Charge Density Analysis and Transport Properties of TTF Based Molecular Nanowires: A DFT Approach

Abstract

The present study has been performed to understand the charge density distribution and the electrical characteristics of Au and thiol substituted tetrathiafulvalene (TTF) based molecular nanowire. A quantum chemical calculation has been carried out using DFT method (B3LYP) with the LANL2DZ basis set under various applied electric fields (EFs). The bond topological analysis characterizes the terminal Au–S and S–C bonds as well as all the bonds of central TTF unit of the molecule. The variation of electron density and Laplacian of electron density at the bond critical point of bonds for zero and different applied fields reveal the electron density distribution of the molecule. The molecular conformation, the variation of atomic charges and energy density distribution of the molecule have been analyzed for the various levels of applied EFs. The HOMO-LUMO gap calculated from quantum chemical calculations has been compared with the value calculated from the density of states. The variation of dipole moment due to the polarization effect and the I-V characteristics of the molecule for the various applied EFs have been well discussed.