Optical regulation by localized states of Cu2+ ions with highly sensitive to trap density and thermalization in manganese-doped perovskite nanocrystals

Mn2+-doped perovskites nanocrystals (NCs) have already been extensively studied in fascinating optical, electronic, and magnetic properties. Such interesting traits make them paid considerable attention in light emitting diodes, solar cells, etc. However, the underlying thermal and photophysical processes governing the overall charge carrier dynamics in Mn-doped NCs are far from clear. Herein, trap concentration and thermalization-dependent optical properties of Mn–Cu co-doped CsPbCl3 NCs were investigated via using steady-state, time-resolved PL spectra, variable-temperature PL spectra, and ultrafast transient absorption spectra. The combined experimental and theoretical studies reveal that Cu2+, as an effective hole trap, can trap the holes from Mn2+ and emit the holes to Mn2+ level at lighter and higher doping, respectively. Moreover, this hole trap is highly thermally sensitive, which is responsible for the abnormal thermal effect of Mn2+ emission with increasing temperature. These findings demonstrate an approach of charge regulation through ion doping, which is meaningful for fabricating efficient photoelectric materials and devices.