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Silver-Gold Bimetallic Alloy versus Core-Shell Nanoparticles: Implications for Plasmonic Enhancement and Photothermal Applications
摘要： Bimetallic plasmonic nanoparticles enable tuning of the optical response and chemical stability by variation of the composition. The present numerical simulation study compares Ag-Au alloy, Ag@Au core-shell, and Au@Ag core-shell bimetallic plasmonic nanoparticles of both spherical and anisotropic (nanotriangle and nanorods) shapes. By studying both spherical and anisotropic (with LSPR in the near-infrared region) shapes, cases with and without interband transitions of Au can be decoupled. Explicit comparisons are facilitated by numerical models supported by careful validation and examination of optical constants of Au-Ag alloys reported in literature. Although both Au-Ag core-shell and alloy nanoparticles exhibit an intermediary optical response between that of pure Ag and Au nanoparticles, there are noticeable differences in the spectral characteristics. Also, the effect of the bimetallic constitution in anisotropic nanoparticles is starkly different from that in spherical nanoparticles due to the absence of Au interband transitions in the former case. In general, the improved chemical stability of Ag nanoparticles by incorporation of Au comes with a cost of reduction in plasmonic enhancement, also applicable to anisotropic nanoparticles with a weaker effect. A photothermal heat transfer study confirms that increased absorption by the incorporation of Au in spherical Ag nanoparticles also results in an increased steady state temperature. On the other hand, anisotropic nanoparticles are inherently better absorbers, hence better photothermal sources and their photothermal properties are apparently not strongly affected by the incorporation of one metal in the other. This study of the optical/spectral and photothermal characteristics of bimetallic Au-Ag alloy versus core-shell nanoparticles provides a detailed physical insight for the development of new taylor-made plasmonic nanostructures.
关键词： Localized Surface Plasmon Resonance (LSPR),Au@Ag core-shell,Ag-Au alloy,Ag@Au core-shell,Bimetallic plasmonic nanoparticles,Photothermal applications
更新于2025-09-23 15:21:01
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Recent advances of plasmonic nanoparticle-based optical analysis in homogeneous solution and at the single-nanoparticle level
摘要： Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles in both homogeneous solution and single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis system.
关键词： Plasmonic nanoparticles,Single-nanoparticle level,Fluorimetric assays,Chemical reactions,Localized surface plasmon resonance (LSPR),Optical analysis,Homogeneous solution,Colorimetric assays,Biological processes
更新于2025-09-23 15:21:01
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Cuvette-based microfluidic device integrated with nanostructures for measuring dual Localized Surface Plasmon Resonance (LSPR) signals
摘要： A spectrophotometer that uses a localized surface plasmon resonance phenomenon is a powerful measurement tool in the biotechnology and bioanalysis fields. We propose a novel cuvette design type that can be used for universal spectrophotometers. The novel cuvette design needs a few μl reagent for measuring, and also two chips for measurement can be loaded and measured at the same time. A new cuvette can easily be used several times because of sample chips to be loaded and unloaded since they are mechanically mounted by screws. Therefore, it can offer advantages to users in terms of cost and time. We verify its possibility for use in the biotechnology and bioanalysis fields by a signal enhancement and dual signal detection.
关键词： spectrophotometer,bioanalysis,nanostructures,microfluidic device,biotechnology,Localized Surface Plasmon Resonance,LSPR
更新于2025-09-23 15:21:01
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Rectifying Behaviour and Photocatalytic Activity in ZnO Nanorods Array/Ag/CuSe Heterostructure
摘要： Ag incorporated vertically aligned ZnO nanorods array/CuSe thin film (ZnO NRs/CuSe TF) have been fabricated via a solution route, thermal evaporation and magnetron sputtering process. Ternary ZnO nanorods/Ag/CuSe heterostructure was studied by X-ray diffractometry, field emission-scanning electron microscopy/energy dispersive X ray spectroscopy, current–voltage measurement and a UV–Vis–near IR spectrophotometer. The photocatalytic performance was estimated by the degradation of Rhodamine B solution under UV–Vis light irradiation. The photocatalytic efficiency of the ZnO NRs/Ag/CuSe heterostructure is higher than that of ZnO NRs/Ag and ZnO NRs/CuSe counterparts due to the robust effects of the three functional components coupling. The localized surface plasmon resonance and two Schottky junctions (e.g. Ag/ZnO and Ag/CuSe) motivates photogenerated electron–hole separation and transfer. This work presents an artificial manipulated system to enhance light harvesting, efficient charge separation and transfer, and low recombination rate in solar energy conversion.
关键词： Photocatalytic activity,Localized surface plasmon resonance (LSPR),Charge separation,ZnO nanorods array/Ag/CuSe heterostructure
更新于2025-09-19 17:15:36
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Plasmonic-Active Nanostructured Thin Films
摘要： Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar cells, super-resolution imaging, organic synthesis, etc. is still emerging. The effectiveness of the plasmonic materials on these technologies depends on their stability and sensitivity. Preparing plasmonics-active nanostructured thin films (PANTFs) on a solid substrate improves their physical stability. More importantly, the surface plasmons of thin film and that of nanostructures can couple in PANTFs enhancing the sensitivity. A PANTF can be used as a transducer for any of the three plasmonic-based sensing techniques, namely, the propagating surface plasmon, localized surface plasmon resonance, and surface-enhanced Raman spectroscopy-based sensing techniques. Additionally, continuous nanostructured metal films have an advantage for implementing electrical controls such as simultaneous sensing using both plasmonic and electrochemical techniques. Although research and development on PANTFs have been rapidly advancing, very few reviews on synthetic methods have been published. In this review, we provide some fundamental and practical aspects of plasmonics along with the recent advances in PANTFs synthesis, focusing on the advantages and shortcomings of the fabrication techniques. We also provide an overview of different types of PANTFs and their sensitivity for biosensing.
