XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PL 02
Electron T ransfer in Nanostructures of Gold Substrates
Modified with SA M and Gold Nanoparticles.
M. Blázquez, T. Pineda, R. Madueño, D. García-Raya
Departamento de Química Física y T.A., Universidad de Córdoba, Spain
mblazquez@uco.es
Nanoscale charge transfer is important in fundamental science and applications in
molecular electronics including sensors, photonics, electrocatalysis, and solar
photoconversion. Progress in the nanoscale charge transfer requires interdisciplinary
collaboration combining a wide range of materials synthesis and characterization.
Important classes of materials at the nanoscale are metal colloids and nanocrystals. The
low dimensions of these materials (1-20 nm) confer them unique properties. The ability
to construct well-defined nanostructures by bottom-up approaches is a major goal in the
field of nanoscale science and technology. In recent years, nanoparticles have been the
subject of numerous investigations being widely accepted as ideal building blocks due to
the ease of preparation and the accurate control over particle size and shape. Surface
derivatization schemes have been developed employing self assembled monolayer
(SAM) with special terminating groups which typically induce nanoparticles
organization on the surface. The SAM is prepared by the spontaneous adsorption of
molecules from liquid or gas phases producing crystalline or semi-crystalline structures
on the substrate surfaces. The high affinity of thiol groups to coin metals generates well
organized layers with a variety of chemical functions exposed to the interface. Many
applications of nanoarchitectures require chemical, optical or biological signals to be
transformed into electrical signals that are readable to modern electronic equipment.
Therefore, the ability to allow electron communication between nanoparticles and the
underlying substrate is essential for these applications. In this work we make a revision
of several procedures for SAM preparation on Au (111) single crystals. The key point is
the preparation of defect free SAMs that may show an electron transfer blocking
behavior [1]. We study some strategies for preparation of gold nanoparticles of different
sizes [2] and characterize the properties of the nanostructured material obtained by the
combination of the SAM and nanoclusters on a single crystal substrate
(Au(111)/SAM/AuNP). It can be shown that electron communication between the
anchored AuNPs and the underlying gold substrate occurs through the insulating
sandwiched monolayer. Under these conditions, the electron transfer occurs by a
tunneling process across the bridging molecules. A general discussion of the
electrochemical behavior of nanoparticle array electrodes on the basis of different
surface methods is carried out.
Acknowledgments: Project CTQ2007-62723/BQU (MEC) and Junta de Andalucía
References
[1] García-Raya, D.; Madueño, R.; Blázquez, M; Pineda, T.; J.Phys.Chem. C, 2010, 114, 3568.
[2] Viudez, A. J.; Madueño R.; Pineda, T.; Blázquez, M.; J.Phys.Chem. C, 2006, 110, 17840.
September, 811, 2010. ISEL - Lisbon 13