SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

Nanotechnology. 2009 Jul 22;20(29):295604. doi: 10.1088/0957-4484/20/29/295604. Epub 2009 Jul 1.

Abstract

Gas-phase silver nanoparticles were coated with silicon dioxide (SiO2) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO2 coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 degrees C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10(7) particles cm(-3).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Equipment Design
  • Gases
  • Metal Nanoparticles / chemistry*
  • Microscopy, Electron, Transmission
  • Nanotechnology / instrumentation
  • Nanotechnology / methods*
  • Photochemistry / methods*
  • Silanes / chemistry
  • Silicon Dioxide / chemistry*
  • Silver / chemistry*
  • Spectroscopy, Fourier Transform Infrared
  • Ultraviolet Rays
  • Vacuum
  • Volatilization

Substances

  • Gases
  • Silanes
  • Silver
  • tetraethoxysilane
  • Silicon Dioxide