Figure 3.

UV–Vis–NIR spectra of the silver nanoparticles prepared with different pH value: a pH 9.17, b pH 9.32, c pH 9.43, and d pH 9.89. The inset shows photographs from left to right corresponding to pH high to low.

Yu et al. Nanoscale Res Lett 2011 6:46   doi:10.1007/s11671-010-9808-6