Scientists from King Abdullah University of Science and Technology (KAUST) and Fraunhofer ISE have achieved 27.8% efficiency in perovskite-silicon tandem solar cells. The breakthrough was made possible through a hybrid fabrication method that combines blade-coating, in place of spin-coating, and evaporation techniques.
This scalable hybrid approach, claim the researchers, offers a promising pathway toward large-scale manufacturing of high-efficiency perovskite-silicon tandem solar cells.
To achieve the 27.8% efficiency, the team combined evaporation and blade-coating to deposit perovskite solar cells onto silicon bottom cells. The inorganic components of the perovskite absorber were first evaporated with a wet-chemical process step, followed by blade-coating of the organic components.
In the process, they found that the coating speed in the hybrid evaporation/blade-coating process does not impact the perovskite thickness, which is the case in one-step blade-coated perovskites. Along with the efficiency level reached, the scientists demonstrated fully textured perovskite silicon tandem solar cells with open-circuit voltages exceeding 1,900 mV.
“Spin-coating is great as a lab technique as it is very flexible and allows for rapid testing of new materials, additives and process parameters. For large scale production it is however not suitable”, explained the Group Lead on Perovskite Materials and Interfaces at Fraunhofer ISE, Dr. Juliane Borchert. “We also expect that the learnings about the dynamics during blade-coating can be transferred to slot-die-coating which is even more suitable for scaling.”
The researchers admit that perovskite-silicon solar cells currently have reached over 33% efficiency, but add that this remains at the lab level. Their large-scale production remains challenging. In January 2025, JinkoSolar claimed a new record of achieving 33.84% perovskite-silicon tandem solar cell efficiency (see JinkoSolar Claims 33.84% Perovskite Tandem Solar Cell Efficiency).
Doctoral Student and Project Lead at Fraunhofer ISE, Oussama Er-Raji stressed that the team’s hybrid route opens a path to the industrial production of perovskite tandem solar cells.
