First-Principles Calculations of Electron Transport through Azulene

Abstract

Electron transport through azulene, a nonalternant hydrocarbon, has been investigated using nonequilibrium Green’s function approach combined with density functional theory. I–V characteristics of azulene wired from different positions between two gold electrodes have been calculated. The results indicated that current strength correlates with orbitals amplitudes. Out of nine investigated azulene dithiolates, four molecular junctions (1,3-, 1,5-, 2,6-, and 4,7-connections) show high current compared with only one position from naphthalene dithiolate (1,4-). A current rectification ratio of ca. 4 was found in case of 2,7-azulene dithiolate. The remaining connections give low to moderate current. Aromaticity and ability of different connections to form quinonoid structure were used to explain electrical conductivity of the studied molecular junctions. The data were interpreted in terms of transmission spectra and molecular projected self-Hamiltonian eigenstates. Orbital symmetry rule and quantum interference have also been discussed.

Attenuation of Redox Switching and Rectification in Azulenequinones/Hydroquinones after B and N Doping: A First‐Principles Investigation

“…0 if atom is carbon h if the atom involved is a heteroatom (6) Considering the bond between atoms 1 and 2, it involves two carbon atoms, so the corresponding adjacent matrix element in A is 1. If we consider the bonding between atoms 5(6) and 13 (14), it involves a carbon atom and an oxygen (sulfur) atom, so the matrix element is taken from the parameterization of heteroatoms in Chapter 5 of Streitwieser's book. [65] The values of h and k used in the present study are given in Table S6, Supporting Information.…”

“…Az, as shown in Figure (with nomenclature carbon positioning according to the International Union of Pure and Applied Chemistry (IUPAC) rules), is feasible for potential usage in future optoelectronic and nanoelectronic applications that is due to their distinctive blue color and their unique electronic properties as explored experimentally and theoretically. [ 14,15 ]…”

“…Az, as shown in Figure 1 (with nomenclature carbon positioning according to the International Union of Pure and Applied Chemistry (IUPAC) rules), is feasible for potential usage in future optoelectronic and nanoelectronic applications that is due to their distinctive blue color and their unique electronic properties as explored experimentally and theoretically. [14,15] Quinone-based organic molecules are identified under the class of redox-active organic compounds carrying two adjacent or separated carbonyl groups in the molecule's ring structure. [16] Being high in their cost productiveness and low in their environmental burden have allowed researchers to explore the benefits of such redox-active materials that have led to significant functionalities for example, that of achieving multiple -conjugated electrons when undergoing redox reactions.…”

Effect of gold electrode crystallographic orientations on charge transport through aromatic molecular junctions

“…So, we computed the eigen states of HOMO and LUMO for three AMJs at zero bias by using Equation (8). The matrix elements of zeroth Green's function G rs (0) R/A for molecular part at Fermi level are expressed as Equation (7) as suggested by El-Nahas et al [44]:…”

“…From Equation (8), a given metal/molecule interface conducts if its HOMO and LUMO coefficients add to each other, i.e. if they are in phase whereas insulates if they cancel each other [44]. We contemplated that 1,1,0 orientation exhibited the delocalised character of electron cloud resulting in ample contribution towards conduction.…”