Magnesium ion doping for enhancing luminescence of lead-free manganese halide perovskites and their application in LEDs

Developing high−performance, high stability, and environmentally friendly luminescent materials is crucial for advancing solid−state lighting technology. To replace toxic lead-based perovskites, this study focuses on lead−free manganese halide perovskite derivatives. Herein, we successfully synthesized bright green-emitting Cs 3 MnBr 5 (tetrahedral structure) and bright red-emitting CsMnBr 3 (octahedral structure) phosphors using a facile and eco-friendly aqueous solution method. To overcome their intrinsic concentration quenching effect and enhance overall performance, Mg 2 + ions were innovatively introduced as dopants. After Mg 2+ doping, the Cs–Mn–Br perovskite materials exhibited significant improvements in both luminescence performance and stability. Their photoluminescence (PL) intensity increased to approximately 130 % of their initial intensity, and the photoluminescence quantum yield (PLQY) of Cs 3 MnBr 5 improved from 52 % to 62 %. For CsMnBr 3 , the PLQY increased from 11.4 % to 17.5 %, the PL intensity was improved by 27 %. Under ambient conditions, the doped Cs 3 MnBr 5 maintained strong luminescence intensity even after 48 h, demonstrating far superior stability compared to the undoped sample. Systematic research has shown that moderate Mg 2+ doping (7.5 % in Cs 3 MnBr 5 and 8 % in CsMnBr 3 ) can reduce the Mn 2+ concentration quenching effect and significantly optimized the optical properties of the material. Application in light-emitting diodes (LED) further demonstrates the potential of Cs–Mn–Br perovskite materials in the field of luminescence. This work not only achieves a synergistic improvement in manganese halide perovskites through a simple ion doping strategy, but also lays a solid foundation for its practical application in environmentally friendly optoelectronic devices.