Electron transport behavior of quinoidal heteroacene-based junctions: effective electron-transport pathways and quantum interference. Issue 45 (13th November 2018)

• Record Type: Journal Article
• Authors: Cheng, Na; Chen, Feng; Durkan, Colm; Wang, Nan; He, Yuanyuan; Zhao, Jianwei
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 45(2018)
• Page Start: 28860
• Page End: 28870
• Publication Date: 2018-11-13
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp05901b
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Due to the additional p-electrons of the S/O atom, the electron transport behavior of heteroacenes is regulated through quantum interference, showing a significant diversity of the current–voltage curves. 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.