Gold Nanoparticle-Based Core−Shell and Hollow Spheres and Ordered Assemblies Thereof

We report on the preparation and characterization of gold nanoparticle (AuNP)-based core−shell particles and hollow spheres and of ordered structures obtained from their self-assembly. Coated particles, comprising polystyrene (PS) cores and polyelectrolyte (PE) or AuNP/PE shells, were prepared by the layer-by-layer technique, that is, via the sequential adsorption of oppositely charged PEs onto PS cores, or by the infiltration of gold nanoparticles into preassembled PE multilayers onto PS particles, respectively. The thickness of the gold nanoparticle-based coatings was varied by altering the number of preassembled PE layers into which gold nanoparticles were infiltrated and by additional electroless gold plating. Hollow spheres were obtained from the core−shell particles by either calcination or by dissolution of the PS core by exposure to tetrahydrofuran. The coated colloids were used as building blocks for the construction of ordered particle assemblies. Two different approaches were employed to form t...