Morphology control of gold nanoparticles on glass surface realized by electric field assisted dissolution method

Abstract

Noble metal nanoparticles have potential applications in photonics, catalysis, and bio-labeling, owing to their much unique optical properties and surface activities. Monodisperse spherical Au nanoparticles with sizes in a range of about 60-80 nm are formed on the glass surfaces via ion sputtering and follow-up heat treatment. At an appropriate temperature, the electric field assisted dissolution process of Au nanoparticles is realized by the strong direct current electric field in step-like feature. In the different color areas of glass surface, it can be found that the original spherical Au nanoparticles are dissolved into the particles with the shape of a lunar eclipse. From surface plasmon resonance absorption properties and scattering electron microscopy images of Au nanoparticles in the different color areas, the influence of experimental condition on property of gold nanoparticle is demonstrated. From the current-voltage characteristics in electric field assisted dissolution experimental process, the physical process of Au nanoparticle dissolution under strong direct current electric field is analysed: the tunneling process of ejected electrons from Au particles to the anode starts, then followed by transfer process of Au cations to the glass matrix and the combination process of electrons from cathode with a positive charge Au particles. The physical mechanism of morphology control of Au nanoparticles realized by electric field assisted dissolution method is discussed in detail.