Blue Upconversion Luminescence Properties of La2(WO4)3:Yb3+/Tm3+Phosphor

2011 ◽  
Vol 399-401 ◽  
pp. 1020-1025
Author(s):  
Jin Sheng Liao ◽  
Hang Ying You ◽  
Qing Xia Wu ◽  
He Rui Wen ◽  
Jing Lin Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Hydrothermal Process ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pumping ◽  
Upconversion Mechanism ◽  
Upconversion Emissions ◽  
Scanning Electron

Monoclinic La2(WO4)3 nanophosphors codoped with Tm3+ and Yb3+ ions were synthesized via hydrothermal process followed by heat treatment. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize as-prepared samples. The dependences of Yb3+/ concentration and laser pumping power on the upconversion emissions were extensively investigated. The results show that upconversion luminescence increases with the Yb3+/ concentration and gets its peak at 30 %. The upconversion mechanism and process in the Yb3+/Tm3+ codoped La2(WO4)3 phosphors were analysed.

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

Synthesis and upconversion luminescence properties of CaF2:Yb3+,Er3+ nanoparticles obtained from SBA-15 template

2010 ◽  
Vol 25 (10) ◽  
pp. 2035-2041 ◽  
Author(s):  
Zhiguo Xia ◽  
Peng Du
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Average Diameter ◽  
Cubic Phase ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Transmission Electron

CaF2:Yb3+,Er3+ upconversion (UC) luminescence nanoparticles have been synthesized using mesoporous silica (SBA-15) as a hard template. The samples were characterized by x-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, transmission electron microscopy, and UC emission spectra, respectively. Highly crystalline cubic phase CaF2:Yb3+,Er3+ nanoparticles are uniformly distributed with an average diameter of about 40–50 nm, and the formation process is also demonstrated. The UC fluorescence has been realized in the as-prepared CaF2:Yb3+,Er3+ nanoparticles on 980-nm excitation. The UC emission transitions for 4F9/2–4I15/2 (red), 2H11/2–4I15/2 (green), 4S3/2–4I15/2 (green), and 2H9/2–4I15/2 (violet) in the Yb3+/Er3+ codoped CaF2 nanoparticles depending on pumping power and temperature have been discussed. The UC mechanism, especially the origin on the temperature-dependent UC emission intensities ratio between 2H11/2 and 4S3/2 levels, have been proposed.

Hydrothermal Synthesis and Electrocatalytic Property for H2O2 Reduction of Co3O4 Nanocubes

2011 ◽  
Vol 311-313 ◽  
pp. 477-480
Author(s):  
Zhi Ai Yang ◽  
Li Jin Feng ◽  
Xia Wang ◽  
Rong Ma ◽  
Jian Ping Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Linear Sweep Voltammetry ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Linear Sweep ◽  
Electrocatalytic Property ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Subscript textThe Co3O4 nanocubes were synthesized by hydrothermal process. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that the products are uniform nanocubes with an average crystallite size about 20-40 nm. Electrocatalytic property of the prepared Co3O4 nanocubes was characterized by linear sweep voltammetry. LSV results indicate that Co3O4 nanocubes exhibit a remarkable electrocatalytic activity for the H2O2 reduction.

scholarly journals Synthesis and Catalase Mimic Activity of MnO2 Nano Powder Prepared by Hydrothermal Process

2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Annealing Temperature ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Atomic Force ◽  
Different Temperatures ◽  
Scanning Electron

Manganese dioxide (MnO2) nanopowder has been synthesized by hydrothermal method. MnO2 was annealed at different temperatures (250, 400, 550, 700˚C). The crystal structure and surface morphology of these nanostructures were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscopy (SEM). The catalase mimic activity (catalytic activity) of MnO2 against hydrogen peroxide (H2O2) was studied by using the new method and found that 400˚C is the best annealing temperature.

The Upconversion Luminescence Properties of Er3+/Tm3+, Yb3+-Codoped Cubic BaLiF3

2016 ◽  
Vol 16 (4) ◽  
pp. 3715-3719 ◽  
Author(s):  
Qinping Qiang ◽  
Linna Guo ◽  
Lili Han ◽  
Yuhua Wang
Keyword(s):  
Energy Levels ◽  
Upconversion Luminescence ◽  
Luminescence Properties ◽  
Excitation Wavelength ◽  
Power Dependence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Upconversion Emissions ◽  
Surfactant Assisted ◽  
Scanning Electron

Cubic BaLiF3 samples were prepared using a facile surfactant-assisted hydrothermal-microemulsion method. The samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The upconversion luminescence (UCL) properties of the Er3+/Tm3+, Yb3+-codoped BaLiF3 samples were measured under a 980 nm excitation wavelength. Moreover, the effects of varying the concentration of Li+ ions on the luminescence properties of Er3+, Yb3+ codoped BaLiF3 were also investigated. The Tm3+, Yb3+ codoped BaLiF3 samples displayed multicolor emissions. This behavior can be explained by the pump power dependence of the upconversion emissions and the energy levels diagram.

