Fabrication and performance evaluation of PFOTES-SiO2/PDMS self-cleaning coatings for photovoltaic applications

Dust accumulation on photovoltaic (PV) glass reduces power output, particularly in arid regions where conventional cleaning requires substantial water and labor. In this work, a facile spraying process was adopted to fabricate hydrophobic composite coatings. Five candidate resin matrices were first screened through approximately 8 months of natural outdoor weathering in Dunhuang, and DC184 was selected based on its balanced weathering stability, wettability, optical transparency, and mechanical properties. PFOTES-modified SiO 2 nanoparticles (PFOTES-SiO 2 ) were incorporated into PDMS to prepare PFOTES-SiO 2 /PDMS coatings. The test results indicated that the coating showed the best overall performance at a PFOTES-SiO 2 loading of 1.2 g. Its water contact angle (WCA) was 136.1°, sliding angle (SA) was 24.5°, and the maximum transmittance reached 86.5% in the wavelength range of 400–1100 nm. The coating also exhibited good mechanical durability and environmental stability, with a pencil hardness of B and an adhesion grade of 1. After 30 days of outdoor exposure, the coated module achieved a self-cleaning efficiency of 35.43% and exhibited a normalized photovoltaic conversion efficiency 5.94 percentage points higher than that of the uncoated module. These results indicate the potential of the coating for reducing dust-induced performance losses in outdoor photovoltaic systems.