Composite Structure Based on Gold-Nanoparticle Layer and HMM for Surface-Enhanced Raman Spectroscopy Analysis.

Zirui Wang,Zhipeng Zha,Shicai Xu,Zhen Li,Runcheng Liu,Ran Zhang,Muhammad Shafi,Yanyan Huo,Tingyin Ning,Shouzhen Jiang,Shuanglu Li,Kunyu Xing,Can Li

doi:10.3390/nano11030587

Abstract

Hyperbolic metamaterials (HMMs), supporting surface plasmon polaritons (SPPs), and highly confined bulk plasmon polaritons (BPPs) possess promising potential for application as surface-enhanced Raman scattering (SERS) substrates. In the present study, a composite SERS substrate based on a multilayer HMM and gold-nanoparticle (Au-NP) layer was fabricated. A strong electromagnetic field was generated at the nanogaps of the Au NPs under the coupling between localized surface plasmon resonance (LSPR) and a BPP. Additionally, a simulation of the composite structure was assessed using COMSOL; the results complied with those achieved through experiments: the SERS performance was enhanced, while the enhancing rate was downregulated, with the extension of the HMM periods. Furthermore, this structure exhibited high detection performance. During the experiments, rhodamine 6G (R6G) and malachite green (MG) acted as the probe molecules, and the limits of detection of the SERS substrate reached 10−10 and 10−8 M for R6G and MG, respectively. Moreover, the composite structure demonstrated prominent reproducibility and stability. The mentioned promising results reveal that the composite structure could have extensive applications, such as in biosensors and food safety inspection.

Highlights

IntroductionThe electromagnetic mechanism (EM) is of critical significance for SERS enhancement mechanisms
Surface-enhanced Raman spectroscopy (SERS), as a molecular detection technology exhibiting high sensitivity, has been broadly employed for environmental monitoring, chemical monitoring, and biosensors [1,2,3,4,5].The electromagnetic mechanism (EM) is of critical significance for SERS enhancement mechanisms
Of metallic surfaces results in electromagnetic field enhancement. This field enhancement has a significant effect on the probe molecules adsorbed on the metal surface, enhancing their Raman signal effectively [13]

Summary

Introduction

The electromagnetic mechanism (EM) is of critical significance for SERS enhancement mechanisms It is implemented using the surface plasmon of the metals to improve the electromagnetic field, elevating the SERS signal to 108 or more [6,7,8,9,10,11,12]. The excitation of the LSPR of metallic surfaces (such as a noble metal nanoparticle layer) results in electromagnetic field enhancement. This field enhancement has a significant effect on the probe molecules adsorbed on the metal surface, enhancing their Raman signal effectively [13]. The researchers fabricated several different substrates [4,14]

Methods

Discussion

Conclusion