Why Porous Silica Anti-Reflection Coatings Fall Short for Solar Modules

The current industry standard for photovoltaic (PV) module anti-reflection coatings, a thin layer of porous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, shows significant durability concerns despite good optical performance. Over the past few years these durability concerns have mounted, with more and more evidence to show the coatings’ vulnerability to abrasion from regular cleaning. The lifetime of these coatings has been shown to be around 5 - 7 years, far below the PV module warranty period of 25 years, which is likely to cause issues with module manufacturers. In addition to durability concerns, the hydrophilic surface can lead to increased soiling. This paper aims to bring together these concerns and make the case that the current anti-reflection coatings are not fit for purpose.