Multilayer Nanoshells Research Articles

Simulation of triple-bands LSPR based on exposed-core MOF with multilayered nanoshell: application in multiplex RI sensing

Simulation of triple-bands LSPR based on exposed-core MOF with multilayered nanoshell: application in multiplex RI sensing

Effects of thermal environment and external mean flow on sound transmission loss of sandwich functionally graded magneto-electro-elastic cylindrical nanoshell

Similar to many new engineering ideas that are actually interdisciplinary subjects, magneto-electro-elastic (MEE) structures also need accurate ways of describing their structural behaviors. Based on nonlocal elasticity theory, the present article investigates the vibroacoustic behavior of a hollow multilayer cylindrical nanoshell where the core layer is made of isotropic functionally graded material (FGM) and other layers are made of MEE materials. The proposed system also is subjected to combined loads which contain a plane sound wave, the initial external electric and magnetic loads, and external mean airflow. The displacement field of structure is described using the third-order shear deformation assumption (TSDA). The derivation of vibroacoustic equations in the form of coupled relations is realized by implementing Hamilton's principle. The material properties of FGM core layer are supposed to vary along the in-plane and thickness directions based on the power-law model. The final objective is to analyze the sound transmission loss (STL) characteristics of the structure and inspect the accuracy of the developed method against existing data followed by comparing the results in terms of geometric and acoustic parameters. The obtained results and the described method can be used advantageously to better optimize such structures by choosing appropriate initial electric and magnetic potentials, flow Mach number, nonlocal parameter, material gradient index, incident angles.

An analytical study of sound transmission loss of functionally graded sandwich cylindrical nanoshell integrated with piezoelectric layers

The multidisciplinary nature of piezoelectric (PZ) structures necessitates precise and efficient methods to express their behavior under different conditions. This article extends the general usage of PZ materials by introducing acoustic and fluid loading effects in a way that an unfilled multilayer cylindrical nanoshell with a functionally graded (FG) material core and PZ layers is subjected to preliminary external electric load, acoustic waves and external flow motion. As the properties of a functionally graded material changes along the shell thickness, a power law model is assumed to be governing such variations of desired characteristics. Evidently, this system includes different types of couplings and a comprehensive approach is required to describe the structural response. To this aim, the first-order shear deformation theory (FSDT) is used to define different displacement components. Next, the coupled size-dependent vibroacoustic equations are derived based on in conjunction with nonlocal strain gradient theory (NSGT) with the aid of Hamilton’s variational principle and fluid/structure compatibility conditions. NSGT is complemented with hardening and softening material effects which can greatly enhance the precision of results. It is expected to use the findings of this paper in the optimization of similar systems by selecting suitable FG index, incident angle of sound waves, flow Mach number, nonlocal and strain gradient parameters, starting electric potential and geometric features. One of the important findings of this study is that increasing the electric voltage can obtain better sound insulation at small frequencies, specially prior to the ring frequency.

Sterically Stabilized Multilayer Graphene Nanoshells for Inkjet Printed Resistors

In the field of printed electronics, there is a pressing need for printable resistors, particularly ones where the resistance can be varied without changing the size of the resistor. This work presents ink synthesis and printing results for variable resistance, inkjet-printed patterns of a novel and sustainable carbon nanomaterial—multilayer graphene nanoshells. Dispersed multilayer graphene nanospheres are sterically stabilized by a surfactant (Triton X100), and no post-process is required to achieve the resistive functionality. A surface tension-based adsorption analysis technique is used to determine the optimal surfactant dosage, and a geometric model explains the conformation of adsorbed surfactant molecules. The energetic interparticle potentials between approaching particles are modeled to assess and compare the stability of sterically and electrostatically stabilized multilayer graphene nanoshells. The multilayer graphene nanoshell inks presented here show a promising new pathway toward sustainable and practical printed resistors that achieve variable resistances within a constant areal footprint without post-processing.

Near-Infrared II Thermoplasmonics of Cuprous Selenide Multilayer Nanoshells: The Role of the Plasmonic Core.

