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Plasmon-Enhanced Fluorescent Sensor based on Aggregation-Induced Emission for the Study of Protein Conformational Transformation
摘要： The alteration in protein conformation not only affects the performance of its biological functions, but also leads to a variety of protein-mediated diseases. Developing a sensitive strategy for protein detection and monitoring its conformation changes is of great significance for the diagnosis and treatment of protein conformation diseases. Herein, a plasmon-enhanced fluorescence (PEF) sensor is developed, based on an aggregation-induced emission (AIE) molecule to monitor conformational changes in protein, using prion protein as a model. Three anthracene derivatives with AIE characteristics are synthesized and a water-miscible sulfonate salt of 9,10-bis(2-(6-sulfonaphthalen-2-yl)vinyl)anthracene (BSNVA) is selected to construct the PEF–AIE sensor. The sensor is nearly non-emissive when it is mixed with cellular prion protein while emits fluorescence when mixed with disease-associated prion protein (PrPSc). The kinetic process of conformational conversion can be monitored through the fluorescence changes of the PEF–AIE sensor. By right of the amplified fluorescence signal, this PEF–AIE sensor can achieve a detection limit 10 pM lower than the traditional AIE probe and exhibit a good performance in human serum sample. Furthermore, molecular docking simulations suggest that BSNVA tends to dock in the β-sheet structure of PrP by hydrophobic interaction between BSNVA and the exposed hydrophobic residues.
关键词： fluorescence sensor,protein conformation,aggregation-induced emission,prion protein,plasmonic enhancement
更新于2025-11-19 16:46:39
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Plasmonic enhancement of photocurrent generation in Photosystem Ia??based hybrid electrode
摘要： We experimentally demonstrate that oriented assembly of red algal photosystem I (PSI) reaction center on a plasmonically active Silver Island Film (SIF) leads to strong enhancement of both fluorescence intensity and photocurrent generated upon illumination. PSI complexes were specifically attached to a monolayer of graphene deposited on the SIF layer. The results of comprehensive fluorescence microscopy point out to the critical role of the SIF layer in enhancing the optical response of PSI, as we observe increased emission intensity. Hence, importantly, the strong increase of photocurrent generation demonstrated for the biohybrid electrodes, can be directly associated with the plasmonic enhancement of optical and electrochemical functionalities of PSI. The results also indicate that the graphene layer is not diminishing the influence of the plasmonic excitations in SIF on the absorption and emission of PSI.
关键词： hybrid electrode,plasmonic enhancement,Photosystem I,graphene,Silver Island Film,photocurrent generation
更新于2025-09-23 15:19:57
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Plasmonic Enhancement of Dye Fluorescence in Polymer/Metal Nanocomposites
摘要： The effect of the plasmonic enhancement of dye fluorescence in poly(vinyl butyral) films containing Ag/SiO2 core-shell nanoparticles has been thoroughly studied. It has been shown that the magnitude of this effect can be quite large (up to 5 times) even for a dye having a very high quantum yield (coumarin 7). Therewith, it substantially depends on the size and concentration of Ag/SiO2 particles and the quantum yield of a dye. The results obtained are discussed with involvement of mechanisms reported in the literature for plasmonic enhancement of fluorescence of dyes characterized by high and low quantum yields.
关键词： plasmonic enhancement,dye fluorescence,quantum yield,polymer/metal nanocomposites,Ag/SiO2 core-shell nanoparticles
更新于2025-09-23 15:19:57
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Improved Photoresponse of UV Photodetectors by the Incorporation of Plasmonic Nanoparticles on GaN Through the Resonant Coupling of Localized Surface Plasmon Resonance
摘要： Very small metallic nanostructures, i.e., plasmonic nanoparticles (NPs), can demonstrate the localized surface plasmon resonance (LSPR) effect, a characteristic of the strong light absorption, scattering and localized electromagnetic field via the collective oscillation of surface electrons upon on the excitation by the incident photons. The LSPR of plasmonic NPs can significantly improve the photoresponse of the photodetectors. In this work, significantly enhanced photoresponse of UV photodetectors is demonstrated by the incorporation of various plasmonic NPs in the detector architecture. Various size and elemental composition of monometallic Ag and Au NPs, as well as bimetallic alloy AgAu NPs, are fabricated on GaN (0001) by the solid-state dewetting approach. The photoresponse of various NPs are tailored based on the geometric and elemental evolution of NPs, resulting in the highly enhanced photoresponsivity of 112 A W?1, detectivity of 2.4 × 1012 Jones and external quantum efficiency of 3.6 × 104% with the high Ag percentage of AgAu alloy NPs at a low bias of 0.1 V. The AgAu alloy NP detector also demonstrates a fast photoresponse with the relatively short rise and fall time of less than 160 and 630 ms, respectively. The improved photoresponse with the AgAu alloy NPs is correlated with the simultaneous effect of strong plasmon absorption and scattering, increased injection of hot electrons into the GaN conduction band and reduced barrier height at the alloy NPs/GaN interface.