关键词： localized surface plasmon resonance (LSPR),plasmonics,gold nanostructures,biosensing,thin film,lithography,nanohole array,nanofabrication
更新于2025-09-19 17:13:59
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TiN-contained polymer-metal core-shell structured nanocone array: Engineering of sensor performance by controlling plasmonic properties
摘要： Metal nanostructures have great potential for optical label-free biosensors based on localized surface plasmon resonance (LSPR). The sensitivity of a metal nanostructure-based label-free biosensor (i.e., plasmonic sensor) depends on its plasmonic properties, which su?er a decrease in sensitivity by energy losses in the metal material. Here, we demonstrate an approach to improve the plasmonic properties of metal nanostructures by controlling the carrier density in the base polymer material using titanium nitride (TiN). It is expected that the light energy absorbed by TiN is converted into excitons, and it will assist LSPs in the metal nanostructure; thus, the losses of the metal material are compensated by the excitons excited in TiN. We designed a TiN-contained polymer-metal core-shell structured nanocone array (NCA), comprising TiN nanoparticles (NPs) in a polymer core and metal shell (Au or Ag), and realized improvement of the refractive index (RI) sensitivity of a label-free biosensor by optimizing the TiN-contained polymer composition. As a result, the TiN-contained polymer-metal NCA, with a TiN NP concentration of 10 wt% in the polymer core, had a 1.5-fold higher RI sensitivity than that of the same NCA without TiN NPs. The results of the resistance measurement of the metal surface with the TiN NP-contained polymer (10 wt%) under light exposure suggest the conversion of exposed light into LSPs of metal via TiN. It is suggested that plasmonic properties and sensor performances can be improved by the presented approach. Moreover, in DNA hybridization detection, an extremely low limit of detection of 117.5 fM was achieved.
关键词： Localized surface plasmon resonance (LSPR),Core-shell nanostructure,DNA detection,Carrier engineering,Biosensor,Titanium nitride
更新于2025-09-16 10:30:52
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Integration of Hybrid Plasmonic Au-BaTiO <sub/>3</sub> Metamaterial on Silicon Substrates
摘要： Silicon integration of nanoscale metamaterials is a crucial step toward low-cost and scalable optical-based integrated circuits. Here, a self-assembled epitaxial Au-BaTiO3 (Au-BTO) hybrid metamaterial with highly anisotropic optical properties has been demonstrated on Si substrates. A thin buffer layer stack (<20 nm) of TiN and SrTiO3 (STO) was applied on Si substrates to ensure the epitaxial growth of the Au-BTO hybrid films. Detailed phase composition and microstructural analyses show excellent crystallinity and epitaxial quality of the Au-BTO films. By varying the film growth condition, the density and dimension of the Au nanopillars can be tuned effectively, which leads to highly tailorable optical properties including tunable localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion shift in the visible and near-infrared regime. The work highlights the feasibility of integrating epitaxial hybrid oxide-metal plasmonic metamaterials on Si towards future complex Si-based integrated photonics.
关键词： silicon integration,hyperbolic dispersion,localized surface plasmon resonance (LSPR),oxide-metal nanocomposite,Hybrid plasmonic metamaterials
更新于2025-09-12 10:27:22
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Ag ion implanted TiO2 photoanodes for fabrication of highly efficient and economical plasmonic Dye Sensitized Solar Cells
摘要： Materials with tunable optical and photoelectric properties are prerequisite for the development of highly stable, economical and efficient dye sensitized solar cells (DSSCs). In this direction, improved plasmonic DSSCs with comparatively higher light harvesting ability and reduced recombination of photo-generated charge carriers have been fabricated using low energy (120 KeV) Ag ion implanted TiO2 photoanodes at variable fluence. Herein, the origin of improved photovoltaic performance of Ag implanted DSSCs against conventional DSSC has been explained using UV-visible, photoluminescence and kelvin probe measurements. Further, the efficient interfacial charge transportation within Ag implanted DSSCs has been demonstrated through EIS measurements.
关键词： Fermi energy equilibration,Ion Implantation,Localized Surface Plasmon Resonance (LSPR)
更新于2025-09-12 10:27:22
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Enhanced Electrocatalysis via Boosted Separation of Hot Charge Carriers of Plasmonic Gold Nanoparticles Deposited on Reduced Graphene Oxide
摘要： The plasmon enhancement on electrocatalysis was investigated on pure Au nanoparticles (AuNPs) and AuNPs-reduced graphene oxide (AuNPs/rGO) hybrid. Upon Localized surface plasmon resonance (LSPR) excitation, hot charge carriers (hot electrons and holes) generate on AuNPs. In the experiments, hot holes are scavenged by glucose, and hot electrons could be efficiently transferred to the external electric circuit under a potential bias, resulting in an observable current enhancement. Then the hot electrons transfer efficiency can be quantitatively compared by the increased current response. It was found that the current density increases more obviously on AuNPs/rGO hybrid compared to pure AuNPs upon light irradiation. Due to the excellent electron mobility of rGO and perfect electron affinity capacity, the hot electrons generated on AuNPs will be efficiently transferred to the closely contacted rGO, then flow into the external circuit generating current. The present study highlights the role of rGO in improving the separation of hot charge carriers to promote the photocatalysis reactions.
关键词： Au nanoparticles (AuNPs),Hot charge carriers,Localized surface plasmon resonance (LSPR),Graphene,Electrochemical method
更新于2025-09-04 15:30:14