Graphene-based LCDs Devised
MANCHESTER, England, May 2, 2008 -- Highly transparent and highly conductive ultrathin films have been produced by dissolving chunks of graphite then spraying the resulting graphene onto a glass surface.
Researchers at the University of Manchester in England used graphene, which is derived from the abundant natural resource graphite, as a transparent conductive coating for electro-optical devices instead of indium, a metal that is becoming increasingly expensive as supplies dwindle. They used the method to make LCDs that contain graphene electrodes, a technology they said could be mass-produced in computers, TVs, mobile phones and other electronic devices within a few years.
The same researchers reported last month that they carved graphene into tiny electronic circuits containing individual transistors about the size of a molecule as a way to continue to make ever-smaller integrated circuits. (See: Transistor is 1 Atom Thick)
"Forget about oil -- our civilization will first run out of indium," said professor Andre Geim of the University of Manchester. "Scientists have an urgent task on their hands to find new types of conductive transparent films." Geim, Kostya Novoselov and colleagues from the School of Physics and Astronomy and the School of Computer Science found graphene, a one-atom-thick sheet of carbon resembling chicken wire, to be ideal for electrodes in LCDs.
Liquid crystal device with electrodes made of graphene. (Image courtesy Mesoscopic Physics Group, University of Manchester)
“Graphene is only one atom thick, optically transparent, chemically inert and an excellent conductor,” said Novoselov, a Royal Society research fellow. “These properties seem to make this material an excellent candidate for applications in various electro-optical devices that require conducting, but transparent, thin films. We believe graphene should improve the durability and simplify the technology of potential electronic devices that interact with light.”
“Transparent conducting films are an essential part of many gadgets including common liquid crystal displays for computers, TVs and mobile phones. The underlying technology uses thin metal-oxide films based on indium. But indium is becoming an increasingly expensive commodity and, moreover, its supply is expected to be exhausted within just 10 years," Geim said.
Graphene-based LCD products could appear in shops as soon as in a few years, Novoselov said.
A research team from the Max Planck Institute for Polymer Research in Germany recently reported in Nano Letters how they had used graphene-based films to create transparent electrodes for solar cells. But the German team used a different technology for obtaining graphene films, which involved several extra steps.
The Manchester team said the films they developed are much simpler to produce and can be used not only in LCDs but also in solar cells. Their work appears in the American Chemical Society’s journal Nano Letters.
For more information, visit: www.manchester.ac.uk
- Metal used in components of the crystalline semiconductor alloys indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP), and the binary semiconductor indium phosphide (InP). The first two are lattice-matched to InP as the light-emitting medium for lasers or light-emitting diodes in the 1.06- to 1.7-µm range, and the last are used as a substrate and cladding layer.
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
- thin film
- A thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most commonly used for antireflection, achromatic beamsplitters, color filters, narrow passband filters, semitransparent mirrors, heat control filters, high reflectivity mirrors, polarizers and reflection filters.
- An image affixed to a transparent photographic film or plate by photographic, printing or chemical methods. It may be viewed by transmitted light.
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