Researchers at Eindhoven University of Technology (TU/e, Netherlands) have developed a replacement for indium tin oxide (ITO), an important material used in displays for all kinds of everyday products such as TVs, telephones and laptops, as well as in solar cells. Unfortunately indium is a rare metal, and the available supplies are expected to be virtually exhausted within as little as ten years. The replacement material is a transparent, conducting film produced in water, and based on electrically conducting carbon nanotubes and plastic nanoparticles. It is made of commonly available materials, and on top of that is also environment-friendly. The results, which also provide new insights into conduction in complex composite materials, were published online yesterday 10 April by the scientific journal Nature Nanotechnology.
The research team has been able to achieve higher conductivity by combining low concentrations of carbon nanotubes and conducting latex in a low-cost polystyrene film. The nanotubes and the latex together account for less than 1 percent of the weight of the conducting film. That is important, because a high concentration of carbon nanotubes makes the film black and opaque, so the concentration needs to be kept as low as possible. The research team was led by theoretical physicist Paul van der Schoot and polymer chemist Cor Koning. Post-doc Andriy Kyrylyuk is the first author of the paper in Nature Nanotechnology.
The researchers use standard, widely available nanotubes which they dissolve in water. Then they add conducting latex (a solution of polymer beads in water), together with a binder in the form of polystyrene beads. When the mixture is heated, the polystyrene beads fuse together to form the film, which contains a conducting network of nanotubes and beads from the conducting latex. The water, which only serves as a dispersing agent in production, is removed by freeze-drying. The 'formula' is not a que
|Contact: Ivo Jongsma|
Eindhoven University of Technology