共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Iwamoto K. Kuroda V. Zaporojtchenko S. Hayashi F. Faupel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):365-367
Recently, production methods of metal nanoparticles have
been investigated extensively, not only for a research use in
laboratory, but also for an industrial use. However, it is
difficult to obtain metal nanoparticles in high amounts and
concentrations with simple methods. In this study, a gold
nanoparticle-polymer composite was prepared with a simple
procedure using a gold salt and a melted polymer. The composite,
which is in a wax state at room temperature, was highly soluble
in water and lower alcohols, moreover the composite was melted
at about 50
°C. 相似文献
2.
P. Billaud J.-R. Huntzinger E. Cottancin J. Lermé M. Pellarin L. Arnaud M. Broyer N. Del Fatti F. Vallée 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):271-274
The extinction spectrum of single silver nanoparticles
with size ranging from 20 to 80 nm is investigated with the spatial
modulation spectroscopy technique using either a tunable laser or a white
lamp as the broadband source. Results are in good agreement with the
prediction of the Mie theory, permitting to extract the nanoparticle size
from the measured absolute value of the optical extinction cross-section. In
contrast, the deduced refractive index of the nanoparticle environment and
the reduction of the electron mean free path show a large dependence on the
precise value of the bulk silver dielectric function. 相似文献
3.
We present extinction measurements on rectangular two-dimensional arrays of gold nanoparticles on a dielectric waveguide.
The spectra exhibit spectrally narrow bands of suppressed extinction within the particle–plasmon resonance, resulting from
destructive interference between the incident light field and the excited waveguide modes. The dependence of the spectral
position of these high-transmission bands on different waveguide modes is investigated in detail.
Received: 3 July 2001 / Published online: 10 October 2001 相似文献
4.
W.L. Zhou E.E. Carpenter J. Lin A. Kumbhar J. Sims C.J. O'Connor 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):289-292
Pure metal iron nanoparticles are unstable in the air. By a coating iron on nanoparticle surface with a stable noble metal,
these air-stable nanoparticles are protected from the oxidation and retain most of the favorable magnetic properties, which
possess the potential application in high density memory device by forming self-assembling nanoarrays. Gold-coated iron core-shell
structure nanoparticles (Fe/Au) synthesized using reverse micelles were characterized by transmission electron microscopy
(TEM). The average nanoparticle size of the core-shell structure is about 8 nm, with about 6 nm diameter core and 1∼2 nm shell.
Since the gold shell is not epitaxial growth related to the iron core, the morié pattern can be seen from the overlapping
of iron core and gold shell. However, the gold shell lattice can be seen by changing the defocus of TEM. An energy dispersive
X-ray spectrum (EDS) also shows the nanoparticles are air-stable. The magnetic measurement of the nanoparticles also proved
successful synthesis of gold coated iron core-shell structure. The nanoparticles were then assembled under 0.5 T magnetic
field and formed parallel nanobands with about 10 μm long. Assembling two dimensional ordered nanoarrays are still under going.
Received 29 November 2000 相似文献
5.
Optical properties and ultrafast electron dynamics in gold–silver alloy and core–shell nanoparticles
Silver and gold are the two most popular metals used for many nanoparticle applications, such as surface enhanced Raman scattering
or surface enhanced fluorescence, in which the local field enhancement associated with the excitation of the localized surface-plasmon–polariton
resonance (SPR) is exploited. Therefore, tunability of the SPR over a wide energy range is required. For this purpose we have
investigated core–shell nanoparticles composed of gold and silver with different shell thicknesses as well as the impact of
alloying on these nanoparticles due to a tempering process. The nanoparticles were prepared by subsequent deposition of Au
and Ag atoms or vice versa on quartz substrates followed by diffusion and nucleation. Their linear extinction spectra were
measured as a function of shell thickness and annealing temperature. It turned out that different gold shell thicknesses on
silver cores allow a tuning of the SPR position from 2.79 to 2.05 eV, but interestingly without a significant change on the
extinction amplitude. Heating of core–shell nanoparticles up to only 540 K leads to the formation of alloy nanoparticles,
accompanied by a back shift of the SPR to 2.60 eV. Calculations performed in quasi-static approximation describe the experimental
results quite well and prove the structural assignments of the samples. In additional experiments, we applied the well-established
persistent spectral hole burning technique to the alloy nanoparticles in order to determine the ultrafast dephasing time T
2. We obtained a dephasing time of T
2=(8.1±1.6) fs, in good agreement with the dephasing time of T
2,∞=8.9 fs, which is already included in the dielectric function of the bulk. 相似文献
6.
