Eur. Phys. J. B (2018) 91: 184
https://doi.org/10.1140/epjb/e2018-90269-3

Regular Article

Switching behavior induced by different substituents of group in single molecular device

¹ School of Science, Jiangnan University, Wuxi 214122, P.R. China
² School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P.R. China

^a e-mail: baoanbian@163.com

Received: 20 April 2018
Received in final form: 11 June 2018
Published online: 3 August 2018

Abstract

We investigate the electronic transport properties of photochromic azobenzene-based molecular devices with Au electrodes using non-equilibrium Green’s function and density functional theory. A reversible switching behavior between cis and trans isomerization is found in the device. In addition, the substituent of −NH₂ on the right end hydrogen atom of azobenzene molecule reduces the switching ratio of current, consequently the disappearance of switching behavior, while the substituent of −NO₂ improves the switching ratio of current. We discuss the different electronic transport induced by different substituents through the transmission spectra, localized density of states, molecular projected self-consistent Hamiltonian and transmission pathways. The observed polarization effect under bias is explained by the evolution of molecular projected self-consistent Hamiltonian of LUMO level. The results indicate that the electron-withdrawing group −NO₂ substituting right terminal hydrogen of azobenzene molecule becomes a candidate for improving the performance of molecular device.