Visible wavelength-independent anti-reflection coatings generated from assembled SiO₂ particles modified with tetraethoxysilane

The objective of this research was the fabrication of visible wavelength-independent anti-reflection coatings by deposition and aggregation of silica nanoparticles. This approach to anti-reflection coatings is important for technologies which avoid sophisticated process and calcination at high temperature. The goal of this research was achieved by modification of a commercially available SiO₂ dispersion with tetraethoxysilane (TEOS) and spin coating of the TEOS–SiO₂ (T–SiO₂) dispersion. The modification resulted in aggregation of T–SiO₂ particles upon evaporation of ethanol aqueous solution and thus assembled into many enlarged bulges at the coating surface. The resulted coating surface morphology resembled moth-eye-like nanostructure that exhibited visible wavelength-independent transmittance enhancement for substrate. More promisingly, owing to this unique behavior, the coated colored substrates display deepened colors without sacrificing any color hues. Such coating is very attractive in many fields such as color displaying and color imaging.