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All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
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Intermolecular Effects on Tunneling through Acenes in Large-Area and Single-Molecule Junctions
Yuru Liu1,2, Luca Ornago3, Marco Carlotti1,2
1Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
The Journal of Physical Chemistry. C, Nanomaterials and Interfaces
|October 23, 2020
Summary
Conductance of single molecules and monolayers with acene-functionalized cores was studied. Increasing acene length enhanced conductance, while intermolecular effects influenced junction bridging and packing in self-assembled monolayers.
Area of Science:
- Molecular Electronics
- Nanotechnology
- Condensed Matter Physics
Background:
- Understanding charge transport in molecular junctions is crucial for developing molecular electronic devices.
- Oligophenyleneethynylene (OPE) derivatives with extended conjugation offer tunable electronic properties.
- The influence of molecular conformation and intermolecular interactions on conductance is not fully understood.
Purpose of the Study:
- To investigate the electrical conductance of single molecules and self-assembled monolayers (SAMs) of acene-functionalized OPEs.
- To correlate conductance with acene length and molecular packing.
- To elucidate the role of intermolecular effects and junction geometry in charge transport.
Main Methods:
- Mechanically Controlled Break Junction (MCBJ) experiments to measure single-molecule conductance.
- Fabrication of SAMs with eutectic Ga-In (EGaIn) top-contacts.
- Theoretical calculations to support experimental observations and predict conductance behavior.
Main Results:
- MCBJ experiments revealed multiple conductance plateaus, with the higher plateau showing increased conductance with acene length, matching theoretical predictions.
- Lower conductance plateaus in MCBJ were attributed to multi-molecule junctions with intermolecular interactions.
- Pentacene derivative SAMs in EGaIn junctions exhibited unusually low conductance, suggesting poor molecular packing and significant intermolecular contacts.
Conclusions:
- Intermolecular effects and junction geometries significantly impact conductance fluctuations between single-molecule and ensemble junctions.
- Acene length is a key factor in tuning single-molecule conductance.
- Studying molecules in both single-molecule and SAM platforms provides complementary insights into charge transport mechanisms.
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