New ‘Spin’ On Organic Solar Cells To Up Power

Scientists really want to make organic solar cells work. They’ve even gone so far as to compile a database of 2.3 million materials that could be used in making them.

What’s exciting about these solar cells, made from semiconducting plastics, is that they can provide thin-film solar delivery systems that hold the promise of being far cheaper to produce than silicon (or other elements). The issue has been efficiency, which tends to be low.

Screen shot from Cambridge University video on organic solar research.

Screen from short Cambridge University video on this organic solar research.

So the latest insight – there have been others! – run up the organic-solar flagpole comes courtesy Cambridge University. A research team says that manipulating the “spin” of electrons in such solar cells “dramatically improves their performance, providing a vital breakthrough in the pursuit of cheap, high performing solar power technologies.”

What, you might ask, is “spin” in this context? According to Cambridge:

“Spin” is a property of particles related to their angular momentum, with electrons coming in two flavours, “spin-up” or “spin-down.” Electrons in solar cells can be lost through a process called “recombination,” where electrons lose their energy – or “excitation” state – and fall back into an empty state known as the “hole.”

The key to making organic solar cells more consistent and efficient, the researchers say, is to arrange the spin in a specific way, which can “block the energy collapse from ‘recombination’ and increase current.”

“This discovery is very exciting, as we can now harness spin physics to improve solar cells, something we had previously not thought possible. We should see new materials and solar cells that make use of this very soon,” Akshay Rao, a research fellow at the Cavendish Laboratory and Corpus Christi College, Cambridge, who led the study with colleagues Philip Chow and Dr. Simon Gélinas, said in a statement.

By boosting organic solar cell efficiency out of the low single digits (in the very best of circumstances; often it’s quite a bit lower), the researchers think it could become useful for use in light emitting diodes, “a new and rapidly growing display technology, allowing for more efficient displays in cell phones and TVs.”

This research was published in the journal Nature. The abstract is available online.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.

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