Figure 6.

Plasmonic properties of the 30–10–30 nm heterotrimer. (a) UV–vis absorbance spectra of experimental and simulated heterotrimer. (b) FDTD simulations showing the distributions of the local electric field enhancement (E/E₀) of trimers at 633 nm. Top: Trimer with a bending angle θ = 0°, average SERS EF about 2 nm away from the central particle is 5.9 × 10⁵. Bottom: Trimer with bending angle θ = 10°, average SERS EF about 2 nm away from central particle is 8.5 × 10⁵. Scale bars: 10 nm. (c) SERS spectrum of TAMRA on a heterotrimer using 633 nm excitation.