The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands
Journal article, 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

Author

E. J. Devid

Leiden University

P. N. Martinho

University of Lisbon

Karlsruhe Institute of Technology (KIT)

Venkata Kamalakar Mutta

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

U. Prendergast

Dublin City University

C. Kubel

Karlsruhe Institute of Technology (KIT)

Karlsruhe Nano Micro Facility

T. Lemma

Dublin City University

J. F. Dayen

University of Strasbourg

T. E. Keyes

Dublin City University

B. Doudin

University of Strasbourg

M. Ruben

University of Strasbourg

Karlsruhe Institute of Technology (KIT)

S. J. van der Molen

Leiden University

Beilstein Journal of Nanotechnology

2190-4286 (ISSN)

Vol. 5 1 1664-1674

Subject Categories

Materials Engineering

Nano Technology

DOI

10.3762/bjnano.5.177

More information

Latest update

6/8/2018 5