Electric-field-assisted alignment of supramolecular fibers

A molecular wire consisting of a metal/molecule/metal junction can be regarded as the basic building block for future nanoelectronics applications. Alongside the great effort expended in the last ten years on the use of single molecules as electroactive components, there is also a growing interest centered on the use of supramolecular architectures as Electroactive species to bridge metallic electrodes. The supramolecular approach can enhance the mechanical and electronic properties of the wire, which should improve the performance of electronic devices. One major challenge in the study of charge transfer across organic molecules is achieving reproducible attachment between metallic electrodes. Although different electrode pairs have been employed, including break junctions, lithographically tailored nanoelectrodes, and a solid substrate and a conductive tip of an atomic force microscope or a mercury drop, new, scalable routes to the controlled incorporation of nanometer-scale objects in the gap between nanoelectrodes are required. We have chosen a gel-forming functionalized 1,3,5-triamide cis,cis-cyclohexane derivative, that is known to self-assemble into supramolecular fibers in aqueous solution through the formation of hydrogen bonds. Due to its wider applicability for electronic applications, we present here attempts to form similar fibers in an organic solvent. Fibers were deposited from solution onto 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).