Control of Morphology of YBO3:Eu by a Mild Hydrothermal Process

2005 ◽  
Vol 475-479 ◽  
pp. 1829-1832
Author(s):  
Ling He ◽  
Yu Hua Wang
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Single Phase ◽  
Hydrothermal Process ◽  
Spherical Shape ◽  
Solid State Reactions ◽  
Main Peak ◽  
Photoluminescence Intensity ◽  
Uniform Size ◽  
Excitation Peak

The phosphors YBO3:Eu with different morphology was successfully realized by mild hydrothermal process with different reaction condition. Highly spherical shape, uniform size and non-agglomeration of YBO3:Eu phosphors particle was obtained at 260°C,which is about 850°C lower than that by solid state reactions. The result of XRD showed that all samples were single phase with vaterite type structure. From IR and NMR spectra, it could be concluded that YBO3 contains mainly BO4 tetrahedra which is in favor for absorption VUV excitation. Monitoring by 598nm emission, the main excitation peak at about 247nm was observed in the excitation spectrum of spherical Y0.95Eu0.05BO3. Correspondingly, under 247nm excitation, the main peak at about 598nm was observed. The photoluminescence intensity (5D0→7F1 transition of Eu3+) of spherical shape of Y0.95Eu0.05BO3 was 1.5 times in comparison with which prepared by solid-state reactions. The best photoluminescence intensity was obtained when the concentration of Eu3+ is at 20 at. %. It indicated that hydrothermal method have a potential in the preparing various particles phosphors for application in displays and lamps.

scholarly journals Energy transfer in single phase Eu3+-doped Y2WO6 phosphors

RSC Advances ◽  
2017 ◽  
Vol 7 (25) ◽  
pp. 14974-14980 ◽  
Author(s):  
J. Llanos ◽  
D. Espinoza ◽  
R. Castillo
Keyword(s):  
Energy Transfer ◽  
High Temperature ◽  
Solid State ◽  
Single Phase ◽  
Solid State Reactions

Inorganic phosphors based on monoclinic Y2WO6 doped with Eu3+ ions were prepared via conventional solid-state reactions at high temperature.

Monodispersed Magnetic Fluids: Synthesis and Characterization

2009 ◽  
Vol 155 ◽  
pp. 155-162 ◽  
Author(s):  
Kinnari Parekh ◽  
R.V. Upadhyay ◽  
V.K. Aswal
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Single Phase ◽  
Magnetic Measurement ◽  
Spherical Shape ◽  
Uniform Size ◽  
Xrd Pattern ◽  
X Ray ◽  
Monodispersed Particles ◽  
Phase Spinel

Magnetite and Co ferrite particles were synthesized with control of particle size distribution via non-aqueous route. The XRD pattern shows the formation of single phase spinel structure with the particle size of 96 Å and 80 Å respectively for magnetite and cobalt ferrite. TEM image of the same shows the particles are nearly spherical with the size matches with that obtained from X-ray and the size distribution is less than 5%. Magnetic measurement also shows the particles of uniform size with high value of saturation magnetization at room temperature compared to that obtained by other route. SANS study confirms our results of monodispersed particles with spherical shape.

Synthesis and Luminescence Properties of Non-Doped Long Persistent Phosphors : Mg2SnO4

2009 ◽  
Vol 421-422 ◽  
pp. 352-355 ◽  
Author(s):  
Akiko Torisaka ◽  
Hiroaki Kaneko ◽  
Kentaro Nomizu ◽  
Sho Abe ◽  
Tadashi Ishigaki ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Spinel Structure ◽  
Single Phase ◽  
Broad Band ◽  
Photoluminescence Intensity ◽  
Inverse Spinel ◽  
Inverse Spinel Structure ◽  
Broad Band Emission ◽  
Band Emission

A white long persistence phosphor was synthesized in a single-phase of Mg2SnO4 which was synthesized by a solid-state reaction. This phosphor crystallized in an inverse spinel structure and showed a broad-band emission from 350nm to 700nm. The afterglow was observed upon the excitation by 254nm. A Li-doped Mg2SnO4 sample showed a higher photoluminescence intensity and a longer lifetime than the non-doped one.

Quaternary Chalcogenide Nanocrystals: Synthesis of Cu2ZnSnSe4 by Solid State Reaction and their Thermoelectric Properties

2013 ◽  
Vol 1543 ◽  
pp. 137-142 ◽  
Author(s):  
Umme Farva ◽  
Chan Park
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Single Phase ◽  
Cost Effective ◽  
Solid State Reaction Method ◽  
Milling Process ◽  
Alloying Effect ◽  
Sem Images ◽  
Uniform Size

ABSTRACTIn this paper, synthesis of Cu2ZnSnSe4 (CZTSe) materials by using simple and cost-effective solid state reaction method from the elemental Cu, ZnO, SnO and elemental Se powders are carried out. The SEM images show spherical, non-uniform size with aggregation of nanopowders. The phase separation and thermal analysis of the milled powders suggested that most of the starting powders reacted because of a mechanical alloying effect during milling process. After the solid state reaction at above 500 °C, the nanopowders crystallized into stannite single phase, which are confirm by XRD spectra. The thermoelectric properties of synthesized powder are under study.

