Anti-Reflection and Dust-Repellant Silica Coatings with Tailored Mechanical and Optical Properties for Desert Conditions

This study addresses the critical challenge of soiling in photovoltaic (PV) systems in harsh desert environments, where high UV radiation and dusty conditions impair solar modules, optical devices, and architectural surfaces. We developed a silica coating with exceptional anti-reflective properties, reducing sunlight reflection and enhancing photon absorption. The research fine-tunes the optical and morphological properties of silica thin films fabricated via reactive RF magnetron sputtering of an SiO2 target, using various oxygen-to-argon flow ratios for precise control. Surface morphology, analyzed through average roughness (Ra) measurements, is closely linked to oxygen content during deposition. Contact angle tests showed that oxygen concentration enhances the hydrophilicity of the coatings. Vickers indentation tests evaluated mechanical properties immediately after deposition and following extended outdoor exposure, indicating that hardness can be tuned by regulating oxygen levels during deposition. These coatings demonstrated remarkable mechanical stability even after 24 months of outdoor exposure in desert conditions. The study also highlights the inverse relationship between dust accumulation and oxygen content in silica films, underscoring their self-cleaning properties. This approach improves the optical and mechanical performance of silica coatings, offering a sustainable solution to maintaining the efficiency of solar modules in desert environments.