Electrical characterization of single molecules in liquid environments

We have developed the mechanical controllable break junction technique for the use in liquid environments in order to characterize the electrical properties of single molecules in their solvents. The metallic electrodes, which form the contacts for the molecular structures, are produced on an insulating substrate in order to reduce all spurious effects coming from parallel conduction through the liquid. We present first electrical characterization of such junctions in dry and in liquid environments. The solvents range from aqueous buffer, which will be used for measurements of DNA fragments, to toluene and THF, which are typical solvents for short, conjugated organic molecules.