1：Experimental Design and Method Selection:

A heterogeneous precipitation method utilizing urea hydrolysis was adopted to coat a SiO2 layer on the surface of Y3Al5O12:Ce3+ phosphor.

2：Sample Selection and Data Sources:

Commercial Y3Al5O12:Ce3+ phosphor from Guangzhou Research Institute of Non-ferrous Metals was used.

3：List of Experimental Equipment and Materials:

Tetraethyl orthosilicate (TEOS), ethanol, nitric acid, ammonium carbonate, urea, distilled water, scanning electron microscope (SU-3500), transmission electron microscope (JEM-2100), X-ray diffractometer (D8 Advance), Fourier transform infrared spectrometer (Nicolet 6700), thermoluminescent dosimeter (FJ-427A1), fluorescence spectrophotometer (F-7000), chamber electric furnace.

4：Experimental Procedures and Operational Workflow:

TEOS was dissolved in a water-ethanol mixture, pH adjusted to 1-2 with nitric acid, then to 6-7 with ammonium carbonate. Phosphor and urea were added under stirring at 95°C for 2h, followed by filtration, washing, drying at 100°C for 12h, and calcination at 1000°C for 1h for thermal stability tests.

5：Data Analysis Methods:

Surface morphologies and compositions analyzed by SEM-EDS and TEM, crystal phases by XRD, chemical bonds by FT-IR, defect concentrations by thermoluminescence, and luminescent properties by photoluminescence.