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Updated: Jun 25, 2026

Covalent Attachment of Single Molecules for AFM-based Force Spectroscopy
Published on: March 16, 2020
Electron transfer mediating properties of hydrocarbons as a function of chain length: a differential scanning
Denis Scaini1, Matteo Castronovo, Loredana Casalis
1SISSA/ETTRA NanoInnovation Laboratory, Sincrotrone Trieste, S.S.14 Km 163.5, 34012 Basovizza, Trieste, Italy.
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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