Suppression of Auger Cross Relaxation in Mn-Doped Core-Shell Perovskite Nanocrystals via Wave Function Engineering

Mn-doped perovskite nanocrystals (NCs) exhibit great application potential because of their unique optical properties. However, the long-lived nature of excited Mn²⁺ easily leads to the coexistence of excited Mn²⁺ and host excitons in a single NC, which inevitably induces an Auger cross relaxation between them, thus significantly limiting the luminescent efficiency of Mn²⁺ due to its competition with internal energy transfer. Herein, we design and prepare a kind of Mn-doped core-shell CsPbCl₃@Cs₄PbCl₆ perovskite NC with Mn²⁺ doped only in the shell layer, which is expected to suppress this Auger process by spatially separating the electronic wave functions. By using pump-pump-probe transient absorption spectroscopy, we demonstrate that the core-shell structure effectively suppresses the Auger process with the Auger relaxation time notably extended from 12.1 to 148.3 ps. Our finding offers an effective strategy to suppress this Auger process in Mn-doped NCs, which is greatly significant for improving their luminescent efficiency.