Surfactant-assisted, shape-controlled synthesis of gold nanocrystals.

The shape control of gold nanocrystals has attracted extensive research interest because of their unique shape-dependent properties and widespread applications. Surfactants have been frequently used in the shape-controlled synthesis of gold nanocrystals in solution. In this feature article, we summarize some of the emerging colloidal approaches towards shape-tailored gold nanocrystals with the assistance of surfactants, focusing on the roles played by surfactants in shape control. We start with a discussion on the general strategies in shape control of gold nanocrystals, which include adsorbate-directed synthesis, seed-mediated synthesis, template-assisted synthesis, and the control of growth kinetics. Then, we highlight some recent progress in the gold nanocrystal synthesis assisted by single surfactants, mixed surfactants, supramolecular surfactants, as well as metal-surfactant complex templates, which is followed by a brief description of the potential applications of shaped gold nanocrystals in catalysis and molecular sensing.