Markus A. Mangold Martin A. Niedermeier Monika Rawolle Beate Dirks Jan Perlich Stephan V. Roth Alexander W. Holleitner Peter Müller‐Buschbaum 《固体物理学:研究快报》2011,5(1):16-18
The optical properties of two‐dimensional assemblies of metal nanoparticles are strongly influenced by the morphological configuration of the metal particles in the layer. Therefore, we correlate the structural and optical properties of two‐dimensional, hexagonal gold nanoparticle arrays. We characterize the structure of the arrays using grazing‐incidence small angle X‐ray scattering (GISAXS). From the GISAXS pattern, we determine the size of the gold particles as well as the lattice spacing of the hexagonal assembly. Based upon these parameters we calculate the dielectric function of the gold particle array using the Maxwell–Garnett effective medium theory. We further deduce the absorption spectrum which closely follows the measured absorption and photoconductance spectrum. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
C. McGinley S. Al Moussalami M. Riedler M. Pflughoefft H. Borchert M. Haase A.R.B. de Castro H. Weller T. Möller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):225-228
We describe photoemission results from pure and Sb-doped SnO2 nanoparticles deposited on gold substrates. Photoelectron spectra with synchrotron radiation were recorded for Sn 3d, Sb
3d and O 1s core levels and valence bands in the 500-1200 eV energy range. For pure SnO2 nanoparticles the surface is terminated by an oxygen rich layer with no obvious surface environment for Sn. When doped n-type
with 9.1% or 16.7% Sb, dopant atoms are concentrated near the surface of the nanoparticles. The valence state of the dopant
atoms is predominantly SbV. Plasmon satellite features are also observed in core level photoemission spectra and their intensity relative to the main
peak increases with increasing photon energy.
Received 30 November 2000 相似文献
8.
A quantitative modeling of the contributions of localized surface plasmon resonance (LSPR) and interband transitions to absorbance
of gold nanoparticles has been achieved based on Lorentz–Drude dispersion function and Maxwell-Garnett effective medium approximation.
The contributions are well modeled with three Lorentz oscillators. Influence of the structural properties of the gold nanoparticles
on the LSPR and interband transitions has been examined. In addition, the dielectric function of the gold nanoparticles has
been extracted from the modeling to absorbance, and it is found to be consistent with the result yielded from the spectroscopic
ellipsometric analysis. 相似文献
9.
The dielectric function of yttrium in the range between 0.2 μm and 2 μm is composed of a harmonic oscillator contribution
due to a discrete interband transition and the contribution of free electrons. Hence, it is possible to discuss surface plasmon
polaritons as well as other electronic resonances in the optical extinction spectra of yttrium nanoparticles. For the latter,
we discuss the broadening of the resonance caused by the aggregation of particles. When particles are lumped into aggregates,
the color of the particle system also changes. Aggregation also affects the surface plasmon resonance in yttrium nanoparticles
in a way comparable to silver or gold nanoparticle aggregates. Comparison is made with the first experimental results on yttriumnanoparticles,
showing that aggregation is the dominant effect for the broad resonance in the measured extinction spectra.
Received: 2 July 2001 / Revised version: 10 September 2001 / Published online: 15 October 2001 相似文献
10.
使用532nm,8ns激光脉冲研究了两种新型的基于富勒烯C60结构体系的金纳米粒子合成物的光学非线性.Z-scan实验结果和理论分析的比较表明,材料的非线性吸收强烈地依赖于材料中的配合体,而非线性折射主要来自金纳米粒子的贡献.而且与熟知的C60甲苯溶液光限幅特性作了比较,分析了光限幅机理.
关键词:
60结构体系')" href="#">基于富勒烯C60结构体系
金纳米粒子
等离子体
光限幅 相似文献
11.