Hydrothermal Synthesis of 3D Flower-Like Bismuth Trisulphide Microcrystallines

2013 ◽  
Vol 634-638 ◽  
pp. 2207-2210 ◽  
Author(s):  
Pin Jiang Li ◽  
Yan Ge Zhang ◽  
Bao Jun Huang ◽  
Chen Yu ◽  
Ling Zhuge ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray ◽  
Laser Raman ◽  
One Step ◽  
Scanning Electron

3D flower-like bismuth trisulphide microcrystallines has been successfully prepared via one step hydrothermal process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser Raman spectrometer techniques. The morphologies of the Bi2S3 microcrystallines were influenced by the surfactant Na2(EDTA), which acts as a structure directing agent.

Polymorphological LaVO 4:Dy 3+ Phosphors: Hydrothermal Synthesis and Luminescent Properties

2011 ◽  
Vol 239-242 ◽  
pp. 1735-1738
Author(s):  
Guo Cong Liu ◽  
Ke Long Huang
Keyword(s):  
Electron Microscopy ◽  
Morphological Evolution ◽  
Hydrothermal Process ◽  
Luminescent Properties ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Rod Bundles ◽  
X Ray ◽  
Rod Bundle ◽  
Scanning Electron

Tetragonal LaVO4:Dy3+ crystals with novel shapes of rod, rod-bundles and needle-like flower were successfully synthesized via a facile and surfactant-free hydrothermal process. The products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL).The experimental results showed that the concentration of the precursor and the reaction temperature played important roles in morphological evolution of LaVO4:Dy3+ crystals (NCs). It was found that needle-like flower LaVO4:Dy3+ exhibited the highest B/Y value compared with rod and rod-bundle samples. Possible growth mechanisms of polymorphological LaVO4:Dy3+ crystals were briefly discussed.

The Facile Hydrothermal Preparation of WO3 and its Photocatalytic Performance under Visible-Light Irradiation

2014 ◽  
Vol 936 ◽  
pp. 347-351 ◽  
Author(s):  
Fen Fen Li ◽  
Hong Tao Gao ◽  
Guang Jun Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Hydrothermal Preparation ◽  
X Ray ◽  
Scanning Electron

The orthorhombic WO3 nanoplates were fabricated via a hydrothermal process, using HBF4 as the acid source. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis diffused reflectance spectroscopy (UV-Vis DRS), respectively. The WO3 nanoplates exhibited nice UV-light driven photocatalytic performance in the degradation of Rhodamine B (RhB).

scholarly journals Influence of Synthesis Method on LTA Time-Dependent Stability

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2122 ◽  
Author(s):  
Claudia Belviso ◽  
Antonio Lettino ◽  
Francesco Cavalcante
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Synthesis Method ◽  
Synthetic Zeolite ◽  
Time Dependent ◽  
Time Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lta Zeolite ◽  
Scanning Electron

Time-stability of LTA zeolite formed by hydrothermal method with or without the action of ultrasonic irradiation was investigated by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results show that 6 months after the synthesis by hydrothermal process with continuous sonication, LTA evolves into a more stable sodalite, whereas no differences are detected 12 months after LTA synthesis by conventional pre-fused hydrothermal process. These data confirm that using the two approaches, different mechanisms control both zeolite crystallization and time-stability of the newly-formed mineral at solid state. The results are particularly important in the light of the synthetic zeolite application.

scholarly journals Use of chitin as a template for the preparation of mesostructured ZSM-5

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 214-218 ◽  
Author(s):  
F. C. Drumm ◽  
J. S. de Oliveira ◽  
M. S. P. Enders ◽  
E. I. Müller ◽  
E. A. Urquieta-González ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Process ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Scanning Electron

Abstract In this work, mesostructured ZSM-5 zeolite was prepared using chitin as a new template to produce mesoporosity. Different amounts of chitin were used for the synthesis of ZSM-5 in order to verify its influence on the formation of mesopores. All samples were prepared by conventional hydrothermal process. For comparison purposes, ZSM-5 zeolite has also been synthesized without a presence of chitin. The samples were characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption techniques. Experimental results showed that the mesopores volume of the obtained samples increased with increasing amount of chitin in the reaction mixture. Therefore, chitin showed to be a promising template for obtaining the ZSM-5 with mesoporous property.

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