关键词： UV photodetection,NP-based photodetectors,Plasmonic enhancement,Nanoparticles
更新于2025-09-23 15:19:57
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Interactions of plasmonic silver nanoparticles with high energy sites on multi‐faceted rutile TiO? photoanodes
摘要： The plasmonic interactions between silver nanoparticles and various rutile TiO2 facets are studied by correlating Advanced Electron Microscopy and Electrochemical Impedance Spectroscopy (EIS) to help design a route towards an optimised polycrystalline film fabrication. By using an Electron Backscatter Diffraction (EBSD) detector, it was determined that using HF as directing agent during the hydrothermal growth of TiO2 promotes the formation of high-angle grain boundaries. Silver photodeposition occurs preferentially at these boundaries, consistent with the presence of high energy sites on the (100)-oriented rutile TiO2 nanorods. Further EIS study showed an increase in the photoelectrochemical activity in the visible range of the solar spectrum for the samples consisting of silver nanoparticles deposited on these grain boundaries.
关键词： Water Splitting,Photoelectrochemistry,Plasmonic enhancement,Electron Microscopy,Grain Boundaries
更新于2025-09-19 17:13:59
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Second Harmonic Generation for Moisture Monitoring in Dimethoxyethane at a Gold-Solvent Interface Using Plasmonic Structures
摘要： Second harmonic generation (SHG) is forbidden from most bulk metals because metals are characterized by centrosymmetric symmetry. Adsorption or desorption of molecules at the metal interface can break the symmetry and lead to SHG responses. Yet, the response is relatively low, and minute changes occurring at the interface, especially at solid/liquid interfaces, like in battery electrodes are difficult to assess. Herein, we use a plasmonic structure milled in a gold electrode to increase the overall SHG signal from the interface and gain information about small changes occurring at the interface. Using a specific homebuilt cell, we monitor changes at the liquid/electrode interface. Specifically, traces of water in dimethoxyethane (DME) have been detected following changes in the SHG responses from the plasmonic structures. We propose that by plasmonic structures this technique can be used for assessing minute changes occurring at solid/liquid interfaces such as battery electrodes.
关键词： second-order nonlinear susceptibility,second harmonic generation (SHG),plasmonic enhancement,battery
更新于2025-09-16 10:30:52
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The improved performance of BHJ organic solar cells by random dispersed metal nanoparticles through the active layer
摘要： In this paper, the performance of bulk heterojunction (BHJ) organic solar cells (OSCs) in the presence of random dispersed Ag nanoparticles (NPs) into the active layer is investigated. By the well-known Maxwell-Garnett effective medium theory, we have analyzed the optical absorption of P3HT:PCBM and PCDTBT:PCBM photoactive blends when spherical Ag NPs are randomly embedded in them. The photocurrent enhancement of OSCs based on the blend:AgNP composites has been examined by an analytical drift-diffusion method. Our theoretical analysis demonstrates a considerable enhancement in the optical absorption of the blends with Ag NPs resulted in the power conversion efficiency (PCE) improvement of the devices up to 65.6% in comparison with the reference blends. In addition, the spectrally correlation of simulated external quantum efficiency (EQE) and the absorption coefficient enhancements proves the influence of localized surface plasmon resonance (LSPR) of the Ag NPs in boosting the performance of the OSC devices.
关键词： plasmonic enhancement,drift-diffusion model,Organic solar cells,effective medium theory,Random distribution
更新于2025-09-16 10:30:52
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Plasmonically Enhanced Upconversion Luminescence via Holographically Formed Silver Nanogratings
摘要： Greatly enhanced upconversion luminescence was demonstrated by integrating the core-shell upconversion nanorods with the Ag nanogratings. Both the Ag nanogratings and upconversion nanorods were fabricated/synthesized in a facile, cost-effective, high throughput way. Experimental results showed that the upconversion luminescence intensity of Er3+ in the core-shell upconversion nanorods can be well tuned and enhanced by changing the shell thickness and the period of the Ag nanograting. The underlying physical mechanism for the upconversion luminescence enhancement was attributed to the plasmonically enhanced near infrared broadband absorption of the periodic Ag nanograting and the localized surface plasmon resonance of Ag nanocrystals. The maximum enhanced factors of 523 nm, 544 nm (green emission) and 658 nm (red emission) of Er3+ ions excited at 980 nm are 3.8, 5.5 and 4.6 folds, respectively. Our fabrication approach and results suggest that such a simple integration is potentially useful for biosensing/imaging and anticounterfeiting applications.
