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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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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Generation of light beams by electron beam excited surface plasmons
摘要： Manipulation of Smith-Purcell radiation (SPR) by electron-bunch excitation of localized surface plasmon (LSP) of gold (Au) disc arrays on Au substrate is investigated by FDTD simulation. When the wavelength of LSP mode is within the SPR emission band, SPR is locked and enhanced at the LSP wavelength. The emission angle of LSP-locked SPR still follows the wavelength-angle relation of traditional SPR. Furthermore, both the emission wavelength and angle increase as the radius and height of Au disc increase.
关键词： FDTD simulation,Smith-Purcell radiation (SPR),localized surface plasmon (LSP)
更新于2025-09-23 15:21:21
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Heterogeneous photocatalyzed C-C cross-coupling reactions under visible-light and near-infrared light irradiation
摘要： With the development of photocatalytic technology and organic synthesis chemistry, the photocatalyzed cross-coupling reaction provides one of the most attractive methodologies for the C-C bond formation and has been booming in recent years. The advantages of the heterogeneous photocatalyzed C-C cross-coupling reaction lie in its environment friendly, easily separated and conveniently recovered catalysts. In this review, we summarized and highlighted recent achievements of heterogeneous photocatalyzed C-C cross-coupling reactions through four aspects: visible light induced C-C cross-coupling reactions catalyzed by Pd supported semiconductor photocatalysts; visible light induced C-C cross-coupling reactions catalyzed by Pd based plasmonic photocatalysts; visible light induced C-C cross-coupling reactions catalyzed by palladium-free photocatalysts; near-infrared light induced C-C cross-coupling reactions.
关键词： Photocatalysis,semiconductor,C-C cross-coupling,localized surface plasmon resonance,Pd
更新于2025-09-23 15:21:21
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Photothermal Effects Induced by Surface Plasmon Resonance at Graphene/Gold Nanointerfaces: A Multiscale Modeling Study
摘要： Surface plasmon resonance (SPR) biosensors have enormous potential in biological recognitions and biomolecular interactions, especially for the real time measurement of disease diagnosis and drug screening. Extensive efforts have been invested to ameliorate the sensing performances, while the photothermal effects, which are induced by the plasmon resonance, have an obvious impact. However, due to the limitations of experimental approaches, the theoretical mechanisms and specific influences of the SPR sensors with photothermal effects are few researched. Here, a multiscale simulation method is developed to investigate the photothermal effects at graphene/gold (Au) nanointerfaces, and to calculate the quantitative contribution of the photothermal effects towards high reliability SPR sensors in order to elucidate their influence on the sensing performances by means of first-principle calculations and molecular dynamics simulations. Our results indicate that the sensitivity and detection accuracy of graphene/Au SPR sensors can be tailored from 0 K to 600 K, due to the tunable dielectric constants of Au and graphene films through temperature variation. By controlling the its material thickness, interfacial combination and lattice strain, an optimized graphene/Au SPR sensor with higher sensitivity, detection accuracy, and reliability to the temperature rising has been achieved. Such multiscale simulation method, which is capable of seeking both the role and the underlying mechanism of the interfacial phenomena, can serve as an excellent guideline for the performance optimization and commercialized application of SPR sensors in the analytical chemistry and biomedical fields.
关键词： graphene/gold nanointerface,photothermal effects,surface plasmon resonance,multiscale simulation method,sensitivity and detection accuracy
更新于2025-09-23 15:21:21
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Near-field spatial frequency filtering model for surface plasmon self-interference virtual probe
摘要： The azimuthal angle relation for obliquely excited standing-wave surface plasmon is analytically studied in detail and thereby a near-field spatial frequency filtering model is proposed, in which the azimuthal angle relation and criterion similar to Heisenberg uncertainty principle are combined to describe the spatial resolving power of surface plasmon self-interference virtual probe imaging system. It is revealed that the incidence coupling possesses spatial anisotropy due to polarization modulation, and the mechanism for spatial resolution degradation is the compression of spatial frequency bandwidth in the near-field domain.
关键词： spatial frequency filter,virtual probe,surface plasmon self-interference
更新于2025-09-23 15:21:21
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A sensitive colorimetric probe for detection of 6-thioguanine based on its protective effect on the silver nanoprisms
摘要： In this work a non-aggregated colorimetric probe for detection of chemotherapeutic drug, 6–thioguanine (6-TG), is introduced. It is based on the protective effect of 6-TG on silver nanoprisms (AgNPRs) against the iodide-induced etching reaction. Iodide ions can attack the corners of AgNPRs and etch them, leading to the morphological transition from nanoprisms to nanodiscs. As a consequence, the solution color changes from blue to pink. However, in the presence of 6-TG, due to its protective effect on the corners of AgNPRs, I- ions cannot etch the prisms and the blue color of solution remains unchanged. Using this effect, selective sensor was designed for detection of 6–TG in the range of 2.5-500 μg L-1, with a detection limit of 0.95 μg L-1. Since with varying the concentration of 6-TG in this range, the color variation from pink to blue can be easily observed, the designed sensing scheme can be used as a colorimetric probe. The method was used for analysis of human plasma samples.
