University of Illinois at Chicago researchers have discovered a way to create a highly sensitive chemical sensor based on the crystalline flaws in graphene sheets. The imperfections have unique electronic properties that the researchers were able to exploit to increase sensitivity to absorbed gas molecules by 300 times.
The team created a micron-sized, individual graphene grain boundary in order to probe its electronic properties and study its role in gas sensing. Their first discovery was that gas molecules are attracted to the grain boundary and accumulate there, rather than on the graphene crystal, making it the ideal spot for sensing gas molecules.
It should be possible to “tune” the electronic properties of graphene grain-boundary arrays using controlled doping to obtain a fingerprint response — thus creating a reliable and stable “electronic nose.” With the grain boundary’s strong attraction for gas molecules and the extraordinarily sharp response to any charge transfer, such an electronic nose might be able to detect even a single gas molecule, and would make an ideal sensor.