MIT unveils Solar Leaf device

Solar device can be made of low cost materialsResearch at the Massachusetts Institute of Technology (MIT) has resulted in the development of an artificial leaf that mimics photosynthesis, which converts sunlight and water into usable energy. The device represents a new type of solar cell, which uses inexpensive materials like nickel and cobalt as catalysts.

The research, led by MIT Professor Daniel Nocera, Ph.D., was presented at the 241st National Meeting of the American Chemical Society on March 27. The device is about 10 times more efficient at photosynthesis. That’s equivalent to about 5.5 percent conversion efficiency, and there’s room for improvement.

“We can get it up to 8 percent without too much trouble. This should be good enough to make commercialization a viable option,” Nocera said.

The catalysts in the solar leaf, nickel and cobalt, split water into hydrogen and oxygen, which can be used in a fuel cell to provide electricity.

“It is a little different than an electrolyzer, which takes the "wired" current to split water,” Nocera said. “Here, this practical leaf takes the wireless current, generated from silicon upon solar irradiation, directly to a fuel.”

The catalyst materials are inexpensive and readily available materials that aren’t hazardous, unlike other forms of photovoltaics, which rely on more expensive materials like gallium and selenium, or other materials like cadmium, which is hazardous when not handled properly.

The device Nocera and his team have developed is highly stable, according to an American Chemical Society press release.

“In laboratory studies, he showed that an artificial leaf prototype could operate continuously for at least 45 hours without a drop in activity,” according to the release.

That’s the maximum time the device has been continuously tested, said Nocera.

The leaf could be used as an inexpensive electricity source in the homes of the poor in developing countries, Nocera said in a press release. “Our goal is to make each home its own power station,” he said.

When placed in a gallon of water, the device could produce enough electricity to power a home in a developing nation for a day.

“One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology,” Nocera said.

While not yet quite ready for commercialization, Nocera founded SunCatalytix to bring the device to market. The company is backed by Polaris Venture Partners and completed a $9.5 million funding round in October 2010.

Other places, like the California Institute of Technology, are also working on this type of device. Cal Tech partnered with the U.S. Department of Energy's Lawrence Berkeley National Laboratory to create The Joint Center for Artificial Photosynthesis (JCAP).

Pictured: Professor Daniel Nocera, courtesy of MIT.