Development of Novel Frontsheets With Protective Coatings to Increase the Durability and Reliability of Glass-Free Lightweight PV Modules

In this work, novel PET-based frontsheet materials with UV-cured coatings were developed and investigated. UV-curing urethane acrylates were selected as innovative, fluorine-free coating systems. Polyurethane coatings exhibit excellent UV resistance, chemical and moisture resistance and, thus, high durability in outdoor applications. A homogeneous application without coating defects such as bubbles, voids or detachments was achieved. Material tests with cross-cut tests showed no separation from the PET substrate. The water vapor transmission rates and the physical (optical and thermal) and chemical properties of the novel polymeric frontsheets were measured and compared with uncoated reference systems and products already on the market. The aging-related changes after irradiation and humid heat storage were investigated and described in detail. Based on this comprehensive study, the newly developed frontsheets can be considered a suitable alternative to polymeric frontsheets with fluorine-containing top layers.