水热合成LuF_3∶Yb^(3+),Er^(3+)微晶及其上转换发射与温度传感特性（英文）

Upconversion Emission and Temperature Sensing Behavior of LuF_3∶Yb^(3+),Er^(3+) Microcrystals Prepared by One-Step Hydrothermal Synthesis

通过在不同pH值下的简易水热法合成不同Yb^(3+)离子(n_(Yb^(3+))/n_(Lu^(3+))=5%~15%)和Er^(3+)离子(n_(Er^(3+))/n_(Lu^(3+))=1%~5%)掺杂浓度的LuF_3∶Yb^(3+),Er^(3+)微晶荧光粉。发现pH值对正交相LuF_3∶Yb^(3+),Er^(3+)的合成起着关键作用。在980nm激发下,LuF_3∶Yb^(3+),Er^(3+)荧光体呈现出以523nm(~2H_(11/2)→~4I_(15/2))和539nm(~4S_(3/2)→~4I_(15/2))为中心的强绿光上转换(UC)发射以及以660nm(~4F_(9/2)→~4I_(15/2))为中心弱红光上转换发射。通过使用X射线衍射(XRD)和光致发光(PL)分析测定了最强发射强度的Er^(3+)和Yb^(3+)的最佳掺杂浓度。浓度依赖性研究表明,达到最强的绿光上转换发光时最佳掺杂浓度为10%Yb^(3+),2%Er^(3+)。通过改变泵浦功率来研究LuF_3∶Yb^(3+),Er^(3+)荧光粉UC发光机制。通过980nm二极管激光器在293~573K的范围内研究了在523和539nm处的2个绿光UC发射带的荧光强度比(FIR)的温度依赖性,发现在490K得到最大灵敏度约为15.3×10^(-4)K^(-1)。这表明LuF_3∶Yb^(3+),Er^(3+)荧光体可应用于具有高灵敏度的光学温度传感器。

LuF3：yb3＋,Er3＋microcrystals codoped with Yb3＋ （rtyb3＋/nLu3＋=5%-15%） and Er3＋ ions （nEJnLu3＋=1%-5%） were synthesized by a facile hydrothermal process at different pH values. It is found that the pH value has a crucial effect on synthesis of the orthorhombic phase LuF3：yb3＋,Er3＋. Under 980 nm excitation, LuF3：yb3＊,E？＋ phosphors exhibit strong green upconversion （UC） emission bands centered at 523 （2H11/12→4I.15.2） and 539 nm （4S3.2→4I15/3） and weak red emissions near 660 nm （4F9a→4I15/2）. The optimum doping concentrations of Er3＋ and Yb3＋ for the highest emission intensity were determined by using X-ray diffraction （XRD） and photoluminescence （PL） analyses. Concentration dependent studies reveal that the optimal composition is 10%Yb3＋ and 2%Er3＋ co-doping concen- tration with a strong green emission. A possible UC mechanism for LuFg：yb3＋,Er3＋ depends on the pump power is discussed. The temperature dependence of the fluorescence intensity ratios （FIR） for the two green UC emission bands peaked at 523 and 539 nm was studied in the range of 293-573 K under excitation by a 980 nm diode laser and the maximum sensitivity was approximately 15.3＋10-4 K-1 at 490 K. This indicates that LuF3：Yb3＋, Er3＋ phosphors are potential candidates for optical temperature sensors with high sensitivity.