Tuning driving forces for preparation of faceted single crystalline Au nanoparticles from Au films

Tailoring the driving force of shape revolution for Au nanoparticles is proposed, and faceted single crystalline Au nanoparticles are prepared by a magnetron sputtering and post thermal annealing route. Theoretical investigation demonstrates that the grain boundary migration is driven by thermal stress at the annealing temperature lower than 600 °C, and in the higher temperature range till up to 900 °C, the shape transformation is driven by minimizing the formation energy. The experimental results successfully replicate the shape revolution of Au films to faceted single crystalline Au nanoparticles, demonstrating that in the first annealing temperature range from 400 to 600 °C, the nanoparticles change more easily from polycrystal grains into single-crystal grains as the annealing temperature increases. While, for the higher temperature range from 700 to 900 °C, the nanoparticles tend to form nanoprisms with regular hexagonal shape when the annealing temperature increasing.