In situ durability of EVA polymer encapsulant with optical analysis techniques for photovoltaic conversion applications

The aim of these investigations was to identify and evaluate appropriate degradation indicators for PV encapsulation materials in order to qualify new and emergent polymeric components and to predict the lifetime of materials and modules. Therefore, the influence of the relevant stress parameters like ultraviolet radiation, corrosion environment and temperature-humidity cycles on the degradation behavior of EVA selected as encapsulant material had to be determined. Therefore, the material properties and the aging behavior were characterized by optical and thermal analysis techniques by infrared (IR) spectroscopy in attenuated total reflection mode (ATR), UV/VIS spectroscopy, photoluminescence spectroscopy analysis, Raman analysis and differential scanning calorimetric (DSC) analysis. Different degradation indicators were derived from the characterization methods and explicitly discussed considering the required property profile of polymers for PV encapsulation materials. Here, we describe a fast and non-destructive optical method to determine the EVA indoor aging.