Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Carbon nanotubes may cheaply harvest sunlight

Michael Arnold
Michael Arnold

Abstract:
University of Wisconsin-Madison researchers are studying how to create inexpensive, efficient solar cells from carbon nanotubes, which are sheets of carbon rolled into seamless cylinders 1-nanometer in diameter. Many researchers are studying how to use nanotubes for mechanical and electronics applications, but Materials Science and Engineering Assistant Professor Michael Arnold is one of the first to apply them to solar energy.

Carbon nanotubes may cheaply harvest sunlight

Madison, WI | Posted on October 20th, 2009

"We are developing new materials and methods to create scalable, inexpensive, stable and efficient photovoltaic solar cell technologies," Arnold says. "Semiconducting carbon nanotubes have remarkable electronic and optical properties that are ideally suited for photovoltaics, so they are an interesting starting point."

Carbon is a promising choice for solar cells because it is an abundant, inexpensive element, and carbon nanotubes have excellent electrical conductivity and strong optical absorptivity. Most current solar cells use silicon, which converts 10 to 30 percent of sunlight absorbed into electricity. This is a good rate, but silicon cells are expensive.

"The cost is upfront for silicon cells, and the cost per kilowatt-hour is five times more than you'd pay for coal over 20 years that's not very motivating for people," says Arnold. With carbon nanotubes, he hopes to achieve efficiency comparable to silicon solar cells for less cost.

Arnold says solar is a valuable energy source since the sun outputs approximately 1,000 watts per square yard. A solar cell that is only 20 percent efficient would generate about 200 watts per square yard on a sunny day, so coating the roof of an average 40-square-yard house with solar cells would make a significant dent in the average energy needs of the household. To have an effect on the national electric grid, Arnold envisions expansive fields of solar cells built in desert regions.

"Solar is a viable technology for producing energy," Arnold says. "It's just too expensive right now."

To create the new carbon nanotube solar cells, Arnold and his students grow nanotube structures and then separate the useful semiconducting nanotubes from undesirable metallic ones. They also separate the tubes according to diameter, which determines a particular nanotube's bandgap, or wavelength of light the tube can absorb. Certain bandgaps are more suitable than others for absorbing sunlight.

After sorting out the useful nanotubes, the team wraps them in a semiconducting polymer to make the tubes soluble. They turn the combined nanotubes and polymer into a solution, which can be sprayed in a thin film onto transparent indium-tin-oxide coated glass substrates. The researchers then deposit an electron-accepting semiconductor and a negative electrode on top of the nanotubes to complete the entire cell.

In creating the new solar cells, Arnold, who is funded by the National Science Foundation, is attempting to answer a variety of fundamental science and research questions. He is studying how charge is generated in the nanotubes in response to light and how different electron-accepting materials affect the efficiency and speed of the separation of that charge.

"The driving question is, can we understand how to both process the tubes to get the morphology we want, and can we also learn how light creates charges in our carbon nanotube materials and how these charges separate?" he says.

####

For more information, please click here

Copyright © University of Wisconsin-Madison

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Controlling phase changes in solids: Controlling phase changes in solids July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

'Seeing' molecular interactions could give boost to organic electronics July 28th, 2015

Discoveries

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Controlling phase changes in solids: Controlling phase changes in solids July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

'Seeing' molecular interactions could give boost to organic electronics July 28th, 2015

Announcements

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Controlling phase changes in solids: Controlling phase changes in solids July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

'Seeing' molecular interactions could give boost to organic electronics July 28th, 2015

Energy

Smaller, faster, cheaper: A new type of modulator for the future of data transmission July 27th, 2015

Reshaping the solar spectrum to turn light to electricity: UC Riverside researchers find a way to use the infrared region of the sun's spectrum to make solar cells more efficient July 27th, 2015

Industrial Nanotech, Inc. Provides Update on PCAOB Audited Financials July 27th, 2015

Ultra-thin hollow nanocages could reduce platinum use in fuel cell electrodes July 24th, 2015

Solar/Photovoltaic

Reshaping the solar spectrum to turn light to electricity: UC Riverside researchers find a way to use the infrared region of the sun's spectrum to make solar cells more efficient July 27th, 2015

Rice University finding could lead to cheap, efficient metal-based solar cells: Plasmonics study suggests how to maximize production of 'hot electrons' July 22nd, 2015

Perovskite solar technology shows quick energy returns: New technology beats current solar panel technology in life-cycle energy assessment July 20th, 2015

Nanowires give 'solar fuel cell' efficiency a tenfold boost: Eindhoven researchers make important step towards a solar cell that generates hydrogen July 17th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project