In this paper, tuning electrical conductivity of benzene-1,4-dithiol (M0) has been done through sequential substitute of the CH groups by nitrogen atoms in the molecular skeleton of the benzene ring and constitutional isomery. I-V characteristics of seven derivatives of M0 using non-equilibrium Green?s function (NEGF) approach combined with density functional theory (DFT) have been investigated. Our findings have been interpreted in terms of transmission spectra and molecular projected self-consistent Hamiltonian (MPSH). The results obtained show a slight effect on the conductivity at low bias with the insertion of nitrogen atoms in the benzene ring while an increase in the conductivity is observed at high bias. The results also showed that constitutional isomery significantly affects the I-V behavior of the diazabenzenes at all applied voltages, at a given bias the current varies by 30-40%. The data give the following conductivity order: pyrimidine-1,4-dithiolate > pyrazine-1,4-dithiolate > pyridazine-1,4-dithiolate. These findings indicate that the structural factors would be helpful for designing molecular wires for nanoscale applications.
Benzene-1,4-dithiol, Molecular wire, NEGF-DFT, Transmission spectra, Isomery effect