A research team from the McCormick School of Engineering and Applied Science of the Northwestern University has developed a novel technique for chemically modifying graphene, paving the way to design thinner, faster flexible electronics.
Since pristine graphene is a zero band-gap material, it is not suitable for the digital circuitry. To tackle this issue and optimize graphene’s functionality, scientists across the world are seeking techniques for chemically modifying the wonder material. The most common technique is the ‘Hummers method’ that uses harsh acids, which cause damage to the graphene lattice’s fabric.
The research team’s innovative technique oxidizes graphene without damaging the fabric of its lattice. Since this technique is reversible, the properties of the resulting chemically modified graphene can be tuned further.
Mark C. Hersam, one of the researchers, explained that graphene oxide produced by the novel technique is reversible and chemically homogeneous, thus delivering well-controlled properties useful for high-performance applications.
In the new technique, the graphene oxide is produced in an ultra-high vacuum chamber in the presence of oxygen gas. Inside the chamber, the oxygen molecules were dissociated into oxygen atoms by heating a tungsten filament to 1500°C. These highly reactive oxygen atoms were then homogeneously introduced into the graphene lattice.
Spectroscopic measurements demonstrate that the electronic properties of the chemically modified graphene differ as a function of oxygen coverage, meaning that this method can alter the characteristics of graphene-based devices. The research team’s next step is to study other ways of chemically altering graphene to synthesize a broad array of materials.
The paper titled ‘Chemically Homogeneous and Thermally Reversible Oxidation of Epitaxial Graphene’ has been reported in Nature Chemistry.
Source: http://www.northwestern.edu