At the UCLA Samueli School of Engineering in Los Angeles, materials scientists have developed a new type of thin-film solar cell that generates more energy from sunlight than conventional cells do. The element features a base consisting of a 2 μm layer of copper, indium, gallium and selenide (CIGS). The team led by Professor Yang Yang then applied a 1 μm layer of perovskite, a cost-effective lead and iodine compound. The two layers are connected by a nanoscale interface that was also developed at UCLA. It gives the solar element a higher level of voltage, allowing it to generate more energy. The two layers are affixed to an approximately 2 mm glass substrate.
The CIGS base layer alone achieves an efficiency of around 18.7%. Together with the perovskite layer, the efficiency increases to 22.4%. The additional performance has now been confirmed by independent tests in the National Renewable Energy Laboratory (NREL) of the US Department of Energy. Professor Yang Yang expects to be capable of improving the efficiency of these two-layer cells by an additional 30%.