Investigation of Transmission Coefficient and I-V Characteristics of OPE-PY-Based Structures Using GOLLUM Program


Present study deals with the electronic properties of donor-bridge-acceptor(D-B-A) molecular systems. By employing the density functional theory, the calculations were carried out to analyze the applications of oligophenylene-pyridene OPE-PY-based structures. All calculations have been carried out using the Gollum program together with SIESTA code at the high end computation unit-Lancaster University-UK. The results showed that, the high occupied molecular orbitals HOMOs are strongly localized on the anchor groups for the structure with pyridyl anchor group. The distribution of the frontier molecular orbitals suggests that the conductance may be dominated by transport through the low unoccupied molecular orbitals LUMOs for the configurations with pyridyl anchor group. The curve of the ionization potential of PY-based configurations structures goes toward low IP (OPE-PY-3˂ OPE-PY-2˂ OPE-PY-1), that means OPE-PY-3 structure needs a small energy to donating electrons in comparison with the others. Also, all the studied molecular systems have semiconductor properties with energy band gap in the order of OPE-PY-2˂ OPE-PY-3˂ OPE-PY-1. In addition, the lowest molecular length is for the structures with carbon triple bonds in the middle. The calculations of the transmission coefficient showed that, the value of the structures without side group is higher than that of the structure with side group. The electrical transport of these molecules could be control by switching from one type of anchor group to another one and that means these molecules could useful for sensing device-applications.