Fig. 4

a Scattering spectra of three particles before (green) and after (blue) their corrosion. Spectra of each particle were given an offset of 1.1 for better visibility. Inset—their corresponding AFM images before and after corrosion showing grown protrusions. b Simulated optical scattering spectra for pure triangular-shaped silver nanoparticle (d = 0) and nanoparticle with a protrusion on the tip and with different sizes (d = 1, 2, 3 × t). Inset shows the calculated geometry of TrNP with the corrosion