We present a numerical investigation of the plasmonic and photothermal properties of two different types of cuprous selenide (Cu2-xSe) concentric multilayer nanoshells (CMNSs), heteroCMNSs and homoCMNSs, comprising an outer Cu2-xSe nanoshell and an intermediate silica layer but with a different nanoparticle core of either Au or Cu2-xSe. Numerical calculations of optical absorption, near-field enhancement, and local temperature increase are performed with varied dimensions. The plasmon modes from both types of CMNSs are interpreted by combining the plasmon hybridization theory with the surface charge distribution. The two CMNSs exhibit remarkable near-infrared II (NIR-II) plasmonic properties tunable by controlling the interaction between the inner core and the Cu2-xSe nanoshell. The distinct temperature increase distributions between the two CMNSs are identified at their NIR-II resonance wavelengths. The correlation between the partial absorption and the temperature increase of the inner core and Cu2-xSe nanoshell suggests the thermal interplay between the components.

Ink synthesis and inkjet printing of electrostatically stabilized multilayer graphene nanoshells

HypothesisMost functional inkjet inks are sterically stabilized nanoparticle dispersions that require a post-printing-process to remove stabilizing materials and gain functionality. This post-process limits material selection and increases fabrication time and complexity for printed devices. By optimizing the electrostatic stability of a carbon nanomaterial dispersed in water or ethylene glycol via pH adjustment, a stable and printable ink should be attainable without a steric stabilizing material and hence the post-process may be avoided. ExperimentsThe electrostatic stability of multilayer graphene nanoshells (MGNS)—an inexpensive and net carbon-negative nanomaterial—dispersed in water and ethylene glycol was studied by measuring zeta potential as a function of pH and modeling energetic potentials between particles. Requirements for electrical percolation of printed MGNS were analyzed and corroborated with electrical measurements. FindingsElectrostatic stability improved with increased zeta potential caused by an increased pH. Ionic strength also increased with pH, causing strong destabilization. By increasing zeta potential while minimizing ionic strength, the maximum solid-loading of MGNS in DI water and ethylene glycol was increased up to 20%. For the MGNS solid-loading achieved here, electrical percolation occurs with 20–30 consecutively printed layers producing a resistivity of 30 Ω-cm. The inexpensive, environmentally-friendly MGNS are a promising material for printed, flexible electronics.

Ultrahigh sulfur content up to 93 wt% encapsulated in multilayer nanoshell of V/V2O5 composite to suppress shuttle effect of lithium–sulfur battery with high-performance

Renowned for its high theoretical specific energy, lithium-sulfur (Li–S) batteries still suffer from the shuttle effect of polysulfides, the insulating nature of sulfur and severe volumetric variations, especially for cathodes with high sulfur contents. Herein, S microsphere encapsulated within a thickness-tunable multilayered thin V/V2O5 nanoshell (S@V/V2O5) was explored as a high-sulfur-content cathode (up to 93 wt%) for Li–S batteries. With a polar V2O5 moiety the nanoshell could physically block and chemically adsorb polysulfides, while the metallic V could assure efficient electron transfer; this multilayered and porous nanoshell could also buffer the volumetric variations of the sulfur core and facilitate Li+ transportation. Such S@V/V2O5 electrode with a 87 wt% sulfur content delivers high specific capacity (1403 mAh g−1) and remarkable areal initial capacity (4.4 mAh cm−2) at 0.2 C, excellent cycling stability (819 mAh g−1 at 0.5 C after 300 cycles), superior high-rate capacity (804 mAh g−1 at 4 C), low self-discharge (759 mAh g−1 after resting 50 days) and a high coulombic efficiency above 90% in a LiNO3-free electrolyte. A current collector-free S@V/V2O5 cathode with sulfur content of 93 wt% is also achieved, which yields stable discharge capacity of 1000 mAh g−1 at 0.2 C after 100 cycles.

Electrochemical Detection of Free Chlorine Using Ni Metal Nanoparticles Combined with Multilayered Graphene Nanoshells

AbstractAn electrochemical detection of free chlorine using carbon‐metal (C−M) composite powder, with a nickel‐metal nanoparticle combined with a multilayered graphene nanoshell (Ni metal@multilayered graphene) as the main component, synthesized from CH4 via multimode microwave‐assisted catalytic decomposition, was studied. Morphological analysis of the C−M composite powder was performed by TEM–EDX and Raman spectroscopy. The C−M composite powder was packed in a porous microelectrode (PME), and its electrochemical activity with respect to free chlorine was evaluated using a potential sweep method. The C−M composite powder exhibited a sufficient activity against free chlorine. A current based on the reduction of free chlorine was observed in the potential < around+0.3 V vs. Ag/AgCl. A linear relationship was observed between the current and the concentration.

