Anti-Reflective TiO2-PDMS Nanopatterned Nanocomposite Coating for Omnidirectional Improvement of Silicon Solar Cells

Solar energy is a primary source of energy for space, as solar cells are light weight and can provide sufficient energy for the length of the mission. However, the energy demand for new missions continues to increase while solar cell technology is approaching its efficiency limits. This indicates that a greater emphasis needs to be placed on reducing losses, both optical and electrical. In addition, UV radiation speeds degradation of solar cells. Currently, cover glass is used to protect solar panels from UV radiation, but are heavy, rigid and can be easily broken on launch. These needs have pushed researchers to explore cover glass replacement, often a transparent encapsulant like polydimethylsiloxane, PDMS, or polymethyl methacrylate, PMMA. These encapsulants are flexible, as transparent as glass, and provide an exciting new platform for experimentation. However, PDMS provides limited protection from UV radiation.

Our coating provides improvements over the raw encapsulant, PDMS, through nano-patterning and by incorporating titanium dioxide nanoparticles into the polymer matrix to modify the optical properties of PDMS. Titanium Dioxide nanoparticles provide excellent UV radiation protection, while not compromising broadband transmission. Through nano-patterning, the coating promotes beneficial light scattering and trapping, while also reducing reflections. Additionally, the nano-patterning provides greater improvements at higher angles of incidence due to its light trapping properties. The resultant nano-patterned TiO2 – PDMS coating is cost effective, UV blocking and omni-directionally enhancing.