1：Experimental Design and Method Selection:

The study used a high-temperature solid-state reaction method to synthesize SrCaGa4O8 phosphors with varying Ga content and under different sintering conditions (air and reduce atmospheres) to investigate intrinsic defects and thermal properties. Theoretical models included Gaussian fitting for emission spectra and Urbach method for trap depth calculation.

2：Sample Selection and Data Sources:

Samples were prepared with compositions SrCaGa4-xO8 (x = 0, 0.1, 0.15, 0.2) and SrCaGa4+yO8 (y = 0, 0.1, 0.15, 0.2), using raw materials SrCO3, CaCO3, and Ga2O3. Data were collected from XRD, PL, PLE, TL, and temperature-dependent PL measurements.

3：1, 15, 2) and SrCaGa4+yO8 (y = 0, 1, 15, 2), using raw materials SrCO3, CaCO3, and Ga2OData were collected from XRD, PL, PLE, TL, and temperature-dependent PL measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included X-ray powder diffractometer with Cu Kα radiation, Hitachi F-7000 fluorescence spectrophotometer with xenon arc lamp, high-temperature fluorescence controller (Orient KOJI, TAP-02), UV-visible spectrophotometer, and FJ-427A1 TL meter. Materials were SrCO3 (Aladdin, 99.99%), CaCO3 (Sinopharm, 99.99%), Ga2O3 (Cinor, 99.99%).

4：99%), CaCO3 (Sinopharm, 99%), Ga2O3 (Cinor, 99%). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Raw materials were mixed and sintered at 1280°C for 10h. XRD patterns were recorded from 10° to 80° 2θ. PL and PLE spectra were measured at room temperature with 220 nm excitation. Temperature-dependent PL spectra were recorded from 293K to 493K. TL curves were measured after UV excitation, heating from room temperature to 673K at 1K/s.

5：0h. XRD patterns were recorded from 10° to 80° 2θ. PL and PLE spectra were measured at room temperature with 220 nm excitation. Temperature-dependent PL spectra were recorded from 293K to 493K. TL curves were measured after UV excitation, heating from room temperature to 673K at 1K/s. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using Gaussian fitting for emission spectra, Tauc method for band gap estimation, and Urbach method for trap depth calculation. Sensitivity was calculated based on intensity ratio derivatives.