Polaronic Magnetic Excitons and Photoluminescence in Mn²⁺-Doped CsCdBr₃ Metal Halides

All-inorganic metal halide materials are eye-catching because of their interesting and excellent optoelectronic properties. In this report, a series of Mn²⁺-doped CscdBr₃ perovskite materials were synthesized by grinding in a mortar. The strong photoluminescence (PL) emission band at 650 nm and its PLQY reaches 54.42% after doping with modest Mn²⁺. The enhanced PL emission is the result of a weak ferromagnetic coupling of Mn–Mn pair to form a magnetic polaron and self-trapped exciton (STE), and the energy transfer from the d–d transition of a single Mn to STE and Mn–Mn pair level is very effective. The doping also enhances the nonlinear optical response of the material by their laser excitations. The photophysical mechanism of Mn-doped CsCdBr₃ has been discussed, and the specific conversion process from the bandedge to each charge state has been analyzed in detail. This kind of material may have significant applications in spintronic or optoelectronic devices.