Soon, stretchy graphene electrodes that promise bendy displays

January 15th, 2009 - 2:07 pm ICT by ANI  

London, Jan 15 (ANI): A new research could lead to the development of transparent and stretchy electrodes made from graphene, which could result in bendy displays.
The research is being undertaken by Byung Hee Hong from Sungkyunkwan University in Suwon, Korea, and his colleagues.
They transferred a wafer-thin layer of graphene, etched into the shape needed to make an electrode, onto pieces of polymer.
The polymers they used are transparent, and one - polyethylene terephthalate (PET) - can be bent, whereas the other - polydimethylsiloxane (PDMS) - is stretchable.
The resulting films conduct electricity better than any other sample of graphene produced in the past.
Until recently, high-quality graphene has been hard to make on a large scale.
To produce their graphene, Hong and his colleagues used a technique that is well known in the semiconductor industry - chemical vapour deposition.
This involves exposing a substrate to a number of chemicals, often at high temperatures. These chemicals then react on the surface to give a thin layer of the desired product.
The results in Hong’’s case were relatively large, high-quality films of graphene just a few atoms thick and several centimeters wide.
The team made the electrodes by using nickel as a catalyst on which to react methane and hydrogen.
Nickel usually catalyses the formation of thick layers of graphite. But, by using a layer of nickel less than 300 nanometers thick and by cooling the sample quickly after the reaction, the researchers could produce up to ten single-atom layers of carbon in graphene’’s signature honeycomb pattern.
The samples aren”t perfect, as each layer covers only around two-thirds of the sample, but Hong says he is working to improve this.
The graphene samples can be chemically etched into specific shapes, and when stamped onto the polymer, they can be bent or stretched by as much as 11 percent without losing their conductivity.
Because the layers of graphene are so thin, the resulting electrodes are transparent, and Hong says that makes the material ideal for use in applications such as portable displays.
It could, for instance, be used to replace indium titanium oxide, which is expensive and inflexible.
“We are planning to get an investment to build up mass-production facility of the large-scale graphene films,” said Hong.
His team is also looking at using the graphene electrodes in photovoltaic cells.
According to Andre Geim, from the University of Manchester, UK, the electrodes are likely to be incorporated in niche applications such as individual ultra-high-frequency transistors. (ANI)

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