Rational Design of Photoswitches Based on Chiroptical Dimethylcethrene at the Single-Molecule Level

Abstract

The reversible conductance-switching behavior of helicene molecules represents one of the most attractive topics in nanoelectronics at the single-molecule scale. Based on the density functional theory combined with the nonequilibrium Green’s function , we present a theoretical investigation into the electronic transport property of molecular junctions, which are composed of graphene nanoribbon electrodes interspaced by the 13,14-dimethylcethrene molecule. The molecule, serving as a prototypical chiral photoswitch with the [5]helicene backbone, is capable of transforming between its ring-closed and ring-open isomers upon light exposure. The result indicates a disparity in conductance between the open and closed configurations, and the switching behavior derived from the difference in electronic structures of molecules is confirmed. Moreover, the on-state and off-state of the molecular junctions are observed to interchange in response to variations in voltage. We demonstrate that dimethylcethrene is a reliable photoswitch with significant application potential for functional nanodevices, whose performance needs further enhancement.

Keywords: first-principles, Electronic transport, Molecular device, Molecular photoswitch, Graphene, Switching effect