1：Experimental Design and Method Selection:

The Eu2+/Eu3+ co-doped LaAlO3 phosphors were synthesized using a high-temperature solid-state reaction method in a reducing atmosphere (5% H2/95% N2). The method was chosen to achieve dual-emitting properties for temperature sensing. Theoretical models include the Van Uitert formula for emission position calculation and equations for fluorescence intensity ratio (FIR) analysis.

2：2). The method was chosen to achieve dual-emitting properties for temperature sensing. Theoretical models include the Van Uitert formula for emission position calculation and equations for fluorescence intensity ratio (FIR) analysis. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: A series of LaAlO3:xEu (x = 0, 0.01, 0.03, 0.05, 0.07, 0.10) samples were prepared using raw materials La2O3 (99.9%), Al2O3 (99.9%), and Eu2O3 (Fluorescence Level), with H3BO3 as flux. Data were collected from synthesized phosphor powders.

3：01, 03, 05, 07, 10) samples were prepared using raw materials La2O3 (9%), Al2O3 (9%), and Eu2O3 (Fluorescence Level), with H3BO3 as flux. Data were collected from synthesized phosphor powders. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a horizontal tube furnace for sintering, powder diffractometer (Bruker D2 PHASER) for XRD, XPS instrument (Thermo Scientific Escalab 250Xi), SEM (HITACHI SU-8010), UV-Vis spectrometer (Shimadzu UV-3600), spectrofluorometer (HORIBA JOBIN YVON PL3-211), and thermal quenching analysis system (Everfine EX-1000). Materials include La2O3, Al2O3, Eu2O3, H3BO3, and BaSO4 as reference.

4：0). Materials include La2O3, Al2O3, Eu2O3, H3BO3, and BaSO4 as reference. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Raw materials were weighed, ground, mixed, sintered at 1000°C for 2h and then at 1600°C for 2h in reducing atmosphere, followed by natural cooling. Samples were characterized using XRD, XPS, SEM, diffuse reflectance, PL, PLE, decay curves, and temperature-dependent luminescence spectra from 293 K to 473 K.

5：Data Analysis Methods:

Data were analyzed using Rietveld refinement for XRD, semiquantitative analysis for XPS, double exponential fitting for decay curves, and FIR calculations with Boltzmann distribution models for temperature sensitivity.