Carbon Nanotube Solution Could Eliminate Need for Indium Tin Oxide in Electronic Displays

It is altogether possible that the best solution to the current rare earth mineral squeeze is for countries other than China to restart their mining of the minerals that they more or less abandoned over twenty years ago.

But based on some recent nanotechnology research it seems this is not the way people want to go. While Japan is pursuing new mineral deposits after their run-in with China last year, there seems to be some sense afoot that nanotechnology could offer a solution without resorting to new mining.

In a Cientifica white paper published last year the solutions take the form of electronics that negate the need for the rare earth minerals. “Through the use of nanotechnologies we can now start to develop processes that do not use rare resources, for example using carbon nanotubes and metallic nanoparticles in polymers to make them conducting rather than applying thin layers of indium tin oxide.”

It appears that this is what researchers at Eindhoven University of Technology in the Netherlands have just done in their development of a material that can replace indium tin oxide (ITO) in electronic displays.

The research, which was originally published in the journal Nature Nanotechnology, proposes as a replacement a material made of carbon nanotubes and plastic nanoparticles and produced in water.

Apparently, the key to the production of the new material is the proportions of carbon nanotubes (CNTs) and the conducting latex. Too high a concentration of CNTs and the film becomes dark and opaque. But by keeping the concentration low they are able to achieve a high conductivity.

While the conductivity is high, it is still a factor of a 100 lower than that provided by ITO. However, the two lead researchers on the project theoretical physicist Paul van der Schoot and polymer chemist Cor Koning believe that this gap can be quickly closed.

"We used standard carbon nanotubes, a mixture of metallic conducting and semiconducting tubes", says Cor Koning in the Nanowerk cited above. "But as soon as you start to use 100 percent metallic tubes, the conductivity increases greatly. The production technology for 100 percent metallic tubes has just been developed, and we expect the price to fall rapidly."

While the price for 100-percent-metallic carbon nanotubes continues to go down, the material is good enough now to be used as an anti-static layer for displays, according to the researchers.

If the new material were to replace ITO in electronic displays, it would not only ease the rare earth squeeze but might also appease the environmentalists since it would be entirely water based without using any heavy metals. But then again, as I’ve stated previously, it would seem environmentalists would only really be satisfied if we eliminated TVs and cell phones altogether. 

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Nanoclast

IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

 
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