Roveri-Versari-Pichierri-2-2026

ABSTRACT: Photovoltaic panels require periodic cleaning to maintain high energy performance, as the accumulation of dust, atmospheric pollutants, and biological contaminants causes irregular and hardly predictable efficiency losses. Currently available market solutions are mainly based on conventional detergents or hydrophobic coatings which, although capable of reducing dirt adhesion, introduce an additional surface layer that can limit light transmission.
This work describes an innovative biomimetic approach based on a hydroalcoholic suspension of zinc-doped titanium dioxide nanocrystals in the anatase phase, characterized by high photocatalytic activity. The treatment, applied by spraying at a dosage of 0.6 mL m-², does not generate a continuous surface film but instead reproduces a functional nanostructure inspired by lotus leaves, characterized by a reversible alternation between hydrophilic and hydrophobic states.
Under solar UV irradiation, the treated surface becomes strongly hydrophilic, promoting uniform water spreading and pollutant solubilization; in the absence of light, the surface reverts to a hydrophobic state, allowing spherical water droplets to roll off and remove residues according to the so-called “lotus effect”. Simultaneously, the photocatalytic reaction generates radical species capable of degrading organic contaminants, inactivating microorganisms, and transforming NOₓ, SOₓ, COₓ, and VOCs into easily removable compounds.
Thanks to a chemically stable adhesion mechanism to the silica-based surface of the panel, the treatment maintains its effectiveness for many years without the need for reapplication, drastically reducing maintenance costs and water consumption while ensuring long-term energy efficiency. The material was synthesized according to patent no. 102025000001332.