Light-Triggered Conductance Switching in Single-Molecule Dihydroazulene/Vinylheptafulvene Junctions
Author(s):
Samuel Lara-Avila, Andrey V. Danilov, Sergey E. Kubatkin, Søren Lindbæk Broman, Christian Richard Parker, Mogens Brøndsted Nielsen
Journal:
The Journal of Physical Chemistry C
Year:
2011
Volume:
115
Pages
18372–18377
DOI:
10.1021/jp205638b
Abstract:
Derivatives of 1,1-dicyano-1,8a-dihydroazulene (DHA) undergo light-induced ring-opening to a corresponding
vinylheptafulvene (VHF), which in turn is thermally reverted to
DHA. Here we have fabricated single-molecule DHA/VHF
junctions and measured light-triggered conductance switching
of these junctions. The DHA/VHF system studied includes a
substituent group at the seven-membered ring. Light-induced
conversion of this DHA to VHF in the junction is supported by a
reduced tunnelling gap in tunnelling density of states. In fact, the
reduced tunnelling gap corresponds to the reduced HOMO
LUMO gap of VHF relative to that of DHA as measured by
absorption spectroscopy and electrochemistry. For this comparison, electrochemical measurements were performed on both the
parent DHA/VHF system and the functionalized system that was subject to transport measurements. In one junction, it was possible
to switch back and forth between DHA and VHF three times, the forward reaction being induced by light and the back-reaction
occurring after waiting a period of time.