Plasmonic Enhancement of Molecule-Doped Core–Shell and Nanoshell on Molecular Fluorescence

This chapter analyzes and discusses the plasmonic enhancement on molecular fluorescence of three types of spherical nanostructures: core–shell, nanoshell (NS), and silica-coated NS. The first one is the molecule-doped core–shell, which is a metal, Au or Ag, nanoparticles (NP) coated by a silica layer, denoted by Au@SiO2 or Ag@SiO2. Another one is the molecule-doped NS, a silica core coated by a metal layer, and the other one is a molecule-doped NS@SiO2. Since the cause of surface-enhanced fluorescence (SEF) is due to the surface plasmon resonance (SPR) of these nanostructures, the chapter particularly analyzes their SPR modes, and discusses the corresponding near-field amplification on the electric field. It illustrates the dependence of the fluorescence enhancement on the molecular location and orientation, particularly at the SPR modes. Furthermore, the chapter discusses the overall performance of a large number of these NPs and the Stokes-shift effects of the fluorescence excitation and emission wavelengths on the enhancement.