Large sheets of graphene film produced for transparent electrodes (w/ Video)

Jun 21, 2010 by Lin Edwards report
The researchers built up a graphene layer on copper foil and then used rollers to transfer the graphene to a polymer support and then onto a final substrate. Image credit: Nature Nanotechnology. (doi:10.1038/nnano.2010.132)

(PhysOrg.com) -- Graphene is a relatively new material with outstanding electrical, chemical and mechanical properties that make it an attractive material for use as flexible conductors of the sort used in gadgets such as touch screens and flat panel TVs. In the past attempts to make large films of graphene have been unsuccessful, but now a team of scientists from South Korea and Japan have succeeded in roll-to-roll production of graphene films, growing them by chemical vapor deposition onto flexible copper substrates.

Graphene is composed of a single layer of carbon atoms in a honeycomb-shaped lattice. It was first isolated in 2004. The material is highly conductive, extremely strong, and is almost transparent, which makes it ideal for high-speed .

The researchers grew their graphene sheets by onto large sheets of copper foil. They coated the graphene with a thin layer of adhesive polymer and then dissolved away the copper backing. Using rollers, the graphene was then pressed against another substrate, such as PET, and the polymer layer was removed by heating, leaving a film of graphene. They repeated the process to produce a sheet of four layers of graphene on top of each other. This four-layer sheet was then treated with nitric acid to improve its .

High-resolution TEM images showing the folded edges of as-grown graphene films with different number of layers. Image credit: Nature Nanotechnology (doi:10.1038/nnano.2010.132)

The rectangular sheets, which measured 76 cm on the diagonal, were of extremely high quality, with the four-layer stack of films exhibiting superior electrical resistance to commercially available transparent electrodes such as indium tin oxides (ITO). The films were almost transparent, allowing 90% of light to pass through.

The team, led by researchers Byung Hee Hong and Jong-Hyun Ahn of Sungkyunkwan University (SKKU) in Seoul, also incorporated their graphene electrodes into a fully functional touch-screen panel, where they outperformed standard electrodes, withstanding double the strain that can be handled by the more fragile ITO. According to Ahn, a graphene-based touchscreen should essentially last forever.

This video is not supported by your browser at this time.
Operation movie for graphene-based touch screen panels. Credit: Sukang Bae et al., Nature, doi:10.1038/nnano.2010.132

Electronics companies have been looking for alternatives to ITO for some time because the indium is extremely expensive. Other options looked at have been films of carbon nanotubes, but these have not succeeded because they tend to have small defects that create visible areas of “dead” pixels in displays. Now that graphene has been manufactured in large sheets and demonstrated in real devices, it may only be a couple of years before graphene finds its way into consumer products.

is produced from a small amount of carbon, and unlike ITO production, uses no rare materials. The copper substrate is recyclable, which makes the process more sustainable.

The paper is published in the journal Nature Nanotechnology.

Explore further: Microfluidics and nanofluidics research provide inexpensive ways to analyze blood and filter water (w/ Video)

More information: Roll-to-roll production of 30-inch graphene films for transparent electrodes, Sukang Bae et al, Nature Nanotechnology advance online publication. Published online: 20 June 2010. doi:10.1038/nnano.2010.132

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User comments : 11

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TAz00
4 / 5 (2) Jun 21, 2010
Touchscreens!? Give us super batteries instead please
Alburton
5 / 5 (3) Jun 21, 2010
Laissez faire...you need to have experience with stuff in order to understand it better..
Plus,Electronics nowadays is as eco-unfriendly as any other industry:what doesnt work is thrown away.
What if we could make any e-device we wanted just out of carbon,with no toxic elements in it?
=) Wouldnt it be nice?
danlgarmstrong
5 / 5 (2) Jun 21, 2010
Forget batteries - super strong materials for the space elevator por favor!
labtvonline
5 / 5 (3) Jun 21, 2010
I've been hearing about graphene for sometime now and I glad to see it finally has come to be produced at a practical size. This material has a bright future and we will begin to see it many of our day to day activities!
Jigga
5 / 5 (1) Jun 21, 2010
Indium is strategic material, whose production is controlled by China. This replacement is of political importance. Of course, indium could be replaced with antimony as well - I'm not sure, whether the lifetime of graphene layers will be comparable.
Eikka
5 / 5 (2) Jun 21, 2010
Of course, indium could be replaced with antimony as well


Carbon is much more abundant anyways, and much more scalable in mass production. I can't figure out how we would ever run short on carbon, whereas with ITO and the like, the more you make the more expensive it becomes as the supply is rather limited anyways, regardless of politics.

Just think about the thousands of square miles of solar panels that would need ITO to work. Or flatscreen panels - they use ITO anyways, touchscreen or not. With further refinements in the manufacturing process, graphene can pull the costs down by many orders of magnitude and then every window, every roof tile can be a solar panel.

Does it matter if it lasts only half the time, when it costs ten times less?
Parsec
5 / 5 (2) Jun 21, 2010
I've been hearing about graphene for sometime now and I glad to see it finally has come to be produced at a practical size. This material has a bright future and we will begin to see it many of our day to day activities!


Average historical discovery to commercial realization time is usually measured in decades. From initial isolation in 2004, to commercial quality and quantity in 6 years is amazing. I would say 1 decade (2014) for real commercial products, and 1.5 decades until super products (space elevator fabrics, super batteries, etc.) i.e. 2020 or so would be incredible.
trekgeek1
5 / 5 (3) Jun 21, 2010
Exponential technology progress is amazing. It really seems like the technological barriers are being quickly knocked down. It seems like yesterday that the mass production of high quality graphene was impossible. Today they've done it and tomorrow we'll be using it. Simply amazing. Cheap, recyclable, indestructible, a perfect technological advancement.
MadPutz
5 / 5 (2) Jun 22, 2010
Exponential technology progress is amazing. It really seems like the technological barriers are being quickly knocked down. It seems like yesterday that the mass production of high quality graphene was impossible. Today they've done it and tomorrow we'll be using it. Simply amazing. Cheap, recyclable, indestructible, a perfect technological advancement.


The Singularity Is Near!
A_Paradox
not rated yet Jun 22, 2010
Well what I want is a polarising layer in my prescription glasses so I can have glare reduction without "tinting". [Optometrists tell me this cannot be had in Australia] I have been thinking lately that this might be achieved with a sandwiched layer of some transparent liquid crystal of the sort which forms optically active polarised filtering when influenced by an electric field. If the field voltage was provided by photo voltaic cells around the frame of the specs, that could work wherever there was a strong enough light source. And this 'ere graphene could provide the thin and transparent electrodes! [Yes?]

Polorised filtering is just wonderful for looking into water on a sunny day, etc, etc,

velniukas
not rated yet Jul 07, 2010
How feasible is it for a hobbyest nowadays to create their own graphene-oled display? Using roll 2 roll or inkjet?
Given
1) Most inks / processes are closely guarded
2) process setup is v complex
3) overall lifetime isn't as important as a commercial product

This is one project I would be very keen to find collaborators on