Clean Power

Published on March 8th, 2013 | by James Ayre


Significantly More Efficient Solar Cells Thanks To New Technique

March 8th, 2013 by  

Significant improvements to solar cell efficiency are now possible because of a new technique created by researchers at the University of Toronto.

solar cell efficiency boost

The new technique greatly improves the efficiency of colloidal quantum dot photovoltaics, which is a design that was already looking attractive as a path to cheap, very efficient solar cells. Previously, though, these quantum dot photovoltaics were not very efficient in the infrared portion of the solar spectrum. Infrared makes up about half of the Sun’s energy that reaches the Earth, so it’s important to harvest this, for maximum efficiency.

But now, the new technique is able to address this, through the creation of spectrally tuned, solution-processed plasmonic nanoparticles. These modified particles allow for a greatly increased degree of control over light’s “propagation and absorption.”

“The new technique developed by Ted Sargent’s group shows a possible 35 per cent increase in the technology’s efficiency in the near-infrared spectral region,” states co-author Dr. Susanna Thon. “Overall, this could translate to an 11 per cent solar power conversion efficiency increase, making quantum dot photovoltaics even more attractive as an alternative to current solar cell technologies.”

“There are two advantages to colloidal quantum dots,” Thon says. “First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum. Changing the size is very easy, and this size-tunability is a property shared by plasmonic materials: by changing the size of the plasmonic particles, we were able to overlap the absorption and scattering spectra of these two key classes of nanomaterials.”

The technique is based around the use of gold nanoshells embedded directly into the quantum dot absorber film. Gold isn’t cheap, though, so the researchers are currently working to find cheaper metals to replace gold, something that they say shouldn’t be difficult.

The new research paper, titled “Jointly-tuned plasmonic-excitonic photovoltaics using nanoshells,” was just published in the journal Nano Letters.

Source: University of Toronto Faculty of Applied Science and Engineering
Image Credit: University of Toronto

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About the Author

'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. You can follow his work on Google+.

  • mds

    Love your quote at the bottom, most of your articles too. Hope you’ll forgive me, I’ve memorized the quote.
    I have to make a minor complaint here. I don’t like it when articles quote an improvement in efficiency without stating what the starting point efficiency you’re referring to. It makes the improvement information meaningless. Solar PV efficiencies range from a few percent to 44% depending on materials/technology you’re talking about. I think that’s Roger’s complaint as well.

    • Hmm, good point. We do that *all the time* — probably in 4/5 or 9/10 articles about efficiency records. Have to keep that in mind.

  • Lowe

    I’m not convince, it will never make mass production .

    • mds

      Based on what exactly?

  • Roger

    That’s nice, but how will this translate on the BRCE chart?

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