Electrospun Gold Nanoprism/Poly(vinyl alcohol) Nanofibers for Flexible and Free-Standing Surface-Enhanced Raman Scattering Substrates

Abstract

Plasmonic resonance from 2D anisotropic metallic nanoparticles for surface-enhanced Raman scattering (SERS) has attracted substantial attention for applications in chemical and environmental monitoring because of its intrinsic electromagnetic “hotspot” and orientation-dependent optical properties. Nevertheless, their sensing applications have been limited by their poor stability toward oxidation and moisture and complicated fabrication processes for large-scale assembly, especially on flexible substrates. In this work, we demonstrate water-stable nanofibers as active SERS substrates electrospun from anisotropic gold nanoprisms (AuNPs) mixed with poly­(vinyl alcohol) (PVA) at a concentration of 2.5–20 nM, followed by cross-linking by glutaraldehyde (GA) vapor at room temperature. Using 4-mercaptobenzoic acid (4-MBA) as the target molecule, we show that the nanofiber mat with 20 nM AuNPs exhibits high sensitivity at a concentration as low as 10–10 M 4-MBA with an enhancement factor of 107 and good uniformity over a very large area (20 cm2) with an average relative standard deviation of <0.074. The cross-linked PVA/AuNP nanofibers are stable against water without an obvious decrease in the SERS signal. In the detection of Rhodamine 6G (R6G) molecules in the water solution, the Raman intensity of R6G shows almost no decay over 3 months compared to that of the as-prepared mat. Further, we show the detection of trace pesticide (10–6 M) on the orange exocarp, suggesting that our fiber mat could be applied for potential applications including food safety, biomedicine, and environmental monitoring.

Machine Learning-Assisted Pesticide Detection on a Flexible Surface-Enhanced Raman Scattering Substrate Prepared by Silver Nanoparticles

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A Review on Gold Nanotriangles: Synthesis, Self-Assembly and Their Applications

“…The optimization of the plasmonic effect for enhanced Raman scattering largely depends on the properties of the enhanced substrate. The anisotropy of AuNPs offers the possibility to tune their plasmonic properties and the inherent electromagnetic "hot spots", thus becoming an effective means to improve the resolution of surface-enhanced Raman spectroscopy (SERS) [13,94].…”

Combining Azimuthal and Polar Angle Resolved Shadow Mask Deposition and Nanosphere Lithography to Uncover Unique Nano-Crystals

“…Chiral spectroscopy and surface-enhanced Raman spectroscopy (i.e., plasmonic methods) are being used intensively for chemical, biological, and environmental monitoring applications. Studies have focused on unique metallic nanostructures with different symmetry, inter-structural gaps, and chirality for controlling electromagnetic hotspots and varying optical properties based on the orientation of structural elements [10][11][12][13][14][15]. Moreover, magnetic memory applications, such as data storage, data transfer, and logical devices rely on the controlled propagation of spin waves through magnonic crystals via exchange interactions.…”