Combined Electrostatic-Covalent Building of Au NPs Multilayers and Their Size-Enhanced Cohesive and SERS Properties
Figure 8
AFM pictures in tapping mode of the fourth layer of the multilayer structure before and after sonication in water for 20 minutes. (a) and (b) correspond to the AFM images of the 15 nm-sized NPs, and (c) and (d), to the 5 nm Au NPs. 15 nm Au NPs: (a) before sonication ( μm), (b) after sonication ( μm); 5 nm Au NPs: (c) before sonication ( μm), (d) after sonication ( μm).
