Assemblies of semiconductor and metal nanoparticles for renewable energy

Nanostructured electrodes were assembled layer-by-layer from polyacrylate-capped Pt nanoparticles (<d>=2.5 +/- 0.6 nm) in a cationic polyelectrolyte. Cyclic voltammetry revealed hydrogen adsorption peaks at the modified nanoparticles characteristic of an activated polycrystalline Pt surface, with a negative shift in the peak potentials indicating a less facile electro-adsorption relative to the polycrystalline electrode, possibly due to nanoparticle surface modification. Current-voltage measurements at multilayers of Pt nanoparticles in polyelectrolytes indicated the feasibility of charge hopping between the particles embedded in the insulating matrix. Such feasibility was also evidenced in photoluminescence quenching of Q-CdS dots (<d>=3.6 +/- 0.5 nm) assembled in polyelectrolytes upon inserting Pt nanoparticles in the architecture.