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Efficient Thin-Film Solar Cells that Convert More Sunlight into Usable Energy


Invention: The University of Florida is seeking companies interested in commercializing thin-film solar cells with enhanced efficiency due to improved optical management overcoming an obstacle to solar energy’s widespread adoption. Solar energy is sustainable renewable produces zero emissions and is one of the world’s fastest-growing energy technologies. According to the United States Energy Information Administration more than 100 American companies manufacture solar cells and modules. While photovoltaics have found widespread off-grid and niche applications they have not yet emerged as a viable alternative to fossil fuels for large-scale power generation. The high cost-per-watt of solar cells is mostly to blame either due to expensive processing and material costs (as is the case with traditional high-performance silicon panels) or low module power conversion efficiencies (from reduced cost thin-film based panels) with most of the latter modules offering 6 to 12 percent light-to-electricity power conversion efficiency. University of Florida researchers have developed devices that combine novel surface texturing and innovative reflectors that increase efficiency in a wide range of photovoltaic devices. The additional texturing layers are compatible with any active layer material manufactured using high-throughput processes and inexpensive. Technology: With active layer thicknesses of a few micrometers or less thin film solar cells offer significant advantages over traditional monocrystalline silicon-based devices including reduced material usage and high-throughput roll-to-roll manufacturing. However thin-film photovoltaics suffer from an intrinsic materials issue: They are limited by tradeoffs among light absorption material cost/layer thickness and electrical performance. So while sufficiently thick absorber layers can absorb almost all incoming light this generally results in reduced device electrical characteristics that limit device efficiency and increased material usage and processing time increasing production cost. University of Florida researchers have developed technology that can increase light absorption and efficiency in thin film devices by improved management of incoming light alleviating these tradeoffs. First applying a textured coating to the light-incident side of a photovoltaic device increases the length of the path the light takes through the device increasing probability of absorption and power generation without increasing layer thickness. Second textured rear reflectors trap light within the active layer of a device increasing its probability of absorption. Both are applied with a soft-lithographic stamping compatible with high-throughput roll-to-roll processing. The texturing material itself is made from inexpensive mechanically robust and commercially available polymers. Results indicate that texturing the light-incident side of a device can increase power conversion efficiency by 10 to 50 percent compared to unmodified surfaces. Rear reflectors can improve performance by up to 25 percent compared to devices with planar reflectors. The mechanism is universally applicable and independent of the active layer material offering greater enhancements as the device/module active area increases. Application: A thin-film photovoltaic cell with novel textured coatings that promises dramatic increases in power conversion efficiency.


1) Cell converts more sunlight into electricity through novel textured coatings enhancing cost-effectiveness 2) Cheaper to manufacture than rigid solar panels increasing profit margins 3) Automated printer-like production is less complicated ensuring there are fewer defects 4) Lighter and more flexible than traditional panels permitting application on a wider range of surfaces

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