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Electrocrystallization of Tetrathiafulvalene Charge-Transfer Salt Nanorods on Gold Nanoparticle Seeds
journal contribution
posted on 2014-08-14, 00:00 authored by Li Li, Pedram Jahanian, Guangzhao MaoThis paper describes electrochemical
synthesis of nanorods of tetrathiafulvalene (TTF) charge-transfer
salt on gold nanoparticle (GNP) seeds. The seed-mediated process was
monitored by cyclic voltammetry, AFM, and field-emission SEM. The
electrodeposition of GNPs (nucleation seeds) on highly oriented pyrolytic
graphite (HOPG) electrodes was studied as a function of the electrolytic
conditions. The GNP size increases with increasing HAuCl4 concentration and decreasing applied overpotential. A morphological
transition from quasi-spherical particles to dendritic aggregates
occurs when the HAuCl4 concentration increases from 0.5
to 1 mM. The electrocrystallization of (TTF)Br0.76 on the
GNP-decorated HOPG was investigated as a function of TTF concentration
and GNP morphology. We observed a preferential nucleation of (TTF)Br0.76 on the GNP seed. The seed-mediated (TTF)Br0.76 crystals display a confined crystal morphology in comparison to
those nucleated on bare HOPG. (TTF)Br0.76 nanorods as small
as 7 nm in height were nucleated on GNPs of 20 nm in height. We also
observed preferential nucleation of (TTF)Br0.76 on high-energy
facets rather than on the most prominent face of the GNP. The nanoconfinement
effect is attributed to the local curvature of the GNP seed that imposes
an interfacial strain, thus limiting the cross-sectional dimension
of the ensuing (TTF)Br0.76 crystal. This study contributes
to the understanding of electrocrystallization at the nanoscale and
a solution-based method to incorporate nanorods on nanopatterns and
nanodevices.