Fig. 3. (A and B) SERS spectra of 10^–9 R6G mixed with Au@AgNPs and Au@Ag-GO nanocomposites, both of which are stored at 4 °C for 0, 7 and 60 days; (C and D) SERS spectra of 10^–9 M R6G mixed with Au@AgNPs and Au@Ag-GO nanocomposites, both of which are placed in sunlight for 0, 12, and 72 hours.