Rational design of photoswitches based on chiroptical dimethylcethrene at the single-molecule level

The reversible conductance switching behavior of helicene molecules is one of the attractive topics in nanoelectronics at the single-molecule scale. By combining density functional theory (DFT) with nonequilibrium Green's function (NEGF), we present a theoretical investigation into the electronic transport properties of molecular junctions composed of graphene nanoribbon (GNR) electrodes interspaced by a 13,14-dimethylcethrene molecule. Our results reveal a significant disparity in conductance between the open and closed configurations, confirming that the switching behavior originates from differences in the molecular electronic structures. Additionally, the on-state and off-state of the molecular junctions are observed to interchange in response to variations in voltage. Within the bias range of [-1.00 V, 1.00 V], the maximum on-off ratio reaches 7. We demonstrate that dimethylcethrene is a reliable photoswitch with substantial potential for application in functional nanodevices, although further optimization of its performance is required.