1：Experimental Design and Method Selection:

The study employed a mechanochemical process known as mechanically induced self-sustaining reaction (MSR) to synthesize ZnSxSe1?x solid solutions. This method involves high-energy ball milling of elemental mixtures to induce exothermic reactions, allowing control over stoichiometry and phase composition.

2：Sample Selection and Data Sources:

Elemental powders of zinc (99% pure, <325 mesh), sulfur (99.5% pure, <325 mesh), and selenium (99.5% pure, <325 mesh) were used. Mixtures with varying atomic ratios (x = 1, 0.8, 0.6, 0.5, 0.4, 0.2, 0) were prepared to achieve different ZnSxSe1?x compositions.

3：5% pure, <325 mesh), and selenium (5% pure, <325 mesh) were used. Mixtures with varying atomic ratios (x = 1, 8, 6, 5, 4, 2, 0) were prepared to achieve different ZnSxSe1?x compositions. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a modified planetary ball mill (Micro Mill Pulverisette 7, Fritsch), AISI 420C stainless steel balls, a tempered steel vial, pressure monitoring system (pressure transducer and recorder), X-ray diffractometer (X’Pert Pro MPD, PANalytical), SEM (Hitachi S-4800), TEM (JEOL-2100-PLUS), Raman microscope (Horiba Jobin-Yvon HR800), and UV–vis spectrophotometer (Cary 300). Materials included argon gas, silicon powder for calibration, and ethanol for sample preparation.

4：0). Materials included argon gas, silicon powder for calibration, and ethanol for sample preparation. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Mixtures were milled under argon atmosphere at 400 rpm. Ignition time (tig) was detected via pressure increase. Post-ignition milling times varied (0 to 480 min). Samples were characterized using XRD, SEM, TEM, Raman spectroscopy, and UV–vis spectroscopy to analyze phase composition, microstructure, and optical properties.

5：Data Analysis Methods:

XRD data were analyzed using Rietveld refinement with FULLPROF software. Raman and UV–vis data were processed to determine phonon modes and band gap energies, respectively, using standard methods like Kubelka–Munk functions.