A possible salicylideneanilines-based optical molecular switch induced by a reversible hydrogen transfer: an ab initio study

Abstract

The electronic transport properties of the salicylideneanilines-based molecular optical switch are investigated using a nonequilibrium Green's function formalism combined with first-principles density functional theory. The molecule that comprises the switch can convert between the enol and keto tautomeric forms upon photoinduced excited state hydrogen transfer in the molecular bridge. Theoretical results show that the current through the enol form is significantly larger than that through the keto form, which realize the on and off states of the molecular switch. The physical origin of the switching behaviour is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap. Furthermore the effect of the donor/acceptor substituent on the electronic transport through the molecular device is also discussed in detail. The switching performance can be improved to some extent through the acceptor substituent.

Keywords:

• molecular switch
• nonequilibrium Green's function
• electronic transport
• density functional theory

PACS::

• 31.15.Ar, 71.15.Mb, 73.23.-b 85.65.+h

Acknowledgment

We thank Chang-Feng Fang and Peng Zhao for useful discussions. This work was supported by National Basic Research Program of China (Grant No. 2009CB929204), the Education Department Foundation of Shaanxi Province, China (Grant No. 09JK461), the Research Fund for the Doctoral Programme (Grant No. BS0813) and the fundament research of Xian Polytechnic University (Grant No. 09XG09).