Beyond silicon: Alternative photovoltaic technologies

The number of photovoltaic (PV) installations worldwide has recently seen tremendous growth owing to the rapid decline in the consumer cost of solar. These devices benefit from the maturity of the silicon industry as a whole, with world record devices reaching approximately 26% efficiency [1], close to the theoretical maximum for that type of device. Alternative device technologies, including concentrated systems and thin film systems, may be able to improve on the efficiency and/or costs of the current Si devices. At this time, both of these alternatives are in use, and comprise a small portion of installations worldwide. However, both technologies face challenges including increasing cell efficiencies, decreasing production costs and optimizing materials. Research and development is focused on addressing these challenges within both concentrated and thin film PV. Addressing these challenges will allow both of these technologies to compete fully with commercial PV.