Solar cells require coating materials with high barrier properties in order to maintain a high efficiency during their lifetime, that are normally achieved using multilayer coatings. However, these coatings basically consist of passive barrier materials, not capable of adapting their response to the environmental change. The protective action of the passive barrier films can be significantly enhanced and strengthened by the addition of an active barrier system, able to continuously adapt its protective action according to the intensity of the environmental degradation phenomena. The driving idea is that of including in suitable polymer substrate specific oxygen absorbers, which are activated by meteorological phenomena (diurnal temperature variation, rain, etc.), thus guaranteeing an active and dynamic protection able to react to the environmental changes.
To this aim, active barrier films were produced with a single screw lab scale extruder using a commercial active PET denominated Poliprotect (M&G). The obtained samples were characterized in terms of barrier, optical, mechanical and thermal properties. Oxygen Absorption Measurements performed in different conditions of relative humidity showed that water plays a fundamental role in activating the absorption phenomenon. The evaluation of the percent transmittance in the UV-Visibile range demonstrated that the produced films have a good transparency > 85%, acceptable for the PV application field. The obtained results highlighted that PoliProtect is a suitable candidate for the production of active barriers for solar cells, since it has high transparency, easy processability and low absorption kinetics, with a scavenging activity lasting more than 150 hours.
