1：Experimental Design and Method Selection:

The study used the classic ceramic method for synthesis, with characterization via X-ray diffraction, IR, Raman, and photoluminescence spectroscopies. Theoretical models included Judd-Ofelt theory for radiative parameter calculations.

2：Sample Selection and Data Sources:

Samples were prepared with different Er3+ concentrations (0.1%, 1%, 3%, 5%) using high-purity chemicals from Sigma Aldrich. Data were collected from absorption, emission, and decay measurements.

3：1%, 1%, 3%, 5%) using high-purity chemicals from Sigma Aldrich. Data were collected from absorption, emission, and decay measurements. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Philips X'pert Pro diffractometer, FTIR-100 Perkin Elmer spectrophotometer, Horiba Jobin-Yvon T64000 spectrometer, Schimadzu UV-3101PC spectrophotometer, Fluoromax 4 P Horiba scientific equipment, pulsed dye laser (Continuum ND60), Nd:YAG laser (Continuum Surelite I-SL10), JobinYvon HR 1000 monochromator, Hamamatsu R1104 photomultiplier tube, and Lecroy 1GHz-wave Runner oscilloscope. Materials included Li2CO3, BaCO3, Er2O3, NH4H2PO

4：Experimental Procedures and Operational Workflow:

Stoichiometric mixtures were ground, heated to 593 K for 8 h, pressed into pellets, and heated at 1023 K for 10 h. XRD patterns were recorded, IR and Raman spectra were measured, absorption spectra were taken, and PL spectra and decays were assessed using specified equipment.

5：Data Analysis Methods:

Data were analyzed using Rietveld refinement for XRD, least-squares fitting for Judd-Ofelt parameters, and Arrhenius equation for thermal quenching. Software tools included those for spectral analysis and fitting.