Wydział Chemii

Joanna Trojan-Piegza

Eugeniusz Zych

2010

Journal of Physical Chemistry C

114

4215-4220

10.1021/jp910126r

Naukowa

Angielski

Artykuł

Three series of Lu₂O₃:Eu ceramic materials doped with different concentrations of Eu³⁺ ions (0.05−5 atom %) were prepared by sintering at the temperature of 1700 °C of nanocrystalline powders. The heat-treatments were performed in oxidizing, slightly reducing, and strongly reducing atmosphere of air, vacuum, and a N₂−H₂ mixture (9:1 by volume), respectively. The radioluminescent properties of these materials have been systematically studied. After exposure to X-rays, independent of the atmosphere of the preparation, the ceramics exhibited an extensive afterglow, especially long and strong for low Eu concentrations. The afterglow and radioluminescence spectra differed significantly with the former showing much more emission resulting from Eu³⁺ ions occupying the S₆ symmetry site in the host compared to the activator in the C₂ position. The effect was especially significant within the range of low and medium Eu concentrations, 0.05−1 atom %. From the decay traces of the persistent luminescence of Lu₂O₃:Eu ceramics it was concluded that the mechanism of the process is governed by the second order kinetics. It is postulated that only Eu³⁺ ions located within the layer containing both S₆ and C₂ metal ion sites are active in the afterglow emission, while those placed within the layer consisting of only the C₂ metal ion sites do not contribute to the afterglow. Another option is that electronic levels of Eu³⁺ in S₆ site are more favorably positioned to intercept migrating from their traps excited carriers.

https://doi.org/10.1021/jp910126r

https://www.acs.org/content/acs/en.html