New solar cell sets world record, focusing the power of 297 suns

Breakthrough indicates scientists are well on their way to 50% efficiency roadmap, experts say

German and French researchers said Thursday that they have achieved a new world record on converting sunlight to energy through a photovoltaic, or solar cell.

The solar cell was able to collect energy at a 44.7% rate of efficiency, which was measured at a concentration of 297 suns.

photovoltaic cell
The world-record setting solar cell that boasts 44.7% efficiency contains four solar sub-cells.

The team of scientists from the Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Let and the Helmholtz Center Berlin jointly announced the "major breakthrough" with their new solar cell. The solar cell contains four solar sub cells and paves the way to achieving their 50% efficiency roadmap, the researchers said in a statement.

"Besides improved materials and optimization of the structure, a new procedure called wafer bonding plays a central role. With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells," Frank Dimroth, project leader in charge of the development work at Fraunhofer ISE, said in a statement.

The efficiency rating means the solar cell collects 44.7% of the sun's spectrum's energy, from ultraviolet to the infrared spectrum, which is converted into electrical energy.

"This world record increasing our efficiency level by more than 1 point in less than 4 months demonstrates the extreme potential of our four-junction solar cell design which relies on Soitec bonding techniques and expertise," Soitec CEO Andre-Jacques Auberton-Herve said in a statement.

The solar cells are made out of several cells using different "III-V" semiconductor materials that are stacked on top of each other. The single sub cells absorb different wavelength ranges of the solar spectrum.

The scientists said it took about three years of research to achieve record efficiency. The previous record was held by the U.S. National Renewable Energy Laboratory, which achieved 43.5% for solar cell conversion. That project was also able to use a focused lens to magnify light to 418 times the intensity of the sun.

Back in May 2013, the German-French team of Fraunhofer ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin had already announced a solar cell with 43.6% efficiency.

Solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants in sun-rich locations.

The new photovoltaic technology, known as III-V multi-junction solar cells, originally came from space technology and have continued to achieve the highest efficiencies for the conversion of sunlight to electricity.

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