The six-junction solar cell designed by NREL scientists is claimed to hold the world record for the highest solar conversion efficiency at 47.1%


John Geisz (left) and Ryan France fabricated a solar cell that is nearly 50% efficient. (Credit: Dennis Schroeder, NREL)

Scientists at the National Renewable Energy Laboratory (NREL) have fabricated a new solar cell with an efficiency of nearly 50%.

The six-junction solar cell designed by the scientists is touted to have the highest solar conversion efficiency at 47.1%, measuring under concentrated lighting.

A variation of the same cell has also recorded an efficiency of 39.2% under one-sun illumination.

NREL scientists used III-V materials to construct the device

To construct the device, the NREL scientists John Geisz and Ryan France used III-V materials, which have a wide range of light absorption properties.

The NREL scientists have designed each of the solar cell’s six junctions to capture light from specific part of the solar spectrum. The device has nearly 140 total layers of several III-V materials to support the performance to these junctions.

Due to such high efficient nature and the costs associated with making them, the III-V solar cells are mostly used to power satellites.

However on Earth, the six-junction solar cell is well-suited in concentrator photovoltaics, said said Ryan France, co-author and a scientist in the III-V Multijunctions Group at NREL.

NREL High-Efficiency Crystalline Photovoltaics Group principal scientist and lead author of a new paper on the record-setting cell John Geisz said: “This device really demonstrates the extraordinary potential of multijunction solar cells.

The paper appearing in the journal Nature Energy is titled, ‘Six-junction III-V solar cells with 47.1% conversion efficiency under 143 suns concentration.’

Geisz’s co-authors are NREL scientists Ryan France, Kevin Schulte, Myles Steiner, Andrew Norman, Harvey Guthrey, Matthew Young, Tao Song and Thomas Moriarty.

Ryan France said: “One way to reduce cost is to reduce the required area, and you can do that by using a mirror to capture the light and focus the light down to a point. Then you can get away with a hundredth or even a thousandth of the material, compared to a flat-plate silicon cell.

“You use a lot less semiconductor material by concentrating the light. An additional advantage is that the efficiency goes up as you concentrate the light.”