Preparation And Characterization Of Silver Nanoparticles

This thesis includes two parts. In the first part, Ag nanoparticles were prepared by silver mirror reaction and annealing in nitrogen. This part is divided into two groups. In the first group, Ag films with different thickness were prepared at different concentration of AgNO3solution, then annealing in N2at500℃for1hour to form Ag nanoparticles. In the second group, Ag nanoparticles were prepared at different annealing temperature. The structural properties of Ag nanoparticles were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the property of light scattering were studied by light scattering spectrometer. In the second parts, Ag nanoparticles were prepared by vacuum thermal evaporation and annealing in nitrogen. The Ag films with32nm thickness were deposited on glass substrates by vacuum thermal evaporation, followed by annealing at different temperature to form Ag nanoparticles. The structural properties of Ag nanoparticles were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). The light scattering property of Ag nanoparticles is studied by light scattering spectrometer. In this thesis, the following conclusions were obtained:1. The XRD measurement results indicated that the crystal structure of Ag nanoparticles prepared by silver mirror reaction is face-centered cubic. The degree of crystallization of Ag nanoparticles prepared at0.06mol/L AgNO3solution and annealing temperature of600℃is the best.2. The thickness of Ag films can be reduced by redcucing the concentration of AgNO3solution. The relationship of concentration of AgNO3solution and thickness of Ag films is linear.3. The results of forward scattering measurement show that light scattering of Ag nanoparticles prepared at0.06mol/L AgNO3solution and annealed at400℃is stronger. The diameter of Ag nanoparticles is about250nm.4. The results of backward scattering measurement show that light scattering of Ag nanoparticles prepared at0.04mol/L AgNO3solution is stronger when scattering angle less than40°, and the diameter of Ag nanoparticles is about295nm. The light scattering of Ag nanoparticles prepared at0.06mol/L AgNO3solution is stronger when scattering angle greater than40°, and the diameter of Ag nanoparticles is about300nm.5. The degree of crystallization of Ag nanoparticles prepared by vacuum thermal evaporation and annealed at500℃in nitrogen is the best.6. The Ag films gradually become isolated Ag nanoparticles with increase of annealing temperature. Completely isolated hemispheres nanoparticles formed when the annealing temperature greater than400℃.7. The results of forward scattering measurement show that light scattering of Ag nanoparticles prepared by vacuum thermal evaporation and annealed at300℃is stronger when scattering angle less than40°. The shape of Ag nanoparticle is irregular, with an average height of about110nm. The light scattering of Ag nanoparticles prepared at annealing temperature of400℃is stronger when scattering angle greater than40°.8. The results of backward scattering measurement show that light scattering of Ag nanoparticles prepared at annealing temperature of300℃is stronger when scattering angle less than25°. The light scattering of Ag nanoparticles prepared at annealing temperature of400℃is stronger when scattering angle greater than25°, and the diameter of Ag nanoparticles is about360nm, with an average height of about250nm.