Luminescence and Mechanism of Mn Substitution in CsCdBr with Two Types of Coordination Number.

Cadmium-based perovskite materials as promising optoelectronic materials have been widely explored, but there are still some special microscopic interaction-dependent properties not fully understood. Here, we successfully synthesized Cs(CdMn)Br crystal by a simple hydrothermal method. In CsCdBr crystals with their intrinsic self-trapped exciton (STE) emission, Cd ions stay in both different coordination sites, and partial replacement of Cd with Mn can modify their luminescence properties significantly. The luminescence peak position of the doped sample was adjusted from 610 nm in the undoped sample to 577 nm in the doped one by the combination of STE and Mn d-d transition, with enhanced photoluminescence quantum yield (PLQY) of ∼50% at a Mn precursor ratio of 40%. Their magnetic responses occur from the coexisting ferromagnetic (FM) and antiferromagnetic (AFM) coupling of Mn pairs in four and six coordination sites, modifying its whole emission profile. This material is valuable for studying the structure-optical properties and finding applications in optoelectronic devices.