Gold nanocages represent a novel class of nanostructures with tunable Surface Plasmon Resonance (SPR). By controlling the length of the arms, their SPR peaks could be tuned from the visible to the near-infrared region with numerous applications in optoelectronic, sensors, nanomedicine and specially cancer diagnosis and treatment. Herein we report synthesis of gold nanocages using a simple procedure based on the galvanic replacement between Ag nanocubes and aqueous gold solution. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultra violet visible (UV-Vis) spectroscopy were used to characterize Ag nanocubes and gold nanocages. Cubic silver nanostructures were first synthesized by conventional polyol method at the presence of sodium sulfide to highly tune the shape and size of the nanocubes. Optimized cubic silver nanostructures were obtained at 90 μl of sodium sulfide injection into the solution. Moreover, the effect of quality of the cubic structure on the shape and uniformity of gold nanocages was investigated. Hollow and porous gold nanocages, with SPR peak ranging from 700 to 800 nm, were successfully obtained at 2.5 mL injection of HAuCl4 into the solution.
