Fig. 4. Color palettes of the rewritable devices in amorphous and crystalline states for different thicknesses of Sb₂S₃.

(A and B) Amorphous (left) and crystalline (right) color palettes with Sb₂S₃ thickness varying from 10 to 70 nm. Scale bars, 100 μm. (C) Reflectance spectra from representative color patches. Solid lines represent the amorphous state, and short dashed lines represent the crystalline state. With increasing thickness of Sb₂S₃, the fundamental (first resonance dip, as indicated) red-shifts out into the infrared and the second harmonic resonance appears within the visible spectrum. (D) Color coordinates from measured spectra plotted on the CIE 1931 chromaticity diagram of the devices with the thickness of the Sb₂S₃ film varying from 10 to 70 nm.