Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Graphene electrodes for organic solar cells

The structure of graphene, a flexible material made of carbon atoms arranged in a layer just one atom thick, is represented in this diagram. Graphic: Christine Daniloff
The structure of graphene, a flexible material made of carbon atoms arranged in a layer just one atom thick, is represented in this diagram. Graphic: Christine Daniloff

Abstract:
Researchers identify technique that could make a new kind of solar photovoltaic panel practical.

By David L. Chandler, MIT News Office

Graphene electrodes for organic solar cells

Cambridge, MA | Posted on January 7th, 2011

A promising approach for making solar cells that are inexpensive, lightweight and flexible is to use organic (that is, carbon-containing) compounds instead of expensive, highly purified silicon. But one stubborn problem has slowed the development of such cells: Researchers have had a hard time coming up with appropriate materials for the electrodes to carry the current to and from the cells. Specifically, it has been hard to make electrodes using materials that can match the organic cells' flexibility, transparency and low cost.

The standard material used so far for these electrodes is indium-tin-oxide, or ITO. But indium is expensive and relatively rare, so the search has been on for a suitable replacement. Now, a team of MIT researchers has come up with a practical way of using a possible substitute made from inexpensive and ubiquitous carbon. The proposed material is graphene, a form of carbon in which the atoms form a flat sheet just one atom thick, arranged in a chicken-wire-like formation.

An analysis of how to use graphene as an electrode for such solar cells was published on Dec. 17 in the journal Nanotechnology, in a paper by MIT professors Jing Kong and Vladimir Bulović along with two of their students and a postdoctoral researcher.

Graphene is transparent, so that electrodes made from it can be applied to the transparent organic solar cells without blocking any of the incoming light. In addition, it is flexible, like the organic solar cells themselves, so it could be part of installations that require the panel to follow the contours of a structure, such as a patterned roof. ITO, by contrast, is stiff and brittle.

The biggest problem with getting graphene to work as an electrode for organic solar cells has been getting the material to adhere to the panel. Graphene repels water, so typical procedures for producing an electrode on the surface by depositing the material from a solution won't work.

The team tried a variety of approaches to alter the surface properties of the cell or to use solutions other than water to deposit the carbon on the surface, but none of these performed well, Kong says. But then they found that "doping" the surface — that is, introducing a set of impurities into the surface — changed the way it behaved, and allowed the graphene to bond tightly. As a bonus, it turned out the doping also improved the material's electrical conductivity.

While the specific characteristics of the graphene electrode differ from those of the ITO it would replace, its overall performance in a solar cell is very similar, Kong says. And the flexibility and light weight of organic solar cells with graphene electrodes could open up a variety of different applications that would not be possible with today's conventional silicon-based solar panels, she says. For example, because of their transparency they could be applied directly to windows without blocking the view, and they could be applied to irregular wall or rooftop surfaces. In addition, they could be stacked on top of other solar panels, increasing the amount of power generated from a given area. And they could even be folded or rolled up for easy transportation.

While this research looked at how to adapt graphene to replace one of the two electrodes on a solar panel, Kong and her co-workers are now trying to adapt it to the other electrode as well. In addition, widespread use of this technology will require new techniques for large-scale manufacturing of graphene — an area of very active research. The ongoing work has been funded by the Eni-MIT Alliance Solar Frontiers Center and an NSF research fellowship.

Peter Peumans, an assistant professor of electrical engineering at Stanford University, who was not involved in this study, says organic solar cells will probably become practical only with the development of transparent electrode technology that is both cheaper and more robust than conventional metal oxides. Other materials are being studied as possible substitutes, he says, but this work represents "very important progress" toward making graphene a credible replacement transparent electrode.

"Other groups had already shown that graphene exhibits good combinations of transparency and sheet resistance, but no one was able to achieve a performance with graphene electrodes that matches that of devices on conventional metal oxide (ITO) electrodes," Peumans says. "This work is a substantial push toward making graphene a leading candidate."

####

For more information, please click here

Copyright © Massachusetts Institute of Technology

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

Eric Berger Wins the National Space Society's 2017 Space Pioneer Award for Mass Media January 19th, 2017

Nanometrics to Announce Fourth Quarter and Full Year Financial Results on February 7, 2017 January 19th, 2017

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Strength of hair inspires new materials for body armor January 18th, 2017

Govt.-Legislation/Regulation/Funding/Policy

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Strength of hair inspires new materials for body armor January 18th, 2017

Self-assembling particles brighten future of LED lighting January 18th, 2017

Nanoscale view of energy storage January 16th, 2017

Academic/Education

Oxford Nanoimaging report on how the Nanoimager, a desktop microscope delivering single molecule, super-resolution performance, is being applied at the MRC Centre for Molecular Bacteriology & Infection November 22nd, 2016

The University of Applied Sciences in Upper Austria uses Deben tensile stages as an integral part of their computed tomography research and testing facility October 18th, 2016

Enterprise In Space Partners with Sketchfab and 3D Hubs for NewSpace Education October 13th, 2016

New Agricultural Research Center Debuts at UCF October 12th, 2016

Nanotubes/Buckyballs/Fullerenes

Captured on video: DNA nanotubes build a bridge between 2 molecular posts: Research may lead to new lines of direct communication with cells January 9th, 2017

Nano-chimneys can cool circuits: Rice University scientists calculate tweaks to graphene would form phonon-friendly cones January 4th, 2017

WPI researchers build liquid biopsy chip that detects metastatic cancer cells in blood December 15th, 2016

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Discoveries

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Strength of hair inspires new materials for body armor January 18th, 2017

Self-assembling particles brighten future of LED lighting January 18th, 2017

Dressing a metal in various colors: DGIST research developed a technology to coat metal with several nanometers of semiconducting materials January 17th, 2017

Announcements

Eric Berger Wins the National Space Society's 2017 Space Pioneer Award for Mass Media January 19th, 2017

Nanometrics to Announce Fourth Quarter and Full Year Financial Results on February 7, 2017 January 19th, 2017

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Strength of hair inspires new materials for body armor January 18th, 2017

Energy

Dressing a metal in various colors: DGIST research developed a technology to coat metal with several nanometers of semiconducting materials January 17th, 2017

Stability challenge in perovskite solar cell technology: New research reveals intrinsic instability issues of iodine-containing perovskite solar cells December 26th, 2016

Nanoscale 'conversations' create complex, multi-layered structures: New technique leverages controlled interactions across surfaces to create self-assembled materials with unprecedented complexity December 22nd, 2016

Safe and inexpensive hydrogen production as a future energy source: Osaka University researchers develop efficient 'green' hydrogen production system that operates at room temperature in air December 21st, 2016

Solar/Photovoltaic

Dressing a metal in various colors: DGIST research developed a technology to coat metal with several nanometers of semiconducting materials January 17th, 2017

Stability challenge in perovskite solar cell technology: New research reveals intrinsic instability issues of iodine-containing perovskite solar cells December 26th, 2016

Going green with nanotechnology December 21st, 2016

Research Study: MetaSOLTM Shatters Solar Panel Efficiency Forecasts with Innovative New Coating: Coating Provides 1.2 Percent Absolute Enhancement to Triple Junction Solar Cells December 2nd, 2016

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