The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands
Artikel i vetenskaplig tidskrift, 2014
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.
gold nanoparticles
aromatic capping ligands
molecular charge transport
surface enhanced Raman spectroscopy
self-assembly
Författare
E. J. Devid
Universiteit Leiden
P. N. Martinho
Universidade de Lisboa
Karlsruher Institut für Technologie (KIT)
Venkata Kamalakar Mutta
Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik
U. Prendergast
Dublin City University
C. Kubel
Karlsruher Institut für Technologie (KIT)
Karlsruhe Nano Micro Facility
T. Lemma
Dublin City University
J. F. Dayen
Université de Strasbourg
T. E. Keyes
Dublin City University
B. Doudin
Université de Strasbourg
M. Ruben
Université de Strasbourg
Karlsruher Institut für Technologie (KIT)
S. J. van der Molen
Universiteit Leiden
Beilstein Journal of Nanotechnology
21904286 (eISSN)
Vol. 5 1 1664-1674Ämneskategorier
Materialteknik
Nanoteknik
DOI
10.3762/bjnano.5.177