Electromagnetic field amplification in Al/Ag spherical nanostructures

The localized electromagnetic field of multilayered nanoshells is studied using quasi-static approach and plasmon hybridization theory. The absorption spectrum of concentric metal–dielectric–metal nanostructures shows three plasmon resonance peaks which are optimized by tuning the geometrical parameters. It has been found that the three-layered nanoshells present different surface plasmon mode when the metal type of inner core and outer shell is exchanged. Silver and aluminum metals have stronger and sharper plasmon modes than that of gold and the outer silver shell has a greater effect on the total plasmonic properties of nanoshell. Three separated plasmon peaks of absorption spectrum of Al–Dielectric–Ag nanoshell cover a wide range from UV to NIR region. In addition, the optimal geometry is discussed to obtain the highest electromagnetic field enhancement in Al–dielectric–Ag nanoshell with special properties.

The Optical Properties of Nano-Materials and Electromagnetic Wave Propagation Visualized with MATLAB

The course of electromagnetic fields and waves has properties of abstract concept, strong theory and complex calculation, thus this course is difficult to study and understand, and then is also difficult to teach. In order to make the understanding of the course easier, MATLAB software is used as a platform in classroom teaching of electromagnetic fields and waves. This paper mainly discusses the electrical field intensity distribution of media sphere materials and the properties of electromagnetic wave propagation with MATLAB software. The optical properties of dielectric-metal core-shell multi-layered nano-shell are also studied with Laplace's equation. To enrich the teaching content and improve a better teaching effect, the optical property of nano-materials and electromagnetic wave propagation are visualized with MATLAB software, which makes the properties of nano-materials and electromagnetic wave propagation understand easily.

Localized surface plasmon resonance properties of symmetry-broken Au–ITO–Ag multilayered nanoshells

The plasmonic properties of symmetry-broken Au–ITO–Ag multilayered nanoshells by shell cutting are studied by the finite element method. The influence of the polarization of incident light and geometrical parameters on the plasmon resonances of the multilayered nanoshells are investigated. The polarization-dependent multiple plasmon resonances appear from the multilayered nanoshells due to symmetry breaking. In nanostructures with a broken symmetry, the localized surface plasmon resonance modes are enhanced resulting in higher order resonances. According to the plasmon hybridization theory, these resonance modes and greater spectral tunability derive from the interactions of an admixture of both primitive and multipolar modes between the inner Au core and outer Ag shell. By changing the radius of the Au core, the extinction resonance modes of the multilayered nanoshells can be easily tuned to the near-infrared region. To elucidate the symmetry-broken effects of multilayered nanoshells, we link the geometrical asymmetry to the asymmetrical distributions of surface charges and demonstrate dipolar and higher order plasmon modes with large associated field enhancements at the edge of the Ag rim. The spectral tunability of the multiple resonance modes from visible to near-infrared is investigated and the unique properties are attractive to applications including angularly selective filtering to biosensing.

Surface plasmon resonance sensor based on photonic crystal fiber filled with gold–silica–gold multilayer nanoshells

We present a surface plasmon resonance sensor based on photonic crystal fiber filled with gold–silica–gold (GSG) multilayer nanoshells for measurement of the refractive index of liquid analyte. The GSG multilayer nanoshells, composed of a silica-coated gold nanosphere surrounded by a gold shell layer, are designed to be the functional material of the sensor because of their attractive optical properties. Two resonant peaks are obtained due to the hybridization of nanosphere plasmon modes and nanoshell plasmon modes. It is demonstrated that the resonant wavelength of the two peaks can be precisely tuned in 560–716 nm and 849–2485 nm, respectively, by varying the structural parameters of the GSG multilayer nanoshells in a compact, sub-200 nm size range. The excellent spectral tunability makes the sensor attractive in a wide range of applications, especially in biosensing in near-infrared region. Furthermore, the influences of the parameters on the performance of the sensor are systematically simulated and discussed. It is observed that the spectral sensitivities of 1894.3 nm/RIU and 3011.4 nm/RIU can be achieved respectively by the two resonant peaks in the sensing range of 1.33–1.38. The existence of two loss peaks also provides the possibility to realize self-reference in the sensing process.

Plasmonic Fano switches in Au–SiO2–Au multilayer nanoshells with broken core

We demonstrate that concentric Au–SiO2–Au multilayer nanoshells with a core broken by removing half of the Au sphere core are sensitively dependent on the polarization orientations of the incident wave and can support highly tunable Fano resonances, realizing multi-wavelength plasmonic Fano switches at the orthogonal incident polarization orientations. The plasmon hybridization theory and coupled oscillator model are used to interpret the interaction between the inner broken core and the outer shell. The Fano resonances in the Au–SiO2–Au multilayer nanoshells with a broken core can be adjusted easily by means of varying the geometrical parameters, showing good tunability. Au–SiO2–Au multilayer nanoshells with a broken core in a compact sub-150 nm size range supports plasmonic Fano switches at the visible and near-infrared spectral regions, providing various applications in switching devices and photonic integrated technologies.

