Can You Help Create the Next Great Solar Cell?

By Jonathan Marshall

Wouldn’t you love to help discover a breakthrough solar cell that could provide nearly unlimited clean energy? Don’t let the fact that you’ve forgotten your high school chemistry, or that your venture bank account is empty, get in the way of your dreams.

Organic Solar Cell Photo

Organic solar cells aren't as efficient as silcon cell – yet.

All you have to do is loan some of your idle computer time to the Harvard Clean Energy Project, and they’ll do the rest.

The project is harnessing the supercomputing power of IBM’s World Community Grid—a distributed computing network formed by more than half a million volunteers with shared research passions—to find the most promising materials for organic, rather than silicon, solar cells.

The same volunteer computing network is also putting 1.8 million computers to work to help fight cancer, find a cure for AIDS, and look for more effective ways to filter water for human consumption.

Doing chemistry by computer, rather than in the lab, can save years of time. Traditional techniques allow researchers to synthesize and screen only a few molecules a year. In contrast, the Harvard project is checking thousands of molecules a day for the characteristics that would make them promising candidates for high-efficiency solar cells.

“Roughly, every 12 hours of donated free [computing] time will result in a new molecule added to our database of candidate organic materials for solar cells,” Harvard’s Alán Aspuru-Guzik, one of the project’s leaders, told PhysOrg.com. “The database will aid scientists in accelerating the discovery of novel solar materials.”

The researchers, who include scientists from Haverford College and the Universidad Nacional Autonoma de Mexico, are focusing on organic compounds, which promise to be far cheaper to manufacture than traditional silicon or cadmium telluride cells. As they note in the Journal of Physical Chemistry Letters, organic cells can be mass produced by roll-to-roll printing, painting or spraying; molded to virtually any shape; and made colored or semitransparent.

Unfortunately, the best organic cells convert only 9 percent of the sun’s energy into electricity, half of what a really good silicon cell can do, and a third of the performance of more exotic cells.

But the Harvard group believes that if they can push the efficiency of organic cells up toward 15 percent, and extend their life to 10 years or more, they could deliver electricity more cheaply than most other sources. Many other research groups are working on this goal as well.

But discovering the right molecule out of literally billions of possibilities is akin to finding one needle in all the world’s haystacks. The Harvard group started by creating a set of 10 million candidate molecules. They are using algorithms borrowed from machine learning, pattern recognition and drug discovery to winnow them down, based on their predicted characteristics.

All this computer analysis will, in turn, help the scientists better understand what chemical types make the best candidates, so they can better target their search.

So far they’ve used more than 4,500 years of computer time to analyze about 2.6 million potential molecules. All their findings will be gathered in a giant database so future researchers can mine it for insights.

Consider signing up to help. Then the next time someone from your family asks to check Facebook or play World of Warcraft, just tell them to come back later. Right now your computer is busy running density functional theory calculations and Dyson orbital analyses that could revolutionize the world’s energy market.

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