scholarly journals Enhancement of Luminescence Efficiency of Y2O3 Nanophosphor via Core/Shell Structure

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1563
Author(s):  
Jae-Young Hyun ◽  
Ki-Hyun Kim ◽  
Jae-Pil Kim ◽  
Won-Bin Im ◽  
Kadathala Linganna ◽  
...  
Keyword(s):  
Annealing Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Core Shell ◽  
Molten Salt Method ◽  
Shell Nanoparticles ◽  
Morphological Studies ◽  
Luminescence Efficiency ◽  
Higher Temperature ◽  
Core Shell Nanoparticles

We successfully fabricated Y2O3:RE3+ (RE = Eu, Tb, and Dy) core and core–shell nanophosphors by the molten salt method and sol–gel processes with Y2O3 core size of the order of 100~150 nm. The structural and morphological studies of the RE3+-doped Y2O3 nanophosphors are analyzed by using XRD, SEM and TEM techniques, respectively. The concentration and annealing temperature dependent structural and luminescence characteristics were studied for Y2O3:RE3+ core and core–shell nanophosphors. It is observed that the XRD peaks became narrower as annealing temperature increased in the core–shell nanophosphor. This indicates that annealing at higher temperature improves the crystallinity which in turn enhances the average crystallite size. The emission intensity and quantum yield of the Eu3+-doped Y2O3 core and core–shell nanoparticles increased significantly when annealing temperature is varied from 450 to 550 °C. No considerable variation was noticed in the case of Y2O3:Tb3+ and Y2O3:Dy3+ core and core–shell nanophosphors.

Core–shell La 1− x Sr x MnO 3 nanoparticles as colloidal mediators for magnetic fluid hyperthermia

2010 ◽  
Vol 368 (1927) ◽  
pp. 4389-4405 ◽  
Author(s):  
E. Pollert ◽  
O. Kaman ◽  
P. Veverka ◽  
M. Veverka ◽  
M. Maryško ◽  
...  
Keyword(s):  
Sol Gel ◽  
Size Fraction ◽  
Core Shell ◽  
Magnetic Studies ◽  
Shell Nanoparticles ◽  
Water Suspension ◽  
Heating Efficiency ◽  
Morphological Studies ◽  
Biological Studies ◽  
Core Shell Nanoparticles

Core–shell nanoparticles consisting of La 0.75 Sr 0.25 MnO 3 cores covered by silica were synthesized by a procedure consisting of several steps, including the sol–gel method in the presence of citric acid and ethylene glycol, thermal and mechanical treatment, encapsulation employing tetraethoxysilane and final separation by centrifugation in order to get the required size fraction. Morphological studies revealed well-separated particles that form a stable water suspension. Magnetic studies include magnetization measurements and investigation of the ferromagnetic–superparamagnetic–paramagnetic transition. Magnetic heating experiments in ‘calorimetric mode’ were used to determine the heating efficiency of the particles in water suspension and further employed for biological studies of extracellular and intracellular effects analysed by tests of viability.

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.

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.

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

scholarly journals Fabrication of Magnetite/Silica/Titania Core-Shell Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suh Cem Pang ◽  
Sze Yun Kho ◽  
Suk Fun Chin
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Sol Gel ◽  
Core Shell ◽  
Silica Nanospheres ◽  
Shell Nanoparticles ◽  
Gel Method ◽  
Uv Light Irradiation ◽  
Silica Nanosphere ◽  
Core Shell Nanoparticles

Fe3O4/SiO2/TiO2core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4nanoparticles were being encapsulated within discrete silica nanospheres, and a layer of TiO2shell was then coated directly onto each silica nanosphere. As-synthesized Fe3O4/SiO2/TiO2core-shell nanoparticles showed enhanced photocatalytic properties as evidenced by the enhanced photodegradation of methylene blue under UV light irradiation.

scholarly journals Silver@mesoporous Anatase TiO2 Core-Shell Nanoparticles and Their Application in Photocatalysis and SERS Sensing

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Yuanzhi Min ◽  
Gao Song ◽  
Ling Zhou ◽  
Xinyue Wang ◽  
Pingying Liu ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Hydrothermal Reaction ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Dye Pollutants ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Core Shell Nanoparticles ◽  
Sers Sensing

Nanostructured noble metal-semiconductor materials have been attracting increasing attention because of their broad application in the field of environmental remediation, sensing and photocatalysis. In this study, a facile approach for fabricating silver@mesoporousanataseTiO2 (Ag@mTiO2) core-shell nanoparticles employing sol-gel and hydrothermal reaction is demonstrated. The Ag@mTiO2nanoparticles display excellent surface-enhanced Raman scattering (SERS) sensitivity and they can detect the methylene blue (MB) molecules with the concentration of as low as 10−8 M. They also exhibit outstanding photocatalytic activity compared with mTiO2, due to the efficient separation and recombination restrain of electron–hole pairs under ultraviolet light. The Ag@mTiO2nanoparticles also present good stability and they can achieve recyclable photocatalytic degradation experiments for five times without loss of activity. Subsequently, the nanoparticles with dual functions were successfully used to in situ monitor the photodegradation process of MB aqueous solution. These results, demonstrating the multifunctional Ag@mTiO2 nanoparticles, hold promising applications for simultaneous SERS analysis and the removal of dye pollutants in environmental field.

scholarly journals Synthesis and Photocatalytic Activity of Magnetically Recoverable Core-Shell Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhen Peng ◽  
Hua Tang ◽  
Yao Tang ◽  
Ke Fu Yao ◽  
Hong Hong Shao
Keyword(s):  
Photocatalytic Activity ◽  
High Efficiency ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Core Shell ◽  
Oily Wastewater ◽  
Strong Response ◽  
Shell Nanoparticles ◽  
Oil Concentration ◽  
Core Shell Nanoparticles

TiO2/SiO2/Fe3O4(TSF) core-shell nanoparticles with good photocatalytic activity that are capable of fast magnetic separation have been successfully prepared by chemical coprecipitation and two-step sol-gel process. The as-prepared TSF nanoparticles were calcined at high temperature in order to transform the amorphous titanium dioxide into a photoactive crystalline phase. The calcined nanoparticles are composed of a Fe3O4core with a strong response to external magnetic fields, a SiO2intermediary layer, and a TiO2outshell. Vibration sample magnetometer (VSM) analysis confirms the superparamagnetism of calcined nanoparticles, which can enhance the recoverable properties of the novel photocatalyst. When the TiO2/SiO2/Fe3O4core-shell nanoparticles are added to the crude oily wastewater, they exhibit high photocatalytic activity in the degradation of crude oily wastewater. The oil concentration could be reduced to lower than 30 ppm within 20 minutes for the case of initial oil concentration less than 350 ppm. It has been found that the TSF nanoparticles could be easily separated from the wastewater and withdrawn by using an external magnetic field. The recovered TSF nanoparticles possess high efficiency in the degradation of crude oily wastewater even after three times successive reuse. The present results indicate that TSF core-shell nanoparticles possess great application perspectives in the degradation of crude oily wastewater.

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