Design Considerations Influencing Optical Response in Gold Spherical Nanoparticles

2017 ◽  
Vol 46 ◽  
pp. 1-11 ◽  
Author(s):  
Amir Maghoul ◽  
Ali Rostami ◽  
Samiyeh Matloub ◽  
Amin Pourrezaei
Keyword(s):  
Cross Section ◽  
Silicon Nanoparticles ◽  
Optical Response ◽  
Resonant Peak ◽  
Core Shell ◽  
Spherical Nanoparticles ◽  
Shell Nanoparticles ◽  
Extinction Cross Section ◽  
The Core ◽  
Core Shell Nanoparticles

In this article, the relations between extinction cross section and Gold nanoparticle's parameters such as dimensions have been investigated. In this work, the extinction cross section of the core-shell nanoparticles is analyzed by changing the shell material and its thickness. By this, the interesting results such as shifting resonant peak in optical response are obtained. Moreover, a new model of nanostructure is proposed in which the resonant peak of extinction cross section can be controlled by adding silicon nanoparticles and impurity in the shell. This method can be used for tuning of the scattering properties of the core-shell nanoparticle. In the following, we demonstrate that the effective epsilon properties can be used for tuning of the desired optical response in the combinational structure of the spherical nanoparticles. At the end, the effective relative epsilon is also calculated for the selected structures. The operational frequency band is selected from 300 (THz) to 900 (THz).

scholarly journals Люминесцентные свойства активированных нанокомпозитов на основе наночастиц структуры "ядро--оболочка"

2019 ◽  
Vol 61 (5) ◽  
pp. 987
Author(s):  
К.К. Пухов
Keyword(s):  
Radiative Decays ◽  
Core Shell ◽  
Spherical Nanoparticles ◽  
Shell Nanoparticles ◽  
The Core ◽  
The Matrix ◽  
Core Shell Nanoparticles ◽  
Luminescent Centers ◽  
Analytical Expressions ◽  
Effective Medium Models

The analytical expressions are derived for the rates of the spontaneous electric–dipole radiative decays of the luminescent centers located in the core-shell nanoparticles and in the matrix of nanocomposite. The effective medium models and local field problems associated with the optical properties of activated nanocomposites based on the subwavelength core-shell nanoparticles are discussed. A detailed analysis of two modern approaches to the problem of spontaneous transitions in luminescent centers located in homogeneous spherical nanoparticles has been carried out.

Aromatic thiol-modulated Ag overgrowth on gold nanoparticles: tracking the thiol's position in the core–shell nanoparticles

Nanoscale ◽  
2019 ◽  
Vol 11 (37) ◽  
pp. 17471-17477 ◽  
Author(s):  
Jiaqi Chen ◽  
Dejing Meng ◽  
Hui Wang ◽  
Haiyun Li ◽  
Yinglu Ji ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Growth Process ◽  
Shell Growth ◽  
Core Shell ◽  
Internal Reference ◽  
Shell Nanoparticles ◽  
Aromatic Thiol ◽  
The Core ◽  
Spatial Trajectory ◽  
Core Shell Nanoparticles

Using DMAB as the Raman internal reference, the spatial trajectory of modulating 4-ATP molecules was tracked during the shell growth process.

Frequency- and Temperature-Dependent Ferromagnetic Resonance of Co/CoO Core-Shell Nanoparticles

2004 ◽  
Vol 818 ◽  
Author(s):  
U. Wiedwald ◽  
J. Lindner ◽  
M. Spasova ◽  
Z. Frait ◽  
M. Hilgendorff ◽  
...  
Keyword(s):  
Ferromagnetic Resonance ◽  
Resonance Field ◽  
Core Shell ◽  
Direct Measure ◽  
Temperature Dependent ◽  
Spin Magnetic Moment ◽  
Shell Nanoparticles ◽  
The Core ◽  
G Value ◽  
Core Shell Nanoparticles

AbstractFerromagnetic Resonance experiments are used to investigate the magnetic properties of monodisperse Co/CoO core-shell nanoparticles with diameters of about 10nm. From frequency- dependent measurements at various frequencies of 9-80 GHz the g-value is determined to be 2.13 which suggests an fcc bulk-like environment of the Co atoms within the core of the particles. This result yields a direct measure of the ratio of orbital to spin magnetic moment νL/νS=0.065. Moreover, from temperature-dependent measurements of the resonance field the anisotropy energy is extracted and found much lower than the hcp bulk value.

PREPARATION AND CHARACTERIZATION OF SURFACE-FUNCTIONALIZATION OF SILICA-COATED MAGNETITE NANOPARTICLES FOR DRUG DELIVERY

NANO ◽  
2014 ◽  
Vol 09 (04) ◽  
pp. 1450042 ◽  
Author(s):  
CONG-WANG ZHANG ◽  
CHANG-CHUN ZENG ◽  
YING XU
Keyword(s):  
Drug Delivery ◽  
Shell Structure ◽  
Drug Carrier ◽  
Point Of View ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Application Potential ◽  
Core Shell Structure ◽  
Core Shell Nanoparticles

Fe 3 O 4– SiO 2 core–shell structure nanoparticles containing magnetic properties were investigated for their potential use in drug delivery. The Fe 3 O 4– SiO 2 core–shell structure nanoparticles were successfully synthesized by a simple and convenient way. The Fe 3 O 4– SiO 2 nanoparticles showed superparamagnetic behavior, indicating a great application potential in separation technologies. From the application point of view, the prepared nanoparticles were found to act as an efficient drug carrier. Specifically, the surface of the core–shell nanoparticles was modified with amino groups by use of silane coupling agent 3-aminopropyltriethoxysilane (APTS). Doxorubicin (DOX) was successfully grafted to the surface of the core–shell nanoparticles after the decoration with the carboxyl acid groups on the surface of amino-modified core–shell structure nanoparticles. Moreover, the nanocomposite showed a good drug delivery performance in the DOX-loading efficiency and drug release experiments, confirming that the materials had a great application potential in drug delivery. It is envisioned that the prepared materials are the ideal agent for application in medical diagnosis and therapy.

