Figure 5.

Spectral shift based on chloroauric acid concentrations. Normalized UV-visible spectra of gold nanoparticles with increasing chloroauric acid concentrations from 0.02 to 0.05 mM in 0.01 mM increments, from 0.1 to 0.5 mM in 0.1 mM increments, and at 1 mM. A red-shifting of the plasmon is observed as the chloroauric acid concentration is increased.