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Super-resolution Mapping of Enhanced Emission by Collective Plasmonic Resonances
摘要： Plasmonic particle arrays have remarkable optical properties originating from their collective behavior, which results in resonances with narrow line widths and enhanced electric fields extending far into the surrounding medium. Such resonances can be exploited for applications in strong light?matter coupling, sensing, lasing, and light harvesting, nonlinear nanophotonics, solid-state lighting. However, as the lattice constants associated with plasmonic particle arrays are on the order of their resonance wavelengths, mapping the interaction between point dipoles and plasmonic particle arrays cannot be done with diffraction-limited methods. Here, we map the enhanced emission of single fluorescent molecules coupled to a plasmonic particle array with ～20 nm in-plane resolution by using stochastic super-resolution microscopy. We find that extended lattice resonances have minimal influence on the spontaneous decay rate of an emitter but instead can be exploited to enhance the outcoupling and directivity of the emission. Our results can guide the rational design of future optical devices based on plasmonic particle arrays.
关键词： light?matter interaction,nanophotonics,single molecule localization,collective resonances,plasmonics,super-resolution microscopy
更新于2025-11-25 10:30:42
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Monolithic metal dimer-on-film structure: new plasmonic properties introduced by the underlying metal
摘要： Dimers -two closely-spaced metallic nanostructures- are one of the primary nanoscale geometries in plasmonics, supporting high local field enhancements in their interparticle junction under excitation of their hybridized “bonding” plasmon. However, when a dimer is fabricated on a metallic substrate, its characteristics are changed profoundly. Here we examine the properties of an Au dimer on an Au substrate. This structure supports a bright “bonding” dimer plasmon, screened by the metal, and a lower energy magnetic charge transfer plasmon. Changing the dielectric environment of the dimer-on-film structure reveals a broad family of higher-order hybrid plasmons in the visible region of the spectrum. Both the localized surface plasmons resonances (LSPR) of the individual dimer-on-film structures as well as their collective surface lattice resonances (SLR) show a highly sensitive refractive index sensing response. Implementation of such all-metal magnetic-resonant nanostructures offers a promising route to achieve higher-performance LSPR- and SLR-based plasmonic sensors.
关键词： Plasmonics,localized surface plasmon resonance,surface lattice resonance,LSPR sensing,refractive index sensing
更新于2025-11-21 11:24:58
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Au@Cu Core-Shell Nanocubes with Controllable Sizes in the Range of 20-30 nm for Applications in Catalysis and Plasmonics
摘要： Predominantly covered by a single type of {100} facets, Cu nanocubes are attractive catalytic material toward reactions such as electrochemical reduction of CO2. Here we report a seed-mediated approach to the facile synthesis of Au@Cu core-shell nanocubes with hexadecylamine and Cl- serving as capping agents toward the {100} facets of Cu and glucose as a reducing agent. The large (12%) lattice mismatch between Cu and Au led to the localized epitaxial growth of Cu shells on the Au seeds and the formation of nanocubes with randomly distributed Au cores. Compared to the same synthesis in the absence of Au seeds, the reduction of Cu(II) ions was greatly accelerated in the presence of Au seeds because of the autocatalytic surface reduction. It was also found that the structure and morphology of the products were highly dependent on the concentration of Cu(II) precursor in the reaction solution. Nanoplates rather than nanocubes were obtained when the concentration of Cu(II) precursor was reduced down to a certain level. By varying the reaction time and/or the amount of Au seeds, the size of the Au@Cu nanocubes could be tuned in a range of 20–30 nm. The as-synthesized core-shell nanocubes exhibited a strong localized surface plasmon resonance peak at 581 nm and the resonance was dominated by absorption rather than scattering. It is expected that the Au@Cu nanocubes with uniform and controllable sizes will find use in a variety of applications such as plasmonics and catalysis.
关键词： lattice mismatch,Copper nanocubes,core-shell nanocrystals,plasmonics,seed-mediated growth
更新于2025-11-19 16:56:35
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Saponification Precipitation Method of CsPbBr3 Nanocrystals with Blue-Green Tunable Emission
摘要： We report on a new synthesis process for halide perovskite nanoplatelets and nanoplates that switches the production process of the cesium precursor from a fatty acid/cesium salt reaction to a cesium base/fatty acid ester reaction, thus enabling the reaction to occur in ambient conditions in minutes instead of hours. The saponification precipitation process reported here, as a result, does not require a vacuum oven or inert reaction environment in obtaining the cesium precursor, or any part of the reaction. Furthermore, the process creates a hygroscopic byproduct that results in a self-drying synthesis. The obtained perovskite nanocrystals exhibit a blue-green tunable emission that occurs via quantum confinement effect, phase, and morphology change. The consequence of these physical processes is that the band gap is highly tunable with temperature and the resulting nanocrystals show remarkable optical properties, while greatly simplifying the production of halide perovskite nanoplatelets and nanoplates.
