纳米SiO2基质中Eu^3＋的发光特性

Luminescent Properties of Eu^(3+) in Nano-Matrix of SiO_2

采用溶胶-凝胶法(sol-gel)制备了Eu^(3+)掺杂SiO_2基质发光材料,分别用荧光(PL)光谱、原子力显微镜(AFM)、扫描电镜(SEM)等分析手段对样品进行了表征,研究了退火温度以及掺杂浓度对发射光潜的影响,并对其发光机制进行了分析。薄膜样品在258 nm光激发下,在620 nm,667 nm处出现了比较少见的双峰红光发射,而620 nm处的光发射最强,说明Eu^(3+)离子处在对称性较低的配位环境中。退火处理温度对样品的发射光谱影响很大,经900℃退火处理的样品发射强度最强。随着掺杂浓度的变化,改变了Eu^(3+)-O^(2-)间的距离,在相同紫外光激发下O^(2-)外层的电子迁移到Eu^(3+)4 f轨道上的能量变化,使得谱线位置出现了移动。

Eu^3＋ -doped SiO2 matrix materials were prepared by sol-gel technique. The samples were characterized by the modern analysis techniques such as the fluorescence spectrum, atomic force microscope （AFM） and scanning electron microscope （SEM） and so on. The influences of annealing temperature and doping concentration on the luminescent properties were studied systematically, and the luminescence mechanism was investigated. When the films were excited at 258 nm, double peak at 620 nm and 667 nm were observed, which was rarely seen, and at 620 nm the emission intensity reached the strongest,which suggested Eu^3＋ ions lay in the coordination environment of the lower symmetry. The annealing temperature made great effect on the emission spectroscopy, the luminescence intensity of the film annealed at 900 ℃ was the strongest. With the variations of doping concentration, the distance between Eu^3＋ and O2 was changed. At the same UV excitation, the outer electron of O2 migrated to the 4f orbit of Eu^3＋ caused the energy changed,and the spectrum position removed.