Shape evolution in Brust–Schiffrin synthesis of Au nanoparticles

• Unexpected time-dependent shape evolution of Au NPs in the Brust–Schiffrin synthesis is observed.
• The evolution is a kinetic-to-thermodynamic control process.
• Various thermodynamically unfavored shapes are formed during the evolution.
• Well-defined triangular plates can be produced considerably by tuning the types of protecting ligands.

The shape evolution and control in the Brust–Schiffrin synthesis of Au nanoparticles (NPs) is presented in this work. Different from the current wisdom, Au NPs undergoes a time-dependent shape evolution. At the beginning, small spherical NPs are produced as reported before. With prolonged time, however, big NPs with many thermodynamically unfavored shapes such as triangle and truncated triangle are formed. And they are ultimately transferred into spherical shape bigger than the original NPs. It is suggested that the shape evolution is a kinetic-to-thermodynamic control process, during which, well-defined triangular plates are produced considerably by tuning the types of protecting ligands. This reveals the potential of fabricating not only size but also shape controllable metal NPs using the popular Brust–Schiffrin synthesis.

Au nanoparticles in Brust–Schiffrin synthesis undergo a time-dependent shape evolution, suggesting the potential of fabricating both size and shape controllable metal nanoparticles.Figure optionsDownload as PowerPoint slide