关键词： plasmonic enhancement,upconversion,core-shell nanorod,nanograting,Holographical synthesis
更新于2025-09-12 10:27:22
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Growing In‐Plane Multiplex Plasmonic Arrays for Synergistic Enhanced Photocurrent Response
摘要： A complete control of the localized surface plasmon resonance (LSPR) properties of different types of metal nanoparticles (size, shape, or composition) in a device by facile techniques with high throughput is crucial to intensively study and apply the LSPR effects to improve device performance. Here, a versatile approach is presented to fabricate macroscopic and in-plane multiplex arrays of plasmonic nanoparticles with well-defined particle size or composition allocation. The polymer layer (poly(N-isopropylacrylamide), PNIPAM) spin-coated on the surface of the substrate is applied as a protective layer to control the growth of the Au nanoparticles in a dip-coating procedure. The relative contribution of LSPR of each particle type can be controlled by selectively adjusting the particle size or composition at the desired position of multiplex arrays on the same substrate. A synergistic enhanced photocurrent response is observed in the metal–semiconductor system, which is attributed to broadened LSPR enhancement of multiplex composition (Au and Au@Ag) structures from the same substrate. The fabrication procedure presented in this study is highly repeatable and feasible for preparing ordered multiplex nanostructures on the same substrate. Furthermore, this method provides a cost-effective and versatile platform for design of multiplex plasmonic nanostructures in sensing, solar energy conversion, and optical processing applications.
关键词： PNIPAM,plasmonic enhancement,Au@Ag,Au,photocurrent response,tunable absorption wavelength
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Evaluation of Plamsonic Enhancement and Quenching of Ag Nanoparticles in Organic Light-Emitting Diode
摘要： The utilization of localized surface plasmon (LSPR) to improve the yield of organic light emitting diode (OLED), has been subject of numerous publications and reports. Several enhancement mechanisms have been highlighted such as the increase of F?rster energy transfer, the enhancement of the OLED electroluminescence as well as the increase of the current I and the decrease of the turn-on voltage V [1,2]. Nevertheless, these mechanisms are still not completely studied and understood. One major problem of using metallic NPs is the inherent losses associated with their conductivity. Another important issue concerns the evaluation of their electrical and optical effects on the total yield enhancement. Besides, the LSPR wavelength and the distance of the metallic NPs from the OLED emitting layer (EML) are very important parameters for a maximum enhancement of the near-field-induced energy transfer between excitons and NPs LSPR. In fact, LSPR modifies the radiative and the non-radiative decay rates of adjacent emitters resulting in two competitive processes: the fluorophores radiation intensity enhancement and the non-radiative quenching of activated fluorophores on the NP metal surface. To obtain an overall enhancement, the resonance energy of the fluorophore and the LSPR should be carefully adjusted with an appropriate distance between the metal NPs and the emitter. In this work, we report a thorough investigation of Ag NPs randomly dispersed into a standard guest-host OLED (Alq3:DCM) by thermal evaporation during the OLED fabrication process. Mainly, we follow-up the interaction between the Ag-thin layer and the excitons by varying the position of Ag-NPs within the OLED stack (fig. 1). At each position of Ag-NPs, we compare the plasmonic-OLED performances to those of the reference one without NPs (zero line) and we bring a general analysis of the electroluminescence efficiency variation as a function of the position of Ag-NPs related to the excitons distribution within the OLED emitting layer. The experimental results allow us to draw the balance between the amplification and quenching due to the Ag-NPs. By considering the spatial distribution of the emission sites in the EML, we particularly, highlighted two competing effects: the LSPR amplification for large distances between the Ag-NPs and the emissive sites, and the quenching effect by metallic NPs for short distances between the Ag-NPs and the emissive sites. Nevertheless, other phenomena such as the influence of Ag-NPs on the charge carriers injection and transport as well as extraction effect should be also taken into account in order to thoroughly understand the effect of plasmonic nanoparticles on the OLED structure performance. Our study enable us to suggest a figure of merit giving the total yield as following (cid:75) (cid:97) σ. (cid:69)a. (cid:69)q. (cid:75)ex, where (cid:86) accounts for the electrical effects, (cid:69)a and (cid:69)b are LSPR amplification and plasmonic quenching, respectively and (cid:75)ex is related to the extraction effect. The weight of the previous parameters depends on the distance NPs-EML with three zones of interest: anode side, cathode side and nearby the EML. Two different physical phenomena are also to be considered on the side of the cathode and the anode (blue and green lines in fig.1), as well as the correlation between near and far field. These results are of a great interest in order to develop new generation of highly efficient OLED-based devices.
关键词： Ag nanoparticles,plasmonic enhancement,localized surface plasmon (LSPR),quenching,organic light emitting diode (OLED)
更新于2025-09-11 14:15:04