Fabricating Gold Nanoparticles And Modified Them On Fiber

It is a hot issue to design and synthesize nanomaterials with controlled compositions, structures and morphologies according to the applicational requirements. The metal nanoparticles with tunable surface plasma resonance (SPR) were intensely attractive for their unique optical properties and their applications in biomedicine, catalysis, electronics, communication and other fields.In this thesis, different morphology of gold nanoparticles was fabricated, and then the reaction mechanism was studied. In theory, we analyzed the origin sources of the special optical properties and according to this discussed the application on fiber sensing was came up. We also did some related experiments.In theory, the generating mechanism of the local surface plasma resonance (LSPR) effect and the surface enhanced Raman scattering (SERS) effect of the Gold nanoparticles is analyzed; the distribution characteristics of evanescent field on the surface of conical fiber is researched, and the structure and testing principle of fiber sensing according to LSPR is concerned.In the experiment, the spherical gold nanoparticles and other shaped gold particles were fabricated by the reduction method and seed-mediate growth method respectively. In the reduction method, sodium citrate and NaBH4 are used as the reductant to product the spherical gold nanoparticles, and characterized the producer by the TEM. Then further comparison is been done to research the difference between this two kinds of methods. Meanwhile the reaction mechanism of the process is been discussed, and the experimental conditions is been considered. Seed–mediate growth method was used to prepare star, spindle and rod nanoparticles. Research on the reaction mechanism and reagent, we come to the conclusion: the morphologies of the production can be effectively controlled by the adjustment of the growth solution and the seed. TEM, UV-Vis spectroscopy and Raman spectroscopy were used to characterize the prepared nanoparticles. Test the difference of UV-Vis spectrum between different sizes of spherical gold nanoparticles. We combined with both TEM pictures and UV-Vis spectroscopy of different morphology nanoparticles indicating that the morphologies impact of the optical properties of gold nanoparticles greatly.In order to search the application of star-shaped gold nanoparticles with predominant LSPR effect, we did a lot of preliminary exploration, trying to modify the nanoparticles on optical fiber, named optical fiber sensor which based on the effect of LSPR. This sensor fall together all the excellent of fiber and gold nanoparticles, such as little interference, signal transduction from fiber and stability, easy to combine with many substances and optical properties of the special advantages. In this paper we explore an effective way to modify star-shaped of gold particles on the tipper fiber.