Can Temperature Control the Size of Au Nanoparticles Prepared in Ionic Liquids by the Sputter Deposition Technique?

Abstract

It was recently discovered that sputter deposition of metal onto the surface of an ionic liquid generates nanoparticles in the liquid with no additional stabilizing agents. We performed small-angle X-ray scattering (SAXS) experiments to investigate the temperature effect on the structure and formation process of Au nanoparticles synthesized by this method. We selected 1-buthyl-3-methylimidazolium tetrafluoroborate as the capture ionic liquid and obtained SAXS intensities of the nanoparticles generated at various temperatures from 20 to 80 °C. The SAXS results revealed that the particle size was relatively uniform for a fixed temperature, and that it strongly depended on the temperature of the capture ionic liquid. Temperature change causes drastic changes in the viscosity of the liquid and the diffusive velocities of the scattered Au particles. Therefore, it is concluded that the collision frequency of the Au particles is one of the important factors in determining their size, as well as the stabilization...