Fano‐like resonance and scattering in dielectric(core)–metal(shell) composites embedded in active host matrices

Jule, Leta Tesfaye; Malnev, V. N.; Mesfin, Belayneh; Senbeta, Teshome; Dejene, F.B.; Rorro, Kittesa

doi:10.1002/pssb.201552221

Cited by 9 publications

(6 citation statements)

References 29 publications

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“…The two resonance at visible region and near/in infrared spectral region is related to the surface resonance of Au at the two interfaces i.e. ; spacer@Au and Au@medium [29]. As shown in the figure (2), the resonance at wavelength around 460 nm associated with inner interface is remain constant, but the resonance associated with outer interface extends from visible to near infrared spectral region that is by controlling the resonance frequency via the shell thickness increase [30].…”

Section: Local Field Enhancement Factormentioning

confidence: 92%

High Tunability of Size Dependent Optical Properties of ZnO@M@Au (M = SiO2, In2O3, TiO2) Core/Spacer/Shell Nanostructure

Kassahun

2019

Adv. Nan. Res.

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This theoretical work presents a comparative study of high tunability size dependent optical properties of quantum dot/wire triple layered core shell nanostructure based on the quasi-static approximation of classical electrodynamics embedded in a fixed dielectrics function of host matrix. In this paper, local field enhancement factor (LFEF), refractive index and optical absorbance of nanocomposite are analyzed by varying core size, thickness of spacer and shell as well as dielectrics function of the spacer for the size of the nanocomposite with the range of 20 nm to 40 nm. For both quantum dot and quantum wire triple layered core shell nanostructure (CSNS), there are two resonances in visible and near/in infrared spectral region with high tunability. When the shell thickness increase and therefore increasing the gold content, the surface plasmon resonance (SPR) at the outer interface shifts to higher energy (blue-shifted) and at the inner interface weak peaks and shifted to lower energy (red-shifted). All of three optical properties, depend on core size, dielectrics and thickess of spacer, thickness of shell, shape of composite and filling factor. For the same thickness of spacer and shell of the two configurations, cylindrical triple layered CSNS less pronounced and shifted to infrared red (IR) spectral region which is recommendable for biological and photocatalysis application.

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Section: Local Field Enhancement Factormentioning

confidence: 92%

High Tunability of Size Dependent Optical Properties of ZnO@M@Au (M = SiO2, In2O3, TiO2) Core/Spacer/Shell Nanostructure

Kassahun

2019

Adv. Nan. Res.

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“…Local field enhancement factor of spheroidal core-shell nanocomposite Since we are using the quasi-static approach, the electric field E 0 (assumed to be directed along the z-axis) is uniform. Then, by using the relation E = − ∇Φ, the local field in the dielectric core E d of the spheroidal nanocomposite can be written as [40]:…”

Section: Theoretical Bases and Calculationsmentioning

confidence: 99%

“…[40], (ii) for the silver shell (ε ∞ = 4.5, ω p = 1.45 × 10 16 rad/s, ν = 1.67 × 10 14 rad/s[41,42]), and (iii) for the dielectric core 2. (for active)[43] .…”

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confidence: 99%

Local field enhancement factor of spheroidal core–shell nanocomposites with passive and active dielectric cores

Hirpha¹,

Bergaga

Ali

et al. 2023

Mater. Res. Express

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We studied the effects of depolarization factor (L), metal fraction (p), and dielectric function of host matrix ("h)on the local field enhancement factor (LFEF) of spheroidal core-shell nanocomposites (NCs) with passive andactive dielectric cores. Solving Laplace’s equations in the quasi-static limit, we obtained expressions of electricpotentials for spheroidal core-shell NCs. Then, by introducing L and the Drude-Sommerfeld model into theseexpressions, we derived the equation of LFEF in the core of spheroidal core-shell NCs. The results show thatwhether L, p, and/or "h vary or kept constant, LFEF of the spheroidal core-shell NCs possesses two sets ofpeaks with passive dielectric core, whereas only a set of peak is observed with active dielectric core. In NCswith passive dielectric core, an increase in any of these parameters resulted in a more pronounced LFEF peaksin the first set of resonances. With both passive and active dielectric cores, increasing L increases the peaks of LFEF of spheroidal core-shell NCs, whereas increasing p shows decreasing tendency on the peaks of LFEF ofthe same material with active dielectric core. Moreover, the highest peak of LFEF is obtained by increasingL than p or "h indicating that change in the geometry of spheroidal core-shell NCs has the highest effect onthe LFEF than the metal concentration and host dielectric function. With the same increase in "h, intensitiesof LFEF of the spheroidal core-shell NCs decrease when the dielectric core is passive and increase when thedielectric core is active. Briefly, the number and intensities of peaks of LFEF of spheroidal core-shell NCs varygreatly when its core is made either passive or active dielectric. Furthermore, by changing parameters like L,p, and "h, adjustable LFEF could be obtained and used for applications in optical sensing, nonlinear optics, andquantum optics.

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“…The local electric field E 1 induced in the dielectric core of the nanocomposite is related to the incident electric field, E , 0 by the following equation [26]:…”

Section: Theoretical Models and Calculationsmentioning

confidence: 99%

Size dependent local field enhancement factor of CdSe based core@shell spherical nanoparticles

Bergaga

Ali

Debela

2022

Mater. Res. Express

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We investigated the size dependent local field enhancement factor (LFEF) of CdSe@Ag and CdSe@ZnSe@Ag core/shell spherical nanoparticles theoretically and numerically within the framework of quasi-static approximation. From the potential distributions in the core, shell(s), and host medium, and using the modified Drude-Sommerfeld model, we separately obtained the expressions for LFEF of core/shell and core/spacer/shell nanocomposites. By changing the sizes of each of the components of the nanocomposites in these expressions, we found that the LFEF of CdSe@Ag increased as the size of the core is decreased. At the same time, the resonance peaks are red shifted in the inner interface and blue shifted in the outer interface of the shell. The result also reveals that whether the shell radius is kept constant or decreased, increasing the core size produces a lower field enhancement factor showing that the core size is a crucial parameter to change the field enhancement factor of the dielectric core and metal shell nanoparticle (NP). When the spacer (ZnSe) is placed between the core (CdSe) and the shell (Ag), the resonance peaks increased with increase in the size of the core which was not observed in the case of the two layered core/shell nanocomposites having the same core and shell sizes. We found that placing the spacer and varying the sizes of the core, spacer, and shell show different effects on the LFEF of the nanocomposite. The possibility of obtaining size dependent LFEF by adjusting the sizes of nanoparticles makes these nanocomposites attractive for applications in nonlinear optics, photocatalysis, and optoelectronics.

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Fano‐like resonance and scattering in dielectric(core)–metal(shell) composites embedded in active host matrices

Cited by 9 publications

References 29 publications

High Tunability of Size Dependent Optical Properties of ZnO@M@Au (M = SiO2, In2O3, TiO2) Core/Spacer/Shell Nanostructure

High Tunability of Size Dependent Optical Properties of ZnO@M@Au (M = SiO2, In2O3, TiO2) Core/Spacer/Shell Nanostructure

Local field enhancement factor of spheroidal core–shell nanocomposites with passive and active dielectric cores

Size dependent local field enhancement factor of CdSe based core@shell spherical nanoparticles

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