Seed Mediated Formation of Bimetallic Nanoparticles by UV Irradiation:  A Photochemical Approach for the Preparation of “Core−Shell” Type Structures

Nano Letters ◽  
2001 ◽  
Vol 1 (6) ◽  
pp. 319-322 ◽  
Author(s):  
Kaushik Mallik ◽  
Madhuri Mandal ◽  
Narayan Pradhan ◽  
Tarasankar Pal
Keyword(s):  
Uv Irradiation ◽  
Bimetallic Nanoparticles ◽  
Core Shell ◽  
Shell Type ◽  
Seed Mediated

scholarly journals Light-Scattering Simulations from Spherical Bimetallic Core–Shell Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Bimetallic Nanoparticles ◽  
Dominant Role ◽  
Scattered Light ◽  
Specific Interaction ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Core Shell ◽  
The Core

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.

scholarly journals Fabrication of Hollow Core-Shell Type Si/C Nanocomposites by a Simple Process

2017 ◽  
Vol 15 (0) ◽  
pp. 69-73 ◽  
Author(s):  
Kei Wakabayashi ◽  
Daichi Yamaura ◽  
Kazuki Ito ◽  
Naoya Kameda ◽  
Toshio Ogino
Keyword(s):  
Core Shell ◽  
Hollow Core ◽  
Simple Process ◽  
Shell Type

scholarly journals CdSe/ZnS Core-Shell-Type Quantum Dot Nanoparticles Disrupt the Cellular Homeostasis in Cellular Blood–Brain Barrier Models

2021 ◽  
Vol 22 (3) ◽  
pp. 1068
Author(s):  
Katarzyna Dominika Kania ◽  
Waldemar Wagner ◽  
Łukasz Pułaski
Keyword(s):  
Gene Expression ◽  
Quantum Dot ◽  
Blood Brain Barrier ◽  
Protein Gene ◽  
Brain Barrier ◽  
Core Shell ◽  
Cellular Homeostasis ◽  
Blood Brain ◽  
Shell Type ◽  
The Impact

Two immortalized brain microvascular endothelial cell lines (hCMEC/D3 and RBE4, of human and rat origin, respectively) were applied as an in vitro model of cellular elements of the blood–brain barrier in a nanotoxicological study. We evaluated the impact of CdSe/ZnS core-shell-type quantum dot nanoparticles on cellular homeostasis, using gold nanoparticles as a largely bioorthogonal control. While the investigated nanoparticles had surprisingly negligible acute cytotoxicity in the evaluated models, a multi-faceted study of barrier-related phenotypes and cell condition revealed a complex pattern of homeostasis disruption. Interestingly, some features of the paracellular barrier phenotype (transendothelial electrical resistance, tight junction protein gene expression) were improved by exposure to nanoparticles in a potential hormetic mechanism. However, mitochondrial potential and antioxidant defences largely collapsed under these conditions, paralleled by a strong pro-apoptotic shift in a significant proportion of cells (evidenced by apoptotic protein gene expression, chromosomal DNA fragmentation, and membrane phosphatidylserine exposure). Taken together, our results suggest a reactive oxygen species-mediated cellular mechanism of blood–brain barrier damage by quantum dots, which may be toxicologically significant in the face of increasing human exposure to this type of nanoparticles, both intended (in medical applications) and more often unintended (from consumer goods-derived environmental pollution).

scholarly journals Effect of Core-Shell Ag@TiO2Volume Ratio on Characteristics of TiO2-Based DSSCs

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ho Chang ◽  
Chih-Hao Chen ◽  
Mu-Jung Kao ◽  
Hsin-Han Hsiao
Keyword(s):  
Conversion Efficiency ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Open Circuit ◽  
Photoelectric Conversion Efficiency ◽  
Core Shell ◽  
Photoelectric Conversion ◽  
Shell Type ◽  
Degussa P25 ◽  
Triton X

This paper aims to develop photoanode material required by dye-sensitized solar cells. The material prepared is in the form of Ag@TiO2core-shell-type nanocomposites. This material is used to replace the titanium oxide powder commonly used in general DSSCs. The prepared Ag@TiO2core-shell-type nanocomposites are mixed with Degussa P25 TiO2in different proportions. Triton X-100 is added and polyethylene glycol (PEG) at 20 wt% is used as a polymer additive. This study tests the particle size and material properties of Ag@TiO2core-shell-type nanocomposites and measures the photoelectric conversion efficiency and IPCE of DSSCs. Experimental results show that the DSSC prepared by Ag@TiO2core-shell-type nanocomposites can achieve a photoelectric conversion efficiency of 3.67%. When Ag@TiO2core-shell-type nanocomposites are mixed with P25 nanoparticles in specific proportions, and when the thickness of the photoelectrode thin film is 28 μm, the photoelectric conversion efficiency can reach 6.06%, with a fill factor of 0.52, open-circuit voltage of 0.64V, and short-circuit density of 18.22 mAcm−2. Compared to the DSSC prepared by P25 TiO2only, the photoelectric conversion efficiency can be raised by 38% under the proposed approach.

Effect of Metal Gradient In Nano Wall of Stratified Type Photocatalyst

2009 ◽  
Vol 631-632 ◽  
pp. 339-344
Author(s):  
Tsugumi Hayashi ◽  
Yohei Baba ◽  
Toshiharu Taga ◽  
Shun Yokoyama ◽  
Hiroaki Suzuki ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Detailed Analysis ◽  
Crystalline Structure ◽  
Visible Light Irradiation ◽  
High Photocatalytic Activity ◽  
Core Shell ◽  
Shell Type ◽  
Metal Element ◽  
Egg Shell

Objective of study was the development of core-shell type ZnS-CdS photocatalyst with the stratified morphology. To form the stratified morphology, condition of the precursor is extremely important. For this purpose, three types of precursors, thus core-shell type, egg-shell type and uniform type, was tried to synthesize by utilizing the results of the calculation. The size of the synthesized precursor particles was about 40-100 nm. Main phase of the particle was gradually changed from ZnO (pH8.0) to Cd(OH)2 (pH9.5). Detailed analysis of the synthesized precursor was clearly demonstrated that these have the crystalline structure and each metal element was co-existed in one particle. Therefore, it could be concluded that core-shell type or uniform type precursor was successfully synthesized. Core-shell type ZnS-CdS stratified photocatalyst could be successfully synthesized by sulfurization for 1h, and it shows the high photocatalytic activity under visible light irradiation.

scholarly journals Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

2017 ◽  
Vol 62 (2) ◽  
pp. 1263-1266 ◽  
Author(s):  
M.-W. Lee ◽  
K.-H. Bae ◽  
S.-R. Lee ◽  
H.-J. Kim ◽  
T.-S. Jang
Keyword(s):  
Grain Boundary ◽  
Diffusion Path ◽  
Boundary Phase ◽  
Core Shell ◽  
Phase Layer ◽  
Sintered Magnets ◽  
The Core ◽  
Shell Type ◽  
Property Changes ◽  
And Diffusion

AbstractWe investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1stpost annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2Fe14B and grain boundary phases covering Nd2Fe14B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3phase.

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