Electromagnetic Field Enhancement Research Articles

A polarization-resolved ECL strategy based on the surface plasmon coupling effect of orientational Au nanobipyramids patterned structures

Here, we developed a polarization-resolved surface plasmon coupling electrochemiluminescence (ECL) strategy based on orientational Au nanobipyramids (Au NBPs) patterned structures. As the surface plasmonic materials, the Au NBPs with large localized electromagnetic field enhancement were used to construct the different patterned structures through the droplet evaporation induced assembly. The distinct morphology of the horizontal and vertical Au NBPs patterned structures provided the different plasmonic properties reflecting on resonance peak positions and polarized absorbance. As a result, the variations of the polarized ECL emission of SnS2 QDs have been regulated by the Au NBPs patterned structures via the surface plasmon coupling progress. Because of the superior polarization-resolved ECL performances, the sensing system was used to analyze the miRNA-21 and miRNA-205 expression level in tumor tissues of triple negative breast cancer patients. The satisfactory results indicated this polarization-resolved sensing strategy possessed great potential for clinical analysis.

Spin-Coated Ag NPs SERS Substrate: Role of Electromagnetic and Chemical Enhancement in Trace Detection of Methylene Blue and Congo Red

This work demonstrates a simple low-cost and reproducible spin-coating method followed by thermal reduction for the uniform growth of silver nanoparticles (Ag NPs) as surface-enhanced Raman scattering (SERS) substrate. In this work, cationic dye MB and anionic dye CR are selected as two different kinds of SERS probe molecules to investigate the differences between electromagnetic field enhancement (EME) and chemical enhancement (CE) mechanisms. The results indicate that SERS spectra of MB molecule on Ag NPs SERS substrate exhibit the shift in the Raman peak positions and high sensitivity (limit of detection, LOD ~ 10−10 M) with large GSERS (~ 109) value, which can be attributed to the contribution from both EME and CE mechanisms. It is found that Cl− halide ions present in the MB molecule are forming surface complex (Ag NPs@Cl−) on the surface of Ag NPs SERS substrate which is confirmed by the XPS investigation, which might be responsible for the CE enhancement in MB molecule. Whereas Congo red being anionic dye showed no shift in Raman peak positions and less sensitivity (LOD ~ 10−8) with GSERS (~ 107) value on Ag NPs SERS substrate, which can be attributed to EME mechanism only. The obtained results suggest that Cl− halide ions present in the MB molecule play an important role by giving large SERS enhancement for MB molecule on Ag NPs SERS substrate. It is expected that this work will provide insight into role of EME and CE mechanisms for cationic dye MB and anionic dye CR.

Revising quantum optical phenomena in adatoms coupled to graphene nanoantennas

AbstractGraphene flakes acting as photonic nanoantennas may sustain strong electromagnetic field localization and enhancement. To exploit the field enhancement, quantum emitters such as atoms or molecules should be positioned in such close proximity to the flake that electron tunneling might influence the optical and electronic properties of the system. However, tunneling is usually not considered if the optical coupling mechanism between quantum emitters and nanoantennas is at focus. This work presents a framework for describing the electron dynamics in hybrid systems consisting of graphene nanoflakes coupled both electronically and optically to adatoms and subject to external illumination. Our framework combines the single-particle tight-binding approach with a nonlinear master equation formalism that captures both optical and electronic interactions. We apply the framework to demonstrate the impact of electron tunneling between the adatom and the flake on emblematic quantum optical phenomena: degradation of coherent Rabi oscillations and quenching of Purcell spontaneous emission enhancement in two-level adatoms in proximity of triangular graphene nanoflakes.

Plasmonic metasurface assisted by thermally imprinted polymer nano‐well array for surface enhanced Raman scattering

AbstractPlasmonic nanometasurfaces/nanostructures possess strong electromagnetic field enhancement caused by resonant oscillations of free electrons, and has been extensively applied in biosensing, nanophotonic and photocatalysis. However, fabrication of uniform nanostructured metasurfaces by conventional methods is complicated and costly, which mitigates a wide‐spread use of this technique in ubiquitous applications. Here, we present a facile and scalable method to fabricate an active nanotrench plasmonic gold substrate. The surface comprises sub‐10 nm plasmonic nanogaps and their formation is assisted by a pre‐fabrication of nano‐imprinted polymer nano‐well arrays. The plasmonic metasurface is optimized to maximize the density of the nano‐trenches by tuning the substrate material, imprinting procedure and film deposition. We show that the surface Raman enhancement due to plasmonic resonances correlates well with trench density and reach a meritorious enhancement factor of EF > 105 over large surfaces.We further show that the electric field strength at the nanotrench features are well explained by finite element method simulations using COMSOL Multiphysics. The plasmonic substrate is transparent in the visible spectrum and conductive. In combination with a scalable bottom‐up fabrication the plasmonic metasurface opens up for a wider use of the sensitive and reliable SERS substrate in applications such as portable sensing devices and for future internet of things.

