Size-controlled growth of colloidal gold nanoplates and their high-purity acquisition

A facile while flexible approach to size-controllable high-purity colloidal gold nanoplates has been presented. By adjusting the quantity of seeds and I(-) through a seed-mediated, cetyltrimethylammonium bromide (CTABr)-assisted synthetic system, the edge length of the gold nanoplates can be adjusted from 140 to 30 nm without changing their thickness or crystal structure. By simply increasing the ion concentration of the reaction solution, the as-prepared gold nanoplates can be deposited due to the different electrostatic aggregation effects between nanoplates and spherical nanoparticles. Effective storage methods to keep the structural and optical stability of these gold nanoplates are also proposed.