Effect of metallic nanoparticle sizes on the local field near their surface

Дынич, Р. А.; Ponyavina, A. N.

doi:10.1007/s10812-009-9125-y

Cited by 18 publications

(16 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[2][3][4][5]13,32 The localized electromagnetic field around the metallic NPs can be significantly enhanced at their resonant frequencies. 33 In addition, the light scattering properties become dominant for larger NPs. Both of these effects contribute to the anti-reflection performance.…”

mentioning

confidence: 99%

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

et al. 2014

View full text Add to dashboard Cite

Light collection efficiency is an important factor that affects the performance of many optical and optoelectronic devices. In these devices, the high reflectivity of interfaces can hinder efficient light collection. To minimize unwanted reflection, anti-reflection surfaces can be fabricated by micro/nanopatterning. In this paper, we investigate the fabrication of broadband anti-reflection Si surfaces by laser micro/nanoprocessing. Laser direct writing is applied to create microstructures on Si surfaces that reduce light reflection by light trapping. In addition, laser interference lithography and metal assisted chemical etching are adopted to fabricate the Si nanowire arrays. The anti-reflection performance is greatly improved by the high aspect ratio subwavelength structures, which create gradients of refractive index from the ambient air to the substrate. Furthermore, by decoration of the Si nanowires with metallic nanoparticles, surface plasmon resonance can be used to further control the broadband reflections, reducing the reflection to below 1.0% across from 300 to 1200 nm. An average reflection of 0.8% is achieved.

show abstract

mentioning

confidence: 99%

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

et al. 2014

View full text Add to dashboard Cite

show abstract

“…An approach based on the theory of the interaction of an electromagnetic field with small spherical particles that was developed by Mie was used to determine the spectral shape of the extinction effectiveness factor. This method is widely used to model the optical characteristics of minute particles [14,[19][20][21]. It is based on the expansion of electromagnetic fields interacting with a small particle over vector spherical harmonics with subsequent calculation of the coefficients of this expansion.…”

Section: Modeling Extinction Of Aqueous Ag and Aumentioning

confidence: 99%

Diagnostics of aqueous colloids of noble metals by extinction modeling based on mie theory

Kozadaev

2011

J Appl Spectrosc

View full text Add to dashboard Cite

Two-factor dependences of the maximum and half-width of a surface plasmon resonance band on both the average diameter of nanoparticles and the scatter in their particle-size distributions were defined for colloidal silver and gold aqueous solutions based on modeling the extinction effectiveness factor by Mie theory. The obtained three-dimensional surfaces determined the shape of calibration curves used to define the average particle diameters and the scatter in their particle-size distributions from measurements of the maximum and half-width of the surface plasmon resonance band in spectra of the silver and gold colloidal solutions. The calibration curves were correlated with experimental samples of aqueous ultradispersed media containing silver and gold nanoparticles.Keywords: colloidal solutions of noble metals, laser erosion, absorption spectroscopy, transmission electron microscopy, scanning electron microscopy, surface plasmon resonance.Introduction. Nanotechnology, which addresses the production and application of nanostructured materials, is currently undergoing vigorous growth [1]. The field is in need of effective diagnostic methods for the parameters of nanoscale materials in a wide variety of media. A characteristic example of this problem is the study of the properties of metal colloids. Traditional methods of visualizing single minute structures (scanning and transmission electron microscopy and atomic force microscopy) provide in this instance little information because they all require a vacuum in the studied region. The colloid actually ceases to exist after deposition on a substrate. Moreover, as a rule, the location of the visualized nanostructure on the sample surface has a considerable influence on its parameters.Many researchers proposed using a surface plasmon resonance (SPR) band to study ultradispersed metal-containing optical media (at least to determine the average particle size d ). The principal studied factor often turns out to be the spectral position of the SPR band maximum [2-10]. According to seminal work in the study of the interaction of optical radiation with ultradispersed media [11-13], the type of particle material, their size and shape [14], the internal structure (layering, presence of inclusions) [3,9,14], characteristics of the medium environment, ordering of the particles [14,15], and the scatter in the particle-size distribution are among the dominant parameters that affect the spectral shape of the SPR band.Discussions of the spectral position of the SPR band maximum (λ max ) [2, 3, 5-7] mentioned the actual particle material in a certain optical medium and, as a rule, used spherical monolithic particles evenly distributed throughout the medium volume without scatter in the particle-size distribution (i.e., the particle-size distribution scatter σ = 0) as an approximation. We agree with all these assumptions except for the last because they enable a good approximation for an acceptable estimate of to be obtained d . Nullifying the contribution of the particle-size dis...

