Experimental solar cells made with two types of pure carbon absorb infrared sunlight that traditional silicon panels ignore and may eventually be used to improve efficiency, according to researchers at the Massachusetts Institute of Technology.
MIT scientists used nanotubes and spherical molecules known as buckyballs to make the first all-carbon photovoltaic cell, the Cambridge, Massachusetts-based university said today in an e-mailed statement.
Infrared light makes up about 40 percent of the solar radiation that hits the earth. Solar cells that absorb that energy may produce more electricity than conventional panels that don’t, according to Michael Strano, a professor of chemical engineering at MIT.
“It’s a fundamentally new kind of photovoltaic cell,” Strano said. “If you could harness even a portion of the near-infrared spectrum, it adds value.” The findings were published this week in the journal Advanced Materials.
The most efficient cells in production today convert about 20 percent of the energy in sunlight into electricity. Boosting the efficiency of traditional solar power panels has helped lower costs to below that of diesel generators in many regions.
More work on the carbon cells is needed to improve their conversion rate to greater than than the 0.1 percent the team at MIT produced, said Rishabh Jain, a graduate student and lead author of the journal article.
“We are very much on the path to making very high-efficiency, near-infrared solar cells,” he said in the statement. “It’s pretty clear to us the kinds of things that need to happen to increase the efficiency,” including more precise control of the shape and thickness of the carbon layers.