Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

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

Iranian Researchers Planning to Produce Edible Insulin January 28th, 2015

Nanoparticles that deliver oligonucleotide drugs into cells described in Nucleic Acid Therapeutics January 28th, 2015

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Spider electro-combs its sticky nano-filaments January 28th, 2015

Govt.-Legislation/Regulation/Funding/Policy

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Researchers Make Magnetic Graphene: UC Riverside research could lead to new multi-functional electronic devices January 27th, 2015

New pathway to valleytronics January 27th, 2015

Nanoshuttle wear and tear: It's the mileage, not the age January 26th, 2015

Academic/Education

Rice's Naomi Halas to direct Smalley Institute: Optics pioneer will lead Rice's multidisciplinary science institute January 15th, 2015

SUNY Board Appoints Dr. Alain Kaloyeros as Founding President of SUNY Polytechnic Institute January 13th, 2015

CNSE's Smart System Technology & Commercialization Center Successfully Recertifies as ISO 9001:2008 January 12th, 2015

SUNY Poly Now Accepting Applications to the Colleges of Nanoscale Science and Engineering for Fall 2015: Full Scholarships Available to Incoming CNSE Students January 7th, 2015

Nanotubes/Buckyballs

Chromium-centered cycloparaphenylene rings for making functionalized nanocarbons January 26th, 2015

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

Carbon nanotube finding could lead to flexible electronics with longer battery life January 14th, 2015

Discoveries

Iranian Researchers Planning to Produce Edible Insulin January 28th, 2015

Nanoparticles that deliver oligonucleotide drugs into cells described in Nucleic Acid Therapeutics January 28th, 2015

Spider electro-combs its sticky nano-filaments January 28th, 2015

Stomach acid-powered micromotors get their first test in a living animal January 27th, 2015

Announcements

Iranian Researchers Planning to Produce Edible Insulin January 28th, 2015

Nanoparticles that deliver oligonucleotide drugs into cells described in Nucleic Acid Therapeutics January 28th, 2015

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Spider electro-combs its sticky nano-filaments January 28th, 2015

Energy

Carbon nanoballs can greatly contribute to sustainable energy supply January 27th, 2015

Visualizing interacting electrons in a molecule: Scientists at Aalto University and the University of Zurich have succeeded in directly imaging how electrons interact within a single molecule January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Solar/Photovoltaic

Visualizing interacting electrons in a molecule: Scientists at Aalto University and the University of Zurich have succeeded in directly imaging how electrons interact within a single molecule January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

New technique helps probe performance of organic solar cell materials January 23rd, 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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE