SiO2 Microsphere Array Coated by Ag Nanoparticles as Raman Enhancement Sensor with High Sensitivity and High Stability

Abstract

In this paper, a monolayer SiO2 microsphere (MS) array was self-assembled on a silicon substrate, and monolayer dense silver nanoparticles (AgNPs) with different particle sizes were transferred onto the single-layer SiO2 MS array using a liquid–liquid interface method. A double monolayer “Ag@SiO2” with high sensitivity and high uniformity was prepared as a surface-enhanced Raman scattering (SERS) substrate. The electromagnetic distribution on the Ag@SiO2 substrate was analyzed using the Lumerical FDTD (finite difference time domain) Solutions software and the corresponding theoretical enhancement factors were calculated. The experimental results show that a Ag@SiO2 sample with a AgNPs diameter of 30 nm has the maximal electric field value at the AgNPs gap. The limit of detection (LOD) is 10−16 mol/L for Rhodamine 6G (R6G) analytes and the analytical enhancement factor (AEF) can reach ~2.3 × 1013. Our sample also shows high uniformity, with the calculated relative standard deviation (RSD) of ~5.78%.

Selective and Accurate Detection of Nitrate in Aquaculture Water with Surface-Enhanced Raman Scattering (SERS) Using Gold Nanoparticles Decorated with β-Cyclodextrins

“…The SH-β-CD@AuNPs nanomaterial substrate developed in this paper exists in colloidal form. Therefore, in this work, the chosen AEF calculation formula [ 80 , 81 , 82 , 83 ] is as follows: where refers to the SERS spectrum of the BTAH molecule, the reaction product of nitrite conversion of nitrate to OPD phantom. refers to the concentration of nitrite nitrogen (mol/L) at the time of detection in the NRS of BTAH, while refers to the NRS of BTAH.…”

“…The SH-β-CD@AuNPs nanomaterial substrate developed in this paper exists in colloidal form. Therefore, in this work, the chosen AEF calculation formula [80][81][82][83] is as follows:…”

Polyethyleneimine-assisted formation of Ag–SiO2 hybrid microspheres for H2O2 sensing and SERS applications

“…However, a double monolayer Ag@SiO 2 and open nanocavity assistant so SERS sample Ag@PDMS were able to show enhancement factors of ∼10 13 and 10 12 , respectively. 75,76 Although these materials offer signicant advantages in terms of AEF, there are certain limitations to the methods used for synthesizing nanocavity-assisted so SERS samples, as the technique used is a liquid-liquid transfer method. In the liquid-liquid transfer method, a rigid substrate is used and the fabrication method involves multiple steps, which makes it complex and cumbersome compared to our synthesis methodology, which is a one-step, cost-effective approach.…”

Switchable Cascade Raman Lasing in a Tellurite Glass Microresonator

“…The use of compact, high-Q microresonators allows obtaining widely tunable low-threshold and narrow-linewidth radiation at wavelengths inside and outside gain bands of traditional laser media. Raman microlasers are of great interest for many applications, including sensing and biosensing. − The dynamics of intracavity radiation under the action of stimulated Raman scattering can be quite rich and complex, and its understanding is very important from the applied and fundamental points of view. For example, it is possible to switch Raman generation between neighboring modes of the same family, to achieve multicascade generation (when the generated first-order Raman wave itself is a pump for a second-order Raman wave, and then the second-order wave pumps a third-order wave, and so on), − to generate a Stokes soliton held in the potential of a dissipative Kerr soliton, to significantly affect mode-locked Kerr combs, and so on.…”