Ultrathin carbon ribbons conduct electricity like metals in first successful synthesis

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: As modern electronic devices shrink, so do the metal electrical wires inside them. However, they start to run into serious problems the smaller they get.

Conventional wires generate excessive heat and suffer a massive spike in electrical resistance that affects overall performance. Carbon wires are touted as a possible replacement because some types could potentially carry huge amounts of current without degrading, while taking up a fraction of the space. And one possible candidate could be a new class of ultrathin conductors known as carbon pentaheptite nanoribbons, synthesized by researchers at the University of Science and Technology of China.

The team details its work in a paper published in the journal Nature. A Research Briefing in the same edition highlights the potential of these nontraditional carbon structures. The researchers wanted to build nanoribbons made entirely of five- and seven-membered carbon rings.

But this is extremely challenging because some of the building blocks are naturally unstable and far too reactive to handle directly. To get around this roadblock, the team came up with a clever workaround. Instead of starting with unstable rings, they deposited a stable molecule containing an eight-carbon ring onto a silver surface.

The scientists heated the surface, which caused each eight-carbon ring to rearrange into two fused five-carbon rings. Heating these chains once more caused neighboring rows to zip together sideways, creating seven-carbon rings between them to complete the ribbon structure. Physicists had predicted back in 1996 that a material made entirely of five- and seven-carbon rings could act like a metal.

But until now, no one had successfully produced these precise carbon structures. So the next stage was putting them to the test to see whether electrons could actually pass through them. Using the sharp tip of a scanning tunneling microscope, the team picked up one end of a ribbon off the surface and passed an electrical current directly through it.