New high UV transparency PV encapsulants: Properties and degradation after accelerated UV aging tests

• The encapsulant formulation influences the reliability of the PV module. • POE and TPO are promising alternative encapsulants to EVA. • UV radiation causes yellowing and degradation of the PV encapsulant. • The encapsulant chemical structure plays a role in the degradation of the PV module. • UV-stressed PV device made of TPO maintains performance better than EVA. To increase the PV modules efficiency, it is very important to improve not only the solar cell production technology, but also the other materials needed in their manufacture. Encapsulant materials, used to ensure the long-term lifespan and stability of solar cells, play an important role in PV module reliability. In fact, most modules breakdowns are linked precisely to the type of polymeric film used in their manufacturing. A detailed understanding of the causes and processes of PV module degradation and material is crucial for a successful development of new components and design of durable and reliable PV module. This article focuses on new high UV transparency polymeric materials usable for Si-based cells encapsulation and carries out thorough testing to evaluate their damaging caused by exposure to UV radiation. To obtain a reasonable evaluation of reliability of these highly UV transparent films, they were exposed to accelerated aging in a climatic chamber and then the changes in their optical, chemical and structural properties were analysed. The evaluating of the effect of UV radiation was also carried out on electrical performance of PV mini-devices made in the laboratory with the new encapsulants. Results have shown that, between the different UV transparent films tested, thermoplastic polyolefin-based encapsulants have a higher stability in long-term behaviour.