Electric-field-assisted alignment of supramolecular fibers

A molecular wire consisting of a metal/molecule/metaljunction can be regarded as the basic building block for future nanoelectronics applications. Alongside the great effort expendedin the last ten years on the use of single molecules aselectroactive components, there is also a growing interest centered on the use of supramolecular architectures as Electroactivespecies to bridge metallic electrodes. The supramolecularapproach can enhance the mechanical and electronicproperties of the wire, which should improve theperformance of electronic devices. One major challenge in the study of charge transfer acrossorganic molecules is achieving reproducible attachment betweenmetallic electrodes. Although different electrode pairs have been employed, including break junctions, lithographicallytailored nanoelectrodes, and a solid substrate and aconductive tip of an atomic force microscope or a mercurydrop, new, scalable routes to the controlled incorporation of nanometer-scale objects in the gap between nanoelectrodesare required. We have chosen a gel-forming functionalized 1,3,5-triamidecis,cis-cyclohexane derivative, that is known to self-assemble into supramolecular fibers in aqueous solution through the formation of hydrogenbonds. Due to its wider applicability for electronicapplications, we present here attempts to form similar fibers in an organic solvent. Fibers were deposited from solutiononto two gold electrodes arranged in a source–drain geometry with micrometer-scale separation. During deposition, a DC voltage was applied between the two electrodes and the system was cooled below its sol–gel transition temperature(Tsol–gel).