通过溶胶凝胶技术制备了掺杂Ce3+离子的纳米SiO2材料,并经较低温度下煅烧,研究其光致发光(PL)性能。X射线衍射(XRD)及透射电子显微镜(TEM)测试结果表明该纳米材料具有非晶态结构,颗粒尺寸为20～30 nm。对其光致发光谱的测定显示:经450 ℃低温煅烧,未掺杂SiO2样品的光致发光谱明显为多峰的宽带结构,而微量Ce3+掺杂的样品在230 nm激发下存在着唯一的一个很强的、主峰位于346 nm左右的紫外发光峰,与未掺杂SiO2及Cu2+掺杂SiO2样品的比较表明该发光峰并非常见的Ce3+离子的d-f跃迁产生的特征发光带,而是起源于SiO2中的某种本征缺陷中心。通过不同煅烧温度以及不同Ce3+离子掺杂量对346 nm发光峰强度的影响,讨论该发光峰起源可能的结构模型。

Nanometer Ce3+-doped SiO2 was prepared by sol-gel method, and it is photoluminescent property was studied. The structure of samples was found to be amorphous with powder size between 20 and 30 nm determined by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. The photoluminescence spectrum of the Ce3+-doped SiO2 annealed at 450 ℃ shows a very strong UV luminescence band at 346 nm under 230 nm excitation. A wide band with multipeaks was also observed under the excitation of 380 nm. Compared with the Cu2+-doped and undoped silica a conclusion can be drawn that the UV luminescence band at 346 nm is originated from the natural defect of silica but not the characteristic luminescence of d-f transition of Ce3+. Based on the relationship of 346 nm band emission intensity with the heat treatment temperature and the concentration of Ce3+ ions in SiO2, the structure model of the 346 nm band was discussed.