UV stable coating for sail-embedded PV power

NASA is seeking advanced thin-film protective coatings for sail-embedded photovoltaic (PV) solar cells. SSS Optical Technologies, LLC (SSSOT) together with Oakwood University and Solestial, Inc. proposes to develop the Polymer Anti-damage Nanocomposite Down-converting Armor (PANDA) coating that uses a polymer nanocomposite impregnated with luminescent nanoparticles (NPs) that absorb solar ultraviolet (UV) radiation and convert it into visible light suitable for PV cells. There are three innovations: (1) By absorbing solar UV PANDA improves UV stability of the solar cell; (2) PANDA combines UV shielding with the use of UV, otherwise wasted, in production of extra electricity; (3) PANDA shields the cell from high-energy cosmic radiation. During Phase I project we evaluated the feasibility of PANDA using three types of solar cells: silicon heterojunction (SHJ) from Solestial, Inc., Copper-Indium-Gallium-Selenide (CIGS) and inverted metamorphic multijunction (IMM). The cells are considered as candidates for space applications due to their light weight and flexibility. Major results of Phase I project are: (1) PANDA coating improved the conversion efficiency of the cells by up to 5%; (2) for all three types of cells PANDA UV stability; (3) computer simulations indicated that 20-micron-thick PANDA can fully shield the solar cells from 1-MeV protons reducing radiation damage by a factor of 4. The overall goals of the Phase II effort will be (1) to optimize PANDA coating (composition, structure, and application methods) and obtain maximal conversion efficiency and operational lifetime of the coated solar cells; (2) to verify experimentally PANDArsquo;s ability to improve radiation tolerance of the coated solar cells. TRL level 5 is expected by the end of Phase II. Deliverables will include experimental data, test reports, and final technical report.