Influence of Time-Temperature Parameters on the Structure and Photoluminescence of (Y1-xEux)(2)O-3 Crystalline Spheres

摘要

In this paper, sphere-like (Y1-x Eu (x) )(2)O-3 nanocrystalline particles with (x = 0.02;0.05;0.06;0.07;0.08, and 0.09) were obtained by the urea-based homogeneous precipitation technology followed by low-temperature crystallization from 600 to 900 A degrees C. The structure and morphology of the (Y1-x Eu (x) )(2)O-3 nanocrystalline particles and thermal stability of the nanocrystalline particles were investigated by means of transmission electron microscopy and x-ray diffraction analysis. The structural evaluation was established in relation to thermal conditions of sphere crystallization to ensure maximally effective luminescence of Eu3+ ions (D-5(0) -> F-7(2) transitions) with the morphological stability, the spherical shape of individual nanocrystalline particles remaining unchanged. The crystalline nanospheres were shown to have the threshold of concentration quenching of luminescence shifted toward lower concentrations of Eu3+ ions in comparison with micropowders of analogous composition. That may be caused by the formation of (Y1-x Eu (x) )(2)O-3 composition with the concentration gradient of Eu3+, followed by accumulation of Eu3+ ions around the grain boundaries.