Electronegativity, symmetry, and bond strength intrinsically control charge transport through five-membered single-molecule junction

Abstract

Density functional theory and Green’s function incorporated tight binding approach have been implemented to investigate the role of electronegativity, symmetry, and bond strength in charge transport of five-membered aromatic molecules, namely cyclopentadiene, thiophene, furan, pyrrole, and 5,5-dimethylcyclopenta-1,3-diene. A novel dependence of charge transport and band gap on the bond strength of the intact segment of molecule was revealed. It is found that decreasing the strength (increasing the length) of the bonds of the sound branch would enhance the electronic transmission and narrow the band gap. In addition, the electronic transmission of the symmetric systems is higher than the asymmetric counterparts and it increases (decreases) with onsite energy of the hetero-site of the symmetric (asymmetric) system.