Bimetallic Nanoshells for Metal - Enhanced Fluorescence with Broad Band Fluorophores.

In this article, we reported the near-field interactions between the Ru(bpy)32+ complexes and plasmon resonances from the bimetallic nanoshells. The metallic nanoshells were fabricated on 20 nm silica spheres as cores by depositing 10 nm of monometallic or bimetallic shells. There were approximately 15 Ru(bpy)32+ complexes in the silica core. The metal shells were constituted of silver and/or gold. The bimetallic shells could be generated in homogeneous or heterogeneous geometries. The homogeneous bimetallic shells contained 10 nm silver–gold alloys. The heterogeneous bimetallic shells contained successive 5 nm gold and 5 nm silver shells, or alternatively, 5 nm silver and 5 nm gold shells. Optical properties of metal nanoshells were studied on both the ensemble spectra and single nanoparticle imaging measurements. The heterogeneous bimetallic shells were found to have a large scale of metal-enhanced emission relative to the monometallic or homogeneous bimetallic shells. It is because the heterogeneous bi...