Investigation on the preparation and luminescence property of (Gd1−xDyx)2O3 (x=0.01-0.10) spherical phosphors

Uniform spheres of (Gd1−xDyx)2O3 (x=0.01-0.10) have been converted from their colloidal precursor spheres synthesized via homogeneous precipitation. The synthesis, particle size control, luminescent properties and energy transfer of the (Gd1-xDyx)2O3 were systematically studied by the combined techniques of fourier transform infrared (FT-IR) spectroscopy, x-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence excitation/ photoluminescence (PLE/PL) spectroscopy, and fluorescence decay analysis. The precursor exhibit mono-dispersed spherical morphology and its size can be efficiently controlled by adjusting the urea content. The phase pure (Gd1−xDyx)2O3 oxides can be obtained by calcining precursor at 600 °C, and the spherical morphology remained at even high temperature of 1000 °C. The (Gd1−xDyx)2O3 phosphors display strong yellow emission at 575 nm (4F9/2→6H13/2 transition of Dy3+) and weak blue emission at 486 nm (4F9/2→6H15/2 transition of Dy3+) upon ultraviolet (UV) excitation of Gd3+ at 275 nm (8S7/2→6IJ transition of Gd3+). The optimal content of Dy3+ was found to be ~2 at% (x=0.02) due to the concentration quenching. Owing to the efficient Gd3+→Dy3+energy transfer, the fluorescent property of the phosphor was significantly improved. The emission intensity of (Gd1−xDyx)2O3 increased with calcination temperature and particle size increasing, while the lifetime for the 575 nm emission gradually decreased. The (Gd1−xDyx)2O3 spheres developed in the present work is expected to be a promising yellow phosphor widely used in the lighting and display areas.