Touch screens made of Carbon

At the moment touch screens are everywhere: Phones storage devices such as iPods, computer screens. The future seems to belong to touch screens. However there are problems. At the moment the material that is used to make touch screens is indium-tin-oxide, ITO, a rare material on earth. Manufacturers are afraid that in the future prices could be artificially driven high by suppliers, or that supplies might even run out.
ITO is the perfect material for the job. It is good at conducting slight electric currents but at the same time it lets the light of the display pass through unhindered.

Researchers from the Fraunhofer Institute in Germany have now come up with a material that is much cheaper while being on a level with the properties of  ITO. It is composed of two layers. One is the carrier, a thin foil made of the inexpensive polymer  polyethylenterephthalate PET which is also used for making plastic bottles. The second one is a mixture of carbon-nanotubes and electrically conducting polymers that is applied to the PET as a solution and forms a thin film when it dries.

(Credit: Copyright Fraunhofer IPA)

In the past these materials have been unstable in UV light or in humidity, but adding carbon-nanotubes has improved stability and made the material durable. Although they have a slightly higher resistance than traditional touch screens they are still perfectly usable in electrical devices. Also due to the fact that the touch-"foil" is flexible it could potentially be used on uneven surfaces.

The new technology will be presented at the nano tech 2011 fair in Tokyo from February 16-18.