pH值对水热法制备LaVO_4:0.5%Eu^(3+)纳米粉体的影响

The effects of different pH values on LaVO_4: Eu^(3+) nano-powders prepared by hydrothermal method

以NH4VO3、LaCl3·nH2O等为原料,采用水热法合成了铕掺杂LaVO4纳米粉体,通过X射线粉末衍射、扫描电子显微镜、荧光测试仪等对制备的粉体进行了表征,考察了不同水热体系pH值(4-13)对产物晶相、微观形貌及荧光性能的影响,探讨了LaVO4晶体的生长机理.结果表明:产物的微观形貌为纳米颗粒或纳米棒,pH值低于10时,产物为单斜相LaVO4纳米晶,荧光强度较低;当pH值为11-13时,产物为四方相和单斜相两相,表现出较强的荧光性.

In this paper, LaVO4：Eu3＋nano-powders are successfully obtained by hydrothermal method as the raw materials of LaCl 3 · nH2 O and NH4 VO3 , etc.The as-obtained products are characterized by X -ray powder diffraction （ XRD） , scanning electron microscopy （ SEM） and fluorescence spectrometer （ PL） .We have studied the effects of different pH values of hydrothermal system on the phase , morphology and fluorescence properties of the product .The growth mechanism of LaVO 4 nanocrystals are discussed .The results show that：The micrography of the prepared LaVO 4 are nano-particles and nanorods .When the pH values of hydrothermal system are below 10 , the phase of the product is m -LaVO4 nanocrystals and the fluorescence properties of the product have lower intensity .On the contratry, when the pH values of hydrothermal system is between 11 to 13, the phase of the product is the mixture of m -LaVO4 and t-LaVO4 nanocrystals which have inhibited hihger flu-orescence properties .