Apr 12, 2002
Researchers bend the rules for solar cells
Researchers at Virginia Tech in the US have used nanometre-thick layers of organic materials to make flexible solar cells. The team used ionic self-assembled multilayers of polymers and fullerene molecules.
"Organic solar cells can be flexible, so you could have deployable sails on a spacecraft, or fold your solar cell into your briefcase," said James Heflin, associate professor of physics at Virginia Tech. "Starting with a conducting polymer, which is a light emitter, we can apply a fullerene layer and produce electrical current from incident light."
The efficiency of organic solar cells is commonly only about one-fifth of that of silicon devices. "We believe we can improve the efficiency by five or 10 times through nanoscale control of the composition and thickness," said Heflin. "We expect organic solar cells will be at least as efficient as silicon within five years."
Nanotechnology helps with solar-cell efficiency by decreasing the distance between the material that acts as the electron donor and the material that accepts electrons. Adding a layer of electron-accepting fullerenes increases the polymer device's efficiency, although the fullerene must be within 10 nm of the light-adsorption site to create a current.
The Virginia Tech scientists presented their work at the 223rd national meeting of the American Chemical Society in Orlando, US, earlier this month.
About the author
Liz Kalaugher is editor of nanotechweb.org.