Anchoring Gold Nanoparticles to Gold Surfaces through Nitroxyl Radicals
O. Święch, A. Kaim,N. Hrynkiewicz-Sudnik, B. Pałys, R. Bilewicz
Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
Abstract
This report describes the interaction of the gold surface with nitroxyl radicals that can
be the basis of a new method for binding gold nanoparticles to gold substrates The gold
surface is separated from the gold nanoparticle layer by thiolated TEMPO radicals in the
sandwich-like system. TEMPO derivatives that separate gold electrode from the layer of
gold nanoparticles were oriented either to or from electrode. In both cases however
nitroxyl radicals play the role of binding units.The sandwich assemblies of both types
were studied by cyclic voltammetry, scanning tunneling microscopy and far-infrared
reflectance spectroscopy proving high efficiency of the method sincebinding of
nanoparticles by means of nitroxylmoiety resulted in higher population of nanoparticles
at the electrode surface when compared to the conventional dithiol approach.
Introduction
There are many reports on constituents of the investigated assemblies containing free
or mobile electronsconstructed from gold nanoparticles(NPs) and the gold surface.The
stable radical used in this work, TEMPO (2,2,6,6-tetramethypiperidine-1-oxyl radical),
and its derivatives have been applied as spin labels (1), spin traps (2), antioxidants (3),
mediators in “living/controlled” free radical polymerization (4), catalysts in oxidation
processes of primary and secondary alcohols to corresponding aldehydes and ketons (5),
and key components for electrode-active organic coatings (6).Systems of gold NPs or
plates grafted with organic molecules bearing mobile electrons were proposed as
components for various type of switchings and spintronic devises (7,8,9,10,11).
So, these interesting technological prospects prompted us to studycomposite
systemsthat could combine the functionalities mentioned above. Thus, our aim was to
prepare gold nanoparticles (NPs) modified with a TEMPO derivative - alkanethiol mixed
monolayer and anchor them to gold electrodes in order to produce sandwich-like
composites consisting of two conductive planes separated by an organic linker.
ECS Transactions, 35 (25) 39-45 (2011)
10.1149/1.3655509 ©The Electrochemical Society
39
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