Colloidal Preparation of γ-Fe2O3@Au [core@shell] Nanoparticles

2003 ◽  
Vol 774 ◽  
Author(s):  
Jiye Fang ◽  
Jibao He ◽  
Eun Young Shin ◽  
Deborah Grimm ◽  
Charles J. O'Connor ◽  
...  
Keyword(s):  
Magnetic Core ◽  
Core Shell ◽  
Medical Systems ◽  
Solution Synthesis ◽  
Organic Solution ◽  
Shell Nanoparticles ◽  
The Core ◽  
Promising Application ◽  
Core Shell Structure ◽  
Core Shell Nanoparticles

Abstractγ-Fe2O3@Au core-shell nanoparticles were prepared through a combined route, in which high temperature organic solution synthesis and colloidal microemulsion techniques were successively applied. High magnification of TEM reveals the core-shell structure. The presence of Au on the surface of as-prepared particles is also confirmed by UV-Vis absorption. The magnetic core-shell nanoparticles offer a promising application in bio- and medical systems.

Enhanced Emission from Single Component Organic Core–Shell Nanoparticles

2007 ◽  
Vol 7 (12) ◽  
pp. 4311-4317 ◽  
Author(s):  
Koushik Dhara ◽  
Krishanu Sarkar ◽  
Partha Roy ◽  
Asim Bhaumik ◽  
Pradyot Banerjee
Keyword(s):  
Rate Constant ◽  
Mixed Solvent ◽  
Condensation Reaction ◽  
Single Component ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Remarkable Feature ◽  
Packing Factor ◽  
The Core ◽  
Core Shell Nanoparticles

By one-step mixed-solvent mediated approach, we have prepared fluorescent organic core–shell nanoparticles with an oligomer (1) derived from the Schiff base condensation reaction of 2,6-diformyl-4-methylphenol and o-phenylenediamine at room temperature. The core and shell structures are generated by the same oligomer (1) featuring the aggregation structure in core different from that in shell. The radial packing factor distribution of oligomer cluster depending on the solvent interaction in the time of nucleation is mainly responsible for the single component core–shell formation. Different morphologies of the core–shell nanospheres (CSNS) and core–shell nanohemispheres (CSNHS) were generated simply by changing the concentration of 1 in chloroform-methanol mixed solvent (1:2). We observed that fluorescent emission from those core–shell nanoparticles is intense whereas as-synthesized oligomer (1) itself is non-fluorescent in dilute solution. The enhanced emission in the core–shell form with more than 50 times increase in fluorescent quantum yield vis-à-vis 1 is a remarkable feature of the study. As UV absorption spectra of nanoparticles are blue-shifted relative to their properties in solution, the observed strong emission in the solid state makes the oligomer an outstanding exception to a well-established rule based on the molecular exciton model. The core–shell nanoparticles have been characterized by FE-SEM, TEM, XRD, nanosecond (ns) time-resolved fluorescence dynamics, UV-Vis and fluorescence spectroscopy. The longer fluorescence lifetimes (τ) of core–shell nanoparticles (3.50 ns and 3.52 ns for CSNS and CSNHS respectively) than 1 as-synthesized (1.28 ns) implies that the formation of the nanoparticles restricts the rotation and vibration of the groups in the molecules. The factor that induces fluorescent enhancement of nanoparticles is mainly ascribed to the increase of radiative rate constant (kr) and simultaneous decrease of nonradiative rate constant (knr).

Iron-Carbon Core-Shell Nanoparticles Obtained with Different Conditions of Synthesis

2017 ◽  
Vol 899 ◽  
pp. 221-226 ◽  
Author(s):  
M.M. Lima ◽  
J.P.Z. Gonçalves ◽  
C. Soares ◽  
Humberto Gracher Riella ◽  
S.C. Fernandes ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Processing Parameters ◽  
Effect Of Temperature ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Shell Mass ◽  
The Core ◽  
Iron Precursor ◽  
Co Precipitation ◽  
Core Shell Nanoparticles

Core–shell Fe2O3@C nanoparticles are very studied due to its biocompatibility with plant and animals cells and due its special properties of chemical adsorption. Thus, the definition of an easy synthesis method of these nanoparticles is very important to the scientific studies and to future applications of these materials. For example, the properties of these nanoparticles depend of the combination between some processing parameters, as the temperature, time, chemical composition, atmosphere and others. The mass yield of the synthesis processes depend of these parameters and are important information. In this work the effect of temperature and of the concentration of the iron precursor were evaluated on the characteristics of the proposed nanoparticles. The nanostructures of Fe2O3 coated with carbon (Fe2O3@C) were synthetized by adapted co-precipitation hydrothermal rote. In 40.0 ml of distilled water was added 1.800 g of glucose, 6.006 g of urea, 0.500 g of polyethylene Glycol (PEG 1500) and different concentrations of iron nitrate Fe (NO2)3.9H2O and different temperature values were applied. The Fe2O3@C core-shell were characterized by scanning electron microscopy (SEM/FEG), Energy Dispersive Scanning (EDS) and X-ray Diffractions (XRD). Results showed that nanoparticles form clusters with different sizes that are dependent on the temperature values and Fe (NO3)3.9H2O concentration. The core-shell mass has a linear relation with the iron precursor mass and the reaction temperatures influences the microstructure of the core-shell nanoparticles.

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