176 resultados para BaFI:Eu2
Resumo:
The luminescence properties of CaBPO5: Eu, Tb phosphor and the sensitization of Ce3+ were investigated. The CaBPO5: Eu, Tb phosphors were synthesized in the ambient air and the emission spectra of Eu3+, Tb3+ and Eu2+ were Observed in the phosphor. The result shows that there is electron transfer between conjugate rare earth ions. Sensitization of Ce3+ can improve the intensity of emission of Tb3+ and Eu2+. A novel trichromatic lamp phosphor codoped with Eu3+-Tb3+ in matrix CaBPO5 is then predicted.
Resumo:
CaY1-xBO4: xEu was synthesied by solid state reaction method, and the displacement and luminescence of the Eu3+ in CaYBO4 host were studied. Two luminescent centers could be observed at certain Eu3+-concentration, indicating that the Eu3+ occupies two different crystallographic sites. This result shows that the Eu3+ occupies two different Y3+ sites in CaYBO4. The investigation on Eu-O charge transfer bands indicates that the larger distortion or the lower symmetry of Eu3+ site is,the shorter wavelength of the Eu-O charge transfer band is. When the Eu3+-concentration is high (x > 0.10), Eu3+ occupies the sites of Ca2+ and is reduced to Eu2+.
Resumo:
The luminescent materials SrB4O7:Eu and BaB8O13:Eu were synthesized, and the valence states of europium in the materials were measured by means of XANES at Eu-L-3 edge. It is found that the Ed(3+) and Eu2+ ions are all present in the materials, and more Eu3+ ions can be reduced in SrB4O7:Eu than in BaB8O13:Eu. The excitation and emission spectra of Eu3+ in SrB4O7:Eu and BaB8O13:Eu were determined.
Resumo:
The spectroscopic feature of divalent Sm2+, Eu2+, Tm2+ and Yb2+ is discussed in this paper. Especially the spectroscopic properties of some berates containing tetrahedral BO4 group such as SrB4O7, SrB6O10 and BaB8O13 doped with these divalent ions are reported. When the divalent alkaline earth ion in these berates is replaced partially by the above trivalent rare earth ion, the charge carried in the produced defects can be used as reductant to reduce the doped rare earth ion into divalent state at high temperature even in air. Therefore, a convenient and safe method is provided to prepared phosphors doped with these divalent rare earths.
Resumo:
KZn F3 KZn F3 Eu, SEM ;XPS , ; ESR ,KZn F3 Eu Eu2 + Eu3 + ,
Resumo:
BaMAl10O17 ,M , ,()M Al2O3 ,Eu2 + ,M=Zn,Cd,Mn,Co,Li Al2O3 ,M=Ca,Be ,Ca ,Be ;Eu2 +M=Li,Be,Zn ,450nm ,50nm , ,Eu2 +M=MnEu2 +Mn2 + ,M=Cd ,Eu2 +
Resumo:
Sm2 + Eu2 + Tm2 + Yb2 + ,SrB4 O7SrB6 O10 BaB8O13 , , , ,
Resumo:
CaY1 -xBO4xEu ,Eu3+CaYBO4Eu3+ , ,Y ;Eu O ,Eu3+ ,Eu O ;Eu3+ (x >0 1 0 ) ,Eu3+Ca2 + ,Eu3+Eu2 +
Resumo:
Eu3+ Tb3+ , , ,Eu3+ Eu2 + ,Eu3+ Tb3+ Eu2 + CaBPO5 Eu ,Tb2 5 4 3 65nmCe3+ ,Ce3+ Eu2 + ,Tb3+ Ce3+
Resumo:
Eu2 + ,Eu2 + :KCaF3BaY2 F8 ,Eu2 + ,Eu2 + ,Eu2 + (F- ) , ,Eu2 + (O2 - ) ;KCaF3 ,H2 ,Eu2 + (O2 - ) ;BaY2 F8 ,H2 ,Eu2 + (O2 - ) ,H2 ,Eu2 + (O2 - )
Resumo:
KMgF3 doped with Eu was synthesized by mild hydrothermal method at 240 degreesC for the first time. The excitation and emission spectra of the KMgF3 : Eu2+ phosphor were measured. Comparing with the sample synthesized through solid state reaction, the variation in the excitation spectra at 360 nm resulted from the existences of V-K color centers; the low emission intensity was due to Eu2+ having transferred part energy to V-K color centers.
Resumo:
When CaS:Sm3+, Eu2+ is excited at 476.5 nm (Ar+), the emission spectra taken at room temperature and at 77 K are different, indicating that there are two competitive energy transfer processes-Sm3+ --> Eu2+ and Eu2+ --> Sm3+ with phonon participation. So, the luminescence intensity of Sm3+ increases first, and then decreases as the concentration of Eu2+ is increasing. (C) 2001 Elsevier Science Ltd. All rights reserved.
Resumo:
Ba Y2 F8 Ce3 + ,Ba Y2 F8 Eu2 + Ba Y2 F8 Ce,Eu, . Ba Y2 F8 Ce F3 Eu F3 Ce3 + Eu2 + Ce3 + Eu3 + . , Ce4 +
Resumo:
77K , Eu2 + Eu2 + Ce3+ KMg F3 . KMg F3 Eu-Ce Eu2 + 6P5/ 2 Ce3+ 4 f 5 d ,
Resumo:
Eu2 + Eu,X( X=Ce,Cr,Gd,Cu) KMg F3 30 0 K 77K , Eu2 + , . Eu2 +
