First-principles study of rectification in bis-2-(5-ethynylthienyl)ethyne molecular junctions

Shundong Yuan; Shiyan Wang; Qunbo Mei; Qidan Ling; Lianhui Wang; Wei Huang

doi:10.1021/jp204161z

First-principles study of rectification in bis-2-(5-ethynylthienyl)ethyne molecular junctions

J Phys Chem A. 2011 Aug 18;115(32):9033-42. doi: 10.1021/jp204161z. Epub 2011 Jul 27.

Authors

Shundong Yuan¹, Shiyan Wang, Qunbo Mei, Qidan Ling, Lianhui Wang, Wei Huang

Affiliation

¹ Jiangsu Key Laboratory of Organic Electronics & Information Displays and Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210046, People's Republic of China.

PMID: 21718049
DOI: 10.1021/jp204161z

Abstract

Using density functional theory (DFT) combined with the first-principles nonequilibrium Green's function (NEGF), we investigated the electron-transport properties and rectifying behaviors of several molecular junctions based on the bis-2-(5-ethynylthienyl)ethyne (BETE) molecule. To examine the roles of different rectification factors, asymmetric electrode-molecule contacts and donor-acceptor substituent groups were introduced into the BETE-based molecular junction. The asymmetric current-voltage characteristics were obtained for the molecular junctions containing asymmetric contacts and donor-acceptor groups. In our models, the computed rectification ratios show that the mode of electrode-molecule contacts plays a crucial role in rectification and that the rectifying effect is not enhanced significantly by introducing the additional donor-acceptor components for the molecular rectifier with asymmetric electrode-molecule contacts. The current-voltage characteristics and rectifying behaviors are discussed in terms of transmission spectra, molecular projected self-consistent Hamiltonian (MPSH) states, and energy levels of MPSH states.