This Small Business Innovation Research (SBIR) Phase II seeks to develop a surface texturing technique that will significantly improve sunlight coupling into various types of solar cells. Surface textures are mandatory to record efficiencies in solar cells. The Omni-Directional Antireflective Coating (Omni-AR) solution showed a reduction in reflection in a large range of incident angles (omni-directional) over a broad spectral range (400-1200 nm). Improved solar cell efficiency of over 10% was demonstrated (experimentally).
The broader impact/commercial potential of this project will be a low-cost, broad-spectrum, omni-directional and substrate-independent surface texture antireflective coating. It is expected to have a significant impact on current and future solar cell technologies. The ability to provide near ideal performance of antireflective coatings to solar cells without a vacuum process is a major step in reducing the cost of solar electricity. This solution-based deposition technique makes it possible to provide a single coating technology that should work with all types of solar cell materials and structures. This project will significantly improve the conversion efficiency in both current and future solar cells (~10%) with a minimum cost increase (~4%).
"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."
The Small Business Innovation Research (SBIR) award resulted in an Omni-Directional Antireflective (Omni-AR™) technology that significantly improves sunlight coupling into solar cells for increased efficiency and shorter payback time. A solution-based application technique means the Omni-AR™ technology is universally applicable as a laminate on glass photovoltaic modules or a direct encapsulant for flexible thin-film solar cells. The Omni-AR™ process can be incorporated in either batch or continuous roll-to-roll manufacturing processes. The ability to apply a cost-effective antireflective coating to solar cells for improved efficiency is a major step in reducing the cost of solar electricity. Omni-AR™ coatings are expected to have a significant impact on current and future solar cell technologies, especially building integrated photovoltaics. The SBIR Phase II research focused on the three areas to improve the commercial viability of the Omni-AR™ technology: materials research to develop mechanically durable materials that have good weatherability over the life of the solar module; modeling and simulation to determine the optimal microstructure size and shape; and micro-embossing process design for Omni-AR™ fabrication. ZT Solar developed UV-curable nanocomposite materials with superior optical qualities, robust mechanical durability, and good weatherability. The Omni-AR coating incorporates microscale surface textures that reduce reflection for a large range of incident angles over a broad spectral range (400-1200 nm) providing more than 10% improvement of solar module efficiency as demonstrated experimentally. Additionally, the textured coating is both hydrophobic and oleophobic creating a self-cleaning feature that will further reduce maintenance costs and improve efficiency over the lifetime of a solar module. ZT Solar will continue commercial development of turn-key systems for large-scale manufacturing and seeks licensing opportunities for the Omni-AR™ technology.
