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Highly ordered Au-decorated Ag nanorod arrays as an ultrasensitive and reusable substrate for surface enhanced Raman scattering
摘要： For surface-enhanced Raman spectroscopy (SERS) substrates, complexity of the fabrication process, sensitivity and stability are factors that need to be considered. We report a simple and novel method for preparing an effective substrate that greatly enhances SERS signals. The SERS substrate is fabricated by selectively electroless deposition of Ag nanoparticles in the highly ordered porous anodized aluminum oxide (AAO) template and then etching it to form Ag nanorod bundles structure, so that the Raman enhancement occurs in the gap between the nanorods and the top of the nanorod bundle, which is verified by finite element analysis. A peculiarity of this method is that this is the first time to synthesize Ag nanorod arrays structure by using it. The results indicated that this prepared substrate has special micro-nano structure and when rhodamine 6 G is selected as the detection reagent, the detection limit is as low as 10?16 M with excellent recyclability. This outstanding array structure has a promising practical application in SERS field.
关键词： Reproducibility,Electroless deposition,Micro-nano structure,SERS,Ag nanorod arrays
更新于2025-09-23 15:21:21
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Surface-nanostructured single silver nanowire: a new one-dimensional microscale SERS interface
摘要： One-dimensional microscale SERS-active interfaces have been intriguing as a newly emerging class of SERS interfaces compared to conventional macroscale SERS substrates. In this work, a stable surface-nanostructured single silver nanowire was fabricated. The nanostructures on the nanowire are formed by nanoscale silver crystal dots with diameters of 20-50 nm. The SERS signals of the crystal violet probe molecules adsorbed on the nanostructures are dramatically enhanced by both electromagnetic and chemical effects. The hot spots generated at the junctions of adjacent nanoscale dots yield highly efficient surface plasmon resonance. Simultaneously, the charge transfer on the atomic-scale silver cluster located at the nanostructured interface causes an enhancement similar to a Raman resonance. The intensity distributions of the SERS peaks on the surface-nanostructured single nanowire are characterized by SERS mapping. It is found that, although the intensities of the SERS peaks are different, their SERS mapping images show uniform SERS enhancement distributions, whereas the noticeable SERS intensity distributions on the single smooth silver nanowire are mainly located on the two ends of the nanowire. The large number of nanoscale crystal dots along with the atomic-scale silver clusters are uniformly and densely distributed on the surface of the single roughened nanowire; these structural attributes induce a uniform and large surface plasmon resonance and charge transfer enhancements on the entire surface of the nanowire. This work indicates that the surface-nanostructured single silver nanowire, synthesized using a quite simple preparation method, performs as an excellent one-dimensional microscale SERS substrate with uniform and high enhancement characteristics, which shows high potential for applications as a new class of SERS-active substrates. Furthermore, the higher enhancement factor of the microscale SERS interfaces can be achieved by introducing other roughened nanowires to assemble a dimer and a trimer as micro SERS substrates, which is consistent with the dark field (DF) measurements.
关键词： Hot spots,Raman,Micro SERS interfaces,Charge transfer,Silver nanowire
更新于2025-09-23 15:21:21
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Synthesis of SiO <sub/>2</sub> @Ag core-shell photonic crystals for SERS application
摘要： Core-shell SiO2@Ag composite spheres with dense, complete and nanoscaled silver shell were prepared by using facile chemical reduction method. Self-assembly of the composite microspheres into 3D photonic crystals (PhCs) was carried out using the vertical deposition method. The core-shell PhCs composites were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy and energy dispersive X-ray spectroscopy (EDX). The results of amplification of Raman scattering by these composite substrates are presented.
