Sol-gel preparation of transparent and superhydrophobic silica coatings for self-cleaning solar panels

Abstract

The increasing significance of photovoltaic power generation within the renewable energy sector is encountered by effective challenges such as dust accumulation and hence light reflection, bird droppings, and water films on solar panels are negatively impacting on their efficiency. In this study, a dual-layer transparent superhydrophobic coating was prepared on a glass substrate by dip coating a sol-gel processed silica sol and further modifying with hydrophobic silica nanoparticles as a low surface energy material. Surface morphology analysis confirmed the formation of a nano-scale hierarchical structure, which is crucial for improving both superhydrophobicity and optical transparency. The optimized coatings demonstrate a water contact angle (WCA) of 154° and sliding angle (SA) of 1.5° with a transmittance of 96.2 %. The superhydrophobic coating revealed remarkable self-cleaning performance against soil and dye contaminants. Moreover, the assessments of mechanical and environmental stability show that the prepared coatings have preserved their properties against mechanical abrasion, adhesiveness, alkaline and acidic solutions, and outdoor weather conditions. Additionally, the coated glass integrated with solar panels, the coatings significantly improved performance of photovoltaic cells. These results indicate a promising approach for enhancing the performance of solar energy systems.