Figure 2

SEM (A) and TEM (B) of as-prepared Au NRs and Au NRs@SiO2, respectively; (C) UV-vis spectra of Au NRs (black) and Au@SiO2 (red); (D) Photographs of Au NRs (a) and Au@SiO2 (b).

SEM (A) and TEM (B) of as-prepared Au NRs and Au NRs@SiO2, respectively; (C) UV-vis spectra of Au NRs (black) and Au@SiO2 (red); (D) Photographs of Au NRs (a) and Au@SiO2 (b).