CTAB-capped Au nanospheres with diameters between 10 nm and 79 nm were obtained via a seed-mediated synthesis reported previously and consisting of three consecutive steps: 1) the synthesis of Au nanosized clusters, 2) their growth into 10 nm Au nanoparticles (seeds), and 3) the growth of the Au seeds into larger spheres. To prepare Au nanoclusters, 5 ml of 0.5 mM HAuCl4 are added to 5 ml of 0.2 M CTAB in a round-bottom flask in a water bath at 27 °C under stirring. Then, 0.6 ml of 0.01 M fresh ice-cold sodium borohydride are added rapidly to the reaction mixture. The stirring is then stopped, and the reaction mixture is left undisturbed for 3 h.