CeO_2∶Eu^(3+)粉末的溶胶-凝胶法制备及发光性能研究  

Preparation of CeO_2∶Eu^(3+) Powders by Sol-Gel Method and Their Photoluminescence Properties

作　　者：王孝东[1] 刘晓华[1] 陈绍军[1] 黎明[1] 刘敏[1] 

机构地区：[1]汕头大学物理系,广东汕头515063

出　　处：《光谱学与光谱分析》2007年第11期2182-2185,共4页Spectroscopy and Spectral Analysis

基　　金：广东省自然科学基金项目(04010998);人事部留学人员科技活动项目择优资助经费;教育部回国留学人员基金资助

摘　　要：采用溶胶-凝胶法制备了不同浓度Eu3+掺杂的CeO2发光粉,样品粉末在紫外光激发下发出明亮的橙红色光。利用X射线衍射(XRD)、热重-差热分析(TG-DTA)和光致发光光谱(PL)对样品的结晶过程和发光性质进行了表征。XRD分析表明在0.2at.%～10at.%的Eu3+掺杂范围内,用溶胶-凝胶法合成的样品在500℃就结晶成纯相的CeO2∶Eu3+多晶粉末。由于Ce4+和Eu3+离子半径十分接近,因而Eu3+在CeO2中具有较高的固溶度。PL激发谱中出现在300～390nm的宽带激发峰起源于基质CeO2的吸收,电子吸收能量后,发生O2-—Ce4+的电荷迁移,再将能量传递给Eu3+。PL发射谱显示Eu3+含量为6at.%的样品发光强度最强,随后出现浓度猝灭。导致发光出现浓度猝灭的机制是电偶极-电四极相互作用。样品烧结温度的升高,促使晶粒长大和结晶完整性提高,从而显著提高了CeO2∶Eu3+粉末的发光强度。CeO2 ： Eu^3＋ phosphor powders with various Eu^3＋ concentrations have been prepared by the sol-gel method. Upon excitation with UV light, the CeO2 ： Eu^3＋ powders showed bright orange red emissions due to the 4f-4f transitions of Eu^3＋ ions. X-ray diffraction （XRD）, TG-DTA and Photoluminescence （PL） measurements were used to characterize the samples. XRD analysis showed that the powders with pure cubic fluorite-type CeO2 phase at an up to 10at. % concentration of Eu^3＋ was obtained at the sintering temperatures from 500 to 1 250 ℃. The large solubility for doping Eu3＋ ions in CeO2 is due to the nearness of ionic radius between Ce^4＋ and Eu^3＋. It was also found that an increase in sintering temperature promotes the grain growth of CeO2 and improves its crystallinity. The excitation spectra of the CeO2 ： Eu^3＋ powders were dominated by a broad band at 300- 390 nm, suggesting the efficient energy transfer from the O^2--Ce^4＋ charge-transfer state to the doping Eu^3＋ in the CeCh ： Eu^3＋ powders. The CeO2 ： Eu^3＋phosphor powders with a 6at. % concentration of Eu^3＋ sintered at 1 250 ℃ revealed the stron- gest photoluminescence and then in abruptly decreased with increasing the doping concentration indicating the concentration quenching. The mechanism of concentration quenching could be explained as the result of the dipole-quadrupole interaction of neighboring Eu^3＋.

关 键 词：CeO2:Eu^3+ 发光 溶胶-凝胶法 

分 类 号：O614.3[理学—无机化学]