Plasmon Enhanced Fluorescence (PEF) of High and Low Quantum Yield Molecules
A new branch of fluorescence has emerged with the use of metallic nanostructures to enhance optical signals: Plasmon enhanced fluorescence (PEF). In the literature it has grown with two different names: surface enhanced fluorescence (SEF) and also metal enhanced fluorescence (MEF). In this thesis, we have explored some of the peculiar properties of plasmon enhanced fluorescence. In particular, we try to relate intrinsic molecular properties of fluorescence such as cross section and quantum yield to the enhanced signal. The source and basic properties of localized surface plasmon resonances is also discussed. The attention is then centre in the plasmon signature on the fluorescence spectrum or spectral profile modification. The matching of plasmon scattering and fluorescence emission assists in constructing fluorophore-nanoparticle systems for PEF applications. Specific experiments are discussed design to test the impact of the fluorophore quantum yield in observed enhancement. Finally, a practical technique to deliver the enhancing nanoparticles onto surfaces containing the analyte is also presented. The latter is intended for practical application and to ensure higher average enhancement values.