A new exploration on the substantial improvement of rectifying behaviors for a donor-acceptor molecular diode by graphene electrodes

Sandwiching a donor-acceptor molecule between two graphene nanoribbon (GNR) electrodes to construct a particular molecular diode, our calculations from the first-principles method predict that such a configuration can lead to dramatically different and unexpected effects. When the GNR electrodes are semiconducting, the rectifying behaviors for this molecule can be enhanced greatly. The maximum rectification ratio rises sharply with an increase of the bandgap size of GNR electrodes and can reach a value more than 4000 as the bandgap is about 0.8 eV, which is of a very significant improvement as compared with previously investigated results for such a molecule coupled to bulk metal electrodes. Therefore, our studies imply that using graphene with a large bandgap as electrodes might be a novel effective pathway to greatly raise rectifying behaviors of a donor-acceptor molecule.