Facile Synthesis of CaCo3 and CaCo3:Eu3+ Phosphors by Solid State Reaction at Room Temperature and the Luminescence Properties

2014 ◽  
Vol 809-810 ◽  
pp. 711-718
Author(s):  
Hua Yue Wang ◽  
Fu Zhong Gong ◽  
Li Ya Zhou ◽  
Lu Sun

The CaCO3 and CaCO3:Eu3+ phosphors have been synthesized by solid state reaction at room temperature without further sintering treatment. The morphology, crystalline structure, and fluorescent properties of the samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), spectrofluorometer, respectively. Also, the influences of Eu3+-doping concentration on the photoluminescence (PL) properties were investigated in detail. The results indicate that the morphology of as-prepared CaCO3 particles are irregular cubic in shape and about 200-400nm in size, while the CaCO3:Eu3+ particles are the aggregates of many small nanoparticles with nearly 30nm in size, indicating that Eu3+ ions have a great influence on the CaCO3 particle morphology and size. The lines around 392nm in luminescence excitation spectrum is the most noticeable. Upon excitation at 392nm, the PL emission spectrum is composed of two band and strong peaks at 589nm and at 613nm. The peaks at 589nm is attributed to magnetic dipole transition 5D0–7F1 and with the increase of the Eu3+-doped concentration, the intensity decreases gradually; but it shows the opposite trend for the peak at 613nm which is attributed to the hyper sensitively forced electric dipole transition5D0–7F2.

2014 ◽  
Vol 215 ◽  
pp. 144-149 ◽  
Author(s):  
Sergey M. Zharkov ◽  
Roman R. Altunin ◽  
Evgeny T. Moiseenko ◽  
Galina M. Zeer ◽  
Sergey N. Varnakov ◽  
...  

Solid-state reaction processes in Fe/Si multilayer nanofilms have been studied in situ by the methods of transmission electron microscopy and electron diffraction in the process of heating from room temperature up to 900ºС at a heating rate of 8-10ºС/min. The solid-state reaction between the nanolayers of iron and silicon has been established to begin at 350-450ºС increasing with the thickness of the iron layer.


2010 ◽  
Vol 33 ◽  
pp. 313-316
Author(s):  
Xiao Jun Wang ◽  
Xiao Chun Zhou

Mg2SnO4 was adopted as the host material of a new red emitting phosphor. Lumin-escence properties of the europium-doped magnesium tin oxide prepared by the low temperature solid state reaction were investigated under 395nm excitation. Under 395 nm excitation, the Mg2SnO4: Eu phosphor exhibits novel red emission at about 613 nm which is assigned to the 5D0 → 7F2 electric – dipole transition. Furthermore, the emission transition 5D0 → 7F2 has been found to be more prominent over the normal orange emission transition 5D0 → 7F1.


Author(s):  
J. R. Heffelfinger ◽  
C. B. Carter

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.


2008 ◽  
Vol 368-372 ◽  
pp. 683-685
Author(s):  
Cheng Wei Hao ◽  
Bo Lin Wu ◽  
Ji Yan Li

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.


2008 ◽  
Vol 37 (11) ◽  
pp. 1881-1886 ◽  
Author(s):  
Guorong Hu ◽  
Xinrong Deng ◽  
Zhongdong Peng ◽  
Ke Du ◽  
Yanbin Cao ◽  
...  

1987 ◽  
Vol 118 ◽  
pp. 123-134 ◽  
Author(s):  
M.E. García-Clavel ◽  
M.J. Martinez-Lope ◽  
M.T. Casais-Alvarez

2021 ◽  
Author(s):  
Hang Yu ◽  
Wenwen Bu ◽  
Zijia Wang ◽  
Zhuoyue Zhao ◽  
Mehwish Jadoon ◽  
...  

Polyoxometalate nanoparticles were synthesized via a concise solid-state reaction method by directly grinding silver nitrate and the polyoxometalate (NH4)5H6PMo4V8O40 at room temperature without the assistance of a surfactant.


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