Matteo Castronovo - Electron Transfer Mediating Properties of Hydrocarbons as a Function of Chain Length: A Differential Scanning Conductive Tip Atomic Force Microscopy Investigation

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      Publication Details (including relevant citation   information): Scaini, Denis, Castronovo, Matteo,   Casalis, Loredana, Scoles, Giacinto, 2008,   2 (3), pp 507-515

      Abstract: The development of novel molecular and   biomolecular devices relies on the understanding of charge   transport across molecule-substrate interfaces. However,   different strategies adopted so far for fabricating and studying   transport through metal?molecule?metal junctions yield values for   the transport coefficients that differ by up to orders of   magnitude even for the same junction. Conductive tip atomic force   microscopy (CT-AFM) allows for the simultaneous measurement of   transport and morphological properties of molecular assemblies,   but absolute transport measurements depend on the nature of the   AFM tip?molecule contact. In this work we present a differential   approach to the study of metal?molecule?metal junctions based on   the combination of AFM-driven nanolithography and CT-AFM. We   nanograft patches of alkanethiol molecules in a self-assembled   monolayer of alkanethiol molecules of different chain length and   measure by CT-AFM the morphology and the transport properties of   the nanopatches and of the reference layer. The method allows for   the determination of the differential resistance between the two   molecular layers and is thus independent of environmental   factors. The validity of this approach is demonstrated by   measuring the tunneling decay constant of alkanethiols as a   function of their length.

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