Probing the surface-enhanced Raman scattering properties of Au–Ag nanocages at two different excitation wavelengths

Abstract

The surface-enhanced Raman scattering (SERS) properties of bimetallic Au-Ag nanocages has been thoroughly investigated by changing the nanocage composition, localized surface plasmon resonance (LSPR) peak position and excitation wavelength. We found a significant dependency on excitation wavelength for the Au-Ag nanocages, independent of the underlying LSPR, which can be extended to other bimetallic SERS substrates. While it is well-understood that plasmon damping can occur for Au nanoparticles when their LSPR peaks are close to interband transition frequencies and thereby attenuate SERS intensities, this study probes an additional aspect and shows that SERS intensities are reduced when the excitation light source is near interband transition frequencies regardless of the LSPR location.

Intense Raman scattering on hybrid Au/Ag nanoplatforms for the distinction of MMP-9-digested collagen type-I fiber detection

“…The gap between NCs significantly increased with increasing size and dimension of the deposited Au or Ag NCs. In addition, the average roughness (R a ) of Ag NC sample S_3 (R a E4.33 nm) was higher than that of Au NC sample G_3 (R a E2.68) due to the shape and physical properties of Au or Ag NCs (Rycenga et al, 2009;Sivashanmugan et al, 2013b;Yamamoto et al, 2013;Yang et al, 2014), as listed in Table S1.…”

“…These values were higher than the corresponding values for Au NCsfibAu_NR samples G_1fibAu_NR, G_2fibAu_NR, and G_3fibAu_NR (13-21 nm). Notably, the EM effect, and thus the SERS effect, is significantly increased by surfaces with a relatively high R a (Costa et al, 2009;Kleinman et al, 2013;Rycenga et al, 2009;Shao et al, 2014;Sivashanmugan et al, 2014Sivashanmugan et al, , 2015Sivashanmugan et al, , 2013aSivashanmugan et al, , 2013bYamamoto Fig. 2(a $ c-i) and S3(a $ c-i) show HR-FETEM images of Ag or Au NCsfibAu_NR.…”

“…S5) (Rycenga et al, 2009;Yang et al, 2014). Moreover, a tiny gap (e.g., o1 nm) formed at the interface between NCs (intra-NCs) and NRs (NCs on NRs), greatly increasing the effect of LSPR around NCs and NCs on NRs and therefore increasing the sensitivity of SERS (Rycenga et al, 2009;Yamamoto et al, 2013;Yang et al, 2014;Yilmaz et al, 2014).…”

Continuous-flow biosynthesis of Au–Ag bimetallic nanoparticles in a microreactor

“…Bimetallic nanoparticles (NPs) with alloy or coreshell structures are of great interest due to their remarkable properties exhibited in catalysis (Stamenkovic et al 2007;Yen et al 2009), optics (Rycenga et al 2009) and magnetics (Yano et al 2009). Among these, Au-Ag bimetallic NPs have been proven to show excellent performance in CO catalytic oxidation reactions at lower temperatures since they can promote the reaction of activated CO with O 2 due to their stronger adsorption capacity with O 2 than pure gold (Sandoval et al 2011;Yen et al 2009).…”

Preparation of Potassium Niobate Nanocrystals by Wet Chemical Reaction at Low Temperature

“…It is well known that nanocube preparation, especially the preparation of perovskite oxide, is difficult. In recent research on nanocube preparation, substances of metals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Also, there have been reports on binary oxides and compounds [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36].…”