Theoretical studies of electron transport properties in bimolecular junctions based on monothiol-anchored carbon chains

Several models of bimolecular junctions were designed based on two different-lengthed and monothiol-anchored carbon chains, and their electron-transport properties were investigated systematically using density functional theory (DFT) combined with the first-principles nonequilibrium Green's function (NEGF). Computational results show that the shorter carbon chain moiety makes more contribution to the conductance of molecular junctions. The comparisons of transport properties among these junctions show that the difference in lengths of two molecules can influence the rectification effect significantly. It indicates the modulation from the shorter carbon chain moiety. Negative differential resistance (NDR) behaviors occur in all of the bimolecular junctions. The rectification and NDR characteristics were discussed emphatically through analyzing the transmission spectra and molecular projected self-consistent Hamiltonian (MPSH).