Engineering of IrO2 nanofiber for surface enhanced Raman scattering

In this paper, we demonstrate the use of nano-engineered Ir/IrO2 nanofibers (NFs) as substrates for surface-enhanced Raman scattering (SERS). We employed the electrospinning and annealing process to fabricate the IrO2 nanofibers featuring of interconnected nanoparticles. The obtained IrO2 NFs were subjected to reduction process as a function of time (5–180 min). IrO2 NFs were fully converted to Ir metal after 120 min of reduction. The resulting structures were examined as SERS substrates using rhodamine 6G (R6G) molecule excited by 632.8 nm laser. A distinct Raman signal of R6G was identified and its intensity gradually increased as a function of the reduction time of IrO2 NFs. UV/vis spectrum of Ir NFs showed increase of absorption at 632.8 nm, concluding that the enhanced Raman signal is due to the electromagnetic field enhancement at the Ir metal. This work is the first to report the nano-engineering of Ir/IrO2 nanofibers for a SERS application.

Enhanced luminescence of Eu-doped films based on gap coupled plasmons

Coupled plasmons are promising candidates for enhancing the luminescence, which can drastically alter the electromagnetic environment of emitters and modulate their emission process. In this paper, we have carried out a comparison of enhanced luminescence based on different plasmonic nanostructures and designed a gap coupled structure Au nanorods (NRs)/space layer/Ag nanoparticles (NPs) film to enhance the photoluminescence (PL) of Eu film. The current result indicates that our maximum enhancement factor is 53.5-fold. And our studies reveal that the Ag NPs film as the substrate provides electromagnetic field enhancement, the space layer as the intermediate layer adjusts the distance to decrease the nonradiative energy transfer. A dominant role of the Au NRs in luminescence enhancement is also indicated due to the perfect match between local surface plasmon resonance (LSPR) of Au NRs and the emission spectrum of Eu. Our designed gap coupled nanostructure has multiple plasmon couplings, which can be beneficial to certain applications such as gap coupled plasmonic nanostructure-based detectors and devices.

Spatiotemporal-Resolved Hyperspectral Raman Imaging of Plasmon-Assisted Reactions at Single Hotspots.

Raman spectroscopy facilitates the study of reacting molecules on single nanomaterials. In recent years, the temporal resolution of Raman spectral measurement has been remarkably reduced to the millisecond level. However, the classic scan-based imaging mode limits the application in the dynamical study of reactions at multiple nanostructures. In this paper, we propose a spatiotemporal-resolved Raman spectroscopy (STRS) technology to achieve fast (∼40 ms) and high spatial resolution (∼300 nm) hyperspectral Raman imaging of single nanostructures. With benefits of the outstanding electromagnetic field enhancement factor by surface plasmon resonance (∼1012) and the snapshot hyperspectral imaging strategy, we demonstrate the observation of stepwise Raman signals from single-particle plasmon-assisted reactions. Results reveal that the reaction kinetics is strongly affected by not only the surface plasmon-polariton generation but also the density of Raman molecules. In consideration of the spatiotemporal resolving capability of STRS, we anticipate that it provides a potential platform for further extending the application of Raman spectroscopy methods in the dynamic study of 1D or 2D nanostructures.

Laser Photochemical Nanostructuring of Silicon for Surface Enhanced Raman Spectroscopy

AbstractIn this work, a novel method of fabricating large‐area, low‐cost surface‐enhanced Raman spectroscopy (SERS) substrates is explained which yields nanostructured surface utilizing laser‐induced chemical etching of crystalline silicon (Si) in an hydrofluoric acid solution. Nanostructuring of Si surface is followed by deposition of a thin noble metal layer to complete the fabrication procedure. A 50 nm thick silver (Ag) layer is shown to maximize the SERS performance. The SERS effect is attributed to the electromagnetic field enhancement originating from the nanoscale surface roughness of Si that can be controlled by the illumination power, etch duration, and the spot size of the laser beam. The SERS substrates are found to be capable of detecting a Raman analyte dye molecule down to 10−11 m. SERS performance of the Ag deposited substrates are compared to gold (Au) deposited substrates at 660 and 532 nm excitation. Nanostructured Si surface with Ag exhibits stronger SERS than with Au under 532 nm excitation exhibiting an enhancement factor as high as 109. Raman enhancement factor is calculated both by SERS spectra experimentally, and using finite‐elements simulation of the electric field enhancement. The applicability of the fabricated substrates is examined by adsorbing different analytes.

