Vivid structural colors of photonic crystals: Self-assembly of monodisperse silica nano-colloids synthesized using an anionic surfactant

Photonic crystals are widely applied in non-fading structural color production areas owing to their easy tunability. However, it is found that achieving high monodispersity in the case of particles diameter less than-100 nm is challenging. The understanding on the mechanism behind the synthesis could help to fabricate photonic crystals. Here we examine the effect of single anionic surfactant on the final particle diameter. Sub-sequently, the fabrication of photonic crystals using various size silica nanoparticles ranging from-250 nm to-50 nm by spin coating method is performed. Vivid structural colors from red to blue are obtained as a function of increasing particle size. This is rather peculiar since most studies shows opposite trend. Furthermore, the colloidal photonic crystals are prepared using spin coating method. The obtained spin coated photonic crystal films exhibit low viewing angle dependent structural colors.