Functional nanostructured surfaces in hybrid sol–gel glass in large area for antireflective and super-hydrophobic purposes

Abstract

We demonstrate the modification of substrate surfaces by the fabrication of thin layer sub-wavelength nanostructures in sol–gel glass in large area on their surfaces. Compared with the traditional methods, the sol–gel method eliminates the etching step and therefore becomes more convenient. It is found that 90% of the height of nanostructures in the master can be transferred into the hybrid SiO₂–TiO₂ sol–gel glass in our experiment, while the horizontal size of the nanostructures can be replicated precisely. The optical characterization results show that the light reflectivity can be reduced by about 1% over a wide waveband ranging from 400 nm to 800 nm for ARS with a height of 32.4 nm. In addition, it is found that the contact angle of the substrate surface with sol–gel nanostructures has been significantly improved from about 47° to 108°. Therefore, it can be concluded that with a thin layer sol–gel glass sub-wavelength nanostructures, the substrate surface can be effectively modified to have the function of both anti-reflectivity and super hydrophobicity, which can find applications in the area of photovoltaic concentrating lenses for enhancing light transmission, antifogging purposes and others.