Graphene turned ultrastiff by optical forging

Researchers at the Nanoscience Center of the University of Jyväskylä have demonstrated how an experimental technique called optical forging can make graphene ultrastiff – increase its stiffness by several orders of magnitude. Graphene typically has ultrasmall bending modulus, but the research group at the University of Jyväskylä has demonstrated how to make graphene ultrastiff using a specifically developed laser treatment. This stiffening opens up whole new application areas for graphene.

Top – Atomic force microscopy images of the suspended graphene drum skin before and after optical forging. Bottom – analogue presentation of how a material can become stiffer when it is corrugated. (Image: University of Jyväskylä)

The same group has previously prepared three-dimensional graphene structures using a pulsed femtosecond laser patterning method called optical forging. The laser irradiation causes defects in the graphene lattice, which in turn expands the lattice, causing stable three-dimensional structures. Here the group used optical forging to modify a monolayer graphene membrane suspended like a drum skin and measured its mechanical properties using nanoindentation.