Bioinspired designer surface nanostructures for structural color

Structural colors originate from the interaction of incident light with nanostructures; classic examples include the striking blue color of Morpho butterfly wings and peacock feathers. Living creatures have evolved and produced various nanostructures, generating a variety of colors. This review focuses on nanoscale structures in the flora and fauna around us, and how, inspired by these natural marvels, researchers have developed many designer surfaces that give colors by tweaking the structural features at the nanoscale within the photonic materials. The basic mechanisms responsible for the colors generated are discussed. Photonic crystals do not allow light of some frequencies to pass through them, a result of the photonic band gap, which allows for beautiful color generation. Resonant interactions between light and structures in the subwavelength dimension result in striking plasmonic colors. The progress in fabrication strategies that allow surface engineering to generate functionalized nanomaterials is discussed, and the applications and key takeaways from the research are highlighted. Bioinspired, nonfading, environmentally safe colors have numerous applications in devices, paints, textiles, automobiles, high-resolution printing, anticounterfeiting, cosmetics, biomedical devices, and intelligent sensors. This review highlights the origin of structural colors, examples of structural coloration in nature, the fabrication of photonic nanostructures, bioinspired photonic material color generation, eco-friendly applications, and challenges.