A double layer coating was designed and fabricated on glass surfaces by sol-gel method using a silica-titania (SiO2–TiO2) thin film as the bottom layer and an inorganic-organic (triethoxy(octyl)silane (OTES) modified SiO2) upper layer. SiO2 and TiO2 sols were prepared using tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TIP) as precursors and nitric acid (HNO3) as catalyst. The refractive index of the SiO2–TiO2 and OTES modified SiO2 layers were 1.79 and 1.45, and their thicknesses were approximately 76.8 nm and 94.2 nm, respectively. The results show an increase of 7% in transmittance respect to the uncoated glass substrate. At the same time, OTES-modified SiO2 top layer significantly improved the hydrophobicity of the system; the water contact angle of film increased from 56° for system without the OTES modified SiO2 layer to 102° for the system with OTES-modified SiO2 top layer. © 2024 The Authors

This research is a contribution to the FunGlass project, which has been financially supported by the European Union Horizon 2020 Research and Innovation Program under Grant 739566. Additionally, the study received support from the Grant Agency of the Slovak Republic under Grant VEGA 1/0431/18 and VEGA 1/0844/21. The authors acknowledge finantial support from MICINN under projects PID2020-115419GB-C21-C22/AEI/10.13039/501100011033. A. H. Haritha would like to thanks Assoc. Prof. Alfonz Plsko for his constant support and advise. The authors would like to express their gratitude to the JECS Trust for providing funding (contract No. 2022301) .

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