SrMgB_6O_(11):Eu^(3+)纳米材料的水热法制备及发光性能研究

Hydrothermal Preparation and Photoluminescence Properties of SrMgB_6O_(11):Eu^(3+) Nanomaterials

采用水热法制备了Eu3+掺杂SrMgB6O11纳米发光材料。利用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FESEM)和荧光光谱对SrMgB6O11:Eu3+样品进行表征。结果表明:采用水热法可以成功地合成粒度均匀、结晶完好的SrMgB6O11:Eu3+纳米发光粉。深入研究了反应温度和pH值对SrMgB6O11:Eu3+纳米材料的晶体结构及形貌的影响。结果表明,在120℃时形成了尖锐且强度最强的衍射峰,同时FESEM也表明此时所得材料为纳米棒组成的规则扇形形貌,此后随着温度的升高,XRD图中衍射峰的位置和强度发生变化,说明荧光粉的晶体结构发生变化,FESEM也表明该荧光粉已变为球形颗粒。归属了发射光谱和激发光谱中各激发峰所对应的能级跃迁。荧光光谱也显示:反应温度和pH值影响着Eu3+在晶格中的对称性,且反应温度为120℃及pH值为9时,Eu3+在晶格中的对称性较好。另外,还初步探讨了纳米粒子的生长机制。

Eu3＋ doped SrMgB6O11 nano-phosphors were prepared by a hydrothermal method. The crystal structure, morphology and luminescence properties of SrMgB6O11： Eu3＋ nano-phosphors were characterized by X-ray powder diffraction （XRD）, field emission scanning electron microscopy （ FESEM ） and fluorescence spectra, respectively. The results showed that with the SrCO3 （ 97% ） MgO （99.5%）, H3BO3 （99.5%） and Eu203 （99.99%） as starting materials, nano-crystal SrMgB6O11： Eu3＋ phosphors were successfully synthesized in 30 ml teflon-lined stainless steel autoclaves by hydrothermal method. The effects of different reaction temperatures （ 120, 140, 160, 180 and 200 ℃ ） and different pH values （7, 8, 9 and 10） on the crystal structure and morphology of SrMgB6O11：Eu3＋ nano-phosphors were also studied.The results of XRI） indicated that the diffraction peaks were sharp and strong when temperature was 120 ℃. Meanwhile the FESEM showed that the morphology was fan-shaped made of nanorods. With the temperature increasing, the diffraction angle and intensity of diffraction peaks were changed in the XRD pattern, and the FESEM showed that the morphology became spherical particles. The peaks of the emission and exctition spectra were assigned to the electron transitions of Eu3＋. The emission spectra also showed that the splitting of the emission peaks changes depended on pH values, and the site symmetry of Eu3＋ was the highest for sample made at 120 ℃ with pH values of 9. The growth mechanism of nano-particles was also discussed.