in solid form (25.8%), unusually long PL lifetime (26.2 ms), large exciton binding energy, strong electron-phonon coupling strength, and an anomalous temperature evolution of Mn-PL decay from a dominant slow decay (in tens of ms scale) at 300 K to a fast decay (in 1 ms scale) at 10 K. These findings provide fundamental insights into the excited-state dynamics of Mn in 0D CsPbCl NCs, thus laying a foundation for future design of 0D perovskite NCs through metal ion doping toward versatile applications.