electronics

Graphene-based gadgets may be just years away

Adam Nucci — Wed, 21 May 2008 13:39:31 -0700

NOTE: This content was aggregated from RSS feed. Original source is http://feeds.feedburner.com/~r/NanotechnologyToday/~3/295312498/graphene-based-gadgets-may-be-just.html

Researchers at The University of Manchester have produced tiny liquid crystal devices with electrodes made from graphene – an exciting development that could lead to computer and TV displays based on this technology.Writing in the American Chemical Society’s journal Nano Letters, Dr Kostya Novoselov and colleagues from The School of Physics and Astronomy and The School of Computer Science, report on the use of graphene as a transparent conductive coating for electro-optical devices – and show that its high transparency and low resistivity make it ideal for electrodes in liquid crystal devices.

Graphene was discovered at The University of Manchester back in 2004, by Professor Andre Geim FRS and Royal Society Research Fellow Dr Kostya Novoselov. This incredible one-atom-thick gauze of carbon atoms, which resembles chicken wire, has quickly become one of the hottest topics in physics and materials science.

“Graphene is only one atom thick, optically transparent, chemically inert, and an excellent conductor,” says Dr Novoselov, from the Manchester research team.

“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.”

Prof Geim said: “Transparent conducting films are an essential part of many gadgets including common liquid crystal displays (LCDs) 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.

“Forget about oil – our civilisation will first run out of indium. Scientists have an urgent task on their hands to find new types of conductive transparent films.”

The Manchester research team has now demonstrated highly transparent and highly conductive ultra-thin films that can be produced cheaply by ‘dissolving’ chunks of graphite – an abundant natural resource – into graphene and then spraying the suspension onto a glass surface.

The resulting graphene-based films can be used in LCDs and, to prove the concept, the research team have demonstrated the first liquid crystal devices with graphene electrodes.

Dr Novoselov believes that there are only a few small, incremental steps remain for this technology to reach a mass production stage. “Graphene-based LCD products could appear in shops as soon as in a few years”, he adds.

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 (1).

But the German team used a different technology for obtaining graphene films, which involved several extra steps.

The Manchester team says the films they have developed are much simpler to produce, and they can be used not only in LCDs but also in solar cells. ###

Notes to editors

(1) Wang, X.; Zhi, L.; Mullen, K. Nano Lett. 2008, 8, 323.

A copy of the paper- ‘Graphene-Based Liquid Crystal Device’ - is available on request. A selection of images are also available to illustrate the story.

Dr Novoselov is available for comment.

For further information please contact Contact: Alex Waddington 01-612-758-387 University of Manchester

Tags: Nano or Nanotechnology and Nanotech or University of Manchester and liquid crystal devices or Graphene

Computer & Information Science

Wireless Power

Matt Daniels — Thu, 28 Feb 2008 19:59:52 -0800

Description

Wireless power technology transmits electricity to devices without the use of cables

Impact: Any low-power device, such as a cell phone, iPod, or laptop, could recharge automatically simply by coming within range of a wireless power source, eliminating the need for multiple cables—and perhaps, eventually, for batteries.

Context: Eliminating the power cord would make today’s ubiquitous portable electronics truly wireless. A number of researchers and startups are making headway in this growing field.

The researchers built two resonant copper coils and hung them from the ceiling, about two meters apart. When they plugged one coil into the wall, alternating current flowed through it, creating a magnetic field. The second coil, tuned to the same frequency and hooked to a light bulb, resonated with the magnetic field, generating an electric current that lit up the bulb--even with a thin wall between the coils.

So far, the most effective setup consists of 60-centimeter copper coils and a 10-megahertz magnetic field; this transfers power over a distance of two meters with about 50 percent efficiency. The team is looking at silver and other materials to decrease coil size and boost efficiency. "While ideally it would be nice to have efficiencies at 100 percent, realistically, 70 to 80 percent could be possible for a typical application," says Soljačić.

Physics & Space Science

Source

http://www.technologyreview.com/read_article.aspx?ch=specialsections&sc=emerging08&id=20248

Space tourism could lower launch cost for small sats

Matt Daniels — Wed, 30 Jan 2008 14:04:42 -0800

Description

The development of space tourism may also contribute to lower launching costs for small, low-mass satellites.

Satellites are just packages of electronics, and the price of electronics is falling without foreseeable end. It is the launch cost ($20m a time) that restricts their use. A successor to the SpaceShip/White Knight combination could deal with that. First, the whole system is more economical than using throw-away rockets. Second, rather than having to wait ages on the ground for the right launch window, an air-launcher can fly to a better location. Such changes could bring satellite ownership to cities, universities and companies. Ultimately, it may bring it within the purse of individuals. Who could resist having their own, private window on the world?

It is famously difficult to predict the market for disruptive technologies, whether they be computers, muskets, jet engines or digital cameras. But cheap access to space, and to the other side of the Earth, is likely to be revolutionary.

Physics & Space Science

Source

http://www.economist.com/opinion/displaystory.cfm?story_id=10566717

Nanowires for Improved Circuits and Spacecraft

Alex Soojung-Kim Pang — Tue, 23 Oct 2007 11:10:30 -0700

Description

Nanoscale wires under development today promise to make electronic circuits faster, more powerful, lighter, and cooler, and provide a very efficient method for transmitting electricity.

Nanowires based either on silicon or on carbon nanotubes have extremely high conductivity and are potential candidates for the next generation of circuits. Nanowires in circuits could be used as a transistor replacement for silicon, as a replacement for copper wires connecting components and as a heat conductor, enabling even faster processors, particularly in portable devices.

