Structure-property relationships in redox-gated single molecule junctions--a comparison of pyrrolo-tetrathiafulvalene and viologen redox groups.
We demonstrate that the electrical "switching" behavior of single molecules connected between two electrode contacts can be controlled by altering their structure and electrochemical characteristics. The electrical properties of gold|molecule|gold single molecule junctions incorporating HS(CH2)6-X-(CH2)6SH, where X = viologen (4,4'-bipyridinium) or pyrrolotetrathiafulvalene, are determined using a scanning tunneling microscopy based technique. The switching behavior, controlled through a tuneable electrochemical gate, changes from an on-off response (viologen) to an off-on-off response (pyrrolotetrathiafulvalene) on changing the central redox group. In contrast, the electrical properties of junctions incorporating redox-inactive HS(CH2)6-1,4-C6H4-(CH2)6SH do not alter significantly as a function of applied potential.
Leary
Edmund
E
Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
Higgins
Simon J
SJ
van Zalinge
Harm
H
Haiss
Wolfgang
W
Nichols
Richard J
RJ
Nygaard
Sune
S
Jeppesen
Jan Oskar
JO
Ulstrup
Jens
J