Sun Li-nan, Meng Qing-yu, Feng Xiao-hui, Zuo Lin, Yu Chen-hai, Ma Li
The Key Laboratory of Advanced Functional Materials and Excited State of Heilongjiang Province, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2011 Dec;31(12):3218-22.
In the present paper, a novel nanophosphor, Y10W2O21:Eu was synthesized through a simple and low-cost method: co-precipitation. The results of XRD show that resultant samples are Orthorhombic phase and primitive lattice. The average crystallographic sizes could be confirmed to be approximately 80 nm by means of the Scherrer formula, which are in good agreement with the particles sizes exhibited by SEM. In the excitation spectra of Y10W2O21:Eu nanophosphor, by monitoring 610 nm, the charge transfer bands (CTB) of O--Eu and O--W, centering at around 270 and 307 nm, can be observed, respectively. The spectral lines shape and locations of excitation peak corresponding to 4f-->4f transitions are similar in all samples. But the relative intensity ratios between O--Eu and O--W CTB excitation peak increase with the Eu3+ doping concentration increasing. The characteristic red emission at around 610 nm of Eu3+ was also observed, ascribed to the (5)D0--(7)>F2 transition of Eu3+, and the optimal doping concentration is 20 mol%. Finally, the transition intensity parameters omega(lamda = 2,4) and the quantum efficiencies of (5)D0 level of Eu3+ were calculated according to Judd-Ofelt theory. The results indicate that Eu(3+5)D0-->(7)F2 610 nm red luminescence can be effectively excited by 394 nm near-UV light and 464 nm blue light in Y10W2O21 host, which is similar to the familiar Eu3+ doped tungstate (e.g., Gd2(WO4)3, CaWO4). Therefore, the Y10W2O21:Eu red nanophosphors may have a potential application for white LED.
在本文中，通过一种简单且低成本的方法——共沉淀法合成了一种新型纳米磷光体Y10W2O21:Eu。X射线衍射（XRD）结果表明，所得样品为正交相和简单晶格。借助谢乐公式可确定平均晶体尺寸约为80 nm，这与扫描电子显微镜（SEM）显示的颗粒尺寸高度吻合。在Y10W2O21:Eu纳米磷光体的激发光谱中，通过监测610 nm处的发射，可分别观察到以约270 nm和307 nm为中心的O--Eu和O--W的电荷转移带（CTB）。所有样品中对应于4f-->4f跃迁的激发峰的谱线形状和位置相似。但随着Eu3+掺杂浓度的增加，O--Eu和O--W CTB激发峰之间的相对强度比增大。还观察到了Eu3+在约610 nm处的特征红色发射，这归因于Eu3+的(5)D0--(7)>F2跃迁，最佳掺杂浓度为20 mol%。最后，根据贾德-奥费尔特理论计算了Eu3+的跃迁强度参数omega(lamda = 2,4)和(5)D0能级的量子效率。结果表明，在Y10W2O21基质中，394 nm近紫外光和464 nm蓝光可有效激发Eu(3+5)D0-->(7)F2 610 nm红色发光，这与常见的Eu3+掺杂钨酸盐（如Gd2(WO4)3、CaWO4）类似。因此，Y10W2O21:Eu红色纳米磷光体在白光发光二极管（LED）方面可能具有潜在应用。
