Posted: November 21, 2008

Nobel Prize winner Heeger sheds light on solar technology progress

(Nanowerk News) The next generation of solar panels promises to be less conspicuous and expensive, but the technology still needs to be made more efficient, said Prof. Alan Heeger, winner of the 2000 Nobel Prize in Chemistry, during a lecture Thursday.
Heeger, a professor of physics at the University of California, Santa Barbara, said there is still much work to be done. Solar panels are currently expensive to install, Heeger said, and they may take more than 12 years to pay for themselves.
"That is far too long to wait," said Heeger, addressing more than 600 professors and graduate students at the Hotel Orrington. "Some people don't even live in their homes for that long."
Heeger headlined Northwestern's 2008 International Institute for Nanotechnology Symposium, which featured lectures from eight researchers, each of whom spoke about their research in a specific nanotechnology field.
"Northwestern is building a major presence in energy-related research," said Professor Chad Mirkin, the director of the International Institute for Nanotechnology. "It's important to bring the world's best and brightest here, where we can gauge where we are today and where we need to go tomorrow."
Heeger's presentation discussed the prospect of perfecting the second generation of solar panels, which employ "electronic inks" that can be "printed" onto thin sheets of film. Pulling out a square foot scroll, Heeger showed a sample of a lightweight, flexible solar cell, which bears little resemblance to the conspicuous black reflective panels that some homeowners decide to mount to their roofs.
However, the sample panel could only output a paltry two watts of electricity.
"We have to improve the efficiency (of these solar cells)," said Heeger. "But we've got a basic platform that we understand."
Heeger went on to mention that the new generation of solar cells is commercially available through a company he co-founded, Konarka Technologies, which sells solar cell sheets that span up to two meters wide and are capable of outputting significantly more electricity.
A main problem that plagues the new solar cells and that Heeger is working to circumvent is their inability to make use of all wavelengths of sunlight: ultraviolet, visible and infrared light; visible light is the only light that can be seen with the human eye. The current generation of solar panels is silicon-based and converts nearly all sunlight it comes in contact with into electricity, giving it high efficiency. The new solar cells, which are made up of carbon-based polymers, have trouble absorbing the infrared light and are not as efficient at harvesting sunlight.
Heeger's plastic solar cells, however, do have their advantages. Because they are much smaller, space can be better utilized.
"Every square meter of sunlight gives us a kilowatt of energy," he said. "The sun is a fantastic source of energy - every hour, we receive sufficient energy to satisfy all energy use by the earth for a year."
Many fellow researchers shared Heeger's view that solar power needs to be adopted quickly.
"It's a shame gas prices have dropped," said Mark Watson, a synthetic chemist at the University of Kentucky. "Americans aren't going to change a thing unless it hurts."
Once the technology is perfected, Heeger said solar energy might be able to become a ubiquitous - and nearly invisible - part of everyday life.
"Take Chicago, for example - you see these huge buildings with double-paned glass everywhere," Heeger said. "In that glass, there should be a semi-transparent thin-film solar cell. All that area is usable. That's the next generation of solar cells, it's going to happen," he said.
Source: The Daily Northwestern (Ganesh Thippeswamy)
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