Terahertz hybrid optical-plasmonic modes: tunable resonant frequency, narrow linewidth, and strong local field enhancement.

Hybrid optical-plasmonic modes have the characteristics of low loss and small mode volume, which will result in the strong localization and enhancement of electromagnetic field. Such advantages of hybrid optical-plasmonic mode are important for the enhancement of light-matter interactions. Here, terahertz (THz) hybrid modes of Fabry-Perot resonances (FPRs) and spoof surface plasmon polaritons (SSPPs) in the modified Otto scheme are investigated both in theoretical and experimental aspects. The device structure is composed of a metal grating silicon waveguide (MGSW) and a metal slit grating (MSG). The two components are vertically stacked with a variable air gap between them. The THz hybrid modes are originated from the far-field coupling of the FPRs and the SSPP supported by the air gap and the MSG, respectively. By changing the thickness of the air gap, the resonant frequency of the FPR-SSPP modes can be tuned in a frequency range of about 0.1 THz. An anti-crossing behavior between two reflection dips corresponding to the guided-mode resonance in the MGSW and the FPR-SSPP mode is observed, which leads to the narrowing of the reflection dips in the anti-crossing region. Numerical simulations show that at the resonant frequencies of FPR-SSPP mode, there is a huge volume-averaged electromagnetic energy enhancement of about 1600 times in the grooves of the MSG, which is around 8.7 times larger than that induced by the SSPP directly launched by free-space electromagnetic field. The hybrid FPR-SSPP modes can be used to construct THz sensors and detectors with high sensitivity.

Observation of domain‐selective defect effects from a CVD‐grown graphene monolayer sandwiched at individual nanoparticle‐on‐mirror plasmonic junctions

AbstractThe author examines the different defect effects of chemical vapor deposition graphene monolayer (CVD‐GM) relying on domain position at an individual nanoparticle‐on‐mirror (NPoM) plasmonic junction. The NPoM, composed of Au nanoparticle (NP)/CVD‐GM/Au thin film (TF), could previously show the mode‐selective Raman enhancement, in which the center domain exhibited the highest Raman enhancement of both radial breathing like mode (RBLM) and D mode considering the local z‐directional electromagnetic (EM) field enhancement effect in the NPoM. Meanwhile, the outer domain of the NPoM also displays the near‐two symmetrical deep pits via atomic force microscope (AFM) with the accompanying lower I[D]/I[D*], higher FWHM[RBLM], I[RBLM], and relatively red‐shifted (tensile strained) Max [RBLM] from surface‐enhanced Raman scattering (SERS) information than the central case. With these observations, the physical loading of Au NP on CVD‐GM/Au TF may induce the threading effect on the most outer position of CVD‐GM at the NPoM, leading to sp2 defect‐rich domains. In contrast, the central domains, where the sp3 defects are rich, exhibit the opposite SERS spectral phenomena, indicating that the near‐flat surface shape of Au NP bottom has a higher probability to exert a strong charge transfer along the z‐direction, resulting in higher I[RBLM] and I[D]/I[D*] than the most outer domain. As such, the author anticipates various chemical sensing using subtle changes in CVD‐GM morphology at both the most outer and center positions in the NPoM with the comparison of each SERS spectral signature.

A Compact, Low-Field, Broadband Matching Section for Externally Powered X-Band Dielectric-Loaded Accelerating Structures

It has been technically challenging to efficiently couple external radio frequency (RF) power to cylindrical dielectric-loaded accelerating (DLA) structures, especially when the DLA structure has a high dielectric constant. This article presents a novel design of matching section for coupling the RF power from a circular waveguide to an <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula>-band DLA structure with a dielectric constant <inline-formula> <tex-math notation="LaTeX">$\varepsilon _{\text {r}}=16.66$ </tex-math></inline-formula> and a loss tangent <inline-formula> <tex-math notation="LaTeX">$\tan \delta =3.43\times {10}^{-5}$ </tex-math></inline-formula>. It consists of a compact dielectric disk with a width of 2.035 mm and a base angle of 60&#x00B0;, resulting in a broadband coupling at a low RF field, which has the potential to survive in the high-power environment. To prevent a sharp dielectric corner break, a 45&#x00B0; chamfer is also added. A microscale vacuum gap, caused by metallic clamping between the thin coating and the outer thick copper jacket, is also studied in detail. Through optimization, most of RF power is coupled into the DLA structure, with no enhancement of peak electromagnetic fields above those of the structure itself. Tolerance studies on the geometrical parameters and mechanical design of the full-assembly structure are also carried out as a reference for fabrication.

