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

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.

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY

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.


2012 ◽  
Vol 535-537 ◽  
pp. 280-283 ◽  
Author(s):  
Hao Ran An ◽  
Feng Shi Cai ◽  
Xue Wei Wang ◽  
Zhi Hao Yuan

Different morphology CuO nanostructures, including platelets, flower-like were simply synthesized at 350 °C controlled by droplet on hydrophobic substrate. This is a simple method which does not require any template, catalyst, or surfactant but can control the morphology of CuO from platelets to flowerlike. The morphologies are strongly dependent on the volume of droplet. Scanning electron microscopy (SEM), Optical microscope and X-ray diffraction (XRD) were used to observe the morphology, crystallinity, and chemical composition of the CuO structures. Growth mechanisms for shape selective CuO synthesis were proposed based on these results.


2011 ◽  
Vol 399-401 ◽  
pp. 1020-1025
Author(s):  
Jin Sheng Liao ◽  
Hang Ying You ◽  
Qing Xia Wu ◽  
He Rui Wen ◽  
Jing Lin Chen ◽  
...  

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.


2016 ◽  
Vol 697 ◽  
pp. 318-321
Author(s):  
Cui Ping Zhong ◽  
Jie Jun Zhang ◽  
Shu Wang Duo

Na (Y1.5Na0.5)F6 microparticks were prepared by hydrothermal method. EDTA as the chelating agent. The samples were characterized by X-ray diffraction, scanning electron microscopy and fluorescence spectrometer. The X-ray diffraction indicates that the crystal shows a hexagon phase structure. Under the excitation of 980nm laser, the Na (Y1.5Na0.5)F6 exhibited strong up-conversion light: 4F9/2→4I15/2(red), 4H11/2/4S3/2→4I15/2(green) and 4G11/2→2H9/2 (near-ultraviolet).


2011 ◽  
Vol 311-313 ◽  
pp. 477-480
Author(s):  
Zhi Ai Yang ◽  
Li Jin Feng ◽  
Xia Wang ◽  
Rong Ma ◽  
Jian Ping Sun ◽  
...  

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.


2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jing Hu ◽  
Qianming Wang

In order to control reaction temperature and reduce processing time, a new method of ultrasound irradiation with microwave heating was used to synthesize (Ln = La, Gd; ) phosphors at only 80°C in 30 minutes. Their crystal structures and morphologies which have been verified by X-ray diffraction (XRD) and scanning electron microscopy (SEM) exhibited gradual changes due to the insertion of lanthanide ions (La or Gd) in calcium molybdates. Codoping of lanthanum ions () would enhance the emission intensities that were supported by fluorescent spectrophotometry (FL).


2014 ◽  
Vol 989-994 ◽  
pp. 383-386
Author(s):  
Li Min Dong ◽  
Fei Lv ◽  
Qin Li ◽  
Zhi Dong Han ◽  
Xian You Zhang

A series of Eu3+, Dy3+ actived Ca1-xBaxSnO3 phosphors were synthesized by coprecipitation method. The structure, morphology and fluorescence property of phosphors were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy. SEM results showed that the as-prepared phosphors are smooth and uniform with the cubic morphology. The incorporation of a small amount of Ba to CaBaSnO3 improved the emission characteristics. Fluorescence spectrum showed the emission intensity is the best with the incorporation of Ba2+ (x = 0.3), when calcination temperature is 900°C.


2013 ◽  
Vol 634-638 ◽  
pp. 2207-2210 ◽  
Author(s):  
Pin Jiang Li ◽  
Yan Ge Zhang ◽  
Bao Jun Huang ◽  
Chen Yu ◽  
Ling Zhuge ◽  
...  

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.


2014 ◽  
Vol 936 ◽  
pp. 347-351 ◽  
Author(s):  
Fen Fen Li ◽  
Hong Tao Gao ◽  
Guang Jun Liu

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).


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