A Combined Multilayer Anti-reflection and Fluorine-free Hydrophobic Coating for PV Module Cover Glass

Porous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> AR coatings are used to increase module efficiency. However, recent testing has highlighted that these coatings are hydrophilic and adhere to soiling on the surface of the module, reducing power output. In addition, any initial AR benefit is lost after a few cleaning cycles due to coating removal by abrasion. To address this issue, a durable multilayer, AR coating has been combined with a fluorine-free, PDMS-based, hydrophobic coating and tested as an alternative coating to porous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. The coatings underwent accelerated UV exposure and liner abrasion testing for 1000 hours and 2000 cycles respectively. After 1000 hours of UV exposure, the combined MAR exhibited negligible loss in performance retaining high transmittance of 94.1 T% as well as maintaining hydrophobicity with a WCA of 108.4°, whilst the porous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> suffered a performance decrease of 0.4 T%. After 2000 cycles of linear abrasion, the combined MAR coating exhibited no degradation, whilst the porous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> suffered degradation to the point where its performance is similar to that of uncoated glass.