Designing color controllable SiO2 amorphous colloidal arrays

Amorphous assembling of SiO2 colloidal spheres is a convenient strategy to obtain amorphous photonic structure, such structure, referred to as SiO2 amorphous colloidal arrays (ACAs), can demonstrate angle-independent structural color owing to constructive interference. To date, an empirical equation for materials researchers to design the color of SiO2 ACAs remains vacant, and several influence factors concerning with the color of SiO2 ACAs are still ignored and uninvestigated. Herein, based on single scattering model, we have proposed an empirical equation to predict the reflection peak of SiO2 ACAs to design their color, and influence factors including background and thickness on the color of SiO2 ACAs were also investigated. By preparing spheres within the designed range as building blocks, SiO2 ACAs with colors varying from blue to red were achieved whose reflection peaks position fits well with the empirical equation. This study can help materials researchers to design and manipulate structural color of SiO2 ACAs while providing insight to understand the origin of structural color of SiO2 ACAs.