TY - JOUR
T1 - In situ measurements of oligoaniline conductance
T2 - Linking electrochemistry and molecular electronics
AU - Chen, Fan
AU - Nuckolls, Colin
AU - Lindsay, Stuart
N1 - Funding Information:
This work was supported by the National Science Foundation through NIRT (ECS01101175) and NSEC (CHE-0117752) awards and the New York State Office of Science, Technology, and Academic Research. We thank Nongjian Tao, Kerry Hipps and Jin He for useful discussions.
PY - 2006/5/9
Y1 - 2006/5/9
N2 - The single-molecule conductance of a dithiolated aniline trimer has been measured under potential control and also under an inert solvent. In each experiment, two sets of currents are found, differing by a factor 4, and these are tentatively assigned to differing connections to the electrodes (e.g., on-top vs. hollow sites). The conductances peak (to 17 ± 1.6 and 5.8 ± 0.85 nS) between the first and second oxidations of the molecule and change smoothly with surface potential. There is no evidence for a coexistence of oxidized and reduced molecules. Measurements made at a fixed surface potential as a function of tip to substrate bias show a peak current at 0.1 V followed by a region of negative differential resistance. This is accounted for semi-quantitatively by modification of the local potential by the applied bias altering the oxidation state of the molecule under the probe. Measurements made in toluene are Ohmic, indicating that the tip does not alter the oxidation state of the molecule in the absence of screening ions. We discuss the role of gap geometry and bonding in these processes.
AB - The single-molecule conductance of a dithiolated aniline trimer has been measured under potential control and also under an inert solvent. In each experiment, two sets of currents are found, differing by a factor 4, and these are tentatively assigned to differing connections to the electrodes (e.g., on-top vs. hollow sites). The conductances peak (to 17 ± 1.6 and 5.8 ± 0.85 nS) between the first and second oxidations of the molecule and change smoothly with surface potential. There is no evidence for a coexistence of oxidized and reduced molecules. Measurements made at a fixed surface potential as a function of tip to substrate bias show a peak current at 0.1 V followed by a region of negative differential resistance. This is accounted for semi-quantitatively by modification of the local potential by the applied bias altering the oxidation state of the molecule under the probe. Measurements made in toluene are Ohmic, indicating that the tip does not alter the oxidation state of the molecule in the absence of screening ions. We discuss the role of gap geometry and bonding in these processes.
KW - Electrochemical gating
KW - Molecular electronics
KW - Oligo aniline
KW - Single molecule conductance
UR - http://www.scopus.com/inward/record.url?scp=33646228845&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646228845&partnerID=8YFLogxK
U2 - 10.1016/j.chemphys.2005.08.052
DO - 10.1016/j.chemphys.2005.08.052
M3 - Article
AN - SCOPUS:33646228845
SN - 0301-0104
VL - 324
SP - 236
EP - 243
JO - Chemical Physics
JF - Chemical Physics
IS - 1 SPEC. ISS.
ER -