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- 2019
- Photovoltaics
- Finite-difference
- Nanotechnology
- Absorption enhancement
- Plasmonics
- Time domain simulation
- Localized surface plasmon resonance
- Optoelectronic Information Materials and Devices
- Islamic Azad University
- Aerospace Research Institute
- Tehran University
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High Sensitivity Refractive Index Sensor Based on the Excitation of Long-Range Surface Plasmon Polaritons in H-Shaped Optical Fiber
摘要： In this paper, we propose and numerically analyze a novel design for a high sensitivity refractive index (RI) sensor based on long-range surface plasmon resonance in H-shaped microstructured optical ?ber with symmetrical dielectric–metal–dielectric waveguide (DMDW). The in?uences of geometrical and optical characteristics of the DMDW on the sensor performance are investigated theoretically. A large RI analyte range from 1.33 to 1.39 is evaluated to study the sensing characteristics of the proposed structure. The obtained results show that the DMDW improves the coupling between the ?ber core mode and the plasmonic mode. The best con?guration shows 27 nm of full width at half maximum with a resolution close to 1.3 × 10?5 nm, a high sensitivity of 7540 nm/RIU and a ?gure of merit of 280 RIU?1. Additionally, the proposed device has potential for multi-analyte sensing and self-reference when dissimilar DMDWs are deposited on the inner walls of the side holes. The proposed sensor structure is simple and presents very competitive sensing parameters, which demonstrates that this device is a promising alternative and could be used in a wide range of application areas.
关键词： optical ?ber sensor,surface plasmon polariton (SPP),surface plasmon resonance,optical waveguides,refractive index (RI) sensor
更新于2025-09-23 15:19:57
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Size dependence of emission enhancement of Tris(8-hydroxyquinolinato) aluminum with plasmonic Al nanostructure
摘要： It is essential to understand which mechanism of localized surface plasmon (LSP) emission enhancement is to be utilized when combining plasmonic metal nanostructures with an emissive material to produce an optoelectronic device. Herein, we report on the size dependence and time-resolved dynamics of photoluminescence (PL) enhancement using three sizes of aluminum nanotriangles (Al NTs) on emission by tris(8-hydroxyquinolinato) aluminum (Alq3) for elucidating its enhancement mechanism. Al nanostructures were fabricated using a nanosphere lithography technique. Two-dimensionally aligned polystyrene (PSt) beads with different diameters were used as mask templates for obtaining the Al NTs. The absorption peaks red-shifted with increasing Al NT size, and hence, were attributed to the LSP resonance. From PL of Alq3 with and without Al NTs, 2–3 fold PL enhancements were observed among the samples with different Al NTs sizes. The significant shortening of the PL lifetime was observed only in Alq3/Al NTs using Ps500, indicating the effective coupling of LSP of Al NTs and the emission, which is also evidenced from the overlapping the PL peak and the LSP absorption. In contrast, the PL emission enhancement due to LSP coupling with the absorption process of Alq3 was dominant in Alq3/Al NTs using Ps200, suggested from the similarity of the PL decay curve with that of bare Alq3, and the excitation energy matching with LSP resonance. From these observation, we can distinguish the LSP coupling process (absorption or emission) from the presence or absence of lifetime enhancement in the time-resolved PL measurements, offering a guideline for designing the optical devices incorporating the metal nanostructures.
关键词： Aluminum nanostructure,Plasmon effect,Time-resolved measurement,Photoluminescence,Localized surface plasmon
更新于2025-09-23 15:19:57
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Electrical Phase Control Based on Graphene Surface Plasmon Polaritons in Mid-infrared
摘要： Phase modulation of light is the core of many optoelectronic applications, such as electro-optic switch, sensors and modulators. Graphene Surface plasmon polaritons (SPPs) exhibit unique properties in phase modulation including dynamic tunability, a small driving voltage and small device size. In this paper, the novel phase modulation capability of graphene SPPs in mid-infrared are confirmed through theory and simulation. The results show that graphene SPPs can realize continuous tuning of the phase shift at multiple wavelengths in mid-infrared, covering the phase range from 0° to 360°. Based on these results, a sandwich waveguide structure of dielectric–graphene–dielectric with a device length of 800 nm is proposed, which shows up to 381° phase modulation range at an operating wavelength of 6.55 μm, given a 1 V driving voltage. In addition, the structure size is much shorter than the wavelength in mid-infrared and can realize sub-wavelength operation. This work paves the way to develop graphene-based tunable devices for mid-infrared wave-front control.
