Temperature-dependent photoluminescence dynamics in Mn2+ doped CsPb(BrCl)3 nanocrystalline film via Cd2+ ion codoping

High Mn 2+ doping concentration can lead to the formation of high-density defects/trap states, which serve as non-radiative recombination centers, seriously restricting the energy transfer efficiency from the host nanocrystals to Mn 2+ . Herein, we introduce Cd 2+ into Mn 2+ -doped CsPb(BrCl) 3 nanocrystalline (NCs) film to effectively suppress non-radiative recombination. The analysis of the structure and composition confirmed the phase and chemical composition of the Cd 2+ -Mn 2+ co-doped CsPb(BrCl) 3  NCs film. Steady-state and time-resolved photoluminescence (PL) spectra revealed the enhanced optical properties of the co-doped CsPb(BrCl) 3  NCs film. The Mn 2+ emission peak is studied in the temperature range of 80 K–300 K. Strong electron-phonon coupling causes an anomalous blueshift and linewidth broadening of the Mn 2+ emission peak with increasing temperature. Temperature-dependent PL spectra confirmed that the energy transfer between the exciton emission peak and the Mn 2+ emission peak was regulated through Cd 2+ doping, achieving the negative thermal quenching effect. This study utilized C 9 H 23 NO 3 Si (APTES) for the surface encapsulation of the NCs film to enhance their stability. Substituting Pb 2+ with Cd 2+ and Mn 2+ enhances the stability of the nanocrystals and alleviates lattice distortion within the [PbCl 6 ] 4- octahedral framework. The experimental results indicate that the Mn 2+ emission peak of the co-doped CsPb(BrCl) 3  NCs film retains 80.7% of its luminescent intensity after 31 days of storage in air, thereby confirming its excellent optical stability.