New molecular shape for electronic circuits discovered

February 18, 2015

Corannulene molecular structure showing the shallow bowl and intrinsic dipole voltage (top), arranged on a copper surface (middle), and assembled (bottom) into a molecular junction (credit: L. Zoppi et al./PCCP)

Corannulene — a carbon molecule with molecular shape similar to fullerene (C60) — has properties that could be ideal for building molecule-size circuits, a team of scientists from SISSA, the University of Zurich, and the University of Nova Gorica in Slovenia has found in theoretical studies.

Imagine taking a fullerene sphere and cutting it in half like a melon. What you get is a corannulene (C20H10) molecule.

The study has just been published in Physical Chemistry Chemical Physics.

Fullerene is formed of carbon atoms arranged in a hexagonal network, shaped like a hollow sphere. Fullerene is known to contain “buckybowl superatom states” (BSS), which are capable of accepting electrons (needed for electronic circuits), but these states are found at very high energies, making them difficult to exploit in electronic devices.

Corannulene molecules can function at almost ten times lower energy than fullerene, making them attractive candidates for nanoscale electronic circuits, the researchers note.

Abstract for Buckybowl superatom states: a unique route for electron transport?

A unique paradigm for intermolecular charge transport mediated by diffuse atomic-like orbital (SAMOs), typically present in conjugated hollow shaped molecules, is investigated for C20H10molecular fragments by means of G0W0 theory. Inclusion of many body screening and polarization effects is seen to be important for accurate prediction of electronic properties involving these diffuse orbitals. Theoretical predictions are made for the series of bowl-shaped fullerene fragments, C20H10, C30H10, C40H10, C50H10. Interesting results are found for the LUMO–SAMO energy gap in C20H10, which is shown to be nearly an order of magnitude lower that that determined for C60. Given the ability to support bowl fragments on metal surfaces, these results suggest the concrete possibility for exploiting SAMO-mediated electron transport in supramolecular conducting layers.