Department of Chemistry, LIEC-UFSCar, Caixa Postal 676, 13560-905 São Carlos, SP, Brazil.
J Fluoresc. 2011 May;21(3):975-81. doi: 10.1007/s10895-010-0671-8. Epub 2010 May 9.
In this work, a SiO(2) spherical were prepared by the Stöber Method and then recovered with a single layer of Eu(2)O(3) oxide (SiO(2)@Eu(2)O(3)) obtained by the Polymeric Precursor Method. The SiO(2)@Eu(2)O(3) powder was heated treated at 100, 300, 400, 500 and 800 °C. The samples were characterized by the Scanning Electonic Microscopy (SEM), Thermal Analysis (TGA/DTA), and the luminescent properties of the SiO(2)@Eu(2)O(3) powders were studied by their emission and excitation spectra as well as by the lifetime measurements of the Eu(3+) (5)D(0) → (7)F(2) transition. The SEM analysis shows that the silica prepared by the Stöber Method is spherical with a particle size of 460 nm. The emission spectra of the SiO(2)@Eu(2)O(3) powders presented the Eu(3+) characteristics bands related to the (5)D(0) → (7)F(J) (J = 0, 1, 2, 3, 4) transitions at 577, 591, 616, 649 and 695 nm, respectively. The band related to the (5)D(0) → (7)F(2) transition is the most intense in the spectra, and its intensity decreases with the temperature enhancement. The decay curves of the SiO(2)@Eu(2)O(3) samples presented monoexponential features, and the obtained lifetime values were higher than the Eu(2)O(3) oxide. It was possible to conclude that the (5)D(0) → (7)F(2) hypersensitive transition is strongly dependent on the Eu(3+) surrounding.
在这项工作中，通过 Stöber 法制备了 SiO(2) 球形颗粒，然后通过聚合前驱体法回收了单层 Eu(2)O(3) 氧化物（SiO(2)@Eu(2)O(3)）。将 SiO(2)@Eu(2)O(3) 粉末在 100、300、400、500 和 800°C 下进行热处理。通过扫描电子显微镜（SEM）、热分析（TGA/DTA）对样品进行了表征，并通过发射和激发光谱以及 Eu(3+)（5）D(0)→(7)F(2) 跃迁的寿命测量研究了 SiO(2)@Eu(2)O(3) 粉末的发光性能。SEM 分析表明，通过 Stöber 法制备的二氧化硅呈球形，粒径为 460nm。SiO(2)@Eu(2)O(3)粉末的发射光谱呈现出与 Eu(3+)相关的特征带，分别对应于 577、591、616、649 和 695nm 的（5）D(0)→(7)F(J)（J=0、1、2、3、4）跃迁。与（5）D(0)→(7)F(2)跃迁相关的带在光谱中最强，其强度随温度升高而降低。SiO(2)@Eu(2)O(3)样品的衰减曲线呈现单指数特征，得到的寿命值高于 Eu(2)O(3)氧化物。可以得出结论，（5）D(0)→(7)F(2) 敏化跃迁强烈依赖于 Eu(3+)的周围环境。
