UV Stable Thin-film Down-converting Polymer Coating for Sail-embedded PV Power

NASA is seeking advanced ultraviolet (UV) stable thin-film protective coatings for sail-embedded photovoltaic (PV) power generating systems. Protective coating shields PV cells from harmful cosmic rays (mostly protons and energetic electrons) and solar UV radiation that causes the light-induced degradation effects in the cell. But the coating itself, often made as a polymer thin film, degrades under long-time exposure to solar UV, leading to the losses of generated PV power. The required coating shall protect sail-embedded PV cells from solar UV radiation and from atomic oxygen (in the case of low-orbit space environment) and high-energy ionizing particles to improve operational lifetime. We propose to develop the Polymer Anti-damage Nanocomposite Down-converting Armor (PANDA) coating of sail-embedded PV cells that, in addition to shielding from solar UV radiation and cosmic rays and being UV stable, converts absorbed solar UV radiation into visible light, therefore simultaneously improving efficiency of embedded photovoltaic cells. Experimental results demonstrate that PANDA technology has the following advantages: (1) improves UV stability of the coated solar cell, (2) combines UV shielding with the use of UV, otherwise wasted, in production of extra electricity, (3) shields the cell from high-energy space radiation. The coating itself has minimal degradation (darkening/yellowing, and sublimation) after long-time exposure to solar UV.