下转换材料β—NaYF_4:Tb^(3+),Yb^(3+)的水热法合成和发光性质研究

Preparation and Luminescence of Down-Conversion Material β—NaYF_4:Tb^(3+),Yb^(3+)

利用水热法合成了粉末发光材NaYF4∶Tb3+,Yb3+。分别用X射线衍射(XRD),光致发光谱(PL)和激发谱(PLE)测试了合成材料的物相结构和发光性质。研究结果表明:合成的NaYF4∶Tb3+,Yb3+材料为六方相的晶体,无立方相的。改变Tb3+和Yb3+的掺杂浓度后晶格结构没有变化,说明离子Tb3+和Yb3+取代的是Y3+离子的晶格位置。在355nm脉冲激光激发下,检测到了Tb3+的5 D3→7 FJ(J=5-0)和5 D4→7 FJ(J=6,5,4,3)可见波段特征发射光和Yb3+950～1 050nm(2 F5/2→2 F7/2)的近红外发光,研究了可见和近红外的发射强度随Yb3+掺杂浓度的变化,表明Tb3+和Yb3+之间存在能量传递,其可能的能量传递方式是共合作能量传递过程。当Tb3+和Yb3+的掺杂摩尔浓度分别是1mol%和6mol%时具有最强的近红外发射。

NaYF4∶Tb3＋,Yb3＋ down-conversion（DC） phosphors were synthesized by hydrothermal method.X-ray diffraction（XRD）,photoluminescence（PL） and photoluminescence excitation（PLE） spectra were used to characterize the samples.Experiment results revealed that samples of NaYF4∶Tb3＋,Yb3＋ crystallized in hexagonal shape without cubic shape.When the doping concentration of Tb3＋and Yb3＋ was altered,the lattice structure of samples did not change,indicating that the Tb3＋ and Yb3＋ ions are completely dissolved in the NaYF4 host lattice by substitution for the Y3＋.The emission from 5D4→7F6（489 nm）,5D4→7F5（542 nm）,5D4→7F4（584 nm）,and 5D4→7F3（619 nm） of Tb3＋ ions was observed,in which the dominant emission was at 542 nm.With single Tb3＋ doping,no near-infrared（NIR） emission was observed under excitation of 355 nm pulsed laser.However,while with Tb3＋ and Yb3＋ codoping,the NIR emission at around 950~1 100 nm from Yb3＋（2F5/2→2F7/2） was observed under the same excitation.The dependence of the visible and NIR-emissions on Yb3＋ doping concentration has been investigated.These results show that there is energy transfer process between Tb3＋and Yb3＋.Furthermore,it is a possible DC process through cooperative energy transfer from Tb3＋ to Yb3＋.When the doping concentration is 1% mol Tb3＋ and 6% mol Yb3＋ respectively,the intensity of NIR emission reaches its strongest.