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Séminaire de Sergio Gómez-Graña

Surfactant-directed self-assembly of metal nanoparticles


Surfactant-directed self-assembly of metal nanoparticles

Sergio Gómez-Graña, Jorge Pérez-Juste, Andrés Guerrero-Martínez,* Luis M. Liz-Marzán*

Colloid Chemistry Group, Departamento de Química-Física, Facultade de Ciencias, Universidade de Vigo, Vigo 36310 (Spain) ; segomez@uvigo.es

In recent years, substantial progress has been made regarding the synthesis of gold nanoparticles, motivated by the potential of nanoscale design to produce a diverse range of topologies with tailored plasmon resonances. Among them, gold nanorods (GNRs) have emerged as precisely plasmonic tunable anisotropic particles by controlling their aspect ratio, and nanorod self-assembly into extended nanostructured arrays. The self-assembly strategy applied to nanoparticle building blocks is a potential starting point for the amplification of the individual components properties and/or the generation of new characteristics unique to the ensemble.[1] By contrast, controlled self-assembly of non-spherical gold nanoparticles, such as GNRs, enables these arrays to undergo defined 1D, 2D, or 3D structures with a vectorial dependence of the desired properties. One area where GNRs are used to build macroscopic devices is in plasmonics because they can be synthesized with tailored optical properties and assembled into optoelectronic devices to manipulate the transfer of light on the nanoscale[2]. We will show herein that the directional self-assembly strategy of NRs can be controlled by using non-conventional surfactants (dimeric or gemini surfactants)[3]. Thus, we take advantage of amphiphilic properties of these surfactants, together with the ability of nanocrystals to register oriented liquid-crystalline phases, to synthesize GNRs that build up novel gemini-assisted standing 2D and 3D superlattices with anisotropic optical properties.[4]
However, if the applications is based in plasmonics properties, silver is more efficient than gold. This high efficiency gives silver an important range of possible applications, for instance silver is the most important patterns for SERS. The synthesis of hybrid nanoparticles of type core/shell is very promising due to the possibility to obtain anisotropic shapes which, without core, the yield is really low[5]. We benefit of the surfactant properties to achieve patterns with more efficiency in plasmon applications.

References :
[1] E.V. Shevchenko, D.V. Talapin, N.A. Kotov, S. O ́Brien, C.B. Murray, Nature 2006, 439, 55.
[2] J. Pérez-Juste, I. Pastoriza-Santos, L.-M. Liz-Marzán, P. Mulvaney, Coord. Chem. Rev. 2005, 249, 1870.
[3] R. Zana, Y. Talmon, Nature 1993, 362, 228.
[4] A. Guerrero-Martínez, J. Pérez-Juste, E. Carbó-Argibay, G. Tardajos, L. M. Liz-Marzán, Angew. Chem. Int. Ed.
2009, 48, 9484.
[5] K.Park, L. F. Drummy, R. Vaia, J. Mater. Chem 2011, 21, 15608.