Highly thermally stable Ce³⁺/Tb³⁺-activated Ba₂MgY₂(BO₃)₄ phosphors prepared by a one-step reductive solid-state...

Highly thermally stable Ce³⁺-activated and Ce³⁺/Tb³⁺ co-activated Ba₂MgY₂(BO₃)₄ (BMYB) phosphors were successfully synthesized by a one-step solid-state reaction under a reducing atmosphere at 850 °C. Compared with the previously reported multi-step synthesis route, the present method considerably shortens the reaction time while simultaneously improving the luminescence performance of the phosphors. High-quality powder X-ray diffraction confirms the formation of single-phase products, and Rietveld refinement suggests that the modified synthesis conditions may induce a certain degree of Mg/Y cation disorder while preserving the reported crystal symmetry. The Ce³⁺-activated BMYB phosphors exhibit broad blue emission with excitation-wavelength-dependent spectral evolution, whereas efficient Ce³⁺ → Tb³⁺ energy transfer enables continuous color tuning from blue to cyan. Most importantly, the optimized synthesis route markedly enhances the thermal stability of the phosphors. The BMYB:0.05Ce³⁺ phosphor retains 73.1% of its room-temperature emission intensity at 150 °C, representing a substantial improvement over previously reported BMYB phosphors, while maintaining excellent chromaticity stability. The Ce³⁺/Tb³⁺ co-doped phosphors also exhibit favorable thermal stability together with efficient energy transfer and tunable emission. These results demonstrate that rational optimization of the synthesis conditions provides an effective strategy for improving the performance of BMYB phosphors and establishes Ba₂MgY₂(BO₃)₄ as a promising UV/near-UV-excitable color-tunable phosphor for solid-state lighting.