Bruno Figeys, Ounsi El Daif
We numerically simulate, using finite-difference time-domain, the optical properties of silver nano discs deposited on the front surface of silicon solar cells. We explore the effect of each of the parameters of such a system, in order to draw some general design rules for the subsequent fabrication of such structures.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
Reflection of near-infrared light is important for preventing heat transfer in energy saving applications. A large-area, mass-producible reflector that contains randomly distributed disk-shaped silver nanoparticles and that exhibits high reflection at near-infrared wavelengths was demonstrated. Although resonant coupling between incident light and the nanostructure of the reflector plays some role, what is more important is the geometrical randomness of the nanoparticles, which serves as the origin of a particle-dependent localization and hierarchical distribution of optical near-fields in the…
In electron energy-loss spectroscopy (EELS) of individual silver nanoparticles encapsulated in silicon nitride, we observe besides the usual dipole resonance an additional surface plasmon (SP) resonance corresponding to higher angular momenta. We even observe both resonances for nanoparticle radii as small as 4 nm, where previously only the dipole resonance was assumed to play a role. Electron beams positioned outside of the particles mostly excite the dipole mode, but the higher-order resonance can even dominate the dipole peak when exciting at the particle surface, the usual choice for maxim…
Random Al and Ag nanoparticle distributions are studied on varying substrates, where we exploit the nanosphere self-aggregation method (NSA) for fabrication. Relying on the measured particle size distributions of these samples, we develop a theoretical model that can be applied to arbitrary random nanostructure layers as is demonstrated for several distinct NSA samples. As a proof of concept, the optical properties of the exact same particles distributions, made from the quasi random modeling input with electron beam lithography (EBL), are investigated from both theory and experiment. Our nume…
The observation of intense visible fluorescence from silver and iron nanoparticles in different solution phases and surface capping is reported here. Metallic silver and iron nanoparticles were obtained by exploding pure silver and iron wires in pure water. Bovine serum albumin protein adsorption on the silver nanoparticles showed an enhanced fluorescence. The presence of poly-vinyl pyrrolidone polymer in the exploding medium resulted in a stabilized growth of iron nanoparticles with enhanced fluorescence intensity. The fluorescence was found to be surface /interface dependant. The fluorescenc…
We study the magneto-optical response of noble metal nanoparticle clusters. We consider the interaction between the light-induced dipoles of particles. In the presence of a magnetic field, the simplest achiral cluster, a dimer, exhibits circular dichroism (CD). The CD of a dimer depends on the directions of the magnetic field and the light wave vector. The CD of a populous cluster weakly depends on the magnetic field. Upon scattering from the cluster, an incident linearly polarized light with polarization azimuth $φ$, becomes elliptically polarized. The polarization azimuth rotation and ellipt…
We present a simple method to prove the presence of an organic shell around silver nanoparticles. This method is based on the comparison between optical extinction measurements of isolated nanoparticles and Mie calculations predicting the expected wavelength of the Localized Surface Plasmon Resonance of the nanoparticles with and without the presence of an organic layer. This method was applied to silver nanoparticles which seemed to be well protected from oxidation. Further experimental characterization via Surface Enhanced Raman Spectroscopy (SERS) measurements allowed to identify this prote…
Terahertz time domain spectroscopy has been used to study low frequency confined acoustic phonons of silver nanoparticles embedded in poly(vinyl alcohol) matrix in the spectral range of 0.1 to 2.5 THz. The real and imaginary parts of the dielectric function show two bands at 0.60 THz and 2.12 THz attributed to the spheroidal and toroidal modes of silver nanoparticles, thus demonstrating the usefulness of terahertz time domain spectroscopy as a complementary technique to Raman spectroscopy in characterizing the nanoparticles.
We study the optical responses of metal nanoparticle chains. Multiple scattering calculations are used to study the extinction cross sections of silver nanosphere chains of finite length embedded in a glass matrix. The transmission and reflection coefficients of periodic 2D arrays of silver nanospheres are also calculated to understand the interaction between nanoparticle chains. The results are in agreement with recent experiments. The splitting of plasmon-resonance modes for different polarizations of the incident light are explored. Results on the effect of disorder are also presented.
