Fabrication and performance of nano-SiO2@PVDF self-cleaning coatings for photovoltaic module applications

Aiming to address the issue of PV efficiency degradation caused by dust accumulation on modules, hydrophobic coatings with high light transmittance, self-cleaning properties, and mechanical durability have become a research hotspot for PV dust removal. In this work, a nano-SiO 2 @PVDF self-cleaning coating was prepared via a spraying method, with tetraethyl orthosilicate (TEOS) and polyvinylidene fluoride (PVDF) as raw materials. Combined with hydrophobic modification by hexamethyldisilazane (HMDS) and enhanced interfacial bonding by the γ-Glycidyloxypropyltrimethoxysilane (KH-560) coupling agent, the micro-nano rough structure and hydrophobic properties were optimized by adjusting the volume ratio of silica sol to PVDF. The coating exhibited a light transmittance of 88.5 % and a pencil hardness of 4H. After 35 cycles of sandpaper abrasion, its contact angle (CA) remained greater than 125°, and it maintained stable hydrophobicity under ultraviolet (UV) aging and pH 1–14 environments. Applied to PV glass, after 14 days of natural dust fall, the coating group had 28.2 % less initial dust coverage than the blank group, with a self-cleaning efficiency of 78.45 %, reducing dust-induced power loss by 68.3 %. This performance stemmed from micro-nano structures forming air films for water droplets to carry dust away, and PVDF's C F bonds protecting SiO 2 from UV degradation. This work provided a highly transparent, hydrophobic, and durable self-cleaning solution for PV stations in arid and dusty areas, alleviating dust-water shortage conflicts, cutting maintenance costs, improving efficiency, and supporting stable PV operation and the national “Dual-Carbon” strategy.