‌Dynamic Structural Color Modulation Using QBIC-Sb₂S₃ Phase-Change Metasurfaces

By integrating the phase-change material Sb 2 S 3 with quasi-bound states in the continuum (QBIC), we designed a QBIC metasurface composed of nanoscale, split-disk Sb 2 S 3 arrays on a flexible polydimethylsiloxane (PDMS) substrate, enabling dynamic structural-color modulation with narrowband response and rapid switching. Our investigation reveals that the synergistic coupling of multipolar resonances in the split-disk geometry—dominated by a strong electric-dipole resonance—significantly amplifies the optical response. Dynamic control of the reflection spectrum is achieved through simultaneous PDMS-strain tuning and crystallinity variation of Sb 2 S 3 . We propose a “crystalline-amorphous dual-state chrominance difference encryption” scheme: the amorphous state provides a wide color gamut for high information capacity, while the crystalline state's narrow gamut enables information hiding. Furthermore, the “crystallinity gradient encoding” strategy proposed in this work enables precise color control, offering a approach for anti-counterfeiting label design.