“…Doping metal cations is an effective strategy to optimize the PL properties of luminescent materials. [29,55,56] Therefore, we introduced Mn 2+ ions into perovskite to evaluate their effect on the luminous performance of Cs 2 CdBr 2 Cl 2 . The excitation spectra of Cs 2 CdBr 2 Cl 2 :xMn 2+ (x = 0, 2%, 5%, 10%, and 20%) are shown in Figure S8 (Supporting Information), while the emission spectra of Cs 2 CdBr 2 Cl 2 :xMn 2+ (x = 0, 2%, 5%, 10%, and 20%) are displayed in Figure 3a.…”