Biomimetic Surface-Enhanced Raman Scattering Nanoparticles with Improved Dispersibility, Signal Brightness, and Tumor Targeting Functions.

The development of biocompatible and nontoxic surface-enhanced Raman scattering (SERS) nanoparticles is of considerable current interest because of their attractive biomedical applications such as ultrasensitive in vitro diagnostics, in vivo tumor imaging, and spectroscopy-guided cancer surgery. However, current SERS nanoparticles are prepared and stored in aqueous solution, have limited stability and dispersibility, and are not suitable for lyophilization and storage by freeze-drying or other means. Here, we report a simple but robust method to coat colloidal SERS nanoparticles by naturally derived biomimetic red blood cell membranes (RBCM), leading to a dramatic improvement in stability and dispersibility under freeze-thawing, lyophilization, heating, and physiological conditions. The results demonstrate that the lyophilized SERS nanoparticles in the solid form can be readily dissolved and dispersed in physiological buffer solutions. A surprising finding is that the RBCM-coated SERS particles are considerably brighter (by as much as 5-fold) than PEGylated SERS particles under similar experimental conditions. This additional enhancement is believed to arise from the hydrophobic nature of RBCM's hydrocarbon chains, which is known to reduce electronic dampening and boost electromagnetic field enhancement. A further advantage in using biomimetic membrane coatings is that the bilayer membrane structure allows nonvalent insertion of molecular ligands for tumor targeting. In particular, we show that cyclic-RGD, a tumor-targeting peptide, can be efficiently inserted into the membrane coatings of SERS nanoparticles for targeting the ανβ3 integrin receptors expressed on cancer cells. Thus, biomimetic RBCMs provide major advantages over traditional polyethylene glycols for preparing SERS nanoparticles with improved dispersibility, higher signal intensity, and more efficient biofunctionalization.

Surface-Plasmon-Assisted Growth, Reshaping and Transformation of Nanomaterials.

Excitation of surface plasmon resonance of metal nanostructures is a promising way to break the limit of optical diffraction and to achieve a great enhancement of the local electromagnetic field by the confinement of optical field at the nanoscale. Meanwhile, the relaxation of collective oscillation of electrons will promote the generation of hot carrier and localized thermal effects. The enhanced electromagnetic field, hot carriers and localized thermal effects play an important role in spectral enhancement, biomedicine and catalysis of chemical reactions. In this review, we focus on surface-plasmon-assisted nanomaterial reshaping, growth and transformation. Firstly, the mechanisms of surface-plasmon-modulated chemical reactions are discussed. This is followed by a discussion of recent advances on plasmon-assisted self-reshaping, growth and etching of plasmonic nanostructures. Then, we discuss plasmon-assisted growth/deposition of non-plasmonic nanostructures and transformation of luminescent nanocrystal. Finally, we present our views on the current status and perspectives on the future of the field. We believe that this review will promote the development of surface plasmon in the regulation of nanomaterials.

Visualizing undyed microplastic particles and fibers with plasmon-enhanced fluorescence

Despite widespread awareness that enormous consumption of plastics is not sustainable, the global production and use of plastics continue to grow. This generates vast amounts of plastic waste and microplastics, ending up e.g., in the marine environment. There are serious challenges in detecting and measuring microplastics, especially in highly diluted natural samples. Here, a new alternative microplastic detection method based on plasmon-enhanced fluorescence (PEF) was developed and tested using fluorescence microscopy. In particular, gold nanopillar-based substrates, displaying (i) high electromagnetic field enhancement, and (ii) surface superhydrophobicity and high adhesion properties, were utilized to enhance the fluorescence emission signal from microplastics in water samples. The fluorescence microscopy imaging revealed remarkable fluorescence enhancement by the PEF substrates on the microplastic particles and fibers with different sizes of both conventional, low-density polyethylene, and biodegradable poly (butylene adipate-co-terephthalate). The limit of detection and quantification by this method was estimated to be as low as 0.35 and 1.2 femtograms, respectively. The observed fluorescence enhancement of the gold nanopillar substrates for the microplastics was ca. 70 times greater than the case of having the microplastics on a glass substrate. Additionally, 3D FEM simulations were performed to further investigate the system's electromagnetic field distribution near the nanostructures. This new method makes undyed microplastics visible in fluorescence microscopy, even particles and fibres too small to be imaged with conventional light microscopy. This can be a great tool for microplastic research, helping us to detect, study, understand microplastic dynamics in water based systems.

