Finite-bias electronic transport of molecules in a water solution

Ivan Rungger, X. Chen, Stefano Sanvito, Udo Schwingenschlögl

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated theoretically by using a combination of empirical-potential molecular-dynamics and first-principles electronic-transport calculations. These are at the level of the nonequilibrium Green’s-function method implemented for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic gating to the molecular junction with a gating potential determined by the time-averaged water dipole field. Such a field is large for the polar benzene-dithiol molecule, resulting in a transmission spectrum shifted by about 0.6 eV with respect to that of the dry junction. The situation is drastically different for carbon nanotubes (CNTs). In fact, because of their hydrophobic nature the gating is almost negligible so that the average transmission spectrum of wet Au/CNT/Au junctions is essentially the same as that in dry conditions. This suggests that CNTs can be used as molecular interconnects also in water-wet situations, for instance, as tips for scanning tunnel microscopy in solution or in biological sensors.
Original languageEnglish (US)
JournalPhysical Review B
Volume81
Issue number23
DOIs
StatePublished - Jun 4 2010

Fingerprint Dive into the research topics of 'Finite-bias electronic transport of molecules in a water solution'. Together they form a unique fingerprint.

Cite this