Manipulating the surface-enhanced Raman spectroscopy (SERS) activity and plasmon-driven catalytic efficiency by the control of Ag NP/graphene layers under optical excitation

Abstract

Highly efficient plasmon-driven catalysis and excellent surface-enhanced Raman spectroscopy (SERS) performance are proportional to the square of the local electromagnetic field (hot spot). However, a proven way to realize the enhancement in intensity and density of “hot spot” still needs to be investigated. Here, we report on multilayered Ag nanoparticle (Ag NP)/graphene coupled to an underlying Cu film system (MAgNP-CuF) which can be used as an effective SERS substrates realizing ultra-sensitive detection for toxic molecules and in situ monitoring the plasmon-driven reaction for p-nitrothiophenol (PNTP) to p,p′-dimercaptobenzene (DMAB) conversion. The mechanism of ultra-sensitive SERS response and catalytic reaction is investigated via Ag NP/graphene layer-dependent experiments combined with theoretical simulations. The research found that the intensity and density of “hot spot” can be effectively manipulated by the number of plasmonic layers, and the bottom Cu film could also reflect the scattered and excitation beam and would further enhance the Raman signals. Moreover, the MAgNP-CuF exhibits outstanding performance in stability and reproducibility. We believe that this concept of multilayered plasmonic structures would be widely used not only in the field of SERS but also in the wider research in photocatalysis.

Plasma-Treated Graphene Surfaces for Trace Dye Detection Using Surface-Enhanced Raman Spectroscopy

“…However, the instability of the metals, susceptible to oxidation and sulfidation, could hinder the efficiency and consistency of the substrate for creating a plasmonic hotspot, thereby decreasing the sensitivity of the target molecules. Besides the metal nanoparticles (NPs), several semiconductors have also been used as SERS sensing materials, such as TiO 2 , MoS 2 nanostructures, CuTe nanocrystals, Cu 2 O nanospheres, InAs/GaAs quantum dots, and graphene and its derivatives. − However, the SERS sensitivity of semiconductors is relatively low as compared to that of metal NPs.…”

Plasmon-Driven Interfacial Catalytic Reactions in Plasmonic MOF Nanoparticles

“…21 In these reports, the PDSC reactions basically occur on the metal−air/water surface. In recent years, it has been reported that the PDSC reactions can occur at the metal−medium interface, such as metal−graphene, 22,23 order to further assist the application of heterogeneous catalysis in new applications and the design of new catalyst materials. Therefore, the PDSC reactions at the interface are a frontier topic worthy of attention.…”

“…In these reports, the PDSC reactions basically occur on the metal–air/water surface. In recent years, it has been reported that the PDSC reactions can occur at the metal–medium interface, such as metal–graphene, , metal–TiO 2 , metal–MoS 2 , and so on. Adjusting the optical and electrical properties of the medium helps to understand the potential kinetics and mechanisms of the catalytic reaction in order to further assist the application of heterogeneous catalysis in new applications and the design of new catalyst materials.…”

Facilely Flexible Imprinted Hemispherical Cavity Array for Effective Plasmonic Coupling as SERS Substrate

“…It is reported that the electromagnetic field intensity is inversely proportional to the distance parameter, which means that the effective SERS signal is generated on the premise that the molecule is located in the confined area around the plasmonic material [10]. Various types of SERS substrate structures ranging from nanoparticle (NP) aggregates [11][12][13][14][15], multidimensional structure [16][17][18][19][20] and composite substrate [21][22][23][24][25][26][27][28][29] were prepared to explore the better enhancement factor (EF) under various conditions. Among them, the cavity system has been paid more and more attention because of its unique light trapping characteristics [30][31][32][33][34][35][36][37][38].…”