Adjustable color and emissivity based on amorphous arrays composed of SiO2@ZnO

Abstract

SiO2@ZnO amorphous photonic crystals (APCs) were mainly manufactured by cladding and self-assembling. In this work, the SiO2 APCs framework are contributed to the desired structural color and the coated ZnO particles are served for reducing the infrared emissivity in 3–5 µm waveband. The effects of SiO2 particle size and ZnO adhesion amount on the visible light properties have been investigated as well as the infrared performance. The results show that with the diminution of SiO2 particles size, the packing quality of SiO2@ZnO is constantly improved since the smaller particle possesses higher electric density and surface energy. In the effects of nuclei size, SiO2@ZnO APCs with different size of building units display different color and low emissivity, and the sample with 250 nm core and 1:2 SiO2/ZnO mass ratio has blue structure and emissivity of 0.303. Meanwhile, the increasing ZnO adhesion amount can also alter the structural color due to the red shift of photonic pseudogap, and the minimum emissivity values keep dropping from 0.496 to 0.236. Finally, the SiO2@ZnO APCs with SiO2 core size of 250 nm and SiO2/ZnO mass ratio of 1:4 exhibit prominent performance with light green and low emissivity of 0.236 which contributes to the compatibility in green vegetation camouflage background and infrared stealth.