SOLID SOLUTION BEHAVIOR OF Y2−x−yGdxEuyO3 NANOPOWDERS DURING PROCESS OF PREPARATION AND THEIR LUMINESCENCE PROPERTIES

Phase transformation during preparation of Y_2−x−yGd_xEu_yO₃  (x + y ≤2) nanoparticles by citric acid chelating and influence of pH value on the powder morphology were studied by FTIR, XRD and SEM. The behavior of solid solution was analyzed through calculation of lattice parameters and unit cell volume of Y_2−x−yGd_xEu_yO₃ and its luminescence property was obtained. The results show that the appropriate condition to prepare cubic Y_2−x−yGd_xEu_yO₃  powder is that the pH value less than 3, calcining at 900 for 2 h. Y_2−x−yGd_xEu_yO₃  powders with spherical morphology and size of 90 nm can be prepared under the condition of pH=1 and adding a little amount of glycol (5%, volume fraction). Luminescence properties of the powders are affected by the ratio of Y, Gd and the content of Eu. The luminous intensity reaches the maximum value when the powder composition
is Y0.2Gd1.65Eu0.15O3. Concentration quenching occurs when y is above 0.15 and then the emission intensity decreases.