Highly transparent, durable, and omniphobic liquid-like coatings for efficient dynamic de-wetting and self-cleaning applications

Abstract

Solar cells, which are contributing significantly to achieving carbon neutrality but suffer from the dust deposition problem that limits their power conversion efficiency. Despite the many desirable properties of self-cleaning coatings to improve the efficiency of solar cells, one formidable challenge in designing coatings for their practical applications lies in integrating transparency, durability, and self-cleaning properties. Herein, we report a multifunctional, durable, and omniphobic liquid-like FEVE-g-PDMS coating, which was readily prepared by embedding highly flexible polydimethylsiloxane (PDMS) chains as dynamic de-wetting agent into the fluorinated ethylene-(hydroxyl-alkyl) vinyl ether (FEVE) matrix. The resultant coating exhibited low roughness and high transparency (89.72 % at 550 nm, the air was used as reference), which could be applied to the protective solar cover glass by facile spraying technique. The PDMS chains with high mobility were enriched on the coating surface and could dynamically rotate/bend/stretch to reduce the energy barriers for the moving liquids, endowing coating with unprecedented dynamic de-wetting property. Importantly, the coating demonstrated self-cleaning property, which could readily slide the liquid and dust contaminants off, resulting in a high efficiency recovery ratio for solar cells (95.37 %). Besides, the coating showed strong adhesion, and durability to ultraviolet rays, humidity and thermal atmospheres, and chemical media. Therefore, the synthetic omniphobic liquid-like coating holds great promise for the development of innovative self-cleaning materials with versatility and durability that are not realizable with conventional solid interface engineering.