光子学报, 2011, 40 (11): 1646, 网络出版: 2011-12-12
超声喷雾共沉淀法制备的Lu3Al5O12∶Eu3+纳米粉体发光特性
Emission Properties of Eudoped NanoLu3Al5O12 Powders by Ultrasonic Atomization and Coprecipitation Method
纳米粉体 发射光谱 光学强度参量 Lu3Al5O12 LuAG Nanopowder Emission spectra Eu3+ Eu3+ ion Optical intensity parameter
摘要
采用新型超声喷雾共沉淀法技术,以Lu2O3、Eu2O3、Al(NO3)3·9H2O为原料,制备了不同浓度Eu3+离子掺杂的Lu3Al5O12纳米粉体.用X射线粉末衍射表征了获得纳米粉体的相,用扫描电镜观察了纳米粒子的形貌.测定了粉体的激发光谱、7F05D2声子边带谱与发射光谱.研究了不同高温烧结温度与Eu3+掺杂浓度对纳米粒子的发光强度与粒子形貌的影响规律.研究表明,当烧结温度高于900 ℃时,粉体发光强度明显增强,并且随着煅烧温度的增加,发光强度有所增强.Eu3+离子的最佳掺杂浓度为5~7 mol%.根据稀土离子Eu3+光学跃起矩阵元的特点,从发射光谱获得Eu3+光学跃起的JO参量Ω2与Ω4.在Eu3+掺杂浓度均为5 mol%时,其强度参量达最小,电声子耦合最强.然后随着掺杂浓度的进一步提高,强度参量略有增加,电声子耦合减弱.说明EuO键强增加,共价性增强,Eu3+的局域环境对称性降低.Ω2值低于Eu3+在玻璃与晶体基质中的情况,这是由于纳米粒子中存在着大量的缺陷以及晶体的结构畸变导致纳米粒子的对称性下降所致.
Abstract
Eu3+ doped nanoLu3Al5O12 powders were prepared by ultrasonic atomization and coprecipitation method with Lu2O3, Eu2O3 and Al(NO3)3·9H2O as raw materials, and the obtained powders were sintered at various temperature. Xray diffraction and scanning electron microscopy were employed to characterize the particle size and phase composition of the nanopowder. The emission, excitation and phononside band spectra of Eu3+∶Lu3Al5O12 were measured. The result indicated when the sintering temperature was higher than 900℃, the luminous intensity was significantly enhanced and the optimum doping concentration of Eu3+ was 5~7 mol%. The Ω2 and Ω4 parameters of Eu3+ for optical transition were calculated from their emission spectra in terms of reduced matrix U(t) (λ=2,4,6) character for optical transitions. The results indicated that the intensity parameters Ω2 reached to minimum and electronphonon coupling to the maximum when the doping concentration of Eu3+ was ~5 mol%. With the increase of Eu3+ content, the optical parameter increased slightly and the electronphonon coupling became weaker. It suggests that the symmetry becomes weaker, the bands of Eu and O atoms become higher and the covalence of Eu and O atoms increases. The Ω2 of the powder shows an obvious lower value by comparing with those of Eu3+ in glass and crystal matrix, which is result from the symmetrical decreasing of the nanoparticles induced by a large number of defects and structural aberrations.
胡元, 夏海平, 张丽. 超声喷雾共沉淀法制备的Lu3Al5O12∶Eu3+纳米粉体发光特性[J]. 光子学报, 2011, 40(11): 1646. HU Yuan, XIA Haiping, ZHANG Li. Emission Properties of Eudoped NanoLu3Al5O12 Powders by Ultrasonic Atomization and Coprecipitation Method[J]. ACTA PHOTONICA SINICA, 2011, 40(11): 1646.