Loading...

Chemical durability of metallic copper nanoparticles in silica thin films synthesized by sol-gel

Akhavan, O ; Sharif University of Technology | 2008

878 Viewed
  1. Type of Document: Article
  2. DOI: 10.1088/0022-3727/41/23/235407
  3. Publisher: 2008
  4. Abstract:
  5. In this study, chemical durability of metallic copper nanoparticles dispersed in sol-gel silica thin films was investigated by exposing the films to air after a reduction process. At first, heat treatment in air for 1 h produced silica films containing crystalline cupric oxide nanoparticles agglomerated on the film surface. Subsequently, reduction of the oxidized films in a reducing environment of N2-H2 for another 1 h at temperatures of 400, 500 and 600 °C resulted in the formation of crystalline metallic Cu nanoparticles diffused in the silica matrix. The time evolution of the surface plasmon resonance absorption peak of the reduced Cu nanoparticles was studied after the reduction processes at different temperatures. By fitting the optical absorption spectra with the Mie model, the conversion of Cu into CuO in the silica films exposed to air was examined as a function of the elapsing time. It was found that increasing the reducing temperature resulted in greater diffusion of the reduced Cu nanoparticles into the substrate, and also, in a decrease in the water content of the silica film. Diffusion of the nanoparticles decreased the number of particles exposed to air, and further, the decrease in the water content densified the silica film surrounding the diffused nanoparticles. While after the reduction process of the films at 400 °C, the presence of water in the film and considerable copper on the surface resulted in conversion of 94% of the reduced Cu into CuO in just 24 h, by reducing the film at the high temperature of 600 °C, no water and small copper concentration could be detected on the silica film so that only 8% of the Cu nanoparticles converted to CuO in as much as 12 months. © 2008 IOP Publishing Ltd
  6. Keywords:
  7. Chemical durability ; Copper concentration ; Cu nanoparticles ; Cupric oxide ; Film surfaces ; High temperature ; Metallic copper ; Metallic Cu nanoparticles ; Optical absorption spectrum ; Oxidized films ; Presence of water ; Reducing environment ; Reducing temperature ; Reduction process ; Silica film ; Silica matrix ; Silica thin films ; Sol-gel silica ; Surface plasmon resonance absorption ; Time evolutions ; Absorption ; Copper metallurgy ; Copper oxides ; Crystalline materials ; Durability ; Gelation ; Gels ; Light absorption ; Nanoparticles ; Oxide films ; Silica ; Sol-gel process ; Sol-gels ; Sols ; Surface plasmon resonance ; Thin films ; Water content ; Copper
  8. Source: Journal of Physics D: Applied Physics ; Volume 41, Issue 23 , November , 2008 ; 00223727 (ISSN)
  9. URL: https://iopscience.iop.org/article/10.1088/0022-3727/41/23/235407/meta