Synthesis of Silver/Graphene Oxide Nanoomposites by Photodeposition and their Surface Enhanced Raman Scattering Properties
| Autor: | Keng-Hao Fan, 范耿豪 |
|---|---|
| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 In recent years, the silver/graphene nanocomposites were synthesis by chemical reduced method which applied to the surface-enhanced raman scattering has been studied, but the reaction process need reductant, it were result in environmental pollution and increased costs. The silver nanoparticles size were increased and low dispersion because the oxygen functional groups on graphene oxide surface were decrease during the chemical reaction, which may decrease surface-enhanced raman scattering effect. In this study, we use photodeposition method to fabricate silver/graphene nanocomposites which without adding reductant and the oxygen functional groups were not affected, so photodeposition method can get high dispersion and small size of silver particles. So far, the silver/graphene nanocomposites were synthesized by photodeposition more used photodegradation of dyes, but no surface enhanced Raman scattering applications, and the silver nanoparticles growth mechanism and control variable is unclear. So, we investgated the surface enhanced Raman scattering (SERS) properties, growth mechanism of silver nanoparticles and material structure of silver/graphene oxide nanocomposites. For Materials characterization, we used X-ray diffraction analyzer (XRD), fourier transform infrared spectroscopy (FTIR), raman spectroscopy (Raman), high-resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS) and high resolution electron spectroscopy (XPS) to analysized crystal structure, surface chemical bonding, surface-enhanced Raman scattering properties, morphology, surface elemental distribution and elemental chemical form, respectively. Make silver/graphene nanocomposites glass substrates to detect surface enhanced Raman scattering intensity of Rhodamine B (Rh B) dye. As a result, when silver nanoparticles deposited onto different chemical state graphene, the silver nanoparticales show the metallic characteristic and the particles size were increased with illumination time. The silver nanoparticles on the graphene oxide (GO) surface were disperse uniform and the particle size were small, but the silver nanoparticles were aggregation on the reduced graphene oxide (RGO), because the oxygen functional groups are active sites for growth silver nanoparticles which can avoid the silver nanoparticles aggregation and increase dispersion on graphene oxide surface. With increase of the amount of silver loadings, the size and density of silver nanoparticles were increased, but the silver nanoparticles were aggregation in high silver concentration. The silver/graphene oxide nanocomposites show surface enhance raman scattering (SERS) active for detect Rhodamine B (Rh B) molecular, and the result show Rh B SERS signals were raised by increasing the silver loading because the silver metal nanoparticles are SERS active sites. In this study, we found graphene oxide is a good carrier for deposition of silver nanoparticles and we can change the illumination time and the concentration of silver to control the silver particle size and density, so that the silver particles can adjustability. The silver/graphene oxide nanocomposites were fabricated by photodeposition not only applied to photodegradation dye but also applied to surfaced enhance raman scattering substrates to detect contraband food additive and biosenser biomedical testing. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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