Improvement of mechanical properties of silica nanoparticle antireflection films via including a tetraethoxysilane-based sol

Antireflection films were made by spin-coating silica nanoparticles on glass substrates. Infiltrating acetic acid-catalyzed tetraethoxysilane (TEOS) aqueous sol into silica nanoparticle coatings and then heat treated to connect nanoparticles to enhance the mechanical properties of silica antireflection films. As films were modified with the sol of 1% TEOS aqueous solution, the value of the film hardness was increased from 0.659 Gpa to 0.835 Gpa. The scratch test results reflected a decreased scratch size for modified films. Slightly affected optical properties were obtained for the films infiltrated with the sol. The results suggested that this facile approach can improve the film's mechanical properties without significantly affecting the film's optical properties.