Theoretical investigation of electron transport properties in organic functional isomers - Ab initio study

Abstract Understanding the electron transport in metal-molecule-metal junctions provide a deeper insight into molecular electronics. We have performed a first principle analysis using Density Functional Theory (DFT) with Non-Equilibrium Green's Function (NEGF) to study the electron transport properties of functional isomers (benzyl alcohol and p-cresol). To understand the electron transport through these molecules we have constructed a metal-molecule-metal junction by sandwiching benzyl alcohol or p-cresol molecule with gold electrodes through a sulfur atom which acts as a linker between the electrode and the molecule. At zero bias the density of states and the projected density of states of these molecules remains the same between −1 eV and 1 eV energy levels. The transmission coefficient of the benzyl alcohol is higher than p-cresol at higher energy levels at zero bias. Current-voltage characteristic shows the differential resistance effect presents in these molecules. At higher bias region, benzyl alcohol molecular junction shows higher conductance than p-cresol molecular junction. Further, current density across the device was calculated to get an insight into the differential resistance behavior in these molecules. From this analysis, we conclude that these molecules can be used for several electronic applications such as switches, oscillators etc.