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Q Cells/HZB:

Record efficiency of 28.7% for perovskite-silicon tandem solar cell

Q Cells’ R&D team in Thalheim, Germany, has worked jointly with Helmholtz-Zentrum Berlin over the past three years to create a tandem solar cell comprising a silicon-based Q.antum  bottom cell and a perovskite-based top cell. This latest record efficiency result of 28.7% is an improvement of almost one percentage point compared with the 2020 record value of 27.8% (which was independently verified by the Fraunhofer ISE Callab).

This boost in tandem efficiency has been enabled by improvement of both the perovskite and the silicon sub cells.  The research and development was partly funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) and the state of Saxony-Anhalt.

While the solar research community has witnessed even higher perovskite-tandem cell efficiencies, these records have been achieved using lab technology that is not directly transferrable into mass production. The achievement of Q Cells and Helmholtz-Zentrum Berlin is noteworthy principally because the 28.7% efficiency was reached using an industry feasible and cost-efficient bottom cell structure based on the Q.antum technology.

Commercialization of perovskite-silicon tandem technology. 

In the past year, Q Cells announced that it is to boost its R&D investment in Germany to €125 million over the next three years. A sizeable portion of that figure is earmarked for the continuous support of Q Cells’ R&D department on the commercialization of perovskite-silicon tandem technology. 

“Our experts have achieved several world records for tandem cells combining perovskite top cells with other bottom cells on a laboratory scale. We promote knowledge and technology transfer and welcome the fruitful collaboration with Q Cells. It is remarkable how close the jointly achieved efficiency with a mass production ready bottom cell already comes to what we can reach at a lab scale”, Prof. Bernd Rech, scientific director of HZB said. 

Also interesting: Perovskite solar cells in a marbled look

Prof. Dr. Steve Albrecht, group leader at HZB and Junior professor at Technische Universität Berlin added: “It is highly exciting that we enable this high tandem efficiency utilizing industry relevant bottom cells with a high market share, so there might be fast impact of the tandem technology to revolutionize the PV market.”

Close collaboration

Dr. Daniel Jeong, CTO of Q Cells, said: “Q Cells is excited to announce this joint new world-record in tandem cell efficiency together with Helmholtz-Zentrum Berlin. Both teams of researchers have collaborated closely to develop a tandem cell technology, which would be able to accelerate the commercialization process and, ultimately, deliver to the industry a genuine leap forward in photovoltaic performance. Q Cells is confident that it can once again shape the next-generation of solar cells, and will continue to invest heavily in supporting research and development in this field.” (hcn)

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