Reactivity of Carbonates in Superheated Steam under Atmospheric Pressure

2014 ◽  
Vol 617 ◽  
pp. 225-228 ◽  
Author(s):  
Kohei Asano ◽  
Yuki Yamaguchi ◽  
Kenjiro Fujimoto ◽  
Shigeru Ito
Keyword(s):  
Solid State ◽  
Superheated Steam ◽  
Single Phase ◽  
Intermediate Phase ◽  
Pure Water ◽  
Decomposition Temperature ◽  
Solid State Reactions ◽  
Temperature Transformation ◽  
Higher Temperature ◽  
Hedvall Effect

The effect of superheated steam on the decomposition of CaCO3 and MnCO3 and on the solid state reactions of ZnCO3-FeOOH and MnCO3-CaCO3 was investigated. A newly developed apparatus for the experiments under 1 atm of pure water vapor was used. CaCO3 decomposed at 800 oC in the superheated steam to form the single phase of CaO. On the other hand, the decomposition was uncompleted in air. CaCO3 transformed into CaO via Ca (OH)2 in superheated steam. During the transformation of carbonate into hydroxide, the crystal lattice is temporarily disordered to make it active, leading lower decomposition temperature of CaCO3. MnCO3 decomposed to form γ-Mn2O3 at above 1000 oC in air, whereas γ-Mn2O3 was obtained at 800 oC in the superheated steam. The solid state reaction in the steam was suppressed for the mixture of ZnCO3 and FeOOH. This seemed to be due to the large difference in decomposition temperature between ZnCO3 and FeOOH. MnCO3 reacted with CaCO3 to form CaMn2O4 at 800 oC in the superheated steam. However, a higher temperature of 1000 oC was required to cause the reaction in air. The low-temperature transformation of MnCO3 and CaCO3 in the superheated steam would affect the reaction. It was concluded that the reactivity of carbonate in super heated steam was promoted by the Hedvall effect, which was caused by the formation of intermediate phase such as hydroxide.

Energy transfer and color tuning in the Ba9Sc2Si6O24:Ce3+,Eu2+,Mn2+ phosphor

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69458-69465 ◽  
Author(s):  
Liu Bian ◽  
Chun-Wei Liu ◽  
Jun Gao ◽  
Xi-Ping Jing
Keyword(s):  
Energy Transfer ◽  
High Temperature ◽  
Solid State ◽  
Single Phase ◽  
Solid State Reactions ◽  
Color Tuning

A series of single phase Ba9−x−ySc2−zSi6O24:xCe,yEu,zMn phosphors was synthesized by high-temperature solid-state reactions.

Synthesis of A1–xA'xNbO3 (A=Na+, K+; A'= La3+, Sr2+) and its Electrical Properties

1996 ◽  
Vol 453 ◽  
Author(s):  
W. Sugimoto ◽  
T. Tahara ◽  
Y. Sugahara ◽  
K. Kuroda
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Low Temperature ◽  
Single Phase ◽  
Solid State Reactions ◽  
Cubic Symmetry ◽  
Resistivity Measurements ◽  
Semiconducting Properties ◽  
Metallic Conduction ◽  
The Relationship

AbstractPolycrystalline samples of A1–xA'xNbO3 (A=Na+, K+; A'= La3+, Sr2+) were prepared by solid-state reactions and the relationship between the structure and electrical properties was examined. Single-phase products were obtained for Na1–xLaxNbO3 (x ≤0.1), K1–xLaxNbO3 (x ≤0.15), Na1–xSrxNbO3 (x ≤0.3), and K1–xSrxNbO3 (x ≤0.5). The structures of the sodium-containing compounds and potassium-containing compounds were indexed according to a pseudocubic and cubic symmetry, respectively. The resistivity measurements showed semiconductive behavior for the lanthanum-containing samples. The strontium-containing samples showed semiconducting properties for x ≤0.2, while a transition to metallic conduction at low temperature was observed for x >0.2.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

The wustite-spinel interface

1987 ◽  
Vol 45 ◽  
pp. 268-269
Author(s):  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Strain Energy ◽  
Matrix Material ◽  
Lattice Misfit ◽  
Solid State Reactions ◽  
Oxygen Sublattice ◽  
Large Particles ◽  
Small Lattice ◽  
Coherent Interfaces

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.

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