Researchers at Massachusetts Institute of Technology have discovered that when placed over substrates of different materials, graphene’s basic properties such as chemical reactivity and electrical conductivity vary dramatically based on the characteristics of the underlying material.
The U.S. Office of Naval Research largely supported the work. The study results have appeared in the Nature Chemistry journal. When the underlying material is silicon dioxide, graphene readily becomes functionalized subsequent to its exposure to certain chemicals. However, when the underlying material is boron nitride, the nanomaterial becomes inert to the same chemicals.
Senior author, Michael Strano informed that it is possible to turn on or off graphene’s ability to create chemical bonds on the basis of the underlying material. The reason for this strange behavior of graphene is its very low thickness so that the electrical fields of atoms in the underlying material strongly affect the chemical reactivity of the nanomaterial. Hence, it is possible to fabricate devices with a micropatterned substrate that comprised some layers of boron nitride as well as silicon dioxide and covered with a graphene layer whose chemical reactivity will get changed based on the hidden patterning.
This paves the way to develop sensor microarrays to detect trace amounts of chemical or biological materials, for instance. Strano stated that the researchers have put forward a new electron-transfer theory to describe the mechanism behind the effect of the underlying material on the chemical behavior of graphene. This new insight holds potential to predict the behavior of the nanomaterial on other substrates.
Lead author, Qing Hua Wang stated that the finding is useful in envisaging the chemical behavior of several different configurations. This idea can inspire other groups for the development of many different things. The MIT team’s next step is to study the chemical reactivity of bilayer graphene whose behavior is expected to be different from that of a single-layer material.
Source: http://web.mit.edu/