1：Experimental Design and Method Selection:

The study involved designing the simplest W-containing peptide, cyclo-GW, and investigating its crystal packing, thermal stability, mechanical strength, photoluminescence, and piezoelectric properties. Methods included crystal growth, structural analysis using SEM and X-ray crystallography, thermal gravimetric analysis (TGA), atomic force microscopy (AFM) nanoindentation, density functional theory (DFT) computations, fluorescence spectroscopy, fluorescent lifetime microscopy (FLIM), and piezoelectric measurements.

2：Sample Selection and Data Sources:

Cyclo-GW powder was dissolved in 10% (v/v) methanol in water, heated to 80 °C, and slowly cooled to room temperature to form needlelike crystals. Reference samples included FF tubular crystals.

3：List of Experimental Equipment and Materials:

Equipment included SEM, AFM, TGA instrument, fluorescence spectrometer, FLIM setup, and a custom-built piezoelectric generator. Materials included cyclo-GW powder, methanol, water, Ag-coated silicon substrates, and Kapton tape.

4：Experimental Procedures and Operational Workflow:

Crystals were grown by dissolution and cooling. Structural analysis was performed using SEM and crystallography. Thermal stability was assessed via TGA. Mechanical properties were measured using AFM nanoindentation. Optical properties were evaluated through fluorescence experiments and microscopy. Piezoelectric properties were tested by fabricating a generator and applying compressive forces.

5：Data Analysis Methods:

Data were analyzed using statistical methods for mechanical properties, DFT for electronic structure calculations, and standard techniques for optical and electrical measurements.