Photoluminescence Lifetimes and Thermal Degradation of Mn2+-Doped CsPbCl3 Perovskite Nanocrystals

The Mn2+-doped CsPbCl3 nanocrystals (NCs) with a low Mn2+ doping concentration were synthesized using different reaction temperatures to control the NC size from 5.3 to 17.4 nm and then were studied by means of steady-state and time-resolved photoluminescence (PL) spectroscopy at various temperatures. The Mn2+ emissions with different quantum yields in the doped NCs in hexane exhibited nearly size-independent and single-exponential decay lifetimes of 1.8 ms at room temperature. The PL lifetimes in all Mn2+ in CsPbCl3-doped NCs had similar temperature dependence from 80 to 300 K, whereas they were size-dependent at elevated temperatures, reflecting thermal degradation of doped NCs. The degradation mechanisms of Mn2+ PL were attributed to the amount of surface defects as nonradiative recombination centers generated in size-unchanged and grown Mn2+:CsPbCl3 NCs. The study provides the detailed understanding of the thermal degradation mechanisms in doped perovskite NCs for optoelectronic applications.