Graphene is a single layer of carbon atoms with interesting properties for a wide range of applications including high-frequency electronics and battery anodes. Its physical, optical and catalytic properties can be further enriched by creating a distribution of nanometric holes randomly distributed on the sheet.

For this purpose, the scientists have exposed a stack (a graphene sheet inserted between layers of polymer and copper) to a flow of heavy ions. The gold 200 ions produced at the GSI accelerator in Darmstadt, Germany are swift enough to create, in normal incidence, traces of damage that are rectilinear, cylindrical and homogeneous along the entire polymer layer, while passing through the graphene layer. These traces are then revealed and the copper is dissolved through a chemical process.

This innovative process includes only a few steps and can be applied to larger formats than techniques that involve masking.

In addition to nanofiltration, nanoporous graphene also has significant application potential in the fields of electronics (for gap opening in field effect transistors), as well as in optics, in catalysis and in the field of sensors.

This work was carried out with the University of Bologna, the Polytechnic University of Turin, Italy, and the GSI heavy ion accelerator team in Darmstadt, Germany.

Large area fabrication of self-standing nanoporous graphene-on-PMMA substrate, Materials Letters. http://dx.doi.org/10.1016/j.matlet.2016.07.133