We show that silver nanoparticles, which are deposited on a terahertz-receiving antenna, can be sintered by intense terahertz pulse irradiation. The conductance of the silver nanoparticles between the antenna electrodes is measured under the terahertz pulse irradiation. The dispersant materials surrounding the nanoparticles are peeled off, and conduction paths are created. We reveal that, during sintering, quantum point contacts are formed, leading to quantized conductance between the electrodes with the conductance quantum, which reflects the formation of atomically thin wires. The terahertz …
Aggregation of dipolar molecules in SiO$_2$ hybrid organic inorganic films: use of silver nanoparticles as inhibitors of molecular aggregation
本研究提出利用银纳米颗粒作为抑制剂，有效抑制SiO$_2$有机无机杂化薄膜中偶极发色团的聚集，从而提升二阶非线性光学器件的性能。
Hot Carriers from Intra- and Interband Transitions in Gold-Silver Alloy Nanoparticles
本文通过原子级建模结合麦克斯韦方程与紧束缚模拟，研究金-银合金纳米颗粒中热载流子生成，发现合金成分可调控带间与带内跃迁贡献，为太阳能转换和传感应用提供设计参数。
For the first time in the world behavioral functions of laboratory mammals exposed to silver nanoparticles were studied with the regard to age. Silver nanoparticles coated with polyvinylpyrrolidone with the size of 8.7 nm were used in the present research as a potential xcenobiotic. Elder mice adapted to the xcenobiotic better than younger animals. Younger animals demonstrated more drastic anxiety than the elder ones. Thus, it is concluded that adaptive homeostasis non-linearly changes with the age. Presumably, it may improve during the prime of life and start to decline just after certain sta…
We study the surface plasmon (SP) resonance energy of isolated spherical Ag nanoparticles dispersed on a silicon nitride substrate in the diameter range 3.5-26 nm with monochromated electron energy-loss spectroscopy. A significant blueshift of the SP resonance energy of 0.5 eV is measured when the particle size decreases from 26 down to 3.5 nm. We interpret the observed blueshift using three models for a metallic sphere embedded in homogeneous background material: a classical Drude model with a homogeneous electron density profile in the metal, a semiclassical model corrected for an inhomogene…
We report the enhancement of the optical second harmonic signal in non-centrosymmetric semiconductor CdS quantum dots, when they are placed in close contact with isolated silver nanoparticles. The intensity enhancement is about 1000. We also show that the enhancement increases when the incoming laser frequency $ω$ is tuned toward the spectral position of the silver plasmon at $2ω$, proving that the silver nanoparticle modifies the nonlinear emission.
The influence of the daily prolonged administration of silver nanoparticles on cognitive functions of model mammals was studied. The accumulation of silver in whole brain, hippocampus, cerebellum, cortex and residual part of mice brain was investigated by highly precise and representative Neutron Activation Analysis and the histological studies were conducted in the present research. Some of the main results of the comprehensive study are the description of the biokinetics of silver in the hippocampus, cerebellum and cortex, the finding of the jump increase of silver in the hippocampus and cer…
Raza et al. recently observed the extraordinarily large energy blueshifts of localized surface plasmon resonances and additional surface plasmon resonances in silver nanoparticles encapsulated in silicon nitride, which are not fully understood yet. By using the quantum model consisting of two subsystems respectively for describing the center of mass and intrinsic motions of conduction electrons of a metallic nanosphere and a coupling occurred between the center of mass and conduction electrons outside the metallic nanosphere, we firstly deduced the general energy and line broadening size-depen…
We study the blueshift of the surface plasmon (SP) resonance energy of isolated Ag nanoparticles with decreasing particle diameter, which we recently measured using electron energy loss spectroscopy (EELS). As the particle diameter decreases from 26 down to 3.5 nm, a large blueshift of 0.5 eV of the SP resonance energy is observed. In this paper, we base our theoretical interpretation of our experimental findings on the nonlocal hydrodynamic model, and compare the effect of the substrate on the SP resonance energy to the approach of an effective homogeneous background permittivity. We derive t…
The evidence of strong coupling between plasmons and molecular excitons for plasmonic nanoparticle (NP) dimers exhibiting ultra-sensitive surface enhanced resonant Raman scattering is the observation of anti-crossing in the coupled resonance. However, it is not easy to experimentally tune plasmon resonance of such dimers for the observation. In this work, we theoretically investigate the anti-crossing properties of the dimers coated by the thin dye films with thicknesses greater than 0.1 nm and gap distances larger than 1.2 nm according to the principles of classical electromagnetism. The plas…
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 o…
In this work, we report X-ray photoelectron (XPS) and valence band (VB) spectroscopy measurements of surfactant-free silver nanoparticles and silver/linear carbon chains (Ag@LCC) structures prepared by pulse laser ablation (PLA) in water. Our measurements demonstrate significant oxidation only on the surfaces of the silver nanoparticles with many covalent carbon-silver bonds but only negligible traces of carbon-oxygen bonds. Theoretical modeling also provides evidence of the formation of robust carbon-silver bonds between linear carbon chains and pure and partially oxidized silver surfaces. A …
Magnetic field controlled nucleation and size selection of silver nanoparticles
本研究通过磁场调控银纳米颗粒的成核过程，揭示了磁场对纳米颗粒尺寸选择的影响机制。
In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) were used to illustrate a selective deposition of silver and copper on Au NPs. The mechanism of silver and copper ions reduction on Au NP with $n$-dodecanethiol coating is discussed.
