Synthesis and Real Structure Group

Magneto-Plasmonic Au-Fe Nanoparticles

Marius Kamp

 

The combination of elements with different functionality into a single nanoparticle is a promising route to the design of multifunctional alloy nanoparticles. In biomedical applications, for instance, nanoparticles made of distinct metals are of special interest because of their unique properties: iron as a magnetic agent for resonance imaging (MRI) or magnetic thermotherapy and gold for its optical properties and its capability to be easily functionalized by thiolated biomolecules. Such alloy nanoparticles have also attracted attention in catalysis or spectroscopy. Apart from the composition, the ultrastructure of binary alloy nanoparticles determines their properties. The real ultrastructure may consist of a homogeneous phase (solid-solution) or phase segregations which can be characterized using advanced high-resolution electron microscopy. In a Fe-Au core-shell structure, an inert shell (gold) can protect a reactive core (iron) from oxidation thereby conserving high magnetization of the core and delivering plasmon resonance by the shell. HRTEM, ED, HAADF-STEM and tomography are used to determine the ultrastructure and morphology of the nanoparticles, EDX and EELS/EFTEM can be utilized to reveal the chemical composition. Further, in situ TEM heating experiments and wet etching experiments are applied to investigate the stability of the bimetallic nanoparticles.

 

DFG-Grant KI 1263/15-1