Constructing 3D and Flexible Plasmonic Structure for High‐Performance SERS Application

Abstract

provide more hot spots, which are introduced by the electromagnetic mechanism (EM). By the virtue of their larger specific surface area and periodic structure, 3D SERS substrates can effectively amplify the optical field around metal nanoparticles (NPs), thereby enhancing the Raman signal. Moreover, the 3D structure of these substrates is beneficial for the enrichment of probe molecules around metal nanoparticles; as a result, one can still obtain a high Raman signal, even under an ultralow concentration. Consequently, an increasing number of researchers are now focusing on the design and fabrication of 3D SERS substrates.To make full use of the merits of the 3D structure, SERS substrates based on 2D materials and metal nanoparticles have been combined and proposed. [23,24] In these 3D SERS substrates, the 3D structure can fully utilize the 3D focal volume of the incident beam and increase the density of the metal nanoparticles. Furthermore, introduction of the 2D material can act as an atomically thick SERS substrate, [25] perfect absorbent layer of molecules, [26] excellent sub-nanometer spacer, [27] and passivation layer for metal, [28,29] and introduce enhancements via a chemical mechanism (CM). Previously, a 3D SERS substrate based on graphene covering a pyramid-shaped Au structure was reported to achieve high enhancement. [30] While the integration of graphene and pyramid-shaped Au was successfully implemented, this 3D SERS substrate was not flexible and did not meet with the requirements when detecting probe molecules on an arbitrary curvilinear surface.Therefore, transformation of these stiff 3D substrates into flexible structures via using various methods has been investigated extensively. Leem et al. reported 3D crumpled graphene-AuNPs hybrid structures for SERS applications using a mechanical self-assembly strategy on a thermally activated polymer. [31] Similarly, Lee et al. fabricated a rippled graphene structure on a polystyrene substrate using a thermal rippling process and demonstrated the increased plasmonic coupling and higher density of the hot spots on the rippled nanostructure. [32] Kumar et al. presented a flexible SERS sensor by depositing Ag on structured polydimethylsiloxane using a Taro leaf as the template and achieved highly sensitive detection for malachite green. [33] Moreover, to fabricate a flexible 3D SERS substrate, the transfer printing technique, [34] shadow Substrate design has attracted much interest in development of an effective surface enhanced Raman scattering (SERS) sensor. A flexible SERS substrate with excellent performance needs to be sensitive to details of the preparation process; this sensitivity represents a significant challenge for practical applications as opposed to laboratory research applications. Here, a 3D flexible plasmonic structure, AgNPs@MoS 2 /pyramidal polymer (polymethyl methacrylate), is fabricated using a simple and lowcost method. Using experiments and theoretical simulations, the SERS performance of the proposed substrate is assessed in terms of ...

Multifunctional Skin‐Inspired Flexible Sensor Systems for Wearable Electronics

“…Among them, the in situ SERS detection based on the flexible substrates is considered as the most promising approach, which is performed by first conformally attaching the flexible SERS substrates onto objective surfaces of interest, followed by the excitation of incident photons and collection of Raman signals from the back side of the SERS substrates. Until now, a diversity of flexible substrates have been applied for in‐situ SERS detection, such as PDMS, PMMA, polyethylene terephthalate (PET), polyethylene (PE), poly(vinylpyrrolidone) (PVP), paper, adhesive tape, as well as nanowires . The conventional methods to prepare active nanostructures on flexible and transparent substrates rely on depositing nanoparticles by physical or chemical routes.…”

Flexible Hybrid Sensor Systems with Feedback Functions

“…[ 297–300 ] The in situ measurement approach is based on conformally attaching the flexible and transparent SERS chips to object of interest and then collecting the SERS signals directly (Figure 9i). [ 301–305 ] Both detection routes promise their extensive applications in healthcare, environmental monitoring, and food safety detection.…”

Composite Structure of Ag Colloidal Particles and Au Sinusoidal Nanograting with Large-Scale Ultra-High Field Enhancement for SERS Detection

“…Surface-enhanced Raman spectroscopy (SERS), as a 'chemical fingerprint' of the target materials, is a sensitive and reliable detection method extensively employed in biosensors [1,2], food security [3,4], and environment safety [5,6]. Considerable efforts have been made to develop the SERS substrate, including fabricating and using a range of structures and materials [7,8].…”