Polymer films in photovoltaic modules: Analysis and modeling of permeation processes

Polymeric films are commonly used as water-vapor barriers, or as substrate materials for barrier coatings in food packaging, photovoltaic devices, organic light emitting diodes (OLEDs), and vacuum isolation materials. The permeation properties of these films determine the level of water in the polymers and inside the devices. The water can cause corrosion and/or degradation of functional properties of the devices. The temperature of solar devices and the ambient water vapor concentration vary over time according, to the solar radiation and the ambient climate. Temperature-dependent permeation and diffusion properties are needed for modeling the water concentration over time in order predict the long-term behavior and the service life of such devices. This chapter describes the measurement of the temperature-dependent permeation coefficient for polymer films different laminates of polymer films, and first results of modeling the processes integrating time series of condition experienced during outdoor exposure.