On-demand nanoparticle-on-mirror (NPoM) structure for cost-effective surface-enhanced Raman scattering substrates

Barik, Puspendu; Pal, Srimanta; Pradhan, Manik

doi:10.1016/j.saa.2021.120193

Cited by 3 publications

(4 citation statements)

References 52 publications

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“…These nanocavities support tightly trapped light and allow the role of lateral confinement upon their plasmonic modes to be explored. Light can be efficiently and robustly trapped as plasmons in nanogaps based on metal–insulator–metal (MIM) configurations, and here we take a scalable widely used scheme based on the Nanoparticle-on-Mirror (NPoM) configuration. − Nanoparticles are inevitably faceted and thus form NPoMs with a MIM plasmonic nanogap of specific lateral shape. The influence of this nanocavity shape, as well as its material properties, are the focus of this work.…”

Section: Introductionmentioning

confidence: 99%

Fingerprinting the Hidden Facets of Plasmonic Nanocavities

et al. 2022

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The optical properties of nanogap plasmonic cavities formed by a NanoParticle-on-Mirror (NPoM, or patch antenna) are determined here, across a wide range of geometric parameters including the nanoparticle diameter, gap refractive index, gap thickness, facet size and shape. Full understanding of the confined optical modes allows these nanocavities to be utilized in a wide range of experiments across many fields. We show that the gap thickness t and refractive index n are spectroscopically indistinguishable, accounted for by a single gap parameter G = n/t 0.47 . Simple tuning of mode resonant frequencies and strength is found for each quasi-normal mode, revealing a spectroscopic "fingerprint" for each facet shape, on both truncated spherical and rhombicuboctahedral nanoparticles. This is applied to determine the most likely nanoscale morphology of facets hidden below each NPoM in experiment, as well as to optimize the constructs for different applications. Simple scaling relations are demonstrated, and an online tool for general use is provided.

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Section: Introductionmentioning

confidence: 99%

Fingerprinting the Hidden Facets of Plasmonic Nanocavities

et al. 2022

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“…Modification of GCE with chitosan and Nafion resulted in a drop in the charge transfer resistance. The slightly elevated R CT value for PVP/GCE than for bare GCE can be explained by the formation of a dielectric shell [ 30 ], which partially dissolved during the pre-washing step. For all copper sulfide functionalized electrodes, the charge transfer resistance decreased, taking the lowest value for Cu-PVP/GCE.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Characterization of Modified Glassy Carbon Electrodes for Non-Enzymatic Glucose Sensors

Mazurków

Kusior

Radecka

2021

Sensors

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The diversity of materials proposed for non-enzymatic glucose detection and the lack of standardized protocols for assessing sensor performance have caused considerable confusion in the field. Therefore, methods for pre-evaluation of working electrodes, which will enable their conscious design, are currently intensively sought. Our approach involved comprehensive morphologic and structural characterization of copper sulfides as well as drop-casted suspensions based on three different polymers—cationic chitosan, anionic Nafion, and nonionic polyvinylpyrrolidone (PVP). For this purpose, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy were applied. Subsequently, comparative studies of electrochemical properties of bare glassy carbon electrode (GCE), polymer- and copper sulfides/polymer-modified GCEs were performed using electrochemical impedance spectroscopy (EIS) and voltammetry. The results from EIS provided an explanation for the enhanced analytical performance of Cu-PVP/GCE over chitosan- and Nafion-based electrodes. Moreover, it was found that the pH of the electrolyte significantly affects the electrocatalytic behavior of copper sulfides, indicating the importance of OHads in the detection mechanism. Additionally, diffusion was denoted as a limiting step in the irreversible electrooxidation process that occurs in the proposed system.

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“…The single-phase water-based reduction of gold by citrate, developed by Turkevich and refined by Frens, produces a uniform and spherical GNP over a tunable range controlled by the reaction time and temperature . Here, GNP with a size of ∼20 nm was synthesized following Turkevich and Frens’s procedure, described in our earlier works. , The detailed synthesis procedure and characterization techniques, including high-resolution transmission electron microscope (HRTEM) imaging, UV–vis spectroscopy, dynamic light scattering (DLS), and Fourier-transform infrared (FT-IR) spectroscopy, are provided in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

“…14 Here, GNP with a size of ∼20 nm was synthesized following Turkevich and Frens's procedure, described in our earlier works. 15,16 The detailed synthesis procedure and characterization techniques, including high-resolution transmission electron microscope (HRTEM) imaging, UV−vis spectroscopy, dynamic light scattering (DLS), and Fourier-transform infrared (FT-IR) spectroscopy, are provided in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Real-Time Probing of Melamine-Induced Gold Nanoparticle Aggregation Kinetics via Evanescent-Wave Coupled Cavity Ring-down Spectroscopy

2023

Self Cite

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Insight into the aggregation kinetics of gold nanoparticles (GNPs) is critical for developing a colorimetric assay extensively used in chemical and biomolecular sensing. The aggregation of NPs plays a significant role in many natural and industrial processes, demanding comprehensive perceptions of the aggregation kinetics at a solid–liquid interface. However, the direct observation of the melamine-induced aggregation process of GNPs in the time-domain still remains a challenge. There is little to no information on the fundamental mechanisms of such kinetics using evanescent waves. Total internal reflection (TIR) has been applied to generate the evanescent field (EF), exploring aggregation kinetics near the solid–liquid interface. Here, we utilized a precise optical cavity-based method, an evanescent-wave coupled cavity ring-down spectroscopy (EW-CRDS), that can probe the melamine-induced aggregation kinetics of GNPs. The key feature of the present method is that the evanescent field generated by TIR illumination harnesses the power of CRDS to study 2D fractals via the collision and attachment of the GNPs and their melamine-induced aggregates at the interfacial region in real-time. This kinetic study reveals a critical point for diffusion-limited aggregation and provides insights into the design and optimization of colorimetric sensors that exploit the aggregation of GNPs. Furthermore, the EW-CRDS is a unique analytical approach that helps to deepen our understanding in probing the real-time aggregation process, detecting the presence of aggregator as compared to UV–vis and dynamic light scattering (DLS) spectroscopy.

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On-demand nanoparticle-on-mirror (NPoM) structure for cost-effective surface-enhanced Raman scattering substrates

Cited by 3 publications

References 52 publications

Fingerprinting the Hidden Facets of Plasmonic Nanocavities

Fingerprinting the Hidden Facets of Plasmonic Nanocavities

Electrochemical Characterization of Modified Glassy Carbon Electrodes for Non-Enzymatic Glucose Sensors

Real-Time Probing of Melamine-Induced Gold Nanoparticle Aggregation Kinetics via Evanescent-Wave Coupled Cavity Ring-down Spectroscopy

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