Chemists make breakthroughs in graphene nanoribon synthesis

Graphene nanoribons may soon be much easier to produce. An international research team led by Martin Luther Halle-Wittenberg University (MLU), the University of Tennessee, and Oak Ridge National Laboratory in the United States has successfully produced this versatile material for the first time directly on the surface of semiconductors. Until now, this was only possible on metal surfaces. The new approach also allows scientists to customize the properties of nanoribons. Storage technology is one of the possible applications of the material. The research team reports on its results in the next issue of Science.

For years, graphene has been considered as the material of the future. In simple terms, it is a two-dimensional carbon surface that resembles a honeycomb. This special structure gives the material distinctive properties: for example, it is extremely stable and ultralight. There is a particular interest in graphene nanofibers, as they are a semiconductor material that could be used, for example, in the electrical and computer industries. “This is why many research groups around the world are focusing their efforts on graphene nanofibers,” explains chemist professor Konstantin Amsharov at MLU. These tapes, which are only nanometer in size, are made up of a few carbon atoms across. Its properties are determined by its shape and width. When the graphene research was just beginning, the bands were produced by cutting larger sections. “This process was very complicated and imprecise,” says Amsharov.

He and colleagues in Germany, the United States, and Poland have now managed to simplify production of the coveted nanoribons. The team produces the material by bonding individual atoms, allowing the properties to be customized. The researchers first managed to produce ribbons on the surface of titanium oxide, a non-metallic material. “Until now, tapes were synthesized primarily on gold surfaces. This is not only relatively expensive, but also impractical,” explains Amsharov. The problem with this approach is that gold conducts electricity. This would directly negate the properties of graphene nanofibers, so this method has only been used in basic research. However, gold was necessary as a catalyst to produce the nanoribons in the first place. Furthermore, nanoribons had to be transferred from the gold surface to another surface, a very complicated task. The new approach discovered by Amsharov and his colleagues solves this set of problems.

“Our new method allows us to have complete control over how the graphene nanoribons are assembled. The process is technologically relevant as it could also be used on an industrial level. It is also more cost-effective than previous processes,” says Amsharov, in summary. There are numerous areas of application for nanoribons: they could be used in future semiconductor and storage technologies and play a crucial role in the development of quantum computers.

Provided by Martin-Luther-Universität Halle-Wittenberg