Probing the hydrophilic behaviour of e-beam evaporated silica thin films for PV-soiling application

In this work, we report on the controlled change of the wetting behaviour of silica thin films deposited by a reactive e-beam evaporation. The as-deposited coated surfaces were treated with acetone solvent using an ultra-sonic bath followed by characterising their contact angles. As confirmed by a repeated contact angle measurement, the silica thin films changed their wetting behaviour from superhydrophilic to hydrophilic which we attributed to the creation of OH groups and hydroxylation process. X-ray photoelectron spectroscopy analysis suggested a SiO _x stoichiometry of SiO_1.85 for the non-treated samples and SiO_1.91 for the solvent-treated ones. Such promising results pave the way to develop a cost-effective and efficient anti-soiling and self-cleaning coating for a large-scale application.