Researchers at the Germany-based Helmholtz Center Berlin (HZB) have announced a thin-film solar cell made of perovskite and copper-indium-gallium-selenide (CIGS) with an efficiency of 21.6%.

The HZB researchers said they used a simple, robust production process suitable for scaling up. Rutger Schlatmann, director of the HZB’s Institute PVcomB, spoke of an “enormous step in the direction of commercial production”. The HZB team’s tandem cell could theoretically reach an efficiency of more than 30%, according to the researchers.

The HZB team applied an ultra-thin, conformal intermediate layer to the CIGS layer, then spun-coated the perovskite layer onto it at the HZB’s HySPRINT lab. In cooperation with the Eindhoven University of Technology, the HZB researchers realized their tandem cell on an area of ​​0.8 cm².

“Record values are only recognized for areas of 1 cm² or more, yet our cell area is just slightly below this threshold,” said Steve Albrecht, co-author of a paper about the research. “Therefore, we now focus [on certifying] this tandem solar cell efficiency and its enormous performance, [through] an independent institution.”