1：Experimental Design and Method Selection:

The phosphors were synthesized using a high-temperature solid-state reaction method. Characterization included X-ray diffraction, photoluminescence spectra, UV-Vis diffuse reflectance, temperature-dependent emission, luminescence decay, and electroluminescence spectra. Density functional theory was used for band structure calculations.

2：Sample Selection and Data Sources:

Samples were prepared with varying Mn4+ concentrations (x = 0.002 to 0.010) using raw materials Na2CO3, MnCO3, SrCO3, and Sb2O

3：002 to 010) using raw materials Na2CO3, MnCO3, SrCO3, and Sb2OList of Experimental Equipment and Materials:

3. 3. List of Experimental Equipment and Materials: Equipment included X-ray diffractometer (D/MAX 2500TC), fluorescence spectrometer (Hitachi F-7000), UV-VIS-NIR spectrometer (Hitachi U-4100), temperature controller, steady-state and transient-state fluorescence spectrometer (FLS920), and spectro-photocolorimeter (PMS-80 Plus). Materials were high-purity carbonates and oxides.

4：Experimental Procedures and Operational Workflow:

Raw materials were mixed, sintered at 750°C for 6h and 900°C for 10h, then ground and characterized. Measurements were conducted at room temperature unless specified.

5：Data Analysis Methods:

Data were analyzed using Kubelka-Munk function for bandgap, Arrhenius equation for activation energy, and exponential fitting for decay times.