Photonic Band Gap Structures for Solar Energy Generation

The demand for renewable energy is motivating R&D efforts toward the development of novel photovoltaic (PV) technology. Efficient and low cost solar cells will have an important role in defense applications particularly powering portable electronic devices. Current solar cells based on single crystal silicon are still not at a level to be cost effective when compared to other forms of electrical generation. The path forward is the development of new concepts in both materials and design that enables the fabrication of high-efficiency, cost-effective solar cells. A powerful approach to improving PV efficiency is to concentrate the light in such a way that the density of photons hitting the cell is substantially increased. This can be achieved by fabricating a plasmonic resonance cavity over each cell. The plasmonic structures make use of local field enhancement to concentrate photons at the PV junction. These junctions can then be stacked, as has been demonstrated previously, to convert photons over the full solar spectrum. The wideband PV devices with plasmonic concentrators can be built using thin-film technology, which will provide a low-cost and highly efficient solar energy source. AEgis will model, design, fabricate and test wideband PV devices with plasmonic resonance cavities.