Tuning the contact conductance of anchoring groups in single molecule junctions by molecular design
A tetraphenylmethane tripod functionalized with three thiol moieties in the para position can serve as a supporting platform for functional molecular electronic elements. A combined experimental scanning tunneling microscopy break junction technique with theoretical approaches based on density funct...
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Veröffentlicht in: | Nanoscale 2019-07, Vol.11 (27), p.12959-12964 |
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Hauptverfasser: | , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A tetraphenylmethane tripod functionalized with three thiol moieties in the
para
position can serve as a supporting platform for functional molecular electronic elements. A combined experimental scanning tunneling microscopy break junction technique with theoretical approaches based on density functional theory and non-equilibrium Green's function formalism was used for detailed charge transport analysis to find configurations, geometries and charge transport pathways in the molecular junctions of single molecule oligo-1,4-phenylene conductors containing this tripodal anchoring group. The effect of molecular length (
n
= 1 to 4 repeating phenylene units) on the charge transport properties and junction configurations is addressed. The number of covalent attachments between the electrode and the tripodal platform changes with
n
affecting the contact conductance of the junction. The longest homologue
n
= 4 adopts an upright configuration with all three
para
thiolate moieties of the tripod attached to the gold electrode. The contact conductance of the tetraphenylmethane tripod substituted by thiols in the
para
position is higher than that substituted in the
meta
position. Such molecular arrangement is highly conducting and allows well-defined directional positioning of a variety of functional groups.
Molecular design allows tuning of the contact conductance of anchoring groups in single molecule junctions. |
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ISSN: | 2040-3364 2040-3372 |
DOI: | 10.1039/c9nr04071d |