Document Type : Original Article

Authors

• Ayoub Kanaani
• Mohammad Vakili ¹
• Mahmood Akbari ²

¹ Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran

² UNESCO-UNISA-ITL/NRF Africa Chair in Nanoscience and Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P.O. Box 392, Pretoria, South Africa

Abstract

In this study, we studied the electronic transport properties of 4,5-bis(2,5-dimethylthiophen-3-yl)furan-2-amine (a Diarylethene) by nonequilibrium green's function (NEGF) joint with density functional theory (DFT). This molecule can be converted from closed-form to open form by ultraviolet irradiation or visible light. We have studied several parameters such as I–V characteristics, electronic transmission coefficients T(E), the effect of electrode materials (Au, Ag, and Pt) on electronic transport properties, on-off ratio and spatial distribution of molecular projected self-consistent Hamiltonian (MPSH) orbitals corresponding to the closed and open forms. The physical origin of switching behavior is interpreted based on the different molecular geometries, location and size of the frontier molecular orbitals and the HOMO–LUMO gap. The results showed that as the molecule changes from closed form to open form (closed → open), conductivity changes from on state (high conductivity) to off state (low conductivity). We investigated the effect of different electrodes (Ag, Au, Pt) and various connection sites (hollow, top, bridge) on conductivity.

Keywords

• Switching behavior
• Density functional theory
• Diarylethene
• Electronic transport
• DFT-NEGF