关键词： Blue-Green Tunable Emission,Saponification Precipitation Method,Hybrid Materials,Magnetic,CsPbBr3 Nanocrystals,Plasmonics,Optical
更新于2025-11-19 16:46:39
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Deep-ultraviolet plasmon resonances in Al-Al <sub/>2</sub> O <sub/>3</sub> @C core-shell nanoparticles prepared via laser ablation in liquid
摘要： We developed a convenient, facile, low cost and ‘‘green” method to synthesize nanoparticles(NPs) with deep-ultraviolet localized surface plasmon resonances (LSPR) based on laser ablation of aluminum target in liquid. The nanoparticles had an Al-Al2O3@C core-shell structure, and the LSPR peak ranged from 240nm to 250nm with the increasing of laser radiation time. It is found that the LSPR peak of the NPs is related to the presence of Al2O3 based on experimental characterization and theoretical simulation. The carbon shell can reduce the oxidation of Al nanoparticles and enhance the stability, which is significant important to achieve the deep-ultraviolet LSPR. Moreover, we demonstrated the enhancement of the blue fluorescence intensity from CsPbBr3-xClx by the Al-Al2O3@C NPs, due to the stronger excitations for CsPbBr3-xClx by the enhancement of localized electromagnetic field from LSPR.
关键词： PL enhancement,plasmonics,localized surface plasmon resonance,Al nanoparticle,deep-ultraviolet
更新于2025-11-14 15:32:45
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Self-Assembled Ordered Three-Phase Au-BaTiO <sub/>3</sub> -ZnO Vertically Aligned Nanocomposites Achieved by a Templating Method
摘要： Complex multiphase nanocomposite designs present enormous opportunities for developing next-generation integrated photonic and electronic devices. Here, a unique three-phase nanostructure combining a ferroelectric BaTiO3, a wide-bandgap semiconductor of ZnO, and a plasmonic metal of Au toward multifunctionalities is demonstrated. By a novel two-step templated growth, a highly ordered Au–BaTiO3–ZnO nanocomposite in a unique “nanoman”-like form, i.e., self-assembled ZnO nanopillars and Au nanopillars in a BaTiO3 matrix, is realized, and is very different from the random three-phase ones with randomly arranged Au nanoparticles and ZnO nanopillars in the BaTiO3 matrix. The ordered three-phase “nanoman”-like structure provides unique functionalities such as obvious hyperbolic dispersion in the visible and near-infrared regime enabled by the highly anisotropic nanostructures compared to other random structures. Such a self-assembled and ordered three-phase nanocomposite is obtained through a combination of vapor–liquid–solid (VLS) and two-phase epitaxy growth mechanisms. The study opens up new possibilities in the design, growth, and application of multiphase structures and provides a new approach to engineer the ordering of complex nanocomposite systems with unprecedented control over electron–light–matter interactions at the nanoscale.
关键词： vertically aligned nanocomposites,plasmonics,epitaxial thin films,metamaterials,three-phase nanocomposites,self-assembly
更新于2025-10-22 19:40:53
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Surface Plasmon Resonance Enhancement of PbS Quantum Dot-Sensitized Solar Cells
摘要： Lead sulfide (PbS)-sensitized quantum dot solar cells (QDSC) were fabricated using TiO2 and TiO2–Au plasmonic nanocomposite films by successive ionic layer adsorption and reaction (SILAR) method. The average size of gold nanoparticles (GNPs) used for fabricating nanocomposite films was ~ 15 nm. Thin plasmonic QDSC, with a film thickness of 10 μm, showed an increase of ~ 11% in photocurrent and ~ 6% in overall energy conversion efficiency compared to the device without GNPs. The improved performance of QDSCs is attributed to the increased absorption due to the plasmonic near-field effects of the incorporated GNPs. High-efficiency PbS/CdS-co-sensitized thick cells with 16 μm bilayer TiO2 also showed improvement in photocurrent and efficiency. The results show that the plasmonic-enhanced absorption can be used to augment efficiency of QDSC devices in much the same fashion as that of dye-sensitized solar cells.
