Prof. Luis Liz-Marzan, Universidade de Vigo

Directing the Growth and Structure of Metal Nanocrystals

Physical Chemistry Seminar Series

The assembly of nanoparticle building blocks is a pre-requisite for the amplification of the properties of the components and/or the generation of new features unique to the ensemble. Usually, nanoparticles employed for these assemblies are spherical and lack a geometrical preference toward directional self-assembly, thus limiting their potential applications. In contrast, controlled self-assembly of non-spherical nanoparticles, such as gold nanorods, enables these arrays to form defined 1D, 2D or 3D structures with a vectorial dependence of the desired properties.

 I shall mainly focus in this presentation on the growth and shape transformation of gold nanorods, in the presence of different types of surfactants and polymers, with discussion of the effects of surface energy and crystallographic structure.1-3 Additionally, it will be shown how, by playing around with surface properties, directional assembly of the same nanoparticles can be successfully achieved.

Formation of standing 2D and 3D superlattices made of gold nanorods will be demonstrated, either when gemini surfactants are used as capping agents in aqueous solution4 or when mixed with gold nanowires.5 The extreme directionality of these assemblies is reflected in the anisotropic optical properties of the crystalline superlattices and allows the design of interesting applications, for example in ultrasensitive detection.6

References:

1. J. Pérez-Juste et al., Coord. Chem. Rev. 2005, 249, 1870-1901.
2. E. Carbó-Argibay et al., Angew. Chem. Int. Ed. 2007, 49, 8983-8987.
3. E. Carbó-Argibay et al., Angew. Chem. Int. Ed. 2010, 49, 9397-9340.
4. A. Guerrero-Martínez et al., Angew. Chem. Int. Ed. 2009, 48, 9484-9488.
5. A. Sánchez-Iglesias et al., Angew. Chem. Int. Ed. 2010, 49, 9985-9989.
6. R.A. Alvarez-Puebla et al., PNAS 2011,108, 8157-8161.

For more information contact Prof. Mostafa El-Sayed (404-894-0292).