Colloidal photonic crystals with narrow stopbands assembled from low-adhesive superhydrophobic substrates.

This article presents a facile approach to centimeter-scale colloidal photonic crystals (PCs) with narrow stopbands assembled on low-adhesive superhydrophobic substrates. The full-width-at-half-maxima of the stopbands are just 12 nm. The narrow stopbands of colloidal PCs are ascribed to the combined effects of perfectly ordered assembly structure, large-scale crack elimination, decreased void fraction, and sufficient thickness of the colloidal PCs. These properties result from a self-assembly process on a low-adhesive superhydrophobic substrate. Latex suspension on this substrate displays a receding three-phase contact line during evaporation, which releases tensile stress induced by latex shrinkage and results in complete elimination of cracks in the colloidal PCs. Furthermore, the simultaneous assembly of latex particles on the outermost layer of a spread liquid film contributes to the perfectly ordered assembly structure. This facile fabrication of centimeter-scale colloidal PCs with narrow stopbands will offer significant insights into the design and creation of novel optical devices.