Unveiling the Excited‐State Dynamics of Mn(2+) in 0D Cs(4)PbCl(6) Perovskite Nanocrystals

Doping is an effective strategy for tailoring the optical properties of 0D Cs(4)PbX(6) (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(2+)‐doped Cs(4)PbCl(6) perovskite NCs and the excited‐state dynamics of Mn(2+) is unveiled through temperature‐dependent steady‐state and transient photoluminescence (PL) spectroscopy. Because of the spatially confined 0D structure of Cs(4)PbCl(6) perovskite, the NCs exhibit drastically different PL properties of Mn(2+) in comparison with their 3D CsPbCl(3) 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(2+)‐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(2+) in 0D Cs(4)PbCl(6) NCs, thus laying a foundation for future design of 0D perovskite NCs through metal ion doping toward versatile applications.