Preparation and luminescence property of Gd2O2S:Tb X-ray nano-phosphors using the complex precipitation method

The Gd2O2S:Tb X-ray nano-phosphors were prepared using the complex precipitation method combined with low temperature sulfurized method. The mixed solution of the ammonium water and ammonium hydrogen carbonate was employed as the complex precipitant. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), photoluminescence (PL) and X-ray excited luminescence (XL) spectra. The results show that the as-prepared samples can be sulfurized completely at 900 degrees C with flowing N-2 containing sulfur vapor, and show the pure Gd,0,S phases with the hexagonal structure. The obtained X-ray phosphor particles are quasi-spherical, disperse well. And the observed particle size of the sample-calcined at 900 degrees C is 30-50nm, while the one calcined at 1100 degrees C is about 50-70nm. Therefore, both of them have successfully realized the nano-sized, which are beneficial to enhance the resolution of imaging system efficiently. When excited by the 254 nm UV light and X-ray, the Gd2O2S:Tb X-phosphors exhibit the same characteristic emission of Tb3+. which arise from the transitions of D-5(3) and D-5(4) excited levels to F-7(J) (J = 0-6) ground states. And the luminescence property of the nanocrystals and the process of energy transfer are studied in details. (c) 2006 Elsevier BA'. All rights reserved.