Onset of Intense Surface Enhanced Raman Scattering and Aggregation in the Au@Ag System

Figure 5

Variation of integrated Raman intensity (left scale, red symbols) alongside aggregate-band extinction (right scale, green symbols) as a function of SERS label titrant concentration; R6G (circles, top), MPY (squares, middle), and MBA (triangles, bottom). The bottom panel also includes the wavelength corresponding to variation in for the localized surface plasmon (blue, triangles). The scale bar indicates a red-shift (up) of 1 nm. The upper left inset shows the variation of computed DLVO barrier to particle aggregation as a function of the estimated -potential for three nanoparticle specimens incubated with different concentrations of R6G (0.0, 0.5, and 1 μM).