Synthesis process of gold nanoparticles in solution plasma

Nagahiro Saito, Junko Hieda, Osamu Takai

Research output: Contribution to journalArticle

127 Citations (Scopus)

Abstract

We describe the dynamics of the synthesis of gold nanoparticles by a glow discharge in aqueous solutions. A pulsed power supply was used to generate discharges in the aqueous solutions. The initial [AuCl4]- ion concentration and the voltage applied between the electrodes were varied. The [AuCl4]- ion was reduced by the H radicals generated in the discharge. The reduction rates were calculated from the changes in the [AuCl4]- ion concentration during the discharge time. Dendrite-shaped nanoparticles of about 150 nm size were formed in discharge during 1 min. The pH of the solution decreased gradually with the increase of the discharge time. The decrease in pH led to the dissolution of gold nanoparticles. The reduction and the dissolution rates increased proportionately with the applied voltage. The size of the gold nanoparticles decreased at 20 nm after running the discharge during 45 min. Moreover gold nanoparticles with exotic shapes, such as triangle, pentagon, and hexagon were also observed. The particles were confirmed to be as polycrystalline gold nanoparticles by electron diffraction patterns. In summary, when the reduction rate lowered as a result of dissolution, anisotropic nanoparticles were formed and continued to grow in size in the solution.

Original languageEnglish
Pages (from-to)912-917
Number of pages6
JournalThin Solid Films
Volume518
Issue number3
DOIs
Publication statusPublished - 2009 Dec 30

Keywords

  • Anisotropic shape
  • Discharge in aqueous solution
  • Gold nanoparticles

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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