Surface Enhanced Fluorescence Of Silver Nanoparticle Self-assemblied Film

Metal nanostructures exhibit remarkable optical properties due to their surface plasmon resonance and generate the effect of surface enhanced fluorescence. As a new spectral technology, surface enhanced fluorescence spectroscopy have the prospect of application in biological analysis and many other areas. Metallic nanoparticles have been shown to enhance the fluorescence emission, increase the fluorescence resonance energy transfer and enhance the excitation efficiency, so surface enhanced fluorescence is intensively dependent on the metallic nanostructure. Therefore, surface enhanced fluorescence spectroscopy can be controllably researched by developing different shapes of nanoparticles and fluorophores, which will greatly promote the development of the theory and applications. Based on the development of surface enhanced fluorescence, There are mainly three aspects in this thesis as follow:1. Spherical silver colloid has been synthesized by a hydrothermal method. The diameter of spherical silver nanoparticle is 75nm. We chose Ru(bpy)32+ as probe and obtain its fluorescence enhancement on spherical silver nanoparticle self-assemblied film. The effect of distance-dependent fluorescence enhancement has been discussed with different number of spacing bilayers. For spherical silver nanoparticle self-assemblied film, the thickness of spacing bilayers is about 9 nm, and the fluorescence enhancement of Ru(bpy)32+ is about 14.2. The fluorescence enhancements of four different fluorophores have been investigated on spherical silver nanoparticle self-assemblied film. They are Ru(bpy)32+, RhB, R6G and Atto610. We chose Atto 610 and Ru(bpy)32+ as probes to evaluate the enhancement of two kinds of silver nanoparticle self-assemblied films. For spherical silver nanoparticle, with the excitation band of fluorophores red shifting, enhancement factor has decreased from 14 to 2.6. The fluorescence enhancements are 1.6 for Ru(bpy)32+ and 2.9 for Atto 610 on tetrahedrons.3. We obtain the FRET of Ru(bpy)32+ to Atto 610 on spherical silver nanoparticle self-assemblied film with different molar ratios. The FRET efficiency has the 2.8-fold increase and the F?rster distance has the 1.33-fold improvement when the molar ratio of acceptor/donor is 0.12.