关键词： SiO2@Ag,photonic crystals,SERS,core-shell,Raman scattering
更新于2025-09-23 15:21:01
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Synthesis and single-particle surface-enhanced Raman scattering study of plasmonic tripod nanoframes with Y-shaped hot-zone
摘要： Herein, plasmonic metal tripod nanoframes with 3-fold symmetry were synthesized in a high yield (ca. 83 %), and their electric field distribution and single-particle surface-enhanced Raman scattering (SERS) were studied. We realized such complex frame morphology by synthesizing analogous tripod nanoframes through multiple transformations. The precise control of the Au growth pattern led to uniform tripod nanoframes embedded with circle or line-shape hotspots. The linear-shaped nanogaps (“Y”-shaped hot-zone) of the frame structures can strongly and efficiently confine the electric field, allowing for strong SERS signals. Coupled with a high synthetic yield of the targeted frame structure, strong and uniform SERS signals were obtained inside the nanoframe gaps. Remarkably, quite reproducible SERS signals were obtained with these structures – the SERS enhancement factors of an average value 7.9 × 10^7 with a distribution of enhancement factors from 2.2 × 10^7 to 2.2 × 10^8 for 45 measured individual particles.
关键词： Nanogap,Nanoframe,Tripod,Hot-spot,Single-particle SERS
更新于2025-09-23 15:21:01
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Microfluidic Platform for Integrated Plasmonic Detection in Laminal Flow
摘要： In this work, we propose a novel approach to design robust microfluidic devices with integrated plasmonic nanoparticles. A strong electric field generated in the gaps between AuBPs – due to the generation of the so-called extrinsic ‘hot-spots’ – was subsequently proved by the volumetric SERS detection of molecules in continuous flow conditions by loading the analyte into the microfluidic channel via a syringe pump. In conclusion, our miniaturized portable microfluidic system aims to detect and identify in real-time with high accuracy analyte molecules in laminal flow, providing thus a groundwork for further complex biosensing applications.
关键词： Gold Bipyramids,Detection in Laminal Flow,LSPR,Microfluidic Chip,SERS
更新于2025-09-23 15:21:01
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Block Copolymer Derived Vertically Coupled Plasmonic Arrays for Surface-Enhanced Raman Spectroscopy
摘要： A surface-enhanced Raman spectroscopy sensing template consisting of gold-covered nanopillars is developed. The plasmonic slab consists of a perforated gold film at the base of the nanopillars and a Babinet complementary dot array on top of the pillars. The nanopillars were fabricated by the incorporation of an iron salt precursor into a self-assembled block copolymer thin film and subsequent reactive ion etching. The preparation is easy, scalable, and cost-effective. We report on the increase in surface-enhanced Raman scattering efficiency for smaller pillar heights and stronger coupling between the dot array and perforated gold film with average enhancement factors as high as 107. In addition, the block copolymer-derived templates show an excellent relative standard deviation of 8% in the measurement of the Raman intensity. Finite difference time domain simulations were performed to investigate the nature of the electromagnetic near-field enhancement and to identify plasmonic hot spots.
关键词： block copolymer lithography,finite difference time domain simulation,SERS uniformity,plasmonic nanomaterials,surface-enhanced Raman spectroscopy,nanofabrication,4-aminothiophenol
更新于2025-09-23 15:21:01
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Novel strategy for fabrication of sensing layer on thiol-functionalized fiber-optic tapers and their application as SERS probes
摘要： This work presents a new strategy to fabricate optical fiber surface-enhanced Raman scattering (SERS) probes with high-performance remote sensing prepared by thiol functionalization of silica fiber taper, and further in situ nucleation and growth of silver nanoparticles (AgNPs). The prepared fiber probes can effectively identify the analyte 4-aminothiophenol (4-ATP) with a limit of detection (LOD) as low as 2.15×10-11 M using a portable commercial Raman spectrometer. Simultaneously, such fiber probes have shown a good reproducibility with the relative standard deviation (RSD) value of 7.6%, and possessed high signal stability at room temperature over one month. Furthermore, this approach provides new insight into the fabrication of fiber SERS probe integrated the advantages in terms of sensitivity, reproducibility and stability, which shows great potential for practical SERS applications.
