中文摘要：

采用水热法,以K2WO4·2H2O和La2O3为原料,以草酸为沉淀-模板剂,在pH=7,180℃下,通过调控草酸的添加量制备出了纯四方相结构的球形KLa（WO4）2：5%Eu^3＋纳米晶。通过X射线衍射（XRD）、扫描电镜（SEM）及荧光光谱（PL）对不同条件下制备出的产物物相、形貌以及荧光性质进行表征,探讨了草酸添加量对产物形貌及发光性能的影响。结果表明,在初始溶液的pH值为7,摩尔比n（C2O4^2-）/n（La^3＋）=0.3-0.5时,得到表面光滑直径为6-7μm的＂足球形＂KLa（WO4）2：5%Eu^3＋纳米晶,在393 nm激发下在614 nm处发光性强,草酸起到控制游离La^3＋浓度和模板剂的作用,草酸添加量对产物的形貌及发光性能起到重要作用。

英文摘要：

The spherical KLa（WO4）2：5%Eu^3＋ nanocrystals with pure tetragonal structure were synthesized by thehydrothermal method using K2WO4·2H2O and La2O3 as the raw materials and oxalic acid as precipitation-template agent atpH = 7 and t = 180 oC. The structural and optical properties of the products prepared under different conditions were studiedsystematically by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and photoluminescence （PL）. The effectsof the amount of oxalic acid on the morphologies and luminescent properties of the product were discussed. The resultsshow that ＂football-shaped＂ KLa（WO4）2：5%Eu^3＋ nanocrystals with a smooth surface and a diameter of 6-7 μm aresynthesized at pH = 7 and mole ratio of n（C2O4^2-）/n（La^3＋） = 0.3-0.5. The most intense emission is observed around 614 nmunder the excitation number of 393 nm. The concentration of La3＋ is controlled by the amount of oxalic acid, which is usedas template agent. The adding amount of oxalic acid plays an important role on the morphologies and luminescenceproperties of the products.