A nonlocal strain gradient hyperbolic shear deformable shell model for radial postbuckling analysis of functionally graded multilayer GPLRC nanoshells

The present study addresses the size dependency in nonlinear instability of functionally graded multilayer graphene platelet-reinforced composite (GPLRC) nanoshells under hydrostatic pressure including jointly the nonlocal elastic and strain gradients stress fields. For this objective, the new unconventional continuum theory namely as nonlocal strain gradient theory of elasticity is utilized within the framework of a refined hyperbolic shear deformation shell theory. Via stacking up a number of individual layers, the graphene platelet (GPL) nanofillers are distributed uniformly and three different functionally graded patterns based upon a layerwise change of the GPL weight fraction through the shell thickness direction. The effective material properties corresponding to uniform (U-GPLRC) and X-GPLRC, O-GPLRC, A-GPLRC functionally graded patterns of dispersion are extracted by Halpin-Tsai micromechanical scheme. By employing jointly the boundary layer theory of shell buckling and a two-stepped perturbation technique, explicit analytical expressions are achieved for nonlocal strain gradient stability curves of functionally graded multilayer GPLRC nanoshells. It is indicated that by increasing the value of GPL weight fraction for the U-GPLRC and O-GPLRC nanoshells, the significance of the both nonlocal and strain gradient size dependencies reduces, while for the X-GPLRC and A-GPLRC nanoshells, it increases.

Nonlinear instability of axially loaded functionally graded multilayer graphene platelet-reinforced nanoshells based on nonlocal strain gradient elasticity theory

With the aid of a more comprehensive size-dependent continuum elasticity theory, the nonlinear instability of functionally graded multilayer graphene platelet-reinforced composites (GPLRC) nanoshells under axial compressive load is examined. To accomplish this end, the newly proposed theory of elasticity namely as nonlocal strain gradient elasticity theory is implemented into a refined hyperbolic shear deformation shell theory to establish a more accurate size-dependent shell model. The graphene platelets (GPLs) are supposed to be randomly oriented with uniform and three different functionally graded dispersions relevant to each layer as the weight fraction of GPL varies layerwise through the shell thickness direction. In accordance with the Halpin–Tsai micromechanical scheme, the effective material properties are achieved corresponding to uniform (U-GPLRC) and X-GPLRC, O-GPLRC, A-GPLRC functionally graded patterns of dispersion. The boundary layer theory of shell buckling and a two-stepped perturbation solving process are employed jointly to capture explicit analytical expressions for nonlocal strain gradient stability curves of axially loaded functionally graded GPLRC nanoshells. Among different patterns of GPL distribution, it is observed that for both nonlocality and strain gradient size dependencies, the maximum and minimum size effects on the critical buckling loads are corresponding to X-GPLRC and O-GPLRC nanoshells, respectively.

Highly tunable extinction properties based on dual symmetry breaking in multilayer nanoshells

In this study, we have demonstrated that the multilayer nanoshells with dual symmetry breaking including the offset both dielectric layer and Au core can realize highly tunable extinction properties which are sensitively dependent on the relative offset direction between the Au core and dielectric layer. By controlling the offset direction of the Au core relative to the dielectric layer, the distinct multipeaked spectra with highly tunable multiple plasmon resonances can be excited selectively. The plasmon hybridization theory is applied to elucidate the origin of these resonances from the interactions of an admixture of both primitive and multipolar modes between the core and the broken nanoshell. Furthermore, the electromagnetic hot spots in dual symmetry breaking is accompanied by local-field enhancements, depending on the offset direction of the Au core relative to the dielectric layer, significantly larger than those obtainable for the single broken nanoparticle case.

