Structure and Luminescence of Europium-Doped Gadolinia-Based Core/Multi-Shell Scintillation Nanoparticles

2009 ◽  
Vol 1164 ◽  
Author(s):  
Teng-Kuan Tseng ◽  
Jihun Choi ◽  
Paul H. Holloway
Keyword(s):  
Charge Transfer Band ◽  
Sol Gel ◽  
Core Shell ◽  
Photoluminescence Excitation ◽  
Shell Nanoparticles ◽  
Direct Excitation ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Pl Emission ◽  
Core Shell Nanoparticles

AbstractScintillating nanoparticles with a SiO2 core and a Gd2O3 shell doped with Eu3+ were synthesized with a sol-gel process. Based on transmission electron microscopy (TEM) data, a ∼13 nm Gd2O3 shell was successfully coated onto ∼220 nm mono-dispersed SiO2 nanocores. Eu3+ ions at concentrations of nominally 5 at% exhibited photoluminescent (PL) emission from the SiO2/Gd2O3 nanoparticles after being calcined at 800 0C for 2 h. The SiO2 remained amorphous after calcining, while the Gd2O3 crystallized to a cubic structure. The PL emission was from the 5D0-7F2 transitions of Eu3+ at 609 and 622 nm. Photoluminescence excitation (PLE) data showed that emission from Eu3+ could result from direct excitation, but was dominated by the oxygen to europium charge-transfer band (CTB) between 250 and 280 nm for Eu3+ doped in Gd2O3. The quantum yield (QY) from thin films drop cast from a mixture of 20 mg of calcined nanoparticles in 500 μL of polymethylmethacrylate (PMMA) and excited in the CTB was 20% for SiO2/Gd2O3:Eu3+ core/shell scintillation nanoparticles. Finally, the above core/shell nanoparticles were passivated with a shell of SiO2 to create e.g. SiO2/Gd2O3:Eu3+/SiO2 nanoparticles. The QYs for this nanostructure were lower than unpassivated nanoparticles which was attributed to a weak CTB for the amorphous SiO2 shell and a higher density of interface quenching sites.

Fe3O4@SiO2 core–shell nanoparticles for biomedical purposes: adverse effects on blood cells

2016 ◽  
Vol 4 (10) ◽  
pp. 1417-1421 ◽  
Author(s):  
C. Achilli ◽  
S. Grandi ◽  
G. F. Guidetti ◽  
A. Ciana ◽  
C. Tomasi ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Magnetite Nanoparticles ◽  
Reverse Micelle ◽  
Blood Cells ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Sol Gel Process ◽  
Core Shell Nanoparticles

Magnetite nanoparticles coated with silica, obtained by a sol–gel process in the reverse micelle microemulsion, were characterized and homogeneously suspended in water in order to assay their biocompatibility toward blood cells, in view of a potential medical use of this material.

Biocompatible luminescent nanoparticles on the basis of calcium phosphate

2011 ◽  
Vol 1355 ◽  
Author(s):  
Sofia Dembski ◽  
Moritz Milde ◽  
Emeline Dassonneville ◽  
Carsten Gellermann ◽  
Torsten Klockenbring ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Sol Gel ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Core Shell Nanoparticles

ABSTRACTLuminescent lanthanide doped SiO2/Hydroxylapatite (HAp) core/shell nanoparticles (NPs) were synthesized by sol-gel technology. The resulting NPs exhibited an amorphous SiO2 core and a crystalline luminescent shell. The formation of the HAp layer was possible at pH 8.5. The characterization of the resulting NPs was done by transmission electron microscopy, X-ray diffraction analysis, inductively-coupled plasma combined with optical emission spectrometry, and photoluminescence spectroscopy. Additionally, the newly developed SiO2/HAp:Ln3+ core/shell NPs were tested for their biocompatibility, e. g. by an in vitro cell culture based assay.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals PREPARATION OF CORE-SHELL SILVER/SILICA NANOPATICLES AND THEIR APPLICATION FOR ENHANCEMENT OF CYANINE 3 FLUORESCENCE

2012 ◽  
Vol 11 (04) ◽  
pp. 1240020 ◽  
Author(s):  
N. SUI ◽  
V. MONNIER ◽  
Z. YANG ◽  
Y. CHEVOLOT ◽  
E. LAURENCEAU ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Steady State Fluorescence ◽  
Covalently Bonded ◽  
Core Shell Nanoparticles ◽  
Steady State Fluorescence Spectroscopy ◽  
Silver Core

Core shell Ag@SiO2 -Streptavidin- Cy3 nanoparticles were prepared. Ag@SiO2 nanoparticles were synthesized via a sol–gel method. Then, Streptavidin- Cy3 was covalently bonded to the Ag@SiO2 surface. These core-shell nanoparticles were characterized by steady-state fluorescence spectroscopy and fluorescence scanning. In presence of the silver core, a 2.5-time enhancement of Cy3 fluorescence intensity was obtained. This result shows that these nanoparticles can be potentially helpful in surface analysis based on biochip.

