Reliability Investigation of Structural Colour Interlayers for Coloured PV Modules

With the increased proliferation of structural colours in PV colouration, concerns are growing regarding the reliability impact of materials used. In the ColorFoil project, structural colour interlayers with integrated threedimensional diffuser structures are being developed. To determine the degradation behaviour of the different materials within such a laminate, accelerated aging is performed on base polymers coated with resin-based diffuser structures and metal-oxides used in structural colours. To accelerate UV exposure degradation testing, custom LED-based UV light sources have been developed and characterized. Results show PET foils to be best suited for interlayer substrates as well as good stability for resin-based and SiO2 coatings after UV exposure. Samples containing TiO2, however, show significant losses in short-circuit current for both EVA and POE encapsulants. It is suggested to be caused by a photocatalytic effect of the TiO2 coating, accelerating polymer degradation.