Exploring moisture barrier properties of thermoplastic polymers for enhanced durability of solar panels

This study focuses on the evaluation and comparison of various materials for barrier films in polymer-based photovoltaic (PV) modules, with a specific emphasis on moisture permeation resistance, optical properties, and durability. The initial phase of the study involved an extensive review of the literature to identify potential solutions. Three materials were selected for the evaluation: film of cyclo-olefin copolymer (COC); a multilayer material (PRX) with thermoadhesive outer sides and a core serving as a barrier film composed of high-density polyethylene; and thin films consisting of a polymer substrate with an aluminum oxide (AlOx) deposition. The number following the acronym indicates the film thickness in micrometers (µm). Through a series of experiments and analyses, the performance of different materials is assessed, providing valuable insights for material selection. The moisture permeation resistance, evaluated using water vapor transmission rate (WVTR), reveals that COC films, particularly 140-COC, exhibit excellent moisture barrier capabilities. Furthermore, PRX-100 exhibited promising results in terms of moisture protection. The assessment of optical properties, specifically light transmittance measurements, indicated that all tested samples exhibited good transparency, with the 40µm COC film demonstrating the highest visual transparency. The findings suggest that the 140-COC film and PRX-100 are favourable options for barrier films in PV modules, offering low WVTR values while maintaining good light transmittance. To comprehensively evaluate the durability of the materials, an accelerated aging test was conducted. It is observed that COC films effectively hinder moisture diffusion, with localized degradation in damaged areas, while thinner COC configurations show degradation across the entire surface. The thicker PRX-100 film displays the best performance, while the AlOx film suffers from delamination. Power loss analysis reveals that the 140µm COC samples perform the best, followed by PRX-100 configuration. In addition to technical performance, comprehensive assessments considering cost, availability, and ease of integration into the manufacturing process are essential for making informed decisions regarding optimal materials for PV module applications. Thus, this study serves as an initial step towards addressing the broader objective of conducting a thorough long-term durability analysis of barrier films for PV modules. Overall, the outcomes of this study provide significant insights into the performance characteristics of the evaluated materials, offering valuable guidance for material selection and future research in the field.