Site-Selective Controlled Dealloying Process of Gold-Silver Nanowire Array: a Simple Approach towards Long-Term Stability and Sensitivity Improvement of SERS Substrate

Abstract

Limitations of achieving highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate greatly concern the suitable method for fabrication of large-area plasmonic nanostructures. Herein we report a simple approach using template-based synthesis to create a highly ordered two-dimensional array of gold-silver alloy nanowires, followed by the controlled dealloying process. This particular step of mild acid etching (15%v/v nitric acid for 5 min) allowed the formation of Raman hot spots on the nanowire tips while maintaining the integrity of highly active alloy composition and rigid nanowire array structure. Full consideration of SERS substrate performance was accomplished using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. Exceedingly higher SERS signal (150-fold) can be achieved with respect to typical gold film substrate. Moreover, an excellent stability of SERS substrate was also determined for over 3 months storage time. In contrast to the previous studies which stability improvement was accomplished at a cost of sensitivity reduction, the simultaneous improvement of sensitivity and stability makes the controlled dealloying process an excellent choice of SERS substrate fabrication. In addition, uniformity and reproducibility studies indicated satisfactory results with the acceptable values of relative standard deviation.

Core–shell Au@AuAg nano-peanuts for the catalytic reduction of 4-nitrophenol: critical role of hollow interior and broken shell structure

“…14 Apart from the morphology, the composition of nanoparticles also inuences their catalytic property. Various AgAu bimetallic hollow nanostructures such as nanosphere, 15,16 nanocubes, [17][18][19] nanowires, 20 nanorods, 14 nanotubes, 21 nanoshells, 22 nanobowls, 23 and nanoframes 24 are highly efficient in various catalytic reactions such as the reduction of nitrophenol, 14 degradation of methylene blue, 25 aniline oxidation, 24 and oxidation of various organic molecules. 26 Zheng et al compared Au nano boxes with their hollow counterpart "nanocages" and reported them as catalytically more active.…”

Plasmonic-induced SERS enhancement of shell-dependent Ag@Cu2O core–shell nanoparticles

“…[13][14][15] For most plasmonic-based SERS study, researchers focus on metal materials, which are induced via localized surface plasmon resonance (LSPR) by light irradiation and provide special optical responsive component in SERS. 16,17 By controlling the sizes, morphologies, composition, and geometry of the particles, we can easily tune the LSPR properties of these particles. [18][19][20][21] Noble metal cores@semiconductor shell nanocomposites have been recognized as a promising functional material with the unique plasma oscillation mode.…”

Plasmon-coupled Charge Transfer in FSZA Core-shell Microspheres with High SERS Activity and Pesticide Detection

“…Figure 2a shows the Raman spectra of 4-MBA (10 −3 M) adsorbed on the FSZA core-shell microspheres and 4-MBA powder. The SERS signals at 839, 1079, 1140, 1183, 1364, and 1587 cm −1 are observed on the FSZA core-shell microspheres 18,19 . The two dominant peaks at 1079 and 1587 cm −1 are assigned to the ring-breathing modes.…”