Anchor-electrode interfaces play a critical role in controlling charge transport in molecular electronic devices. In this work, we study the charge transport properties of molecular junctions based on para-linked oligophenyls terminated with a wide variety of different chemical anchors in a nonpolar solvent. Our results show that we can systematically control the number of covalent bonds (0, 1, or 2) formed between thiol anchors and gold interfaces for p-terphenyl molecules under a range of experimental conditions. Surprisingly, we observe a strikingly large jump in conductance in amine- and thiomethyl-terminated p-terphenyl junctions at high applied bias. We posit that this phenomenon arises due to <i>in situ</i> formation of Au-N and Au-S covalent bonds at one interface under high electric fields. We systematically study the dative to covalent bond transition using a variety of different chemical anchors and experimental conditions. Together with molecular modeling and density functional theory simulations, these results support our hypothesis regarding dative to covalent transitions in chemical anchors. Overall, we envision that this work will open new avenues for using electrostatic catalysis to manipulate anchor-electrode interfaces and to design programmable electronic devices.

Manipulating chemical bonds on metal interfaces at the single molecule level

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.