Mass synthesis of single-crystal gold nanosheets based on chitosan

Single-crystal Au nanosheets with {1 1 1} planes as basal surfaces have been synthesized on the basis of the polysaccharide chitosan. The preferential adsorption of polar groups in chitosan molecules on {1 1 1} planes of Au nuclei may account for the formation of anisotropic nanosheets. Appropriate precursor (HAuCl4) concentrations are vital for the formation of Au nanosheets. The Au nanostructures thus prepared exhibit interesting shape-dependent optical properties. This convenient, environmentally friendly and low-cost route may be amenable to mass production.