1：Experimental Design and Method Selection:

The hydrothermal method was used to prepare the phosphors, followed by calcination at 900℃. The crystal structure, PLE/PL, and fluorescence decay behavior were investigated.

2：0℃. The crystal structure, PLE/PL, and fluorescence decay behavior were investigated. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples were prepared with varying Tb3+ content (x=0.01-0.15). Data were collected using XRD, PLE/PL spectra, and fluorescence decay measurements.

3：01-15). Data were collected using XRD, PLE/PL spectra, and fluorescence decay measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Powder X-ray diffraction (XRD) (Model D8 ADVANCE, BRUKER Co., Germany), fluorescence spectrophotometer (FP-6500, JASCO, Tokyo, Japan), integrating sphere (Model ISF-513, JASCO, Tokyo, Japan), 150-W Xe-lamp.

4：Experimental Procedures and Operational Workflow:

Dissolution of Gd2O3 and Tb4O7 in nitric acid, preparation of mother salt solution, hydrothermal reaction at 120℃ for 24 h, calcination at 900℃ for 2 h.

5：Data Analysis Methods:

XRD patterns were analyzed for phase purity, PLE/PL spectra for excitation and emission properties, and fluorescence decay curves for lifetime measurements.