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CNT electrodes go transparent

Flexible electronics have taken an important leap forward with the development of a new type of flexible, transparent electrode made using carbon nanotubes (CNTs). [size=2][color=red]Quinton Williams of Jackson State University in the US and colleagues made the electrode by applying boron-doped CNTs to glass and polymer film surfaces. The devices are 89% transparent to visible light and are robust – they maintain their conducting properties even after being folded and exposed to harsh environmental conditions.[/color][/size]
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Indium tin oxide (ITO) is commonly used to make transparent electrodes today. However, it is unsuitable for flexible electronic applications because it loses its conductivity when folded. Organic polymers are promising alternatives to ITO but their problem is that they break down over time when exposed to air.
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[url=http://nanotechweb.org/cws/article/tech/31738/1/071109][img]http://images.iop.org/objects/nano/news/thumb/6/11/9/071109.jpg[/img]
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Now, Williams and co-workers have come up with a new solution to this challenge. The researchers have prepared conducting, transparent flexible films around 20 nm thick on polyethylene terephthalate (PET), by applying thin coatings of boron-doped single-walled CNTs. This is the first time that boron-doped CNTs have been exploited as transparent electrodes. [^D2LQ @i
"By using boron-doped CNTs, we are demonstrating the importance of specialized CNTs for specific applications," Williams told [i]nanotechweb.org[/i]. "As an analogy: in the early days of optical telecommunications, only standard 'vanilla' telecom fibre was used. Today, many specialized types or 'flavours' of fibres are used, depending on the application. The same will also hold true for CNTs."
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The researchers exploited the good electrical and mechanical properties of chemically doped CNTs by using a network of them as the transparent anode in a flexible light-emitting device. They made their materials by experimenting with the solubility of doped nanotubes and developing a process for dispersing the CNTs in a polymer suspension. A homogenous thin layer of the CNTs was then distributed onto the polymer via spin coating. d:H#F/zm,l%A

.s2z0jPGJ(X D Williams and colleagues found that the samples remained mechanically robust even after high temperature and humidity tests. Electrical tests also showed that the films retained their conductivity after being completely folded. This is a big advantage over ITO and means that transparent CNT-based conducting materials are prime candidates for replacing this material in flexible electronic devices. (v'Z2v2O)^e
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+| n;h`N)I!I So what applications could these materials actually be used in? "Low cost flexible electronic products for consumers and electronic paper," said Williams. Another potential, military, application is in lightweight foldable electronic displays and maps with dynamic content for increasing situational awareness on the battlefield, he adds.
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"We are now planning to develop p- and n-type nanomaterials for the flexible electronics revolution as an analogue to the silicon wafer in the microelectronics era." i+E bC^5kT+zRc(q+C

q#oc y%\0Y` The researchers reported their work in [i]Appl. Phys. Lett.[/i].
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Source: [i]nanotechweb.org[/i]