对于金纳米颗粒在化学和生物传感中的应用,找到具有高品质因子的金纳米颗粒形状是近年来的研究热点。基于T矩阵方法和介电函数的尺寸修正模型,本文从理论上定量研究了金纳米旋转椭球的尺寸对其折射率灵敏度、半峰宽以及品质因子的影响。为了获得最佳传感性能,对品质因子进行了优化,并得到了最优的颗粒尺寸参数。结果发现,短半轴为11 nm和长半轴为49 nm的金纳米旋转椭球具有最大品质因子6.76。优化后的金纳米旋转椭球可以作为理想的化学和生物传感器。本研究为金纳米旋转椭球在化学和生物传感的应用中提供重要的理论依据。 相似文献
12.
G. A. Torchia L. B. Scaffardi C. Méndez P. Moreno J. O. Tocho L. Roso 《Applied Physics A: Materials Science & Processing》2008,93(4):967-971
This work presents a method, based on measurements of the optical extinction spectra, to determine the size of spherical gold
nanoparticles produced using the femtosecond laser ablation process in deionized water. By using an improved theoretical model
that modifies the contribution of the free electrons to the dielectric function introducing a size-dependent term, it is possible
to fit the full experimental extinction spectrum considering a certain size distribution. Additionally, in order to obtain
complementary measurements of the size distribution, TEM analysis was performed. The results obtained showed that the predominant
nanoparticle size distribution ranges from 1 to 11 nm in terms of radii. An optical extinction measurement together with an
appropriate theoretical model based on Mie’s theory represents a simple, low-cost, fast and easy method to describe a multimodal
size distribution of spherical gold nanoparticles. 相似文献
13.
B. Högberg H. Olin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):299-302
Self-assembly of complex, non-periodic nanostructures can only be achieved by using anisotropic building-blocks. The
building blocks need to have at least four bonds pointing in separate directions [J. Comput. Theor. Nanosci. 3, 391 (2006)]. We have previously
presented a method for the synthesis of such building-blocks using DNA-functionalized gold nanoparticles. Here, we report
on the progress in the experimental realization of this scheme. The first
goal, in a process to make programmable self-assembly building-blocks using nanoparticles, is the production of dimers
with different DNA-functions on the two component particles. We report on the fabrication of anisotropically
functionalized dimers of nanoparticles of two different sizes. As a result of their anisotropy, these demonstrator
building blocks can be made to assemble into spherical structures. 相似文献
14.
J. Lermé B. Palpant B. Prével E. Cottancin M. Pellarin M. Treilleux J.L. Vialle A. Perez M. Broyer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(1):95-108
The optical response of free and matrix-embedded gold metal clusters AuN is investigated in the framework of the time-dependent local-density-approximation (TDLDA). The characteristics of the surface
plasmon resonance are carefully analyzed as a function of the model parameters and the particle radius. The strong influence
of the frequency-dependence of the 5d core-electron dielectric function in the vicinity of the interband threshold is emphasized. The size evolution of the Mie-frequency
in free gold clusters exhibits a noticeable blue-shift trend as the particle size decreases, much stronger than in silver
clusters. The width and shape of the resonance, essentially ruled by the decay via the interband transitions, are found closely correlated to the imaginary component of the core-electron dielectric function.
In presence of a surrounding matrix the blue-shift trend is largely rubbed out. Agreement with recent experimental results
on size-selected gold clusters embedded in an alumina matrix may be achieved by taking into account the porosity effects at
the metal/matrix interface. The comparison with the predictions of classical models is also provided.
Received: 9 March 1998 / Revised: 5 June 1998 / Accepted: 3 July 1998 相似文献
15.
A fluorescence-based detection scheme that uses ligand functionalized gold nanoparticles is proposed. The transduction scheme is based on the strong quenching of the fluorescence emission exerted by metallic surfaces on fluorophores positioned in their immediate vicinity (< 5 nm). Binding of fluorophore-labeled anti-biotin to biotinylated gold nanoparticles resulted in decreased fluorescence emission intensity. Subsequent competitive dissociation of labeled anti-biotin with D-biotin resulted in increased fluorescence emission intensity. These interactions occurred by means of specific molecular recognition because when the binding sites of anti-biotin were saturated with D-biotin prior to interaction with the gold nanoparticles; changes in the fluorescence emission intensity were not observed. 相似文献
16.
