Eindhoven University of Technology Researchers have developed a replacement for indium tin oxide (ITO). Supplies of this rare metal are expected to be exhausted within 10 years. The replacement material is a transparent, conducting film produced in water based on electrically conducting carbon nanotubes and plastic nanoparticles. The results, which also provide new insights into conduction in complex composite materials, were published yesterday by the scientific journal Nature Nanotechnology.The research team was able to achieve higher conductivity by combining low concentrations of carbon nanotubes and conducting latex in a low-cost polystyrene film. Together the nanotubes and latex comprise less than 1& 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 must 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, dissolve them in water and add conducting latex (a solution of polymer beads in water) 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 is removed by freeze-drying.
The film has an important advantage over ITO: It's environment friendly, all the materials are water based and no heavy metals like tin are used.
