Properties Of Metal Nanoparticles And Their Applications

The synthesis and applications of metal nanomaterials suggests their great potential foreground in the physical science, chemical science and materials science, especially for unique properties, such as surface effect, volume effect, quantum size effect and macroscopic quantum tunneling effect. These properties render new applications in optics, electrics, chemists and catalyzers. The properties of noble metal nanomaterials attract much attention in recent years. Metal materials in nano-scale have predominant characters which bulk metal lacks of. In particular, metal nanomaterials have excellent optical properties due to the surface plasmon resonance (SPR). SPR is a physical concept of describing the collective oscillations of conduction band electrons in the electromagnetic field, which is influenced significantly by size, shape and surrounding medium. Size and shape of nanoparticles has been the effective control of all concerned. In recent years, with a wide range use of surface-enhanced Raman scattering, fluorescence effect of gold and silver nanoparticles, metal nanoparticles have been widely used in catalysis, photocatalysis, information storage, surface-enhanced Raman, solar cells, bio-sensors, chemical sensors, nonlinear optics, optoelectronics and other fields.This thesis focus emphasis on the synthesis, properties and applications of gold and silver nanoparaticls:the thermal decomposition of inorganic salts in oil phase for synthesis of silver nanoparticles, resulting in different size; using of citrate reduction of HAuC14 in the aqueous phase for synthesis of gold nanoparticles. With changing different protective agent (oil amine, carboxylic acides of different chain length), the size and solubility of the metal nanoparticles change. Besides, the means of transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), UV-visible absorption spectroscopy (UV-Vis) were used to characterized the metal nanoparticle's phase, size, morphology and optical properties; through different sulfhydryl groups replacing the surface protective agent, we studied the size and surface protective agents dependence of SPR effects. Furthermore, we use spin-coating after photolithography electrodes, to study the electronic properties of metal nanoparticles, and to explore the possible applications in semiconductor devices; when the size of metal nanoparticles drastically reduced, its boiling point sharply decline. After the sintering of the nanoparticles, they can be applied as the electrods of organic semiconductor devices. This paper illustrated the use of silver nanoparticles to serve as electrodes, and explored the role of sintering temperature and sintering time. Finally, we studied the interaction between the absorption spectra of metal nanoparticles, semiconductors and dyes, exploring their prospects for the applications in solar cells.This thesis mainly focused on the use of chemical liquid phase synthesis methods, combining the structure, performance and applications together, expecting offering help in the preparation of fuctional devices and dye-sensitized thin film solar cells.