Chemists create a single 2-D sheet of bonded buckyballs

The newest carbon allotrope is a mash-up of two classics. Graphene is highly conductive, while buckyballs (C₆₀) are insulators. Jian Zheng at the Chinese Academy of Sciences wanted to investigate what electrical properties a nanomaterial that combined structural features of both might display. To explore this question, Zheng and his team made 2-D, single-layer sheets of polymerized buckyballs (Nature 2022, DOI: 10.1038/s41586-022-04771-5).

Chemists have previously produced chains and sheets of polymerized C₆₀, but until now have been unable to isolate just one layer of the stuff to study its properties. Single sheets of graphene behave very differently from stacks of the material; Zheng suspected an isolated layer of 2-D bonded buckyballs might have similarly distinct properties.

Zheng and his colleagues heated buckyballs with magnesium powder, resulting in planar networks of polymerized C₆₀ separated by metal ions. Depending on the recipe, the buckyball networks in these layers were bridged together in either a hexagonal or a rectangular pattern. The researchers then exchanged the Mg ions with a bulky organic ion, allowing them to peel the layers apart. That made it possible for the researchers to obtain a single slice of the honeycombed buckyball network like a sheet of bubble wrap.

When they tested the conductivity of this 2-D nanomaterial, Zheng and his colleagues found that a single layer of the hexagonally-coordinated network acts as a semiconductor with electrical activity in between graphene and C₆₀. Zheng plans to further investigate the unique properties of this new carbon allotrope and its potential applications in electronic devices.