Chen X P, Zhang Q Y, Yang C H, Chen D D, Zhao C
MOE Key Lab of Specially Functional Materials and Institute of Optical communication Materials, South China University of Technology, Guangzhou 510641, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Oct 1;74(2):441-5. doi: 10.1016/j.saa.2009.06.040. Epub 2009 Jun 24.
This paper reports on comparative investigation of structure and luminescence properties of tetragonal LiYF(4) and BaYF(5), and hexagonal NaYF(4) phosphors codoped with Er(3+)/Yb(3+) by a facile hydrothermal synthesis. The products were characterized by X-ray diffractometer, scanning electron microscope, and photoluminescence spectroscopy. Intense visible emissions centered at around 525, 550 and 650 nm, originated from the transitions of (2)H(11/2) --> (4)I(15/2), (4)S(3/2) --> (4)I(15/2), and (4)F(9/2) --> (4)I(15/2) of Er(3+), respectively, have been observed in all the samples upon excitation with a 980 nm laser diode, and the involved mechanisms have been explained. Based on the green up-conversion emission performance, the Yb(3+) concentrations of Er(3+)/Yb(3+)-codoped LiYF(4), BaYF(5), and NaYF(4) phosphors have been optimized to be 10, 20, and 20 mol*%, respectively. The quadratic dependence of fluorescence on excitation laser power has confirmed that two-photon contribute to up-conversion of the green-red emissions.
本文报道了通过简便的水热合成法对四方相LiYF₄和BaYF₅以及六方相NaYF₄共掺杂Er³⁺/Yb³⁺的磷光体的结构和发光性能进行的对比研究。通过X射线衍射仪、扫描电子显微镜和光致发光光谱对产物进行了表征。在980 nm激光二极管激发下，所有样品中均观察到了分别源于Er³⁺的²H₁₁/₂→⁴I₁₅/₂、⁴S₃/₂→⁴I₁₅/₂和⁴F₉/₂→⁴I₁₅/₂跃迁的、中心位于525、550和650 nm左右的强烈可见发射，并对相关机制进行了解释。基于绿色上转换发射性能，共掺杂Er³⁺/Yb³⁺的LiYF₄、BaYF₅和NaYF₄磷光体中Yb³⁺的浓度分别优化为10、20和20 mol%。荧光对激发激光功率的二次依赖性证实了双光子对绿-红发射的上转换有贡献。