One possibility is that nanoscale wires made from a combination of silicon and metal could connect nanoscale and macroscale electronics together, allowing for hybrid electronic components. In another, more revolutionary application, it is envisaged that wires made entirely of carbon nanotubes could conduct electricity many times farther and more efficiently than copper wires and weigh only a fraction as much. It is possible that these wires would be able to conduct electricity with little or no resistance and without dissipating electricity as heat. NASA hopes that carbon nanotube wires will miniaturise spacecraft, reducing weight and size compared to vehicles made with traditional copper wires.

To date, however, only several centimeter-length carbon nanotube wires have been created, far from the the quantity necessary for large-sized applications or even limited mass quanitites. Various stakeholders are investing substantial resources in testing nanowire properties and expanding manufacturing capabilities."

This will be enabled by:

Continuing investment in testing nanowire properties and expanding manufacturing capabilities
Development of the capability to consistently manufacture specific types of carbon nanotubes

Early indicators include:

Investment by US NASA of several million dollars in Rice University's Carbon Nanotechnology Laboratory to see a 1-meter-long prototype of pure carbon nanotube wire by 2010
Heavy investment by Intel in nanowire research and development (both carbon nanotube- and silicon-based) as one of the few promising solutions to keep Moore's Law on track through 2015 and beyond

What to watch:

Carbon nanotube wires start to be mass produced.

Signals

Conductive Polymers: The New Silicon?

Alex Soojung-Kim Pang — Tue, 23 Oct 2007 11:10:29 -0700

Description

The unique properties of conductive polymers are likely to find application in a wide variety of electronic devices within the next couple of decades.

Plastics have traditionally been used as insulators, for instance as the casing around copper wire, because they conduct electricity so poorly. In the 1970s, however, researchers demonstrated that polymers doped with certain compounds could actually function as conductors of electricity. Because of plastic's flexibility, low cost, and light weight, the possibility of fashioning transistors from it to create plastic electronics holds great commercial interest. The use of ink-jet technology to print plastic transistors onto a range of materials has been demonstrated and is a major driver of the research into conductive polymers because of the benefits plastic offers over traditional silicon transistors.

Organic semiconductors are unlikely to ever achieve the switching speeds possible with silicon-based semiconductors, so plastic chips are unlikely to replace silicon ones in personal computers in the near future. Their use in display devices, however, has shown great promise, and the first commercial applications of conductive polymers are already on the market in displays for digital cameras and electric razors. Over the coming decade, an increasing number of display screens on common products are likely to incorporate organic light-emitting diodes (OLEDs). Such screens will be less expensive and more energy-efficient than existing LED display technology, which may be superseded altogether by OLEDs. Large displays that are just a few millimetres thick are already in development.

In 5 to 20 years, the next generation of products using conductive polymers are likely to be bendable displays and electronics, specifically electronic paper and wearable electronics. Electronic paper has already been field tested in rigid displays that update sale prices at department stores. A commercial prototype for a flexible version has been produced by Polymer Vision in conjunction with E Ink. Joseph Jacobson of MIT's Media Laboratory and E Ink envisions 'the last book', which could contain the contents of the Library of Congress in something the size of a binder. Cheap plastic chips may also reduce the cost of radio-frequency identification tags (RFIDs) and so increase the number of applications of RFID technology.

Another application of conductive polymers already in development is electromagnetic shielding, which could be used for antistatic protection and cloaking from radar. Static is estimated to cause $15 billion in damage annually to electronic devices. The ability to incorporate conductive polymers into everyday materials such as textiles opens up the possibility of new kinds of chemical sensors and new forms of monitoring. Clothing that could change its properties as the temperature changes is one possibility. Electronic skins that respond to pressure have been imagined for robotic hands. Conductive polymers might also provide the basis for better rechargeable batteries. Given the ubiquity of plastics and semiconductors in modern life, in the future many computing and other electronic devices will make use of the unique properties of conductive polymers.

This will be enabled by:

Competition between the LED and OLED technologies to drive down the price of OLEDs so manufacturers will make the switch
Continuing discovery of new polymers with conductive properties to give engineers more of a selection
Development of organic or hybrid chips with greater stability in reponse to environmental stresses -- temperature and humidity
Development of new production techniques, especially advances ink-jet printing of circuits

Early indicators include:

Awarding of the Nobel Prize in Chemistry in 2000 to Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa for pioneering research into conductive polymers
Publication in December 2000 of a paper by Henning Sirringhaus of Cambridge University in Science demonstrating the ability to use ink-jet technology to print high-resolution organic transistors just 5 mm apart
Introduction in 2002 by Kodak and Sanyo of a small, rigid OLED display for use in digital cameras and cell phones
Joining of forces by major manufacturers such as Dow, Motorola, and Xerox, and DuPont and Lucent Technologies, to develop new polymer inks and printing methods
Revelation in 2003 by Plastic Logic at the Society for Information Display Conference of the first plastic-electronics ink-jet-printed active-matrix display
Publication in 2004 by Vitaly Podzorov at Rutgers University and colleagues at the University of Illinois at Urbana-Champaign of results showing that a year-long effort to remove impurities produced an organic semiconductor with 200-fold increase in speed

What to watch:

Plastic chips replace silicon chips in inexpensive appliances.
OLEDs supplant LEDs.
The global market for organic display devices grows from around $219 million to around $3 billion in the next 5 to 10 years.