The Preparation and Characteristic of Superparamagnetic Core/Shell Nanoparticles

2013 ◽  
Vol 274 ◽  
pp. 432-435
Author(s):  
Hong Xia Shen ◽  
Zheng Zhi Yin ◽  
Qiong Cheng
Keyword(s):  
Biomedical Applications ◽  
Superparamagnetic Nanoparticles ◽  
Bioactive Molecules ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Vibration Sample Magnetometer ◽  
Diffraction Patterns ◽  
Core Shell Nanoparticles

Superparamagnetic core/shell nanoparticles have been prepared successfully by the reduction of Au3+ onto the surface of superparamagnetic nanoparticles. The core/shell nanoparticles were characterized by Transmission electron microscopy (TEM), X-ray powder diffraction patterns (XRD), UV–vis spectrophotometer, Vibration Sample Magnetometer(VSM) and micro-confocal Raman system. The results revealed that the prepared core/shell nanoparticles were covered by Au shell. These superparamagnetic nanoparticles can be highly sensitively detected and afford new opportunities for biomedical applications through chemical bonding of bioactive molecules with the Au shell of nanoparticles.

Synthesis and Magnetic Properties of FePt Nanoparticles with Hard Nonmagnetic Shells

2007 ◽  
Vol 7 (1) ◽  
pp. 350-355 ◽  
Author(s):  
Shishou Kang ◽  
Shifan Shi ◽  
G. X. Miao ◽  
Zhiyong Jia ◽  
David E. Nikles ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystallographic Orientation ◽  
Sol Gel ◽  
Molar Ratio ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Spherical Core ◽  
Size And Morphology ◽  
Core Shell Nanoparticles

Chemically synthesized FePt nanoparticles were coated with nonmagnetic SiO2 and MnO shells by sol–gel and polyol processes. TEM images show that the FePt/SiO2 nanoparticles exhibit a thick spherical shell. The size and morphology of the MnO shell can be controlled by changing the reaction temperature, the molar ratio of surfactants/Mn(acac)2, and/or the concentration of precursor. The morphology of the MnO shell can be either spherical-like or cubic-like, depending on whether the molar ratio of surfactants/Mn(acac)2 is less than or larger than 2. From XRD measurements, the spherical core/shell nanoparticles exhibit 3D random crystallographic orientation, while the cubic core/shell nanoparticles prefer (200) texture. The magnetic moment of FePt particles can be enhanced by coating with SiO2 and MnO shells. Furthermore, the agglomeration of FePt particles upon the thermal annealing can be significantly inhibited with SiO2 and MnO shells.

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

Preparation of ZnO@void@SiO2 Rattle Type Core–Shell Nanoparticles via Layer-by-Layer Method

NANO ◽  
2016 ◽  
Vol 11 (09) ◽  
pp. 1650103 ◽  
Author(s):  
Xiaoman Wang ◽  
Junda Song ◽  
Hongling Chen
Keyword(s):  
Sol Gel ◽  
Carbon Layer ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
Hexagonal Wurtzite Crystal Structure ◽  
Transmission Electron ◽  
Measurement Results ◽  
Average Size ◽  
Core Shell Nanoparticles

In this paper, we prepared the rattle type nanoparticles ZnO@void@SiO2 by two successive coating processes, followed by heat treatment. The carbon layer was formed over ZnO surface with the aid of the hydrothermal treatment of glucose. Then the resulting composite was used to fabricate a silica shell on the surface by sol–gel method. Finally, ZnO particles were released but still trapped inside the silica hollow after calcination, that is, ZnO@void@SiO2. The composites were characterized by scanning and transmission electron microscope, N2 adsorption experiment, X-ray diffraction, Fourier transform infrared spectroscopy and UV-Vis absorption spectra. The rattle type structure was conformed and the sphere-like structure with the average size of 70 nm and hexagonal wurtzite crystal structure were also observed. The measurement results of optical properties showed even though ZnO@C@SiO2 presented no photocatalysis, ZnO@void@SiO2 showed high activity even the ZnO core was encapsulated with the SiO2 hollow.

Preparation and characterization of sol–gel derived Er3+–Yb3+ codoped SiO2/TiO2 core–shell nanoparticles

2010 ◽  
Vol 64 (7) ◽  
pp. 846-848 ◽  
Author(s):  
Shujie Pang ◽  
Xianliang Li ◽  
Zuosen Shi ◽  
Guang Yang ◽  
Zhanchen Cui
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles
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