Site selectively excited luminescence and energy transfer of X1-Y2SiO5:Eu at nanometric scale
Site selectively excited luminescence and energy transfer of X1-Y2SiO5:Eu at nanometric scale
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DOI：
10.1063/1.371246
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发表时间：
1999-09
影响因子：
3.2
通讯作者：
M. Yin;C. Duan;Wei-ping Zhang;L. Lou;S. Xia;J. Krupa
中科院分区：
文献类型：
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作者：
M. Yin;C. Duan;Wei-ping Zhang;L. Lou;S. Xia;J. Krupa
在正常条件下，Y2SiO5中存在两种不同类型的结构，称为X1和X2。在X1型中，Y3+离子占据两个位点，分别被9个和7个氧离子包围，而在X2型中，只有6个和7个氧离子参与。采用溶胶-凝胶法制备了粒度约为50 nm的纳米级X1-Y2SiO5晶体。低温下的选择性激发显示出四个不同的发光中心。其中两个属于嵌入在X1-Y2SiO5中的Eu3+，另外两个归因于Y2O3:Eu相和表面上的特定位置。后一位点的出现可能与样品的纳米尺寸有关。在激发光谱上也观察到明显的从位点2到位点1的激发能转移。随着Eu3+浓度的增加，能量转移率迅速增加，当Y2−xSiO5:Eux中x=0.7时，15k时2位没有荧光发生。两个地点的5D0水平Eu3+的寿命测量为…
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 ...