Sol-gel synthesis, characterization, and photoluminescence properties of sub-micron Gd2O2SO4 powders

The advanced phosphorescent Gd2O2SO4 (GOS) sub-micron powders were successfully synthesized through a sol-gel method uti lizing commercial ly available Gd(CH3CO2)(3)center dot xH(2)O, (NH4)(2)SO4, and CO(NH2)(2) as precursors. GOS phosphors were characterized by differential thermal analysis-thermogravimetry (DTA-TG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analyzer (PSA), and time-resolved spectrometer (TRS). The results showed that the samples calcinated at different temperatures from 950 to 1200 degrees C were composed of the different Gd-based phases. All analyzes confirmed that pure Gd2O2SO4 crystalline structure was produced at 950 and 1000 degrees C. However, this structure deteriorated over 1000 C. At temperature range of 1100 and 1200 C, Gd2O3 and Gd2S3 structures were observed in the powder. The powders at 950 degrees C exhibit a surface morphology smaller than 1 mu m. In a fully deoxygenated moiety, when excited at 356 nm, the phosphors exhibited well-shaped narrow emission bands centered at 542 nm and biexponential decay times. The phosphorescence of the material was oxygen resistive and wavelength dependent.