Multiaxial oil-repellent surfaces for self-cleaning of sticky dust and enhanced photovoltaic efficiency

A bioinspired self-cleaning strategy for solar cells has been proposed to enable the automatic removal of dust deposited on surfaces. However, the presence of oil-based sticky residues from volatile organic compounds poses a significant challenge for water-based cleaning methods. In this study, we introduce oil-repelling surfaces capable of self-cleaning in any orientation to address oily dust contamination. The proposed surface features a disconnected grid pattern with domed top surfaces and hyperbolic sidewalls. The hyperbolic sidewalls contribute to superomniphobicity, while the domed top surfaces minimize oil adhesion and enhance the efficiency of photovoltaic cells. Additionally, the disconnected grid structure enhances lateral liquid repellency, achieving higher contact angles compared to connected grid designs. When applied to thin-film crystalline silicon solar cells, the surface texture enhances photovoltaic efficiency through the light-scattering effect of the lens-shaped features. Furthermore, the proposed surface demonstrates mechanical stability under repeated bending.