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Surface plasmon-enhanced near-field thermal rectification in graphene-based structures
摘要： We propose a thermal rectification structure composed of InSb and graphene-coated 3C-SiC separated by a nanoscale vacuum gap. To obtain an obvious thermal rectification effect, the permittivities of these materials are all considered to be temperature-dependent. Numerical calculations based on fluctuation electrodynamics reveal that the introduction of graphene into the structure enhances significantly near-field radiative heat flux and thermal rectification efficiency owing to the strong coupling of surface plasmon-polaritons between InSb and graphene. In general, the rectification efficiency above 60% can be maintained for the vacuum gap less than 70 nm. The rectification efficiency exceeding 95% is realized for a vacuum gap of 10 nm and a chemical potential of 0.1 eV. Increasing the emitter’s temperature leads to the drastic increase of the rectification efficiency in a wider temperature range. A lower chemical potential seems more favorable to raising rapidly the rectification efficiency. The above results might be helpful in designing a thermal diode with higher efficiency and wider vacuum gap.
关键词： near-field radiative heat transfer,thermal rectification,InSb,surface plasmon-polaritons,graphene,3C-SiC
更新于2025-09-10 09:29:36
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Localized surface plasmon resonance on two-dimensional HfSe <sub/>2</sub> and ZrSe <sub/>2</sub>
摘要： HfSe2 and ZrSe2 are newly discovered two-dimensional (2D) semiconducting transition metal dichalcogenides with promising properties for future nanoelectronics and optoelectronics. We theoretically revealed the electronic and optical properties of these two emerging 2D semiconductors, and evaluated their performance for the application of localized surface plasmon resonance (LSPR) at extreme conditions — in-plane direction versus out-of-plane direction and monolayer versus multilayer. First, the energy band structure and dielectric constants were calculated for both the monolayer and multilayer structures using Kohn-Sham density functional theory with van der Waals corrections. A parallel-band effect observed in the monolayer band structure indicates a strong light-matter interaction. Then, based on the calculated dielectric constants, the performance of the LSPR excited by Au sphere nanoparticles was quantitatively characterized, including polarizability, scattering and absorption cross-sections, and radiative ef?ciency using Mie theory. For the multilayer HfSe2 and ZrSe2, the LSPR showed very comparable intensities in both the in-plane and out-of-plane directions, suggesting an isotropy-like light-matter interaction. In a comparison, the LSPR excited on the monolayer HfSe2 and ZrSe2 was clearly observed in the in-plane direction but effectively suppressed in the out-of-plane direction due to the unique anisotropic nature. In addition to this extraordinary anisotropy-to-isotropy transition as the layer number increases, a red-shift of the LSPR wavelength was also found. Our work has predicated the thickness-dependent anisotropic light-matter interaction on the emerging 2D semiconducting HfSe2 and ZrSe2, which holds great potential for broad optoelectronic applications such as sensing and energy conversion.
关键词： ZrSe2,anisotropy,plasmon,2D materials,HfSe2
更新于2025-09-10 09:29:36
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Theoretical Calculation of the Optical Properties of Dielectric Material @ Noble Metal Core-Shell Composite Nanoparticles
摘要： Objectives: Methods: Surface plasmon exhibited in nano-sized particles such as gold, silver, copper has recently attracted a great deal of attention due to the enhancement and tunable optical properties in the visible to near-infrared region of the electromagnetic spectrum. In this work, the optical properties of dielectric material at noble metal core-shell nanoparticles Mie theory is the analytical method is used to study via parameters of extinction, scattering and absorption efficiencies. The samples for studying were the composites of a dielectric material core coated by a thin noble metal (Ag, Au, and Cu). The core size was fixed at 50 nm, while the metal shell thicknesses were varied from 3 nm to 40 nm. The calculated optical properties were found that the surface plasmon resonance can be enhanced and tuned the wavelength from the near ultraviolet to near infrared regions by varying the shell thickness. The dielectric core coated with a thin noble metal to promote the properties of the core can be applied in the field of plasmonic nanolaser, nonlinear plasmonic antenna, light trapping in thin-film organic solar cells, and biomedical research.
关键词： Dielectric Material @ Noble Metal Core-Shell,Surface Plasmon
更新于2025-09-10 09:29:36
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11.2: <i>Invited Paper:</i> Electrochromics for Full Color e-Paper and Energy-Saving Application
摘要： Novel multicolor electrochromic (EC) device based on electrochemical silver deposition was successfully demonstrated. The EC device exhibited reversible multicolor change of primary colors― transparent, magenta, cyan, yellow, black (CMYK) and silver mirror ―in a single cell by using electrochemical method which controlled the morphology of silver deposit.
