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Published on January 15th, 2013 | by James Ayre

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Triple-Junction Solar Cell Being Developed By US Navy Is To Break Through The 50% Conversion Efficiency Barrier

January 15th, 2013 by  


Solar cells with a more than 50% conversion efficiency may be a reality in the near future, thanks to new research from the US Naval Research Laboratory’s Electronics Technology and Science Division.

triple junction solar cells record

Image Credits: US Naval Research Laboratory

The solution to the old efficiency barrier is a newly-designed, triple-junction solar cell that has the potential to greatly exceed 50% conversion efficiency.

“This research has produced a novel, realistically achievable, lattice-matched, multi-junction solar cell design with the potential to break the 50 percent power conversion efficiency mark under concentrated illumination,” said Robert Walters, Ph.D., Naval Research Laboratory research physicist. “At present, the world record triple-junction solar cell efficiency is 44 percent under concentration and it is generally accepted that a major technology breakthrough will be required for the efficiency of these cells to increase much further.”


 
A ‘multi-junction solar cell’, is essentially, a solar cell where each specialized ‘junction’ is designed to very efficiently absorb and use different wavelength bands in the solar spectrum. Theoretically, it’s possible to create an ‘infinite-junction’ solar cell that could reach conversion efficiencies as high as 87 percent. But to do that, it’s necessary to create a semiconductor material system that is able to “attain a wide range of bandgaps and be grown with high crystalline quality.”

The new breakthrough that the researchers have made, is the identification of “InAlAsSb” quaternary alloys, “a high band gap material layer that can be grown lattice-matched” to the already useful “InP.”

With the material, the researchers were able to create a new solar cell design that they think will lead to power conversion efficiencies over 50%.

While this sounds like a great breakthrough, there is still a lot to be done before this leads to actual improved efficiency solar cells. 
 





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About the Author

James Ayre's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy.



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