Unveiling the effects of Mn doping on magnetic and photoelectric properties of Cs4PbBr6 crystals

Metal halide perovskites have attracted extraordinary attention due to their excellent photoelectric properties and diverse crystal structures. The introduction of transition elements through doping serves as a potent strategy to modulate their physical and chemical properties. This approach has proven effective in imparting ferromagnetic semiconductor characteristics, which are essential for applications in spin light-emitting devices and semiconductor spintronics. Here, we synthesized Cs4PbBr6 and Mn-doped Cs4PbBr6 (Mn:Cs4PbBr6) perovskite single crystals. Magnetization measurements reveal that Mn:Cs4PbBr6 exhibits a ferromagnetic behavior at 30 K. Complementary density functional theory calculations suggest that the observed magnetism arises from the introduction of single-spin energy states by the doped Mn in the bandgap. Moreover, we observed a negative photoconductivity (NPC) effect at room temperature in the Mn-doped samples. This NPC phenomenon is attributed to the absorption and desorption of oxygen molecules on the surface of Mn:Cs4PbBr6 crystals. Our findings provide a foundation for the development of highly selective gas sensors in the future.