关键词： Silver electrodeposition,Electrochromism,Localized surface plasmon resonance,Electrochemistry,Multicolor
更新于2025-09-10 09:29:36
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A Method for Estimating the Filling Rate of the Mold Cavity in Nanoimprint Lithography
摘要： When the dimensions of a microelectronic structure decrease, high manufacturing costs are inevitable. A low cost and high throughput manufacturing technique for nanostructures is desired. Nanoimprint lithography involves patterning the resist through physical deformation by using a mold at nanoscale and has the potential to meet these expectations. Therefore, nanoimprint lithography has been extensively studied in recent years. Many real time measurements have been proposed for enhancing the yield of nanoimprint lithography. Among these measurements, the application of surface plasmon resonance has the advantage of quick, highly accurate analysis. In surface plasmon resonance application, the mold contains a gold ?lm for exciting surface plasmon resonance and an adhesion layer is applied to both sides of the gold ?lm to increase the lifespan of the mold. However, the effect of the geometric characteristics of the adhesive layer on the surface plasmon resonance spectrum and the mechanical strength of the mold has not been extensively studied. To improve the detection accuracy and reliability of the measurement, this study investigated the aforementioned effect. Analytical and experimental investigations con?rmed that the shape of the spectrum is in?uenced by the surface roughness and thickness of the titanium adhesion layer. To maintain the sharpness of the resonance dip, we suggest reducing the thickness of the titanium adhesion layer to below 6 nm and maintaining the surface roughness below 3 nm. Moreover, the proposed mold structure conforms to these requirements and is applied to estimate the ?lling rate. The measurement results demonstrate that the surface plasmon resonance spectrum is clearly affected by the mold ?lling. Speci?cally, the change in the surface plasmon resonance spectrum curve and resonance angle can indicate the quality of the imprinted pattern. This study demonstrates the effectiveness and high sensitivity of the proposed technique for estimating the ?lling rate of the mold cavity in nanoimprint lithography.
关键词： Nanoimprint Lithography (NIL),Surface Roughness,Filling Rate,Surface Plasmon Resonance (SPR),Non-Destructive Measurement
更新于2025-09-10 09:29:36
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D-shaped PCF sensor based on SPR for the detection of carcinogenic agents in food and cosmetics
摘要： D-Shaped PCF sensor working on the principle of Surface Plasmon Resonance is scrutinized in our work by Finite element method. Indium titanium oxide (ITO) is coated over the flat surface of the sensor and over it the analyte is placed which enhances the excitation of Plasmon in the intermediate surface which is the major part in sensing. In our work we have achieved the maximal spectral sensitivity of 50000 nm/RIU accompanied by high resolution 4x10-4 RIU, and also maximum amplitude sensitivity of 1266.67 RIU?1. We have numerically investigated the SPR sensing performance by considering the diameter of the core which can be optimized by varying the air-hole diameter and also the proposed model enables the feasibility of D-shaped PCF structure with very high sensitivity near IR region. Among the proposed SPR sensors, our sensor achieved the highest sensitivity range and it can be used for various chemical and bio-sensing applications.
关键词： D shaped PCF,Amplitude Sensitivity,Surface Plasmon Resonance,Finite element method,Bio Sensor
更新于2025-09-10 09:29:36
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Copper-surrogated galvanic displacement of silver dendrite imprinted on flexible and transparent silk fibroin membrane as a SERS-active substrate and sub-dividable catalyst
摘要： By employing copper grid as a surrogate agent, we present a facial, reagent-free and cost-e?ective approach to imprint the exquisite silver dendroid nanostructures on ?exible silk ?broin membrane, which double roles as both optical enhancers and catalytic-active sites over many chemical reactions. Unlike the conventional rigid substrates, this hybrid Ag/protein composite exhibits many previous-inaccessible properties of ?exibility, transparency, biocompatibility, molecular permeability and optical manipulation. The galvanic displacement was facilitated by a high pressure uv-lamp illumination (365 nm), shortening the dendroid growth time to be within a few minutes. The resulting substrate was characterized by microscopic image, revealing a decent 3D Ag dendrite architecture and interpenetrated crystal network, which arguably enlarged the entire surface area and keenly regulated the optical/electric property of ?brillated protein ?lm. The underlying principle of copper-initiated silver reduction and growth of crystal structure was discoursed and veri?ed with in-situ spectroscopic interrogation. Moreover, our comprehensive study supports that sub-dividable substrate enables to perform catalytic reaction under a wide range of conditions. This exploration renders a thrust to expand biopolymeric membrane into a wide breadth of applications of bendable devices through chemical modi?cations, exhaustively and economically.
