溶胶-凝胶法制备Ce3+掺杂纳米SiO2材料光致发光研究

通过溶胶-凝胶技术制备了掺杂Ce^3＋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20～30nm。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Ce^3＋掺杂的样品在230nm激发下存在着唯一的一个很强的、主峰位于346nm左右的紫外发光峰，与未掺杂SiO2及Cu^2＋掺杂SiO2样品的比较表明该发光峰并非常见的Ce^3＋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Ce^3＋离子掺杂量对346nm发光峰强度的影响，讨论该发光峰起源可能的结构模型。

Photoluminescence Studies of Nanometer Ce3+-Doped SiO2 Synthesized by Sol-Gel Method

Nanometer Ce~(3+)-doped SiO_2 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 Ce~(3+)-doped SiO_2 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 Cu~(2+)-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 Ce~(3+). Based on the relationship of 346 nm band emission intensity with the heat treatment temperature and the concentration of Ce~(3+) ions in SiO_2, the structure model of the 346 nm band was discussed.