关键词： Mid-infrared,phase modulation,graphene surface plasmon polaritons
更新于2025-09-23 15:19:57
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Highly Efficient Solara??Catalytic Degradation of Reactive Black 5 Dye Using Mesoporous Plasmonic Ag/ga??C <sub/>3</sub> N <sub/>4</sub> Nanocomposites
摘要： An azo dye, Reactive Black 5 (RB5), was degraded by three photocatalysts of g-C3N4, Ag(2 %)/g-C3N4, and Ag(5 %)/g-C3N4 with the specific surface areas of 34.41, 28.70, and 35.58 m2 g?1 and the band gaps of 2.52, 1.56, and 1.71 eV under sunlight illumination, respectively. The results showed 40 mg/L of g-C3N4 could degrade completely 10 ppm RB5 at pH 3.4 within 10 min under sunlight irradiation with the first-order rate constant of 0.312 min?1. Under the same conditions, the complete degradation time of RB5 reduced to 5 and 7 min when the plasmonic nanocomposites of Ag (2 %)/g-C3N4 and Ag (5 %)/g-C3N4 were used as photocatalysts, respectively. Ag content had an important influence on the photocatalytic activity of g-C3N4 against RB5 so that Ag (2 %)/g-C3N4 possessed the best photocatalytic efficiency with the rate constant of 0.795 min?1. In fact, Ag nanoparticles through the surface plasmon resonance effects and by accepting the photogenerated electrons could improve the visible-light absorption and increase charge separation of g-C3N4. The results showed superoxide radical is the main oxidant in the photodegradation of RB5.
关键词： Surface Plasmon Resonance,Photocatalysis,RB5 dye,Graphitic carbon nitride,Ag/g-C3N4 nanocomposites
更新于2025-09-23 15:19:57
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Ultrathin InP annular nanohole arrays for efficient light absorption solar cells
摘要： This Letter proposes ultrathin InP films consisting of annular nanohole arrays (ANAs) for highly efficient solar cells. By tailoring the inner and outer radii of ANAs properly and combining antireflection coating (ZnO) and back-reflector (Ag), the photocurrent generated in the InP based dielectric-semiconductor-metal (DSM) configuration can be increased dramatically by 124.6% with respect to the planar solar cell of equal geometric thickness (100 nm). The fact that the DSM-ANA structure is able to harvest broadband and wide-angle incident light can be attributed to the excitation of leaky waveguide modes, Bloch modes, and surface plasmon polariton modes. This work provides a promising and feasible way to design and fabricate efficient ultrathin InP photovoltaic and other optoelectronic devices.
关键词： light absorption,ultrathin InP films,dielectric-semiconductor-metal configuration,annular nanohole arrays,surface plasmon polariton modes,solar cells
更新于2025-09-23 15:19:57
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Large-area grain-boundary-free copper films for plasmonics
摘要： Ultrasmooth single-crystalline metallic thin films provide several key advantages for the fabrication of well-defined and high-resolution plasmonic nanostructures, particularly complex integrated nanocircuits. For this purpose, copper is generally regarded as a poor plasmonic material compared to gold and silver because of its notorious oxidation issues when subjected to air exposure. Here, we report on the use of large-area grain-boundary-free copper films grown epitaxially on sapphire substrates in combination with focused ion beam milling to pattern plasmonic nanostructures with superior quality. The copper surfaces prepared using a single-crystalline copper sputtering target exhibit a very low roughness without any grain boundaries for varying film thicknesses and a strong resistance to oxidation, overcoming the bottleneck in conventional copper film fabrication. Surface plasmon resonance measurements show that improved dielectric constants with higher conductivity and long-term stability can be achieved using the single-crystalline copper films. Plasmonic nanohole arrays patterned from these high-quality films are found to display a stronger field enhancement compared to those made from polycrystalline copper films, thus resulting in an enhanced extraordinary optical transmission performance. This study suggests that our fabrication method is ideally suited for applications in copper-based plasmonic and nanophotonic devices as well as integrated nanocircuits on a large scale.
关键词： Single-crystalline films,Polycrystalline films,Surface plasmon resonances,Copper,Extraordinary optical transmission
更新于2025-09-23 15:19:57
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Tailored Engineering of Bimetallic Plasmonic Au@Ag Core@Shell Nanoparticles
摘要： A distinctive synthetic method for the efficient synthesis of multifunctional bimetallic plasmonic Au@Ag core@shell nanoparticles (NPs) with tunable size, morphology, and localized surface plasmon resonance (LSPR) using Triton X-100/hexanol-1/deionized water/cyclohexane-based water-in-oil (W/O) microemulsion (ME) is described. The W/O ME acted as a “true nanoreactor” for the synthesis of Au@Ag core@shell NPs by providing a confined and controlled environment and suppressing the nucleation, growth, agglomeration, and aggregation of the NPs. High-resolution transmission electron microscopic analysis of the synthesized Au@Ag core@shell NPs revealed an “unusual core@shell” contrast, and the selected area electron diffraction and Moiré patterns showed that Au layers are paralleled to Ag layers, thus indicating the formation of Au@Ag core@shell NPs. Interestingly, the UV?visible spectrum of the Au@Ag core@shell NPs exhibited enthralling plasmonic properties by introducing a high-frequency quadrupolar LSPR mode originated from the isolated Au@Ag NPs along with a low-frequency dipolar LSPR mode originated from the coupled Au@Ag NPs. The effective plasmonic enhancement of the Au@Ag core@shell NPs is attributed to the extreme enhancement of the localized electromagnetic field by coupling of the localized surface plasmons of the Au core and Ag shell. The mechanisms for the nucleation and growth of Au@Ag core@shell NPs in W/O ME have been proposed. A unique electron transfer phenomenon between the Au core and Ag shell is elucidated for better understanding and manipulation of the electronic properties, which evinced the development of Au@Ag core@shell NPs through suppression of the galvanic replacement reaction.
