Figure 4

(A) Normalized extinction spectra of Au NRs@SiO2 with different shell thickness from 2 nm to 20 nm; (B) Linearity curve of plasmon shift vs. the thickness of silica.

(A) Normalized extinction spectra of Au NRs@SiO2 with different shell thickness from 2 nm to 20 nm; (B) Linearity curve of plasmon shift vs. the thickness of silica.