Researchers from Germany have constructed a full-sized tandem photovoltaic module which, according to the study, has a higher theoretical maximum efficiency than standard PV modules.

The module was developed by researchers at the Fraunhofer Institute for Solar Energy Systems (ISE) and Oxford PV. It uses tandem cell technology, stacking an ultra thin perovskite cell over a standard silicon solar cell. It has a maximum efficiency of over 40% compared with standard silicon modules, which can only reach a maximum efficiency of 30%.

The tandem cells were produced by Oxford PV in M6 format at its factory in Brandenburg, Germany. Perovskite, a lightweight, low-cost compound can absorb short wavelengths of light that silicone cells cannot, converting more sunlight into electricity.

“This new world record is a crucial milestone for Oxford PV, proving that our tandem solar cells can deliver record-breaking performance when assembled into solar panels,” says David Ward, chief executive officer.

The glass-glass panel developed by the Fraunhofer ISE team is 1,68 sqm and has an output of 421 W and claims to be “the world’s most efficient perovskite tandem solar module in industrial format”.

Researchers used and adapted equipment that is already available in mass production in order to avoid expensive adaptations, says professor Stefan Glunz, head of Photovoltaics at Fraunhofer ISE. “The fact that mass production-compatible technology was used for its manufacture demonstrates the enormous potential of tandem technology for the PV industry.”

Commercial production of the tandem solar cells will begin later this year. The team is currently undergoing extensive long-term stability tests on the module, in an effort to obtain certification.