Theoretical Study of Sensitivity and Localized Surface Plasmon Resonance of Ag-Dielectric Core-Shell Multi-layered Nanosphere

Localized surface plasmon resonances (LSPRs) of Ag-dielectric-Ag multi-layered nanoshell are studied by quasi-static approximation and plasmon hybridization theory. Absorption properties of multi-layered nanoshell with the silver core and nanoshell separated by a dielectric layer exhibit strong coupling between the core and nanoshell. The result shows absorption spectrum of LSPRS is influenced by the refractive index of surrounding medium, the dielectric constant of middle dielectric layer, the thickness of inner core radius and outer shell layer. LSPR shift of the longest wavelength \(\left |\omega _{-}^{-}\right >\) is red-shifted with increasing the inner core radius. It is interesting to find that longer wavelength \(\left |\omega _{-}^{+}\right >\) mode is mainly effected by the ratio constant of the surrounding medium refractive index e 4 to the middle layer dielectric constant e 2. \(\left |\omega _{-}^{+}\right >\) mode takes place a blue-shift with increasing inner core radius when e 2 > e 4, a red-shift when e 2 \) mode shows the different property as that of increasing the inner core radius. The underlying mechanisms are analyzed with the plasmon hybridization theory and the distribution of induced charge interaction between the inner core and outer shell. In addition, the influence of core radius, middle dielectric layer radius and outer shell radius to sensitivity of Ag-dielectric-Ag multi-layered nanoshell are also reported, a higher sensitivity could be gotten by adjusting geometrical parameters. Our theoretical study could give an easy way to analyze properties of the core-shell nanosphere based on plasmon hybridization theory and the induced charge interaction, and usefully broaden the applications in nano-optics.

Surface-Enhanced Raman Scattering in Tunable Bimetallic Core-Shell

In this paper, optical properties of multilayer spherical core-shell nanoparticles based on quasi-static approach and plasmon hybridization theory are investigated. Calculations show that light absorption spectrum of bimetallic multilayer core-shell has three intense plasmon resonance peaks, which are more suitable for multiplex biosensing based on surface-enhanced Raman scattering (SERS) and localized surface plasmon resonance (LSPR). The plasmon resonance peaks in bimetal nanshells are optimized by tuning the geometrical parameters. In addition, the optimal geometry is discussed to obtain the Raman enhancement factor in bimetallic multilayer nanoshell. SERS enhancement factor is calculated with consideration of dampings due to both the electron scattering and the radiation at the boundary and modified Drude model in dielectric function of bimetallic nanoshell. It is shown that bimetallic nanoshell with the small size exhibits strong SERS enhancement factor (~6.63 × 105) with additional collision dampings and ~2.9 × 109 with modified Drude model which are suitable for biosensing applications. In addition, any variation in blood concentration and oxygen level can be detected by this bimetallic core-shell nanoparticle with sensitivity of Δλ/Δn = 264.91 nm/RIU.

Highly-Tunable Magnetic and Electric Responses in the Perforated Au-SiO2-Si Multilayer Nanoshells

In this work, we have demonstrated that the perforated Au-SiO2-Si multilayer nanoshells can support additional magnetic response besides electric response, where Si core provides additional magnetic response, unlike regular metal-dielectric-metal multilayer nanoshells exhibiting pure electric response. Dipole radiative enhancement is used to analyze magnetic and electric responses of the perforated Au-SiO2-Si multilayer nanoshells and the spectral features of nanoshells can be used to quantitatively characterize by the coupled oscillator model. The magnetic and electric responses of the perforated Au-SiO2-Si multilayer nanoshells are dependent sensitively on the incident angles of light due to the symmetry breaking and can be easily tuned by means of varying the geometry. The unique capability of the perforated Au-SiO2-Si multilayer nanoshells exhibiting magnetic-electric responses can provide various applications.

Switching between optical bistability and multistability in plasmonic multilayer nanoparticles

We study the nonlinear optical response of multilayer metallic nanoparticles driven by an electromagnetic wave, which can show large field enhancement, hence significantly enhancing optical processes. In addition to optical bistability (OB), we find that optical multistability (OM), which plays a more important role in some applications than OB, is achievable and can be obtained in a multilayer plasmonic nanoparticle. Our results demonstrate that owing to strong localized fields created in the core and each layer of multilayer nanoshells, which occurs in the particles at frequencies close to the surface plasmon resonance, multilayer nanoparticles are promising systems with unique optical characteristics to control the light by light at the nanometer scale. It is demonstrated that OB can be converted to OM via adjusting the wavelength of the applied field and the size of the nanoshell, and the system can manifest optical hysteresis. It is found that the optical bistable or multistable threshold and the shape of hysteresis loops are strongly dependent on the thickness of shells, the incident wavelength, the permittivity of the surrounding medium, and the composition of the core and the inner/outer layers. We also give a discussion on the impact of the exciton-plasmon interaction and the intrinsic size effect on the nonlinear optical response of multilayer spherical nanoparticles.