Reproduction of Biomimetic Structural Colors via µm‐Scale Ni Textures

A µm‐scale Ni texture coated with a dielectric multilayer Bragg stack is developed to cost‐effectively reproduce a variety of biomimetic structural colors on a large scale. The reflectance of the highly reflective region by the Bragg‐stacked flat Ni‐surface is significantly reduced, while the high‐order reflection in the shorter wavelength region increases due to the interference effect inside the triangular Ni texture. This high‐order reflectance is easily adjusted to regulate the reflection color according to the shape of the Bragg stacked Ni textures. The observed reflectance spectra show that the monochromaticity increases as the apex angle of the Ni textures decreases, whereas the amount of color mixture increases as the area of the flat portion formed in them increases. Thus, this color change is quantified by analyzing the variation in the peak wavelength and bandwidth of the reflection spectrum according to the shape of the Ni textures and the thickness of the Bragg stack. Also, by fabricating the triangular Ni textures with gradually decreasing thickness of the Bragg stack from the ridges to the valleys, the continuous change of the reflection color is demonstrated effectively as the location of the incident light reflected from the texture changes. A µm‐scale triangular Ni texture coated with the Bragg stack is developed to reproduce biomimetic structural colors over a large area. The effect of various structural parameters on the reflectance spectrum and the corresponding color is investigated systematically. The fabricated Ni textures with gradually decreasing thickness of the Bragg stack effectively demonstrate the continuous change of the structural colors.