SBIR Phase I: An Omni-Directional Antireflective Coating from Solutions

The Small Business Innovation Research (SBIR) Phase I project will develop a novel Omni-Directional Antireflective Coating (Omni-AR) to improve light collection in photovoltaic cells. The coating consists of a monolayer of microscale silica particles partially immersed into a film of spin-on glass. Its antireflection is broad spectrum and less dependent on sunlight incident angle, thus omni-directional. More importantly, the coating is prepared from solutions, ensuring its low cost. The research activities include 1) development of coating processes which allow large-area, uniform and close-packed coating of solar cells with monolayer silica particles; 2) optical simulation to optimize the designs of Omni-AR coatings and 3) testing of commercial polycrystalline silicon solar cells with Omni-AR coatings. Except anisotropically-etched pyramids on single-crystalline silicon, there is currently no cost effective method to produce surface texture on any other types of solar cells. Through this project, the technical feasibility and commercial potential of Omni-AR will be demonstrated. Such a low-cost, broad-spectrum, omni-directional and substrate-independent AR coating will have a significant impact on current and future solar cell technologies, including polycrystalline silicon, amorphous silicon, ribbon silicon, copper indium diselenide, cadmium telluride and organic semiconductors, by significantly improving their efficiency with a minimum cost increase. These solar cells currently have ~60% of the solar cell market.