Fraunhofer ISE CalLab Marks 40 Years With 152 Verified Solar Efficiency Records

The calibration laboratory at the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE), known as CalLab, has completed 40 years of testing and measuring solar technology. Established in 1986 to test solar cells, the laboratory expanded its work to photovoltaic modules in 1991. Since then, it has measured thousands of solar devices and played an important role in verifying advances in photovoltaic technology.

Over four decades, CalLab has officially confirmed 152 world efficiency records, including 86 records for solar cells and 66 for solar modules. Its work has covered the development of solar technology from conventional silicon devices to advanced tandem and multi-junction structures.

CalLab confirmed its first world efficiency record in 1992. The record was achieved by a small silicon solar module with an efficiency of 16.4%. Since then, improvements in cell materials, manufacturing processes and module design have significantly increased efficiency levels. In 2025, a silicon solar module developed by LONGi achieved an efficiency of 26.2%, setting a new world record for silicon module efficiency.

As conventional silicon technology approaches its physical efficiency limits, researchers are increasingly focusing on tandem and multi-junction solar cells. These technologies combine different semiconductor materials in multiple layers to capture a wider range of sunlight and improve conversion efficiency.

CalLab has upgraded its testing capabilities to measure these emerging technologies. In 2022, the laboratory verified a quadruple-junction solar cell that achieved an efficiency of 47.6%, marking the highest solar cell efficiency recorded at the time. More recently, CalLab confirmed a 34.4% efficiency record for a solar module developed by AZUR SPACE, temicon and Fraunhofer ISE. The result represents the highest efficiency reported for a solar module.

Measuring advanced technologies such as perovskite-silicon tandem cells requires specialized equipment and precise testing methods. CalLab uses advanced systems, including a multispectral solar simulator, to reproduce different parts of the solar spectrum and accurately assess device performance.

The laboratory also works with equipment manufacturers and international standards committees to improve measurement procedures. This cooperation helps establish consistent testing practices for emerging photovoltaic technologies.

Fraunhofer ISE has highlighted the importance of independent calibration laboratories in maintaining transparency in the global solar market. Accurate and traceable measurements allow manufacturers, researchers and investors to compare technologies on a consistent basis.

Through independent testing and calibration, CalLab continues to support technological development while helping ensure that efficiency claims made across the solar industry can be measured and trusted.