New nanoparticle may make clunky solar panels obsolete

June 10, 2014 by  
Filed under Solar Energy Tips

Researchers at the University of Toronto have designed and tested a new class of nanoparticle that more efficiently converts sunlight to electricity, even when exposed to air.

According to a statement from the University, these solid, stable, light-sensitive nanoparticles, called colloidal quantum dots, could lead to cheaper and more flexible solar cells. The work, led by post-doctoral researcher Zhijun Ning and Professor Ted Sargent, was published this week in Nature Materials.

Just three months ago, Sargent and his group published research showing a way to “tune” quantum dots to better convert infrared solar energy to electricity. This new research shows a way to improve quantum dots’ performance in the presence of air, making them much easier to work with on a practical level.

Collecting sunlight using these tiny colloidal quantum dots requires layers of two types of semiconductor materials: n-type, which are rich in electrons; and p-type, which are poor in electrons. The problem? When exposed to the air, n-type materials bind to oxygen atoms, give up their electrons, and turn into p-type. Ning and colleagues demonstrated a new colloidal quantum dot n-type material that does not bind to oxygen when exposed to air.

The new material achieved solar power conversion efficiency up to eight percent—among the best results reported to date.

On top of this high efficiency, the researchers said, the material opens up a world of new optoelectronic devices, including more sophisticated weather satellites, remote controllers, satellite communication, or pollution detectors.

The powerful little dots could also be mixed into inks and painted or printed onto thin, flexible surfaces, such as roofing shingles, dramatically lowering the cost and accessibility of solar power for millions of people.

“The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency,” said Sargent. “The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels.”

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