A new world record has been set for solar cell efficiency, or so we are told by researchers at the Fraunhofer Institute for Solar Energy Systems, Germany. They have revealed a triple-junction cell that has a conversion efficiency of 41.1% (press release).

Solar cell efficiencies are notoriously hard to pin down. Claims are often made, but not considered ‘official’ until they are independently verified by a recognised body. A quick search online, for example led me to a claim from a consortium that includes the University of Delaware of a cell with 42.8 % efficiency.

So what’s the real answer? And do these incremental advances mean anything?

The answer is complicated. There is no doubt that more efficient solar cells are needed, and research into them is vital. But the type of device we’re talking about here is way too pricey and made out of far too rare materials to ever see use in a widespread commercial market. Gallium, indium and arsenic were used in this latest device, none of which are cheap or in plentiful supply.

I turned to a paper by Martin Green from the ARC photovoltaics centre of excellence at the University of New South Wales, Sydney, Australia. He has taken it upon himself to chart the numerous different efficiency records in the solar power world that exist and what the latest record is for each (paper). As far as I could see, the best multijunction cell so far, according to Green, was reported last year and tested at the US’s National Renewable Energy Laboratory. It had an efficiency of 40.8%. So, if the Fraunhofer’s cell is verified, they are right to claim the world record! Well done!

Image: Fraunhofer ISE