Durable high-performance water-based anti-reflective coating for PV module glass

Without an antireflective coating, more than 4% of incident light is reflected from the standard front cover glass of photovoltaic (PV) modules. Module efficiency is one of the most important levers to impact the cost-per-watt of solar and recovering some of this reflected light with a simple anti-reflective coating (ARC) has become widespread. The types of ARC can vary in deposition method (roll coating, spray coating, sputtering, etc.) as well as composition and performance. The most widely adopted coatings today are based on a porous silica film with a thickness optimized for the solar spectrum. Current coatings, however, have room for improvement in both the performance and cost, giving manufacturers reason to seek new solutions that drive down the levelized cost of electricity (LCOE). In this work, we report the test results for a new AR coating from WattGlass showing significantly improved optical performance compared to the traditional AR coatings. The WattGlass AR coating takes advantage of water-based chemistry that is more environmentally friendly than the sol-gel process used in standard production coatings. This chemistry allows a high performance and durable coating to be deposited and cured at room temperature and is compatible with an industry standard glass tempering process. The samples under test in this work were subjected to extensive environmental and accelerated lifetime testing performed by CREST (Centre for Renewable Energy Systems Technology) at Loughborough University.