A numerical method for calculation electronic structure of a nanosystem composed of a pseudoisocyanine (PIC) molecule assembled on a silver nanoparticle is developed. The electronic structure of the silver nanoparticle containing 125 atoms is calculated within the local density version of the density functional method. A model of an Ag atom embedded in the center of a spherical jellium cluster is used. The host electron Green function is calculated by means of the spherically symmetric expansion. The principal theoretical tool is the scattering theory using the Green function method. The molec…
Debye temperature decrease, residual resistivity increase and electron-phonon coupling constant increase as crystallite size decreases have been found from electrical resistivity in temperature range 5 K to 300 K of well-characterized Ag nanoparticles synthesized with oleylamine, trioctylphosphine and/ polyvinylpyrrolidone with Scherrer sizes ranging from 15.1 nm to 33.4 nm. Notably, about 36 % reduction in Debye temperature in 15.1 nm compared to bulk Ag is found. Remarkably, usual phonon drag peak found in Seebeck coefficient for bulk Ag turned into dips or phonon drag minima in these NPs th…
Parity is a ubiquitous notion in science and serves as a fundamental principle for describing a physical system. Nanometer-scale metal objects are predicted to show dramatic differences in physical properties depending on the electron-number parity. However, the identification of the electron-number parity effects in real metal nanoparticles has remained elusive because of the variations in various features of nanoparticles. Here we report the nuclear magnetic resonance (NMR) detection of the dynamic effect of the electron-number parity in silver nanoparticles. With theoretical modeling of the…
Quantitatively linking morphology and optical response of individual silver nanohedra
本文通过关联电子断层成像与光学显微光谱，定量研究单个银纳米多面体的三维形貌与散射、吸收截面光谱之间的关系，并揭示表面几个原子层银锈对光谱失配的解释作用，从而支持等离激元纳米材料的预测性设计。
The "metallic" temperature variation of the electrical resistivity of chemical nano gold-silver coatings with a silver content of 6.6 % at. up to 13.1 % at. determined in the temperature range 4.2-300 K. Features of low-temperature measurements of the resistance of nano-coatings were found and explained. The possibility of the appearance of superconductivity in them is discussed.
Exploring the formation of gold/silver nanoalloys with gas-phase synthesis and machine-learning assisted simulations
本文结合实验与机器学习辅助分子动力学模拟，研究了金/银纳米合金的原子级形成机制，发现金原子在表面偏聚的现象由电荷转移和静电相互作用而非表面能决定。
Unified Finite-element Model for Transient Absorption and Raman Scattering of Vibrating Noble Metal Nanoparticles
本文基于 COMSOL Multiphysics 建立统一有限元模型，同时模拟贵金属纳米粒子的瞬态吸收与拉曼散射光谱，并通过多种金、银纳米结构验证其拟合与模式分析能力。
Quantum nanosystems involve the coupled dynamics of fermions or bosons across multiple scales in space and time. Examples include quantum dots, superconducting or magnetic nanoparticles, molecular wires, and graphene nanoribbons. The number (10^3 to 10^9) of electrons in assemblies of interest here presents a challenge for traditional quantum computations. However, results from deductive multiscale analysis yield coarse-grained wave equation that capture the longer-scale quantum dynamics of these systems; a companion short-scale equation is also developed that allows for the construction of ef…
Plasmonic color printing with semicontinuous metal films is a lithography-free, non-fading, and environment-friendly method of generation of bright colors. Such films are comprised of metal nanoparticles, which resonate at different wavelengths upon light illumination depending on the size and shape of the nanoparticles. To achieve an experimentally demonstrated structure that was optimized in terms of broader color range and increased stability, variable Ag semicontinuous metal films were deposited on a metallic mirror with a sub-wavelength-thick dielectric spacer. Femtosecond laser post-proc…
Light-matter interaction at the atomic scale rules fundamental phenomena such as photoemission and lasing, while enabling basic everyday technologies, including photovoltaics and optical communications. In this context, plasmons --the collective electron oscillations in conducting materials-- are important because they allow manipulating optical fields at the nanoscale. The advent of graphene and other two-dimensional crystals has pushed plasmons down to genuinely atomic dimensions, displaying appealing properties such as a large electrical tunability. However, plasmons in these materials are …
Engineering strong coupling with molecular coatings in optical nanocavities
通过在银纳米颗粒表面涂覆分子聚集体，重构局部电磁真空，使量子发射体实现Rabi振荡，突破强耦合观测限制。
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。