Enhanced Silicon Solar Cells for UAVs

Solar cells for Unmanned Aerial Vehicles (UAVs) must be cost effective, lightweight, and high performance. Current solar UAVs leverage one of two cell technologies: Gallium Arsenide (GaAs) and silicon. GaAs cells are able to achieve high efficiency levels (above 30%) but their high cost ($100 - $200 per watt) makes them unaffordable for most applications. Silicon cells are far lower cost (roughly $1-$3 per watt), but their efficiency levels are lower (20-25%). A recent study published by our team has demonstrated the ability to enhance the performance of medium-grade silicon cells by 10% to 54% after applying a thin film layer of nano particles made of semiconductor oxides (ZnO) that captures energy in the UV spectrum and down-converts it to visible wavelengths that can be captured by silicon. If the same performance improvement can be achieved with the highest-grade silicon cells, then these lower-cost cells would reach performance levels only previously attainable with GaAs, but at 100X lower cost. This technology breakthrough would reduce the cost of solar-based UAVs by more than 50%. This project will demonstrate that by carefully selecting the thickness, composition and doping of ZnO nano particle layer attached to the silicon solar cell of nominal conversion efficiency 25%, we can attain a conversion efficiency approach numbers only previously attainable using Gallium-Arsenide (GaAs).