Rice University in the US has developed flexible, transparent electronics made from graphene.
The thin-film electrode could potentially be used with touchscreen displays, solar panels and OLED lighting.
The hybrid graphene film is could replace indium tin oxide (ITO), which is widely used as a transparent conductive component in flat-panel display electronics. However concerns have been raised over the supply and consequent price of indium. ITO is a ceramic material, and its brittleness is not ideal for non-flat surfaces, making it less suitable for new touchscreen display designs.
The transparent electrode developed at Rice University combines a single-layer sheet of highly conductive graphene with a fine grid of metal nanowire. Researchers claim the material easily outperforms ITO and other competing materials, with better transparency and lower resistance to electrical current.
The metal nanowires, in combination with the graphene, give the film its high transparency and high conductivity. These are two attributes are critical if the film is to be scaled up and to contend with established transparent conductive oxide films such as ITO.
Metal grids
Postdoctoral researcher Yu Zhu, who has worked on the technology at Rice University, says the fine metal meshes show good conductivity, but gaps in the nanowires to keep them transparent also make them unsuitable as standalone components in conductive electrodes.
Combining the materials, however, enables the metal grid to strengthen the graphene, and the graphene fills the empty spaces between the grids. The researchers found a grid of 5µ nanowires made of inexpensive, lightweight aluminium did not detract from the material's transparency.
The metal grids could be easily produced on a flexible substrate via standard techniques, including roll-to-roll and inkjet printing. Techniques for making large sheets of graphene are also improving rapidly, so that the technology is ready to be scaled.
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Subscribe to +Plastic Electronics magazine
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OLEDs World Summit 2011
The 13th annual OLEDs World Summit - one of the longest-running events in this sector - is being held Sept. 26-28, 2011, at the Argonaut Hotel in San Francisco, California. The summit is presented by IntertechPira in conjunction with the OLED Association, and will cover both lighting and display applications
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Nanomaterials underpin ITO alternatives coming to market
Recent months have seen unprecedented commercial progress by nanomaterial products developed as alternatives to transparent conductive oxide materials such as indium tin oxide
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EU project to deliver conductive inks for printed electronics
A project funded under the European Seventh Framework Programme will develop the low-cost conductive inks needed to produce high-volume printed electronic devices.
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