Figure 2.

Verification of the growth of 5 nm AuNPs in the presence of H₂O₂ and HAuCl₄. (a) With the addtion of varying amounts of H₂O₂ into the mixture of 5 nm AuNPs (8.3 nM) and HAuCl₄ (0.6 mM), the solutions changed gradually from colorless to red. (b) Appearance of the absorption bands at around 530 nm reflects the colorless-to-red process. (c) A_530nm values were plotted against various concentrations of H₂O₂. Error bar: standard deviations of three independent measurements. (d–f) TEM images of 5 nm AuNPs (d) and those after adding (e) 10, (f) 100, and (g) 1000 μM of H₂O₂, respectively. Scale bar, 50 nm.