Influence of TEOS concentration and Triton additive on the nanostructure silica sol-gel anti-reflective coatings

Abstract

Nanostructured silica antireflective coatings were fabricated on glasses by sol-gel technique. Various silica sols [varying in composition: tetraethyl orthosilicate (TEOS) concentration and Triton additive] were synthesised by the acidic catalysed process and then subsequently coated on substrates. The coatings prepared in this work were characterised using UV-visible spectroscopy, Fourier-transformed infrared spectrophotometer and filed emission scanning electron microscopy. Results indicated that the dense silica films permit a considerable reduction of these light reflections compared with uncoated glasses in all the cases studied, but the degree of reduction is different depending on the composition of the precursor solution. It was found that the transmittance increased from 0.915 for the bare slide up to 0.96 for the best made sample corresponding to the Triton-doped silica. The addition of Triton x-100 to the silica sols improved the optical property of thin films due to existence of nanoporous in the coatings. The SiO2 concentration is an effective parameter to prepare the antireflective films. Decrease in SiO2 precursor cause to decrease in gelation time and, therefore; the suitable SiO2 particles and pores are well formed.