Y. Tai J. Murakami K. Saito M. Ikeyama K. Tajiri M. Watanabe S. Tanemura T. Mizota 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):261-263
Plasma desorption mass spectrometry has been applied to
characterization of dodecanthiol-passivated gold nanoparticles.
An overview of the experimental set-up and mass analyses for the
nanoparticles prepared in different conditions are shown. Mass
distributions were found to shift to higher mass regions with
increasing reaction temperature and reaction period. The results
are consistent with those of transmission electron microscopy
observations, UV-visible absorption spectra and also with a
reported laser desorption mass spectrometry. 相似文献
17.
D. Lee S. Lee H. Kim D.-J. Jang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):303-306
DNA-connected strings of gold nanoparticles are arranged
to form very uniformly annular arrays having various diameters
of a few micrometers by adjusting evaporation conditions as well
as the concentrations of gold nanoparticles and
phosphorothioate-modified oligonucleotides. The circles are
formed by the dry hole-opening mechanism rather than by the
Marangoni effect. However, their sizes are very diverse and
their circumferences are approaching to show single-particle
thinness instead of close-packed particle cluster thickness
owing to DNA-linked gold nanoparticle strands. 相似文献
18.
V. Anikeyev V. V. Temnov U. Woggon E. Devaux T. W. Ebbesen 《Applied physics. B, Lasers and optics》2008,93(1):171-176
We discuss the implications of a frequency-dependent complex dielectric function ε(ω) of a metal for the interpretation of scanning near-field optical microscopy (SNOM) measurements in the vicinity of metallic
nanoapertures. For subwavelength slits in gold films we observe distinct spatial intensity oscillations in the near-field
signal for specific wavelengths in the visible spectrum. These oscillations of the SNOM signal far away from the nanoslit
are ascribed to a constructive interference between the propagating surface plasmon (SP) with light scattered parallel to
the gold–air interface. In these spatial SNOM-signal oscillations information about the surface plasmon dielectric function
is encoded which can be extracted, for example, in surface plasmon interferometry for applications as sensors or waveguides. 相似文献
19.
A. Li Bassi C.E. Bottani B.K. Tanner A. Stella P. Tognini P. Cheyssac R. Kofman 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(1):31-38
The abrupt change of velocity in surface acoustic waves in thin films of amorphous SiOx containing nanometre scale -Sn crystals is shown to be directly associated with the size-dependent melting of the nanoparticles, confirming preliminary
experiments. High resolution thin film powder diffraction using synchrotron radiation shows that the abrupt redshift in the
Brillouin spectra satellites occurs at the same temperature as the melting of the nanoparticles, evident for the loss of the
Bragg peaks. Effective medium theory is used to explain the origin of the anomaly. A central peak in the Brillouin spectrum,
the intensity of which shows a maximum at the melting temperature, can be interpreted in terms of overdamped fluctuations
in the dielectric function. The melting temperature as a function of particle size is in agreement with theoretical predictions.
No evidence for strain could be found on the X-ray diffraction profiles; the a- and c-axis thermal expansion coefficients are the same as those in bulk tin.
Received 30 March 2000 and Received in final form 24 July 2000 相似文献
20.
F.J. García-Vidal J.M. Pitarke 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(2):257-265
Optical-absorption cross-sections and energy-loss spectra of aligned multishell carbon nanotubes are investigated, on the
basis of photonic band-structure calculations. A local graphite-like dielectric tensor is assigned to every point of the tubules,
and the effective transverse dielectric function of the composite is computed by solving Maxwell's equations in media with
tensor-like dielectric functions. A Maxwell-Garnett-like approach appropriate to the case of infinitely long anisotropic tubules
is also developed. Our full calculations indicate that the experimentally measured macroscopic dielectric function of carbon
nanotube materials is the result of a strong electromagnetic coupling between the tubes. An analysis of the electric-field
pattern associated with this coupling is presented, showing that in the close-packed regime the incident radiation excites
a very localized tangential surface plasmon.
Received 18 January 2001 相似文献