Solar cell breaks world record for efficiency

Researchers at the National Renewable Energy Laboratory claim to have designed a solar cell with 40.8 percent efficiency, the world's most efficient yet.

Elsa Wenzel

Department of Energy researchers claimed Wednesday to have broken the world record for efficiency in a solar cell.

Their cell converted 40.8 percent of light into electricity at the National Renewable Energy Laboratory in Golden, Colo. They subjected the cell to the equivalent concentrated light of 326 suns.

Researchers grew the solar cell upside down on a wafer of gallium arsenide rather than thick germanium, and then removed the wafer.

The development could lead to flexible, lightweight solar cells used in land-bound, concentrated photovoltaics as well as in space satellites.

The previous record for photovoltaic efficiency was 40.7 percent. Scientist Mark Wanlass is credited for leading that design. A key innovation in those multi-junction solar cells was to space their atoms at uneven intervals. Researcher John Geisz led the team that expanded Wanlass' work to improve efficiency.