Berlin Scientists Set Solar Cell Efficiency Record

February 2023

32.5 percent – that’s the new world best mark for a tandem solar system converting incident solar radiation into energy.

The record was set in late 2022 by researchers at the solar-cell technology institute Helmholtz Zentrum Berlin (HZB) and confirmed by European Solar Test Installation in Italy. The HZB’s system is listed on US National Renewable Energy Lab’s Best Research-Cell Efficiency Chart .

Tandem solar cells split the spectrum of sunlight into segments and use a solar cell that is optimized to each section. The sections are then intelligently interfaced. The HZB’s cell consists of a silicon bottom cell and a perovskite top cell, a technology also being explored at other German research institutions.

“At 32.5 percent, the solar cell efficiency of the HZB tandems is now in ranges previously only achieved by expensive III/V semiconductors,” said HZB Scientific Director, Professor Bernd Rech, on the institute’s website.

Photo of the perovskite/silicon tandem solar cell. You can see the active bluish area in the middle of the wafer, which is enclosed by the metallic, silvery electrode. © Johannes Beckedahl/Lea Zimmerman/HZB