Modified crystal shows potential for solar-cell efficiency

MIT Technology Review : Perovskite solar technology has reached efficiencies in four years that took more than a decade to reach using silicon and cadmium telluride solar cells. Andrew Rappe of the University of Pennsylvania and his colleagues have developed a new perovskite material—a class of compounds characterized by a specific crystalline structure—with properties that suggest it could be used in solar cells to convert 50% of the energy in sunlight into electricity. That would be more than twice as effective as the current best conventional cells. The material is the first to combine the ability to generate an electric current without the presence of an electric field with a high responsiveness to visible light. Rappe’s team also demonstrated that the structure can be modified to respond to other wavelengths. However, the material has not been tested in an actual solar cell yet, and the amount of current it produces is much lower than conventional materials.