Researchers at Cambridge, Imperial and Singapore have developed a method to print ultrathin coatings on next-generation solar cells, allowing them to work in tandem with silicon solar cells to boost efficiencies.
Photovoltaics, or solar cells, work by absorbing sunlight to produce clean electricity. But photovoltaics can absorb only a fraction of the solar spectrum, which limits their efficiencies. The typical efficiency of a solar panel is only 18-20%.
Researchers have been searching for a way to overcome this efficiency limit with an approach that is cost-effective and can be used across the world. Recently, researchers have started developing ‘tandem’ solar cells by stacking two solar cells, absorbing complementary parts of the solar spectrum, on top of each other. The most promising of these tandem solar cells is a perovskite device stacked on a silicon device. Perovskites absorb visible light, whereas silicon absorbs near-infrared light: a perovskite-silicon tandem solar cell could realistically achieve 35% efficiency within the next decade.
A team of researchers from Cambridge’s Department of Materials Science and Metallurgy led by Professor Judith Driscoll and Dr Robert Hoye, working with Imperial College London and the Solar Energy Research Institute of Singapore, have developed a method to ‘print’ a protective coating of copper oxide over the perovskite device. They have shown that only a 3nm thick coating is sufficient to prevent any damage to the perovskite after depositing the transparent top electrode. These devices reach 24.4% efficiency in tandem with a silicon cell.
Click here to read the full University of Cambridge article.
Click here for the ACS Energy Letters (2020) publication: Robert A. Jagt et al. ‘Rapid Vapor-Phase Deposition of High-Mobility p-Type Buffer Layers on Perovskite Photovoltaics for Efficient Semitransparent Devices.’ ACS Energy Letters (2020). DOI: 10.1021/acsenergylett.0c00763
Image: Perovskite solar cell with oxide coating. Credit: Rob Jagt