1：Experimental Design and Method Selection:

A solvothermal method was used to synthesize Yb/Er/Tm-doped Na3ZrF7 nanocrystals, aiming to achieve dual-only, well-separated emission bands for temperature sensing. The design rationale includes controlling particle size and doping concentrations to tune thermal quenching effects.

2：Sample Selection and Data Sources:

Samples were prepared with varying concentrations of Yb, Er, and Tm ions (e.g., 20Yb/2Er/0.5Tm) and different mean particle sizes (e.g., 25 nm, 45 nm, above 100 nm) by adjusting NaOA content. Data were collected from synthesized nanocrystals.

3：5Tm) and different mean particle sizes (e.g., 25 nm, 45 nm, above 100 nm) by adjusting NaOA content. Data were collected from synthesized nanocrystals. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Materials included ZrOCl2·8H2O, Ln(NO3)3·6H2O (Ln=Tm, Er, Yb), sodium oleate (NaOA), NH4F, oleic acid (OA), oleylamine (OM), cyclohexane, and ethanol. Equipment included a powder diffractometer (Bruker D8 Advance), TEM (FEI Tecnai G2 F20), EDS (Aztec X-Max 80T), spectrofluorimeter (Edinburgh Instruments FLS920), adjustable laser diode (980 nm), temperature controller (TAP-02, ORIENT KOJI), spectrofluorometer (Edinburgh Instruments FS5), and TSL setup (SL085).

4：5). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Nanocrystals were synthesized by dissolving precursors in ethanol, mixing with OA, OM, and NaOA, adding NH4F, heating in an autoclave at 130°C for 12 h, washing with ethanol and cyclohexane, and centrifuging. Characterizations involved XRD, TEM, EDS, UC emission spectra measurement under 980 nm excitation, temperature-dependent photoluminescence studies, decay curve recording, and TSL measurements.

5：Data Analysis Methods:

Decay curves were fitted with a bi-exponential model to calculate lifetimes. FIR was calculated as I800/I673, and temperature sensitivities (Sa and Sr) were derived from FIR vs. temperature plots. Statistical analysis included fitting equations and comparison with reported systems.