title: Role of solvents in the electronic transport properties of single-molecule junctions.
abstract: We report on an experimental study of the charge transport through tunnel gaps formed by adjustable gold electrodes immersed into different solvents that are commonly used in the field of molecular electronics (ethanol, toluene, mesitylene, 1,2,4-trichlorobenzene, isopropanol, toluene/tetrahydrofuran mixtures) for the study of single-molecule contacts of functional molecules. We present measurements of the conductance as a function of gap width, conductance histograms as well as current-voltage characteristics of narrow gaps and discuss them in terms of the Simmons model, which is the standard model for describing transport via tunnel barriers, and the resonant single-level model, often applied to single-molecule junctions. One of our conclusions is that stable junctions may form from solvents as well and that both conductance-distance traces and current-voltage characteristics have to be studied to distinguish between contacts of solvent molecules and of molecules under study.
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Luka-Guth
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hambsch
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bloch
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ehrenreich
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Bernd Michael
authors.initials: BM
authors.lastname: Briechle
authors.affiliation: Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany.
authors.forename: Filip
authors.initials: F
authors.lastname: Kilibarda
authors.affiliation: Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Sendler
authors.affiliation: Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Sysoiev
authors.affiliation: Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Huhn
authors.affiliation: Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany.
authors.forename: Artur
authors.initials: A
authors.lastname: Erbe
authors.affiliation: Physics Department, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Scheer
keywords: electrochemical environment; mechanically controllable break junction; molecular electronics; polar solvent; single-molecule junctions