Optimizing the quasi-equilibrium state of hot carriers in all-inorganic lead halide perovskite nanocrystals through Mn doping: fundamental dynamics and device perspectives.

Hot carrier (HC) cooling accounts for the significant energy loss in lead halide perovskite (LHP) solar cells. Here, we study HC relaxation dynamics in Mn-doped LHP CsPbI nanocrystals (NCs), combining transient absorption spectroscopy and density functional theory (DFT) calculations. We demonstrate that Mn doping (1) enlarges the longitudinal optical (LO)-acoustic phonon bandgap, (2) enhances the electron-LO phonon coupling strength, and (3) adds HC relaxation pathways Mn orbitals within the bands.