The control of the morphology and size of a certain material at the nanoscale is a hot topic because of the spectacular effects that small changes produce on their properties (optical, magnetic, electronic…). Colloidal synthesis has proven extremely useful to prepare a wide variety of nanoparticles with tight control of size and shape. Still, much of the knowledge in this area is empirical and no general rules can be provided for a rational nanomaterial design. We are particularly interested in the synthesis of metal nanocrystals with well-defined properties as well as in understanding and control the nucleation and growth processes involved during the synthesis. Though eminently fundamental, this research is required for the design of nanoparticles with tailored properties that can be used for practical applications. Thus, our group has developed different strategies to fabricate the different types of metal nanoparticles, mainly plasmonic, with different configurations (single-component, core-shell, alloys, dimers, cages, etc.).
In the case of plasmonic nanoparticles, we fully analyze their optical properties, which originate from the so-called localized surface plasmon resonance (LSPRs). It can be described as the collective coherent oscillation of electrons from the conduction band with respect to a positive metallic lattice, occurring when a metal nanoparticle is excited by the incident light. In the case of Au, Ag, and Cu, the optical properties typically lie in the visible-NIR range and can be easily modulated by tuning particle size and shape, as well as interparticle distance and the refractive index of the surrounding medium.
Moreover, we are also interested in combining metal nanoparticles with other materials (metal, silica, polymer, macrocycles, etc.) to fabricate hybrids materials with defined composition, surface chemistry, configurations, and so on for achieving multifunctional or enhanced properties.
