Robindro Singh L, Ningthoujam R S, Sudarsan V, Srivastava Iti, Dorendrajit Singh S, Dey G K, Kulshreshtha S K
Department of Physics, Manipur University, Canchipur-795003, India.
Nanotechnology. 2008 Feb 6;19(5):055201. doi: 10.1088/0957-4484/19/05/055201. Epub 2008 Jan 14.
Nanoparticles of Eu(3+) doped Y(2)O(3) (core) and Eu(3+) doped Y(2)O(3) covered with Y(2)O(3) shell (core-shell) are prepared by urea hydrolysis for 3 h in ethylene glycol medium at a relatively low temperature of 140 °C, followed by heating at 500 and 900 °C. Particle sizes determined from x-ray diffraction and transmission electron microscopic studies are 11 and 18 nm for 500 and 900 °C heated samples respectively. Based on the luminescence studies of 500 and 900 °C heated samples, it is confirmed that there is no particle size effect on the peak positions of Eu(3+) emission, and optimum luminescence intensity is observed from the nanoparticles with a Eu(3+) concentration of 4-5 at.%. A luminescence study establishes that the Eu(3+) environment in amorphous Y (OH)(3) is different from that in crystalline Y(2)O(3). For a fixed concentration of Eu(3+) doping, there is a reduction in Eu(3+) emission intensity for core-shell nanoparticles compared to that of core nanoparticles, and this has been attributed to the concentration dilution effect. Energy transfer from the host to Eu(3+) increases with increase of crystallinity.
通过在140 °C的相对低温下于乙二醇介质中进行3小时的尿素水解，然后在500和900 °C下加热，制备了Eu(3+)掺杂的Y(2)O(3)纳米颗粒（核）以及覆盖有Y(2)O(3)壳层的Eu(3+)掺杂的Y(2)O(3)纳米颗粒（核壳结构）。通过X射线衍射和透射电子显微镜研究确定，500和900 °C加热样品的粒径分别为11和18纳米。基于对500和900 °C加热样品的发光研究，证实了粒径对Eu(3+)发射峰位置没有影响，并且在Eu(3+)浓度为4 - 5原子百分比的纳米颗粒中观察到了最佳发光强度。发光研究表明，非晶态Y(OH)(3)中的Eu(3+)环境与晶体Y(2)O(3)中的不同。对于固定浓度的Eu(3+)掺杂，核壳纳米颗粒的Eu(3+)发射强度相对于核纳米颗粒有所降低，这归因于浓度稀释效应。从主体到Eu(3+)的能量转移随着结晶度的增加而增加。
