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.