Peer-Reviewed Journal Details
Mandatory Fields
Devid E.;Martinho P.;Kamalakar M.;Prendergast ú.;Kübel C.;Lemma T.;Dayen J.;Keyes T.;Doudin B.;Ruben M.;van der Molen S.
Beilstein Journal of Nanotechnology
The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands
3 ()
Optional Fields
Aromatic capping ligands Gold nanoparticles Molecular charge transport Self-assembly Surface enhanced Raman spectroscopy
© 2014 Devid et al. We prepare and investigate two-dimensional (2D) single-layer arrays and multilayered networks of gold nanoparticles derivatized with conjugated hetero-aromatic molecules, i.e., S-(4-{[2,6-bipyrazol-1-yl)pyrid-4-yl]ethynyl}phenyl)thiolate (herein S-BPP), as capping ligands. These structures are fabricated by a combination of self-assembly and microcontact printing techniques, and are characterized by electron microscopy, UV-visible spectroscopy and Raman spectroscopy. Selective binding of the S-BPP molecules to the gold nanoparticles through Au-S bonds is found, with no evidence for the formation of N-Au bonds between the pyridine or pyrazole groups of BPP and the gold surface. Subtle, but significant shifts with temperature of specific Raman S-BPP modes are also observed. We attribute these to dynamic changes in the orientation and/or increased mobility of the molecules on the gold nanoparticle facets. As for their conductance, the temperature-dependence for S-BPP networks differs significantly from standard alkanethiol-capped networks, especially above 220 K. Relating the latter two observations, we propose that dynamic changes in the molecular layers effectively lower the molecular tunnel barrier for BPP-based arrays at higher temperatures.
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