Redox state dependence of single molecule conductivity.
Spontaneous formation of stable molecular wires between a gold scanning tunneling microscopy (STM) tip and substrate is observed when the sample has a low coverage of alpha,omega-dithiol molecules and the tunneling resistance is made sufficiently small. Current-distance curves taken under these conditions exhibit characteristic current plateaux at large tip-substrate separations from which the conductivity of a single molecule can be obtained. The versatility of this technique is demonstrated using redox-active molecules under potential control, where substantial reversible conductivity changes from 0.5 to 2.8 nS were observed when the molecule was electrochemically switched from the oxidized to the reduced state.
Haiss
Wolfgang
W
Centre for Nanoscale Science, Chemistry Department, University of Liverpool, Liverpool L69 7ZD, U.K. w.h.haiss@liv.ac.uk
van Zalinge
Harm
H
Higgins
Simon J
SJ
Bethell
Donald
D
Höbenreich
Horst
H
Schiffrin
David J
DJ
Nichols
Richard J
RJ