Preparation and luminescence property of Gd 2O 2S:Tb X-ray nano-phosphors using the complex precipitation method

Abstract

The Gd 2O 2S: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 °C with flowing N 2 containing sulfur vapor, and show the pure Gd 2O 2S 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 °C is 30–50 nm, while the one calcined at 1100 °C is about 50–70 nm. 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 Gd 2O 2S:Tb X-phosphors exhibit the same characteristic emission of Tb 3+, which arise from the transitions of 5D 3 and 5D 4 excited levels to 7F J ( J = 0–6) ground states. And the luminescence property of the nanocrystals and the process of energy transfer are studied in details.