关键词： Anti-cancer drugs,Anisotropic nanoparticles,Surface plasmon resonance,Nanomaterials
更新于2025-09-23 15:21:21
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A Strategy for In-Situ Imaging of Cellular Alkaline Phosphatase Activity Using Gold Nanoflower Probe and Localized Surface Plasmon Resonance Technique
摘要： In this work, a simple and ultrasensitive localized surface plasmon resonance (LSPR) method that use Au nanoflowers (AuNFs) as probe was designed for in-situ monitoring of alkaline phosphatase (ALP) activity. The AuNFs was fabricated by hydrogen tetrechloroaurate-induced oxidative disruption of polydopamine-coated Au nanoparticles (AuNPs) and subsequently growth of Au nanopetals on AuNPs. The as-prepared AuNFs showed a much higher LSPR capability and stronger scattering color change than AuNPs. The strategy for in-situ cellular ALP activity detection relied on the deposition of Ag on AuNFs surface, which changed the morphology of AuNFs and led to a tremendous LSPR response and scattering color change. The deposition of Ag shell on AuNFs was related to ALP activity, where ALP catalyzed the hydrolysis of L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate to form L-ascorbic acid (AA), then AA reduced Ag+ to Ag and deposited onto AuNFs. With this concept, the ALP activity could be monitored with a detection limit of 0.03 μU L-1. Meanwhile, the ALP activity of single HepG2 cells and HEK 293 cells was tracked with proposed approach, which indicated the trace expression level of ALP in HEK 293T cell and overexpressed level of ALP in HepG2 cells. After treated with drugs, the cellular ALP activity of HepG2 cells was decreased with the treating time and dose increasing. Therefore, the proposed strategy could be used for tracking the cellular ALP activity, which paved a new avenue for cell studies, and hold great potential for discovering novel ALP-based drugs applications.
关键词： cellular activity,alkaline phosphatase,localized surface plasmon resonance,in-situ imaging,gold nanoflowers
更新于2025-09-23 15:21:21
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[Springer Series in Optical Sciences] Fano Resonances in Optics and Microwaves Volume 219 (Physics and Applications) || Light-Tunable Fano Resonance in Metal-Dielectric Multilayer Structures
摘要： Recent progress on Fano resonances exhibited by metal-dielectric multilayer structures is reviewed. The Fano resonance in the multilayer structures is caused by coupling between a surface plasmon polariton mode supported by a metal-dielectric interface and a waveguide mode supported by a system of three dielectric layers. Electromagnetic calculations of attenuated total reflection spectra demonstrate the feasibility of realizing the Fano resonance, and the predicted Fano resonance was indeed observed experimentally. Since the structure is simple, it is easy to add the photofunctionality to the structure. Incorporation of photofunctional dye molecules into the waveguide layer made it possible to tune the Fano resonance by light irradiation.
关键词： Fano resonance,light tuning,surface plasmon polariton,waveguide mode,metal-dielectric multilayer structures
更新于2025-09-23 15:21:21
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Raman spectroscopic determination of hole concentration in undoped GaAsBi
摘要： Raman spectra of the undoped GaAs1-xBix (0<x<0.037) grown on GaAs by molecular beam epitaxy were investigated. With an increase of Bi component, we find that the longitudinal optical phonon-hole-plasmon-coupled (LOPC) mode first appears in the vicinity of the unscreened longitudinal optical (ULO) phonon frequency, and then shifts towards near the transverse optical (TO) phonon frequency. A new vibrational modes (~287 cm-1) between the TO and the ULO phonons was verified by use of low temperature polarized Raman measurement and the corresponding scattering intensities are found to be linearly proportional to the composition of Bi in GaAsBi. The hole concentrations determined by using the LOPC/ULO Raman intensities ratio increase from ~6.5×1016 to ~2.8×1017 cm -3 with Bi content and the measured results are in agreement with Hall measurements. Furthermore, the influence of excitation laser power on the estimation of the hole densities is discussed with the help of power dependent Raman spectroscopy.
关键词： Hall measurements,LO-phonon-plasmon–modes,Raman Spectroscopy,GaAsBi,Hole density
更新于2025-09-23 15:21:21
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Double-sided Polished Ultra-stable and Ultra-sensitive Optical Fiber Sensor
摘要： A double-sided polished photonic crystal fiber (DP-PCF) for surface plasmon resonance(SPR) sensing is designed and analyzed by using the finite element analysis software COMSOL 5.5. The suggested design shows strong sensitivity stability in the low refractive index (RI) region (1.33 ～ 1.39) and ultra-high sensitivity in the high RI region (1.39 ～ 1.43), respectively. The structural parameters of the proposed sensor are studied to analyze the stability and high sensitivity of the fiber sensor. The introduced DP-PCF sensor offers high sensitivity of 32,434 nm/RIU in the RI range of 1.39 ～ 1.43 due to its special double-sided polishing design.
关键词： Photonic crystal fiber,Sensor,Surface plasmon resonance,Surface plasmon polariton
更新于2025-09-23 15:21:01
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Unified theory of plasmon-induced resonance energy transfer and hot electron injection processes for enhanced photocurrent efficiency
摘要： Plasmons in metal nanoparticles (MNPs) promise to enhance solar energy conversion in semiconductors. Two essential mechanisms of enhancement in the near-field regime are hot electron injection (HEI) and plasmon-induced resonance energy transfer (PIRET). Individual studies of both mechanisms indicate that the PIRET efficiency is limited by the short lifetime of the plasmon, whereas the hot electrons result from the plasmon decay. The development of a unified theory of the coupled HEI and PIRET processes is fundamentally interesting and necessary for making reliable predictions but is complicated by the multiple interactions between various components that participate in the enhancement process. In this paper, we use the model-Hamiltonian approach to develop a combined theoretical framework including both PIRET and HEI. The coupled dynamics as well as the time evolution of hot electron energy distribution are studied. The theory further predicts an interference-induced asymmetry in the spectral dependence of PIRET, which can be used to distinguish it from HEI. As the relative contributions of PIRET and HEI strongly depend on the size of the MNPs, this presents itself as a simple route to control the strength of their contributions. The results presented here can further guide future applications of plasmonic solar energy harvesting.
关键词： plasmon,metal nanoparticles,hot electron injection,solar energy conversion,plasmon-induced resonance energy transfer
更新于2025-09-23 15:21:01