Conductance switching in single light-sensitive molecular device with carbon nanotube electrodes

• Published in: Journal of applied physics 2014-08, Vol.116 (8)
• Main Authors: Xia, Cai-Juan, Gao, Kun, Zhang, De-Hua, Yang, Mao, Feng, Fei-Long
• Format: Article
• Language: English
• Subjects: Applied physics; Carbon; Chirality; Current voltage characteristics; Density functional theory; Electrodes; First principles; Green's functions; Isomers; Molecular machines; Optical switching; Resistance; Single wall carbon nanotubes; Switches
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4894144

By applying nonequilibrium Green's function formalism combined first-principles density functional theory, a new mechanism for optical switch of single molecular device with carbon nanotube electrodes is proposed. The molecule comprises the switch can convert between enol and keto isomers upon photoinduced excited state hydrogen transfer in the molecular bridge. Theoretical results show that these two isomers exhibit very different current-voltage characteristics both in armchair and zigzag junction, which can realize the on and off states of the molecular switch. Meantime, the chirality of the single-walled carbon nanotube (SWCNT) electrodes strongly affects the switching characteristics of the molecular junctions. The maximum value of on-off ratio can reach 72 at 1.6 V for the switch with zigzag SWCNT electrodes, suggesting potential applications of this junction in future design of light-driven molecular switches.