The compatible performance of three-dimensional SiO2–ZnO amorphous photonic crystals in adjustable structural color and low infrared emissivity

In high temperature environments, most low-emissivity coatings show monotonous and dull colors which make the visible-infrared compatible stealth still challenging. To achieve a wide range of color selection, in this work, three-dimensional (3D) SiO2–ZnO amorphous photonic crystals (APCs) are manufactured by electrodepositing Zn2+ into 3D SiO2 APCs, investigating the compatibility of adjustable structural color and low emissivity. A variety of structural colors could be easily obtained by modulating the diameter of SiO2 nanospheres. In addition, the experimental parameters of spin-coating counts and electrodeposited time are studied to optimize the compatible performance of color and infrared emissivity. The results indicate that the doped ZnO effectively reduces the infrared emissivity in 3–5 μm waveband without changing the structural color of SiO2 APCs. However, excess electrodeposited time of ZnO would cause the structural color faded gradually because of the increased refractive index and destroyed periodical structure. The adequate spin-coating counts is helpful for the bright structural color, but excess spin-coating counts would induce more defects in periodic structure and result in more absorption in 3–5 μm waveband. When the spin-coating counts and electrodeposition content of Zn2+ in the SiO2 APCs are properly modulated in this study, the SiO2–ZnO APCs can exhibit a good compatibility in desired structural color and low infrared emissivity (~0.4), as well as excellent thermal stability. This study provides a new approach for the design of multi-spectrum compatible stealth materials.