Fabrication of mono-dispersed cerium oxide nanopowders via mixed solvothermal route

Monodisperse and single-phase cerium oxide nanopowders were synthesized by mixed solvothermal route,Ce(NO3) 3·6H2O as raw materials,poly(vinylpyrrolidone) (PVP) as stable agent. The cerium oxide nanopowders could be controlled from 50 to 60 nm by adjusting the ratio between ethanol absolute and water at 160 °C. With methanol instead of ethanol absolute,the reaction temperature could be lowered to 130 °C.     

Fabrication and properties of La modified AZO powders via a gaseous penetration processing

A new kind of AZO powders were synthesized by co-precipitation method with the doping content of Al was 3.0 wt%. Further modification of La to the powders was done via a gaseous penetration processing. Changes in constitution,structure,and electrical conductivity caused by doping and penetration were characterized. The doping of Al lowered the resistivity of AZO powders from over 1×1014(ZnO made domestically) to 4.24×107 Ω·cm. But more effective modification via gaseous penetration processing decreased the resistivity of La penetrated AZO powders to the lowest point of 2.45×105 Ω·cm. The optimal penetration conditions coordinated by orthogonal test were that La3+ content of the penetration solvent was 2.0 wt.%,and that the penetration processing lasted for 5 h at the temperature of 480 oC. XRD analysis demonstrated that the doping process of Al only leaded to the changes of the peak width and intensity without new phases appearing. Yet,new phases appeared after the processing of gaseous penetration of La,which indicated that La enter the AZO powders thus complex reactions occurred to form the extra compounds. EDAX analysis,coupling with XRD,provided the evidence that La did exist in the penetrated AZO powders and the potential sign of the generation of extra compounds. Through SEM images,it was illustrated that the gaseous penetration processing progressed the growth of grain size in the shape of rod and generated distinguishable phases of extra compounds.     

Synthesis and luminescence properties of SrAleO4：Eue＋,Dy3＋ hollow microspheres via a solvothermal co-precipitation method

SrAl2O4:Eu2+,Dy3+ hollow microspheres were successfully prepared through a facile and mild solvothermal co-precipitation combining with a postcalcining process.The structure and particle morphology were investigated by X-ray diffraction(XRD),scanning and transmission electron microscopy(SEM and TEM)pictures,respectively.The mechanism for the formation of spherical SrAl2O4:Eu2+,Dy3+ phosphor was preliminary presented.After being irradiated with ultraviolet(UV)light,the spherical phosphor emitted long-lasting green phosphorescence.Both the photoluminescence(PL)spectra and luminance decay,compared with that of commercial bulky powders,revealed that the phosphors had efficient luminescent and long lasting properties.It was considered that the SrAl2O4:Eu2+,Dy3+ hollow microspheres had promising long-lasting phosphorescence with potential scale-dependent applications in photonic devices.     

Synthesis of CaWO4：Eu3＋ phosphor powders via ethylene glycol route and its optical properties

Eu3+ doped CaWO4 with tetragonal system were prepared at comparatively low temperature (125 ?C) in ethylene glycol medium. The phosphor was further investigated by X-ray diffractometer (XRD), photoluminescence spectrophotometer (PL), Fourier transform infra red (FT-IR) spectroscopy and transmission electron microscopy (TEM). XRD analysis indicated a decrease in the unit cell volume of CaWO4 with increasing Eu3+ ion concentration. It indicated the homogeneous substitution of Ca2+ ions in CaWO4 by the Eu3+ ions. TEM images showed that the particle size ranged from 20 to 200 nm and it could extend the application of the nanoparticles. The photoluminescence study showed that the intensity of electric dipole transition (5D0→7F2) at 614 nm dominated over the magnetic dipole transition (5D0→7F1) at 592 nm. The optimum concentration of Eu3+ for the highest luminescence was found to be 20 at.%. The as prepared samples were found to be dis-persible in water and methanol.     

Synthesis and characterization of Y_2O_2S:Eu~(3+),Mg~(2+),Ti~(4+) nanorods via a solvothermal routine

Y2O2S:Eu3+,Mg2+,Ti4+ nanorods were prepared by a solvothermal procedure.Rod-like Y(OH)3 was firstly synthesized by hydrothermal method to serve as the precursor.Y2O2S:Eu3+,Mg2+,Ti4+ powders were obtained by calcinating the precursor at CS2 atmosphere.The Y2O2S:Eu3+,Mg2+,Ti4+ phosphor with diameters of 30-50 nm and lengths up to 200-400 nm inherited the rod-like shape from the precursor after calcined at CS2 atmosphere.The Y2O2S:Eu3+,Mg2+,Ti4+ nanorods showed hexagonal pure phase,good dispersion and exhibite...