show abstract

“…An analysis of these plots shows that the topology of the distribution of the field enhancement regions is essentially invariable for small particles and undergoes a transformation as the particle size increases. For small spherical particles (a < 10 nm) the field patterns are typically symmetric inside and outside the particle with respect to all three main cross section planes passing through the center of the particle [4]. The regions with the highest field amplitudes, the "hot spots," are concentrated predominantly on the particle surface near its diametrally opposite poles along the polarization vector of the incident light.…”

mentioning

confidence: 99%

“…3. Spectral variations in Q NF (1, 2), m i (5), and the product Q NF m i (3,4) for silver nanoparticles with a radius a = 10 nm neglecting (1, 3) and including (2, 4) particle size effects. Fig.…”

mentioning

confidence: 99%

“…The spectral variation in the efficiency factors for attenuation Q ext(1)(2)(3)(4) and scattering Q NF(5)(6)(7)(8) in the near zone by 10-nm-radius silver nanoparticles embedded in a nonabsorbing matrix with a refractive index of 1.to calculations which neglect and include, respectively, the size dependence of the refractive index of spherical silver nanoparticles.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Local field enhancement near spherical nanoparticles in absorbing media

2009

Self Cite

View full text Add to dashboard Cite

It is shown by numerical simulation that the enhancement of the field near metallic nanoparticles is most significant in the transparency region of the matrix material and falls off as the absorption coefficient rises. In an absorbing matrix medium this leads both to an increase in the fraction of energy absorbed by the matrix material and to a substantial transformation in its spectral distribution. This is illustrated for the case of copper phthalocyanine with silver nanoparticles. By choosing the size of the introduced plasmon nanoparticles it is possible to enhance the absorption in the visible for the materials used in solar cells and thereby increase their energy efficiency. Introduction.When plasmonic nanoparticles are present in a medium, surface plasmon absorption bands form and cause a substantial enhancement in the local electromagnetic field in the spectral region of the plasmon resonance [1-4]. The surface plasmon resonance responsible for the enhancement in the local field is primarily a characteristic of the metal from which the nanoparticles are made. However, certain features of this effect are determined by the sizes and shapes of the nanoparticles, and their organization (nanostructure), but also depend on the optical properties of the medium in which the nanoparticles are embedded. By changing the shape and size of the nanoparticles it is relatively easy to control the characteristics of the surface plasmon resonance.The possibility of local field enhancement in a medium turns out to be attractive for applications in photovoltaic solar cells, since an enhanced field raises the fraction of energy absorbed in the medium, which is proportional to the local field intensity. This is one of the concepts now under rapid development for raising the conversion efficiency for solar energy, both for cells with traditional semiconductors (silicon [5], gallium arsenide [6]) and thin film cells based on organic semiconductors [7].Up to now primary attention has been devoted to the features of the plasmon resonance and the local field enhancement in transparent media. However, absorption in a matrix material does affect the efficiency with which light is scattered [8][9][10][11]. Thus, one should expect changes in both the intensity and the character of the localization of "hot spots," and a transformation in the resulting absorption spectrum of the composite medium. In addition, with regard to absorbing media (and highly absorbing materials are used in photovoltaic cells), the presence of an additional spatial dependence of the wave field has a significant effect on the procedure for calculating and characterizing light scattering [12][13][14][15].Numerical Simulation Technique. The field near the surface of a spherical particle was determined by an approach based on Mie's theory. Our own computer program developed for the case in which the surrounding medium is absorbing was used. The near field distribution was described with the aid of the near zone scattering efficiency factor Q NF [2]. The factor Q NF ...

show abstract

Effect of metallic nanoparticle sizes on the local field near their surface

Cited by 18 publications

References 11 publications

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing

Diagnostics of aqueous colloids of noble metals by extinction modeling based on mie theory

Local field enhancement near spherical nanoparticles in absorbing media

Contact Info

Product

Resources

About