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Electron transport behavior of quinoidal heteroacene-based junctions: effective electron-transport pathways and quantum interference.

Accepted version
Peer-reviewed

Type

Article

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Authors

Cheng, Na 
Chen, Feng 
He, Yuanyuan 

Abstract

The electron transport behavior through a series of molecular junctions composed of tetracene (TC) and S/O substituted-TC (S/O-TC) has been studied using density functional theory (DFT) combined with the non-equilibrium Green's function (NEGF) method. The unique transport behavior has been interpreted using correlated quantum interference and electron transport pathway models. In the TC system, two dominant electron transfer channels exist as demonstrated by a detailed transmission pathway analysis. In the substituted S/O-TC systems, the electron transport behavior is regulated through either constructive or destructive quantum interference due to the existence of additional p-electrons, leading to a significant diversity of current-voltage curves. Compared to the TC molecule in the bias region from 0 to 1.0 V, an α-connected molecular junction exhibits a greater current, whereas a β-connected molecular junction shows a smaller current. The substitution with O and S atoms shows a minor effect on the conductance of the molecular junctions. In order to clarify the role of heteroatoms, a series of artificial models designed by removing specific sulfur and carbon atoms in α-S-TC have been investigated in detail. The results have demonstrated that only the S heteroatom on one side of the molecule contributes to the junction conductivity through constructive quantum interference. It has also been observed that current exchange occurs between the two electron transfer channels.

Description

Keywords

0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics

Journal Title

Phys Chem Chem Phys

Conference Name

Journal ISSN

1463-9076
1463-9084

Volume Title

20

Publisher

Royal Society of Chemistry (RSC)