New Chemical Functionalization Concept for Anti-Reflective and Anti-Soiling Front Glass of PV Modules Based on Surface Structuring and Modification

This works presents a new functionalization concept for front glasses of PV modules and an analysis of their anti-reflective and anti-soiling properties. The described functionalization technology is based on surface structuring and modification obtained by a low cost chemical treatment. The functionalized, nanostructured surface is part of the original glass and no additional coating is required, which makes it more reliable. Nanostructured glasses are compared to conventional anti-reflective coated and untreated reference glasses. The optical and self-cleaning properties of the glasses are investigated by spectrally resolved optical analysis and by a newly developed anti-soiling test method, respectively. Additionally, the performance of 1-cell modules equipped with these glasses is simulated on the basis of optical data and measured electrically in solar simulators. 60-cell modules with different glasses are compared for their electrical performance. It is shown that the anti-reflective behavior of a glass with nanostructured surface without any additional anti-reflective coating is as good as conventional solar glass with standard antireflective coating. Furthermore, it is shown that loss in integral transmission after soiling process is significantly reduced (25 % relative) by a proper wet chemical surface treatment. This reduces solar module operation costs in arid regions.