3D SERS substrate based on Au-Ag bi-metal nanoparticles/MoS₂ hybrid with pyramid structure

Abstract

It is very vital to construct the dense hot spots for the strong surface-enhanced Raman scattering (SERS) signals. We take full advantage of the MoS edge-active sites induced from annealing the Ag film on the surface of the MoS. Furthermore, the composite structure of Au-Ag bi-metal nanoparticles (NPs)/MoS hybrid with pyramid structure is obtained by the in situ grown AuNPs around AgNPs, which serves the optimal SERS performance (enhancement factor is ~9.67 × 10) in experiment. Due to the introduction of AuNPs with the simple method, the denser hot spots contribute greatly to the stronger local electric field, which is also confirmed by the finite-different time-domain (FDTD) simulation. Therefore, the ultralow limit of detection (the LOD of 10 and 10 M respectively for the resonant R6G and non-resonant CV), quantitative detection and excellent reproducibility are achieved by the proposed SERS substrate. For practical application, the melamine molecule is detected with the LOD of 10 M using the proposed SERS substrate that has the potential to be a food security sensor.

In-situ electrospun aligned and maize-like AgNPs/PVA@Ag nanofibers for surface-enhanced Raman scattering on arbitrary surface

“…To assess the SERS performances of the electrospun AgNPs/PVA@Ag nanofibers substrate, the enhancement factor (EF) was evaluated using the formula [30]:…”

Raman spectroscopy combined with multivariate analysis to study the biochemical mechanism of lung cancer microwave ablation

“…The biochemical responses of cancerous tissue to MWA treatment can be further elucidated by studying the molecular changes induced by the thermal effects by comparison of tissues pre-and post-therapy. Raman spectroscopy is an ideal technique for this type of study in that it can provide a "fingerprint" of the structure and conformation of molecule [12][13][14][15][16]. This information can be used to improve the pathological and biochemical interpretation of tissue samples, as well as the ability to identify subtle biochemical variations with high sensitivity and specificity [17][18][19][20][21][22][23][24].…”

Facile Fabrication of Micro/Nano Hierarchical SERS Sensor via Anisotropic Etching and Electrochemical Treatment for Malachite Green Detection

“…Studies have shown that the SERS signal can be enhanced by changing the 2D planar substrate into a 3D microstructure substrate, for example, silicon nanowire [5], and pyramid structure [6][7][8][9]. This microstructured SERS substrate has a large surface area, therefore increases the number of effective hot spots, and further enhances the sensitivity of the SERS signal [10]. The microstructured silicon pyramid is particularly interesting one.…”

“…In some SERS studies [7][8][9], It has been proven that the Si pyramids can increase the amount of the hot spots by providing large surface area and create strong local electric field [9]. However, substrates with only 3D microstructures are not sufficient to generate strong SERS signals, and studies have shown that strong local surface plasmons (SERS hot spots) occur at the nano-gaps between noble metal nanostructures [9,10]. Therefore, it is preferred that the SERS substrate can have both micron and nanostructures, which will greatly increase the SERS signal strength.…”