Researchers at Rice University have created “rivet graphene,” 2D carbon that incorporates carbon nanotubes for strength and carbon spheres that encase iron nanoparticles, which enhance both the material’s portability and its electronic properties.
Transferring graphene grown via CVD is usually done with a polymer layer to keep it from wrinkling or ripping, but the polymer tends to leave contaminants behind and degrade graphene’s abilities to carry a current. According to the Rice team, rivet graphene proved tough enough to eliminate the intermediate polymer step, and the rivets also 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 for using graphene in electronic devices, this is said to be an all-around superior material.Tests proved rivet graphene retained the strength of Rice's past development - rebar graphene (which incorporates nanotube reinforcement), as well as 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 layers of carbon wrapped around a 30-nanometer iron core, called “nano-onions” by the lab. The structures are grown in place in the CVD furnace after the dispersal of nanotubes and deposition of graphene. A final step welds all the elements together.
Rivet graphene is transparent enough for flexible and transparent electronics, the researchers said, and the simplified process should be scalable.