Figure 4

LSPR spectra of flower-like Ag nanostructures and flower-like Ag-Au hetero-nanostructures. (a) Is the spectrum of flower-like silver nanostructures before reacting with the HAuCl₄. (b–d) Are spectra of Ag-Au hetero -nanostructures obtained by reacting with 0.05 mM aqueous solutions of HAuCl₄ for 10 min, 30 min and 40 min respectively. (e–f) Are spectra of Ag-Au hetero-nanostructures obtained by reacting with 0.5 mM aqueous solutions of HAuCl₄ for 10 min and 30 min respectively.