Characteristic electron transport on pyridine-linked molecular devices with graphene nanoribbons electrodes and gold electrodes

The electrodes in the molecular devices play a crucial role in creating functional organic electronic devices. We employed the first-principles calculations to investigate the conjugated pyridine-terminated molecule-4, 4′-vinylenedipyridine attached to monolayer zigzag graphene nanoribbons (ZGNRs) and Au electrodes. Results show that the ZGNRs-based device exhibits excellent electrical properties. It has larger equilibrium conductance or stronger transmission capacity due to higher strength of individual channel and stronger delocalization of electronic states at the Fermi level. The transmission of two devices near the Fermi level is influenced by resonant electron transport through the discrete energy and the edge states. Comparatively, different from the rising trend of gold-based device with the increasing voltage, the current of the device with ZGNRs electrodes changes in a completely different way with the augment of the applied voltage, exhibiting a negative differential resistance effect unexpectedly. The changing trends of the current through two devices are elucidated by the evolution of the transmission peak nearest to the Fermi level.