Photodegradation Behavior of Ethylene/Vinyl Acetate Copolymer (EVA) Film for Solar Cell Encapsulant

In this study, we investigated the photodegradation behavior of an ethylene/vinyl acetate (EVA) film for solar cell encapsulant. The EVA film was exposed to the weathering apparatus, equipped with a xenon-arc lamp for simulated sunlight exposure conditions. Since photodegradation mainly induces changes and variations on the materials surface, a variety of technical approaches were employed to characterize the modifications of the EVA film surface, and then the deterioration behavior of optical properties was discussed in term of the morphological changes. And also, photo- degradation caused the composition modification of the EVA film surface by the incorporation of oxygen to the polymer chains, which could make the wettability of the film hydrophilic. Finally, the photo-induced deformation behavior of the EVA film influenced by the light intensity depending on the type of lamp was discussed in order to show the importance of the light source.