Rapid Electron Tunneling Through Oligophenylenevinylene Bridges
Hadley D. Sikes,1
John F. Smalley,2*
Stephen P. Dudek,1
Andrew R. Cook,2
Marshall D. Newton,2*
Christopher
E. D. Chidsey,1*
Stephen W. Feldberg2*
We measured rate constants of thermal, interfacial
electron transfer through oligophenylenevinylene bridges between a gold electrode and a tethered redox species in contact with an aqueous electrolyte using the indirect laser-induced temperature jump technique. Analysis of the distance dependence indicates that, unlike
other bridges studied to date, the rate constants are not limited by
electronic coupling for bridges up to 28 angstroms long. The energy
levels of the bridges relative to those of the redox species rule out
hopping through the bridge. We conclude that, out to 28 angstroms, the
transfer is limited by structural reorganization and that electron
tunneling occurs in less than 20 picoseconds, suggesting that
oligophenylenevinylene bridges could be useful for wiring molecular
electronic elements.
1 Department of Chemistry, Stanford University,
Stanford, CA 94305-5080, USA.
2 Brookhaven National
Laboratory, Upton, NY 11973, USA.
*
To whom correspondence should be addressed. E-mail:
smalley{at}bnl.gov, newton{at}bnl.gov, chidsey{at}stanford.edu,
feldberg{at}bnl.gov