关键词： localized surface plasmon resonance,Au@Ag core@shell,bimetallic plasmonic nanoparticles,electron transfer phenomenon,water-in-oil microemulsion
更新于2025-09-23 15:19:57
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AIP Conference Proceedings [AIP Publishing ADVANCES IN BASIC SCIENCE (ICABS 2019) - Bahal, India (7–9 February 2019)] ADVANCES IN BASIC SCIENCE (ICABS 2019) - Plasmonic response of gold nanoparticle in ZnO-Au hybrid structure
摘要： Surfaceplasmon resonance (SPR) is a phenomenon that provides tunable control of nanoparticle light absorption and scattering.The resonant metallic nanoparticles have proven to be efficient systems for electromagnetic control at nanoscale also have ability to localize and enhance the optical field via excitation plasmonic resonances. The tunability of plasmonic nanoparticle makes them highly useful in numerous applications such as molecular detection, solar energy devices, cancer detection and treatment. Hybrid nanostructures representing combination of different materials possess properties which are absent in separate components forming the hybrid. These hybrid nanostructures have found applications in photocatalysis, solar cells, plasmon enhanced spectroscopy like SERS, building blocks to construct photodetectors and in biological and chemical sensors. In this paper we summarize the characterization of plasmonic properties of spherical gold nanoparticles dispersed in ZnO matrix and estimation of the dielectric constant of the matrix.
关键词： Mie theory,gold nanoparticles,Surface plasmon resonance,ZnO-Au hybrid structure,dielectric constant
更新于2025-09-23 15:19:57
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Improving light harvesting and charge extraction of polymer solar cells upon buffer layer doping
摘要： It is an important strategy to improve the performance of polymer solar cells (PSCs) by incorporating metal nanoparticles into functional layers. Herein, gold (Au)@titanium dioxide (TiO2) plasmonic core-shell nanoparticles (PCSNPs) are synthesized and doped into zinc oxide (ZnO) as hybrid electron transport layer in PSCs. Improved light trapping and electrical conductivity are achieved through localized surface plasma resonance of Au@TiO2 PCSNPs. As a result, the short-circuit current density is apparently enhanced, while remaining the unchanged open-circuit voltage. The maximum PCE of 8.801% is obtained when 1.5 wt% Au@TiO2 PCSNPs are introduced into the ZnO layer. This study provides a new inspiration for the development of high efficiency PSCs.
关键词： Surface plasmon resonance,charge transport,Au@TiO2 PCSNPs,Light trapping,Electrical conductivity
更新于2025-09-23 15:19:57
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Terahertz shifted Fano resonance-induced plasmon-soliton in graphene-plasmonic waveguide with magnetic impurities
摘要： Fano resonance is a quantum effect particularly useful for determining the optical spectra of semiconductor heterostructures and radiation enhancement of semiconductor-based devices. We deal with the nonlinear amplitude equation to find the nonlinear plasmon modes and breather solutions in a magnetic impurities-added graphene-plasmonic waveguide at near and mid-IR frequency range. The results show that the coupling degree between the plamon modes and breather solutions in order to form plasmon-solitons is intensely influenced by the effective nonlinear refraction assigned to the waveguide and also by the Fermi energy; tunable plasmon-solitons can be formed with a lowly required bias voltage. We also deduce that the stable plasmon-solitons and subsequently the most condensed radiative feature with the largest effective propagation length can be obtained at interband transition edge if the resonance of the effective nonlinear refraction is of Fano type. The reason is inferred as the presence of a reversible mechanism caused by the optical doping which in turn bears a successive competition between the diffraction and nonlinearity. Accordingly, we indicate that the Fano resonance- induced plasmon-soliton modes supported by the Co-added graphene-plasmonic waveguide experience a frequency shift up to Δω ? 60 THz in contrast to the plasmon-soliton modes in the pristine graphene-based waveguide. This in turn, proposes a novel technique for the spectroscopy of magnetic impurities-added graphene-dielectric heterostructures. On the other hand, very sensi- tive modulation of the nonlinear response tunable with a low Fermi energy as presented in this study can delineate modern schemes for the next generation graphene plasmonic devices including the nanoscale radiation sources, modulators, biosensors and couplers.
关键词： Fano resonance,Graphene plasmonic waveguide,Plasmon-soliton,Nonlinear refraction,Breather solution,Magnetic impurities
更新于2025-09-23 15:19:57