Q.F. Xu, Y. Zhao, B. Kujan, A. Lyons
ARL Designs LLC, United States
pp. 624 - 627
Keywords: self-cleaning, anti-reflective, AR, ARC, PV, photovoltaics, polymer, coating
Photovoltaic panels face two major challenges in maximizing and maintaining their electrical output – reflections and soiling of the outer glass surface. To address these challenges, we developed a durable, transparent high-performance polymeric coating on glass with a nano-scale surface roughness that imparts both anti-reflective (AR) as well as superhydrophobic (SH) properties. The hierarchical surface features create a graded refractive index that reduces reflections as well as imparts superhydrophobicity. Tests were performed to evaluate the effect of process parameters on properties. AR-SH films were produced that increased the percent transmission from 91.8% for plain glass to 93.0% for the ARL Designs treated glass over the full visible spectrum. Transparent surfaces were made that were superhydrophobic with contact angles as high as 165o and slip angles as low as 1o. Mechanical durability of the prepared coating was demonstrated using water impingement, (i.e. an accelerated rain test). Chemical durability was demonstrated by immersion of the coated glass in an alkali solution capable of oxidizing many organics as well as etching glass. Initial results indicate that the surface is both chemically stable and robust to approximately 30 years of rainfall in Central Park, NYC.