Improved Efficiency Retention in Silicon Solar Cells by PDMS-Based Nanocomposite Encapsulations

In this work, we discuss the fabrication and application of polymer nanocomposite (PNC) films as encapsulants that offer a one-stop solution for heat- and moisture-based degradation issues of silicon solar cells. The PNC encapsulant films were fabricated by dispersing ∼0.45 wt. % zinc oxide (ZnO) or titanium dioxide (TiO 2 ) nanoparticles into a dilute solution of polyethylene glycol (PEG) in chloroform, followed by addition of polydimethylsiloxane (PDMS) and subsequent curing at 80 °C for 20 min. The resulting PNC films of thickness ∼450 μm were used as front encapsulants for commercially available mini silicon solar cells. We show that these PNC films enable >80% retention of power conversion efficiency (PCE) after hot-air aging up to 150 °C, while the unencapsulated cells retained only ∼50% of their initial PCE. Moreover, when heated to 60 and 90 °C, the surface temperature of PNC-encapsulated cells was ∼5–8 °C lower compared to unencapsulated cells. Furthermore, when subjected to a damp-heat aging test (60 °C, 85% relative humidity for 1 week), the PNC-encapsulated cells retained >50% PCE, while the unencapsulated cells retained only ∼17% PCE. The hydrophobicity and structural integrity of the encapsulant films were preserved despite exposure to high humidity and elevated temperatures. These results highlight the potential of the fabricated PNC films as effective encapsulants to seamlessly mitigate degradation caused by both humidity and heat, thus paving a route to extend the lifespan of silicon photovoltaics deployed in tropical climatic zones.