Clean Power

Published on January 25th, 2017 | by Tina Casey

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Holy Hot Polarons, Batman! New Perovskite Solar Cell Shows Promise

January 25th, 2017 by  

Forget everything you know about solar cells and check this out. A research team based at the University of Göttingen in Germany has come up with something they call an “entirely new” way to harvest energy from sunlight. In effect, the new solar cell puts the brakes on excited electrons, extending their lifetime. The result is a more efficient solar cell, with less energy lost in the form of heat and more energy converted to electricity.

To ice the cake, the new solar cell is based on one of CleanTechnica’s favorite materials, a class of synthetic crystalline materials called perovskites.

An “Entirely New” Way To Harvest Solar Energy

To be clear, the new solar cell is a long way from reaching your rooftop, unless the temperature in your area routinely hits -35 degrees Celsius. The research team has only achieved the effect at that super-cold temperature, so the next steps include turning up the heat to a more temperate range.

The solar cell is described as “entirely new” in the press materials, and that depends on what your definition of “entirely” and “new” is. Perovskite solar cells are not entirely new. The new angle is the perovskite structure that the team was able to define, which revealed new insights about the way materials convert solar energy to an electrical current.

That new structure could form the basis of a simple, solid-state solar cell that lends itself to low cost, high volume manufacturing.

You can get all the details online at the journal — no paywall! — Advanced Energy Materials under the title, “Evolution of Hot Polaron States with a Nanosecond Lifetime in a Manganite Perovskite.

The gist of it is that the team was able to use the latest ultra-precise analytical equipment to confirm that in its chilled state, a solar cell based on manganite perovskite forms a specific crystalline structure that “traps” excited polarons (loosely speaking, polaron refers to the way atoms and electrons interact).

Here’s what that looks like:

Here’s the explainer from main author Dirk Raiser of the Max Planck Institute for Biophysical Chemistry in Göttingen:

In conventional solar cells, the interaction between the electrons and the lattice vibrations can lead to unwanted losses, causing substantial problems, whereas the polaron excitations in the perovskite solar cell can be created with a fractal structure at certain operating temperatures and last long enough for a pronounced photovoltaic effect to occur.

Got all that?

Moving forward, the trick will be to replicate that same structure at warmer temperatures. The team is also looking into ways to achieve the same effect by strategically introducing additional light.

Meanwhile, Over Here In The US…

CleanTechnica is happy to bring you clean tech news from all over the world, but it looks like we may have to skip over the entire US Department of Energy and its network of legendary national laboratories for the time being (Berkeley Lab is one of our favorites, btw).

The US Department of Defense also has a network of labs engaged in clean tech and we may not have much to say about those for the foreseeable future, too.

That’s because the newly inaugurated President Trump has been clamping down on communications from various federal agencies, and Congress is on the way to providing him with a budget that makes steep cuts in the Energy Department and elsewhere.

If you’re a US citizen and that matters to you, call your representatives in the House and Senate. (the links go to government lookup sites if you don’t know who your reps are). If they are Republicans, you can assume they support the President’s energy policies. If they are Democrats, call them anyways and let them know you support clean tech research.

While we’re on the topic of President Trump, the crowd at the Women’s March On Washington was easily twice the size of the crowd that turned out for Inauguration Day. Size matters!

Actually, any size matters. Here’s the viewpoint from the University of Denver’s Erica Chenoweth, a professor who studies nonviolent protest and is compiling a database of the march and affiliated actions (cited in The Atlantic):

“It’s a really empowering thing to be noticed and to be tallied,” she said. “That actually came to be much more evident to me when people started emailing us and tweeting at us, reporting that they had two, five, seven, 12 people in their tiny outpost.”

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Images (solar cell photo is cropped): via University of Göttingen.


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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



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