Researchers from the Photovoltaics Laboratory (KPV-Lab) at King Abdullah University of Science and Technology (KAUST) have reported a perovskite/silicon tandem solar cell with a power conversion efficiency (PCE) of 33.2%—the highest tandem device efficiency in the world to date, surpassing that of Helmholtz Zentrum Berlin's (HZB) record at 32.5% PCE.
The tandem device was reportedly certified by the European Solar Test Installation (ESTI) and listed at the top of the National Renewable Energy Laboratory's (NREL), Best Research-cell Efficiency Chart.
Led by Dr. Stefaan De Wolf from KAUST's Solar Center, the team has steadily been perfecting the perovskite/silicon tandem cell concept since 2016—developing new materials, methods and device structures, and tackling fundamental challenges, such as how to uniformly cover the micrometer-sized pyramidal surface of silicon cells with perovskite material.
The new tandem solar cell combines perovskite top cells on industrially compatible, two-sided textured silicon bottom cells. The perovskite top layer absorbs blue light best, while the silicon foundation absorbs red light best. The combination of these materials maximizes the capture and conversion of sunlight into electricity more efficiently than the conventional single-junction silicon analogs.
"This new record is the highest PCE of any two-junction solar cell under non-concentrated light, attesting the tremendous promise of perovskite/silicon tandems to deliver ultra-high performance photovoltaic modules, which is critical to rapidly achieve renewable energy goals towards combatting climate change," De Wolf said.
The collective knowledge and skills of several lead researchers have been said to contribute to the recent achievement, in particular Dr. Esma Ugur, who specializes in optical spectroscopy and the analysis and visualization of cell defects; Dr. Erkan Aydin, an expert in the scalability and stability of ultra-efficient tandem solar cells; and Dr. Thomas Allen, who focuses on c-Si bottom cell development.
The team is currently exploring scalable methods to produce industrial-scale perovskite/silicon tandem cells with areas exceeding 240 square centimeters, as well as strategies to obtain highly stable tandem devices that will pass the critical industrial stability protocols.