关键词： Galvanic replacement,Surface-enhanced Raman scattering,Sub-dividable catalyst,Silk membrane,Plasmon-driven photo-reduction
更新于2025-09-10 09:29:36
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Broad-range ultrafast all-optical red-shifting of EUV surface plasmons: Proof-of-principle and advanced surface nanotexturing in aluminum
摘要： Using aluminum as an example, ultrafast sub-ablative broad-range (EUV-IR) spectral tuning of surface plasmon resonance in metals by IR femtosecond laser pulses was demonstrated by theoretical modeling of prompt surface optics for strongly photoexcited materials and of their surface plasmon-polariton (SPP) dispersion curves, as well as by experimental multi-shot laser imprinting of surface plasmon-polaritons as large-scale regular surface ripples with minimal sub-di?raction periods down to 200 nm. According to laser-pump self-re?ection and charge emission experiments, the key issue in the prompt optical tuning (spectral red-shifting) of EUV surface plasmon resonance in aluminum by the IR laser pulses is related to ultrafast surface charging of its surface via intense electron emission during the laser pump pulse, depleting its surface electron density and simultaneously decreasing its surface/bulk plasma frequencies, at the corresponding negligible surface ablative etching.
关键词： Surface nanoripples,Femtosecond laser excitation,Spectral tuning,EUV surface plasmon resonance,Electronic heating and charging,Aluminum
更新于2025-09-10 09:29:36
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Light irradiation enhanced CO2 reduction with methane: A case study in size-dependent optical property of Ni nanoparticles
摘要： Ni/Al2O3 catalysts and bulk Ni nanoparticles, with the average sizes of Ni particles varying from 2.7 nm to 238.0 nm, were synthesized and evaluated in CO2 photoreduction with methane (CRM). It was found that the catalytic activities of the Ni-based catalysts were all increased almost linearly with light intensity in the range of 0–1.07 W cm?2, with the optical properties of Ni particles being regarded to account for the activity enhancement. Wavelength dependent performance study suggested that Ni LSPR dominated for the optical property of smaller Ni nanoparticles whereas interband transition played gradually increased role in improving the activities over larger Ni particles. To the best of our knowledge, it is the first time to study the size-dependent optical properties of Ni nanoparticles, meanwhile, this study offers a foundation to further improve the efficiency of Ni-based catalysts in CO2 utilizations.
关键词： Ni nanoparticles,Interband transition,CO2 photoreduction,Localized Surface plasmon resonance,Photocatalysis
更新于2025-09-10 09:29:36
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Manipulation of surface plasmon resonance for high photocatalytic activity of Ag-Bi2WO6 hetero-architecture
摘要： The plasmonic photocatalyst of Ag-Bi2WO6 was employed to investigate the effect of surface plasmon resonance (SPR) on the visible-light photocatalytic activity. Generally, it is accepted that metal nanoparticles as electron traps on the surface of semiconductor photocatalyst can effectively inhibit the recombination of photo-generated electron-hole pairs, provide more active sites and thereby enhance the photocatalytic activity. Nevertheless, SPR effect confirmed in Ag-Bi2WO6 plays an important role in the photoreaction enhancement in the meantime. In this case, a facile and more efficient method was introduced to synthesize Ag-Bi2WO6 hetero-architecture on basis of an ascorbic-acid-assisted route. The results and analysis show that a optimize photocatalytic efficiency can be achieved by elaborately manipulating SPR effect. For instance, the highest photocatalytic efficiency of 96.46% after 150 min visible-light irradiation was obtained as the molar ratio of Bi2WO6:Ag is 10:2, which suggest that it would be a promising candidate for photo-catalysis application. Eventually, a possible mechanism for the formation of Ag-Bi2WO6 hetero-architecture and its enhanced photocatalytic activity was proposed and discussed.
关键词： Heterojunctions,Photocatalysis,Ag nanoparticles,Bi2WO6,Surface plasmon resonance
更新于2025-09-10 09:29:36