International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The efficiency of photovoltaic (PV) systems is significantly influenced by surface contamination, which can reduce light transmission and energy conversion performance. In this study, self-cleaning nanostructured coatings based on titanium dioxide (TiO₂ ), zirconium dioxide (ZrO₂ ), and their doped and composite variants (with Y₂ O₃ and Eu₂ O₃ ) were synthesized using the sol-gel method and applied to photovoltaic glass substrates. The coatings were characterized in terms of their optical transmittance, surface morphology (AFM), wettability (contact angle), and crystallographic properties (XRD). Results indicate that TiO₂ coatings offer superior superhydrophilic behavior, while stabilized ZrO₂ -based composites show excellent transparency, surface homogeneity, and long-term durability. Eu₂ O₃ -doped coatings exhibit additional luminescent functionalities, potentially useful for photonic enhancement. These findings highlight the potential of sol-gel coatings in improving PV panel performance via integrated passive cleaning mechanisms and multifunctional surface engineering.

Experimental vitreous samples with the presence of self-cleaning coatings applied by the sol-gel method were selected, which were tested in a real environment under cyclic atmospheric conditions in different TPPs / TPP-Sofia and TPP-Republika, Pernik/. The resulting thin films were studied by UV-NIS – VIR spectroscopy, AFM, contact angle, etc. The experimental samples are potentially applicable in the operation of photovoltaic panels with increased efficiency and sustainability in the conditions of an industrial environment and under the influence of various meteorological factors.

They have been conducted on ellipsometry and contact angles. The contact angles of a surface coating on glasses applied in photovoltaics were measured. This study used a DSA 100-Expert (Krüss GmbH, Germany) to measure contact angles on glass substrates. Contact angles were measured using the DSA 100-Expert tilt table accessory to identify both advancing and receding contact angles. A drop of deionized water is deposited on the glass substrate and then the table is tilted at a constant rate of 5 degrees per minute, to a tilt angle of 90 degrees.

The aim of this paper is to review the cleaning of solar photovoltaic (PV) systems and applied coatings that eliminates costly automated cleaning systems by using nano-sized TiO2 combined with various organic binders.