Researchers from King Abdullah University of Science and Technology (KAUST) have fabricated efficient, two-terminal monolithic perovskite-silicon tandem solar cells and tested them outdoors. The tandem device that resulted from this research was found to be more stable than conventional perovskite cells and, importantly, optimized for use in industry.
The findings of KAUST Research Scientists Dr. Erkan Aydin and Dr. Thomas Allen, and colleagues in Professor Stefaan De Wolf's group, indicate that the temperature dependence of both the silicon and perovskite bandgaps—which follow opposing trends—shift the current-matching-optimization point away from that for two-terminal tandems under standard test conditions.
“These findings imply that the ideal bandgap of the perovskite cell for optimal device performance should be lower than previously thought. Such lower-bandgap perovskites are known to be much more stable,” said De Wolf.
The team’s finding could hold great promise for the commercialization of perovskite-silicon tandem solar cells. Their findings indicate that bromide-lean perovskite top cells, with narrower bandgaps at standard test conditions are potentially the best way forward to boost the efficiency of conventional silicon solar cells.
After fabrication, the tandem cells were put into the KAUST outdoor photovoltaic test field station, providing the first real operational test for such devices in KSA and confirming the improvement in performance.
“For years, the gold standard of solar power has been silicon, representing over 95% of the market. This publication is the first of its kind to report on tandem silicon-perovskite cells outdoors and demonstrate their viability—a critical next step for enabling new and more efficient solar technology to enter the market. We look forward to working with Dr. De Wolf through our impact-focused research translation program to scale up this technology, truly one of society’s grand challenges,” said Vice President of Innovation and Economic Development (I&ED) at KAUST, Kevin Cullen.