Effects of amino-nitro side groups on electron device of oligo p-phenylenevinylene molecular between ZGNR electrodes

Abstract

We study the electronic transport property for a molecular device of an oligo (p-phenylenevinylene) (OPV) molecule without or with different side groups between two zigzag-edged graphene nanoribbon (ZGNR) electrodes. By using ab initio calculations based on density-functional theory, the effects of negative differential resistance (NDR) and spin-rectifying in I–V characteristics are revealed and explained for the proposed molecular device. Our analysis indicates that the NDR behavior comes from the conduction orbital being suppressed under certain bias voltage, while the rectifying effect is because of the asymmetry distribution of the highest occupied molecular orbital or the lowest unoccupied molecular one as well as the corresponding coupling between the molecule and electrodes. Interestingly, the transport property of the device can be improved by introducing amino-nitro side groups to the OPV molecule. The NDR behavior can be much enhanced for molecule with amino side group, and the rectification can be improved for molecule with amino and nitro side groups, respectively. In particular, the NDR behavior of peak to valley ratio can be much enhanced and a molecular rectifier which offers rectification ratio of more than three orders of magnitude up to 2863 by adding NH2 and NO2 side groups to OPV molecule, respectively.