Rivet graphene (outlined in yellow) is nearly as transparent as pure graphene, and retains its strength and conductivity even when flexed. Photo: Tour Group/Rice University.Nanoscale ‘rivets’ can provide graphene with enhanced properties that may speed the wonder material's adoption in products like flexible, transparent electronics, according to researchers at Rice University.
In a paper in ACS Nano, the Rice lab of chemist James Tour reports the creation of ‘rivet graphene’. This is produced by incorporating carbon nanotubes and carbon spheres encasing iron nanoparticles into the two-dimensional carbon material, enhancing its portability and electronic properties.
Until now, researchers have had to use a polymer layer to transfer graphene grown via chemical vapor deposition (CVD), in order to keep it from wrinkling or ripping. But the polymer layer tended to leave contaminants behind and degrade graphene's ability to carry a current.
"Rivet graphene proved tough enough to eliminate the intermediate polymer step," Tour said. "Also, the rivets make interfacing with electrodes far better compared with normal graphene's interface, since the junctions are more electrically efficient.
"Finally, the nanotubes give the graphene an overall higher conductivity. So if you want to use graphene in electronic devices, this is an all-around superior material."
Tests proved that rivet graphene retained the strength of the Tour lab's rebar graphene (which incorporates just the carbon nanotubes for reinforcement) as well as the rebar's ability to float on water. But the rivets also enhanced the material's ability to transfer current between electrodes and the graphene, even when bent, the researchers reported.
The rivets are made from layers of carbon wrapped around a 30nm iron core, dubbed ‘nano-onions’ by the lab. These structures are grown in place in the CVD furnace after the dispersal of nanotubes and the deposition of graphene. A final step welds all the elements together, Tour said.
Rivet graphene is transparent enough for flexible and transparent electronics, and the simplified process should be scalable.
This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.