Scientists at the Karlsruhe Institute of Technology (KIT) and the Technical University of Darmstadt have devised a novel sensor to detect gas molecules. The sensor combines a graphene transistor with a customized metal-organic coating, representing the prototype of an entirely new class of sensors.
Thanks to this combination, the sensor allows selective detection of molecules in the gas phase. Unlike commercially available sensors, it responds to neither alcohol nor humidity.
Ralph Krupke, Professor at the Institute of Nanotechnology (INT) of KIT and the Institute of Materials Science of TU Darmstadt, said, “Graphene is a modification of carbon with a two-dimensional structure. By nature, it is susceptible to foreign molecules that attach to the surface. However, Graphene does not exhibit any molecule-specific interaction that is needed for use as a sensor. To reach the required selectivity, we have made a metal-organic framework grow on the surface.”
By growing a surface-mounted metal-organic framework (SURMOF) directly on a graphene field-effect transistor (GFET), scientists represented a selective sensor platform that offers high sensitivity and simple read-out of a GFET and high selectivity of a SURMOF.
Professor Christof Wöll, who heads KIT’s Institute of Functional Interfaces (IFG), said, “Combination of the unique electronic properties of Graphene with the high chemical variability of MOFs opens up great potential. As various kinds of SURMOFs can be produced and chemical designs of the interface between GFET and SURMOF may vary, the work opens up an entirely new class of sensors with a specifically adjusted selectivity and sensitivity. Here, simulation helps, as we can create many MOFs on the computer without having to synthesize them.”
- Sandeep Kumar et al., Sensing Molecules with Metal-Organic Framework Functionalized Graphene Transistors, Advanced Materials (2021). DOI: 10.1002/adma.202103316