Electronic Resource
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
86 (1999), S. 3751-3757
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Two different types of structure called X1 and X2 are existing in Y2SiO5 at normal conditions. In X1 type, Y3+ ions occupy two sites where they are surrounded respectively by nine and seven oxygen ions, while in X2 structure, only six and seven oxygen ions are involved. Nanometric scale X1-Y2SiO5 crystals were prepared by sol-gel method with particle size around 50 nm. Site selective excitation at low temperature has shown four different luminescent centers. Two of them belong to Eu3+ embedded in X1-Y2SiO5, the other two are attributed to Y2O3:Eu phase and to a particular site on the surface. The occurrence of the latter site may be related to the nanometric size of the sample. A pronounced excitation energy transfer from site 2 to site 1 was also observed on excitation spectra. The energy transfer rate increases rapidly with increasing Eu3+ concentration and for x=0.7 in Y2−xSiO5:Eux, no fluorescence takes place in site 2 at 15 K. The lifetimes of the 5D0 levels of Eu3+ in the two sites were measured as a function of Eu3+ concentration. The results have shown that the lifetime of the 5D0 level of Eu3+ in site 2 decreases with increasing Eu3+ concentration. The energy transfer rate dependence upon temperature was studied in detail and compared to a theoretical simulation. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.371246
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