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Low temperature self-agglomeration of metallic Ag nanoparticles on silica sol-gel thin films

Akhavan, O ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1088/0022-3727/41/19/195305
  3. Publisher: 2008
  4. Abstract:
  5. A facile sol-gel synthesis for self-agglomeration of metallic silver nanoparticles, with fcc crystalline structure, on the silica surface in a low annealing temperature has been introduced. X-ray photoelectron spectroscopy (XPS) revealed initial agglomeration (∼30 times greater than the nominal concentration of Ag) of the nanoparticles on the surface of the dried film (100 °C) and also their oxidation as well as easy diffusion (with 0.08 eV required activation energy) into the porous silica thin films, by increasing the annealing temperature (200-400 °C). By raising the Ag concentration from 0.2 to 1.6 mol% in the sol, the average size of the Ag nanoparticles increased from ∼5 to 37 nm corresponding to a redshift of the optical plasmon resonance absorption peak from 404 to 467 nm. The high concentration of Ag (1.6 mol%) in the sol resulted in a rough surface containing compact nanoparticles. Using power spectral density analysis of the atomic force microscopy images, we have found that the highest contributions in the surface roughness of the dried silica films were caused by the particles ranging from ∼62 to 159 nm. The particles smaller than ∼39 nm did not show any detectable contributions in the surface roughness of the dried silica film. Based on the XPS analysis, a mechanism has also been proposed for the self-agglomeration of the Ag nanoparticles on the surface of the aqueous sol-gel silica thin films. © 2008 IOP Publishing Ltd
  6. Keywords:
  7. Absorption ; Activation energy ; Agglomeration ; Annealing ; Chemical sensors ; Colloids ; Concentration (process) ; Curing ; Electric fuses ; Friction ; Gelation ; Gels ; Molecular orbitals ; Molecular spectroscopy ; Nanoparticles ; Nanostructured materials ; Nanostructures ; Oxides ; Photoelectron spectroscopy ; Silica ; Sol-gel process ; Sol-gels ; Sols ; Surface diffusion ; Surface properties ; Surface roughness ; Thick films ; Thin films ; X ray photoelectron spectroscopy ; Ag nano-particles ; Annealing temperature ; Atomic force ; Average size ; Crystalline structures ; H igh concentrations ; Low temperature ; Metallic silver ; Optical- ; Plasmon resonance absorption ; Porous silicas ; Power-spectral-density analysis ; Red shifting ; Rough surfaces ; Self-agglomeration ; Silica films ; Silica sol gels ; Silica surfaces ; Sol-gel silica ; Sol-gel synthesis ; XPS analysis ; Silver
  8. Source: Journal of Physics D: Applied Physics ; Volume 41, Issue 19 , 2008 ; 00223727 (ISSN)
  9. URL: https://iopscience.iop.org/article/10.1088/0022-3727/41/19/195305/meta