关键词： Gold nanoparticles,Quantum dot-sensitized solar cells,Plasmonics,Photovoltaics
更新于2025-10-22 19:40:53
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Surface-enhanced Raman scattering (SERS) imaging of bioactive metabolites in mixed bacterial populations
摘要： Bacteria frequently live in mixed multispecies communities, shaped by the action of bioactive metabolites that are secreted by the residing microbial species. The identification and tracking of such chemical exchange processes is fundamental toward understanding how these particular extracellular molecules modulate microbial communities and functions. In this context, most chemical imaging approaches so far have focused on the analysis of metabolic interactions occurring between microbial populations co-cultured separately. We demonstrate here the application of surface-enhanced Raman scattering (SERS) spectroscopy as a valuable imaging tool for the non-invasive detection and visualization of metabolites secreted by Escherichia coli and Pseudomonas aeruginosa bacteria, cultured as mixed populations and thereby mimicking the complexity of natural microbial communities. SERS enabled the simultaneous detection and in situ visualization of indole and pyocyanin, revealing the down-regulation of pyocyanin expression due to indole signaling. The successful detection of chemical interactions in mixed bacterial populations shows the potential of SERS for the investigation of the chemistry underpinning multispecies microbial communities.
关键词： Quorum sensing,Plasmonics,Indole,SERS imaging,Pyocyanin
更新于2025-09-23 15:23:52
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Coupling of Fluorophores in Single Nanoapertures with Tamm Plasmon Structures
摘要： Metal nanostructures (such as plasmonic antennas) have been widely demonstrated to be excellent devices for beaming and sorting the fluorescence emission. These effects rely on the constructive scattering or diffraction from different elements (such as metal corrugations or nanorings) of the nanostructures. However, subwavelength-size nanoholes, without nearby nanoscale features, results in an angularly dispersed emission from the distal surface. Herein, we demonstrate for the first time the emission redirection capabilities of a single isolated nanoaperture milled in a thick silver film deposited on a dielectric multilayer. Specifically, we show that a dye dissolved in ethanol filling in the nanoaperture can couple to Tamm Plasmon Polariton (TPP) modes of the structure. Due to the small in-plane wavevectors of the TPPs, the fluorescence from Tamm-coupled dyes within the nanoaperture is emitted normally to the sample surface, with a minimum angular width of about 12.54o. This kind of fluorescence manipulation has proven to be effective with various nanoaperture shapes, such as circles, squares, and triangles. Our work is also the first experimental demonstration of lateral coupling of fluorophores with TPPs in nanoholes, with potential applications in bioanalysis and biosciences.
关键词： Optical,Plasmonics,and Hybrid Materials,Magnetic
更新于2025-09-23 15:23:52
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Gold-Iron Oxide Yolk-Shell Nanoparticles (YSNPs) as magnetic probe for Fluorescence-based detection of 3 base mismatch DNA
摘要： Seed-mediated Gold-Iron oxide yolk-shell nanoparticles (YSNPs) were synthesized and functionalized with cy5 attached- thiolated single strand DNA probe for the detection of mutated DNA. The optimum concentration of thiolated DNA determined from a bathochromic shift of surface plasmon resonance (SPR) peak, was 0.177μM. The effect of pH (2 to 10), temperature (4, 37, 60 and 100 °C), and ionic strengths (1 M to 4 M) on the stability of ssDNA probe tethered YSNPs, studied with the assistance of flocculation parameter. The detection of mutation in DNA was possible using such ssDNA probe functionalized and stabilized nanoparticles. The hybridization of the oligonucleotide probe with the complementary, non-complementary and mutated DNA strands are determined via their respective intensities of the fluorescence of cy5, an efficient fluorescent marker. The intensities help in the comprehension of the specificity of the system. The report predicts controlled efficiency of hybridization with the aid of Hamaker constant, which is determined as 1.15 x 10-20 J for DNA functionalized YSNPs. The minimum concentration of target DNA detected using this methodology was 1.2×10-11 mol/L.
关键词： Plasmonics,Fluorescence,YSNPs,Au-Fe3O4,Point mutations
更新于2025-09-23 15:23:52