Gaptronics: multilevel photonics applications spanning zero-nanometer limits

Abstract With recent advances in nanofabrication technology, various metallic gap structures with gap widths reaching a few to sub-nanometer, and even ‘zero-nanometer’, have been realized. At such regime, metallic gaps not only exhibit strong electromagnetic field confinement and enhancement, but also incorporate various quantum phenomena in a macroscopic scale, finding applications in ultrasensitive detection using nanosystems, enhancement of light–matter interactions in low-dimensional materials, and ultralow-power manipulation of electromagnetic waves, etc. Therefore, moving beyond nanometer to ‘zero-nanometer’ can greatly diversify applications of metallic gaps and may open the field of dynamic ‘gaptronics.’ In this paper, an overview is given on wafer-scale metallic gap structures down to zero-nanometer gap width limit. Theoretical description of metallic gaps from sub-10 to zero-nanometer limit, various wafer-scale fabrication methods and their applications are presented. With such versatility and broadband applicability spanning visible to terahertz and even microwaves, the field of ‘gaptronics’ can be a central building block for photochemistry, quantum optical devices, and 5/6G communications.

Large electromagnetic field enhancement in plasmonic nanoellipse for tunable spaser based applications

We theoretically demonstrated a class of plasmonic coupled elliptical nanostructure for achieving a spaser or a nanolaser with high intensity. The plasmonic ellipse is made up of gold film substrate. The proposed structure is then trialed for various light polarizations, moreover, a simple elliptical nanostructure has been chosen primarily from which different cases have been formed by geometry alteration. The structure supports strong coupled resonance mode i.e. localized surface plasmon (LSP). The localized surface plasmon resonance (LSPR) of the investigated system is numerically examined using the finite-element method (FEM). The calculations showed that the LSPR peaks and the local field intensity or near field enhancement (NFE) of the active nanosystem can be amplified to higher values by introducing symmetry-breaking techniques in the proposed ellipse and its variants. The coupled nanostructure having different stages of wavelengths can be excited with different plasmonic resonance modes by the selection of suitable gain media. In addition, a small-sized nanolaser with high tunability range can be developed using this nanostructure. The spaser phenomena are achieved at several wavelengths by changing light polarization and structure alteration methods. Giant localized field enhancement and high LSPR values enable the proposed model to be highly appealing for sensing applications, surface-enhanced Raman spectroscopy, and much more.

LSPR optical fiber sensor based on 3D gold nanoparticles with monolayer graphene as a spacer.

Localized surface plasmon resonance (LSPR) optical fiber biosensing is an advanced and powerful label-free technique which gets great attention for its high sensitivity to refractive index change in surroundings. However, the pursuit of a higher sensitivity is still challenging and should be further investigated. In this paper, based on a monolayer graphene/gold nanoparticles (Grm/Au NPs) three-dimensional (3D) hybrid structure, we fabricated a D-shaped plastic optical fiber (D-POF) LSPR sensor using a facile two-step method. The coupling enhancement of the resonance of this multilayer structure was extremely excited by the surface plasmon property of the stacked Au NPs/Grm layer. We found that the number of plasmonic structure layers was of high importance to the performance of the sensor. Moreover, the optimal electromagnetic field enhancement effect was found in three-layer plasmonic structure. Besides, the n*(Grm/Au NPs)/D-POF sensor exhibited outstanding performance in sensitivity (2160 nm/RIU), linearity (linear fitting coefficient R2 = 0.996) and reproducibility. Moreover, the sensor successfully detected the concentration of glucose, achieving a sensitivity of 1317.61 nm/RIU, which suggested a promising prospect for the application in medicine and biotechnology.