关键词： Thiol functionalization,SERS performance,Probe,Silver nanoparticles,Optical fiber
更新于2025-09-23 15:21:01
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Construction of Long Narrow Gaps in Ag Nanoplates
摘要： Hexagonal Ag nanoplates with long and ultra-narrow gaps (about 90 nm in length, 2 nm in width) are synthesized via seed-mediated growth method. By growing around the polymer shell on the seed, the Ag domain cannot merge at the meet-up point, leaving a long narrow gap in the resulting plate. These gapped nanoplates exhibit high sensitivity in SERS detection, with limitation of 10-9 M for 2-naphthalenethiol.
关键词： SERS,ultra-narrow gaps,Ag nanoplates,seed-mediated growth
更新于2025-09-23 15:21:01
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Optimizing the SERS Performance of 3D Substrates through Tunable 3D Plasmonic Coupling toward Label-free Liver Cancer Cell Classification
摘要： Three-dimensional (3D) plasmonic nanostructures are emerging as excellent surface-enhanced Raman spectroscopy (SERS) substrates for chemical and biomedical applications. However, the correlation of the 3D (including both of the in-plane and out-of-plane) plasmonic coupling with the SERS properties to deepen the understanding of 3D SERS substrates remains a challenge. Here, we perform correlated studies of 3D plasmonic coupling and SERS properties of the 3D hierarchical SERS substrates by tuning the multiscale structural elements. The effect of 0D (the size of building blocks), 1D (the thickness of the 3D substrates) and 2D (the composition of individual monolayers) structural elements on 3D plasmonic coupling are studied by measuring the UV-Vis-NIR spectroscopy and SERS performance. It shows that both of the extinction spectra and SERS enhancement are tuned at the 3D structural level. It is demonstrated that the plasmonic resonance wavelength (PRW) stemmed from the 3D plasmonic coupling is correlated with the SERS averaged surface enhancement factor (ASEF), and which is improved by over 10-fold at the optimum 3D nanostructure. The optimized substrate is used to quantitatively analyze two small biological molecules. Moreover, as a proof-of-concept study, the substrate is first applied to differentiate between living liver normal and cancer cells with a high prediction accuracy through the spectral features of the cell membranes and the metabolites secreted outside the cells. We expect that the tuning of plasmonic coupling at 3D level can open up new routes to design high performance SERS substrates for wide applications.
关键词： liver cells,3D substrates,3D plasmonic tuning,SERS,structural parameters
更新于2025-09-23 15:21:01
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Molecular-Level Control over Plasmonic Properties in Silver Nanoparticle/Self-Assembling Peptide Hybrids
摘要： The plasmonic properties of silver nanoparticle (AgNP) arrays are directly controlled by AgNP size, shape, and spatial arrangement. Reported here is a strategy to prepare chiral AgNP arrays templated by two constitutionally isomeric aromatic peptide amphiphiles (APAs), KS C′EKS and C′EKSKS (KS = S-aroylthiooxime-modi?ed lysine, C′ = citrulline, and E = glutamic acid). In phosphate bu?er, both APAs initially self-assembled into nanoribbons with a similar geometry. However, in the presence of silver ions and poly(sodium 4-styrenesulfonate) (PSSS), one of the nanoribbons (KS C′EKS) turned into nanohelices with a regular twisting pitch, while the other (C′EKSKS) remained as nanoribbons. Both were used as templates for synthesis of arrays of ～8 nm AgNPs to understand how small changes in molecular structure a?ect the plasmonic properties of these chiral AgNP/APA hybrids. Both hybrids showed improved colloidal stability compared to pure AgNPs, and both showed enhanced sensitivity as surface-enhanced Raman spectroscopy (SERS) substrates for model analytes, with nanohelices showing better SERS performance compared to their nanoribbon counterparts and pure AgNPs.
关键词： self-assembling peptide,silver nanoparticle,plasmonic properties,chiral AgNP arrays,SERS
更新于2025-09-23 15:21:01