Plasmon-enhanced photocatalytic cumulative effect on 2D semiconductor heterojunctions towards highly-efficient visible-light-driven solar-to-fuels conversion

The photocatalytic activity of a semiconductor is heavily influenced by its photocatalytic cumulative effect on the four consecutive photo-physiochemical processes, including (I) light harvesting, (II) charge separation, (III) charge migration, and (IV) charge utilization. However, it is still a tremendous challenge to enhance the photocatalytic cumulative effect by simultaneously sensitizing the total above I-IV processes of the semiconductor. Herein, we synthesized the well-designed plasmonic Au@Pt/CdS/C3N4 heterostructure through assembling Pt/CdS-selective-coated Au nanocubes onto the two dimensional (2D) ultrathin C3N4 nanosheets (NSs). We have also demonstrated that selectively coating CdS nanoparticle-clusters (NPCs) and Pt nanoparticles (NPs) onto the surfaces and edges of Au NCs could boost the II and III processes of the formed Au@Pt/CdS NCs based on the resonance energy transfer (RET) and “hot electron” transfer (HET) behaviors, respectively, due to the localized surface plasmon resonance (LSPR) of Au NCs. The assembly of the Au@Pt/CdS NCs onto the C3N4 NSs formed lots of 2D Au/CdS/C3N4 interface, where the Au-LSPR not only boosted the I process at the “type II” heterojunction regions of CdS/C3N4, but also improved the II process of C3N4 NSs via the local electromagnetic field enhancement (LEFE). Furthermore, the quasi-2D porous structure of CdS NPCs increased the surface active-sites at the 2D CdS/C3N4 interface, therefore enhancing the IV process. As such, when normalizing the effective active area as the Au@Pt/CdS/C3N4 hetero-interface region, the plasmonic heterostructure exhibited the ∼ 17.2-fold and ∼ 14.3-fold enhancements on the photocatalytic H2 evolution and CO2 reduction as compared to the CdS/C3N4 heterojunction, respectively.

Improved SERS detection of anionic pollutant with Ag Nanoparticles-decorated ZnAl layered double hydroxide nanosheets array

Enrichment is a valuable strategy to further improve the detection limit. In this work, ZnAl-layered double hydroxide (ZnAl-LDH) nanosheets array in situ synthesized on Al foil was used as the enrichment frame for surface-enhanced Raman spectroscopy (SERS) substrate to further improve the detection limit of anionic pollutant. High density of Ag nanoparticles (Ag-NPs) with an average diameter of 29 nm sputtered onto the surface of the ZnAl-LDH could create localized electromagnetic field enhancement for SERS detection. The as-prepared Ag-NPs@ZnAl-LDH composite substrates showed improved sensitivity to anionic pollutants methyl orange and erythrosin B, demonstrating the promising potentials to improve the detection limit of anion analytes based on SERS spectroscopy.

Surface enhanced electrochemiluminescence of the Ru(bpy)32+/tripropylamine system by Au@SiO2 nanoparticles for highly sensitive and selective detection of dopamine

Surface enhanced electrochemiluminescence (SEECL) emission of the Ru(bpy)32+ (bpy = 2,2′-bipyridyl)/tripropylamine (TPA) system by Au@SiO2 core/shell nanoparticles (NPs) was achieved owing to the electromagnetic field enhancement induced by localized surface plasmon resonance (LSPR) of internal Au cores. The Ru(bpy)32+/TPA system in electrolyte solution showed a maximum ECL enhancement when a glassy carbon electrode (GCE) was modified with Au@SiO2 NPs (Au@SiO2/GCE; Au core, ca. 68 nm; silica shell, 12 nm). The ECL emission of the system in the case of Au@SiO2/GCE was 29 fold stronger than the ECL emission in the case of bare GCE, ca. 39 fold stronger than the ECL emission in the case of hollow silica NP-modified GCE, and 100 fold stronger than the ECL emission in the case of AuNP-modified GCE. To the best of our knowledge, the respective folds of ECL enhancement in the Ru(bpy)32+/TPA system by the LSPR-induced electromagnetic field of AuNPs are the largest reported to date. The ECL emission of TPA•+ radical cations was detected for the first time taking the advantage of the electromagnetic field enhancement. A SEECL platform based on the Au@SiO2/GCE in the Ru(bpy)32+/TPA system was constructed for the detection of dopamine (DA). This is the first example that the AuNP-enhanced ECL emission was quenched by DA for the selective detection of DA, and a wide linear range of 0.01–600 μM directly relevant to DA concentration was obtained with a low detection limit of 0.004 μM and high sensitivity and accuracy. The mechanism that the ECL emission of the Ru(bpy)32+/TPA system was quenched by DA for the detection of DA was clearly elaborated. The level of DA in human serum was determined using the SEECL platform.