Eu~(2+) activated long persistent strontium aluminate nano scaled phosphor prepared by precipitation method

摘要

This paper reports the detailed preparation process of Eu~(2+) activated long lasting Sr_4Al_(14)O_(25) nano sized phosphor by precipitation method. Scanning electron microscopy (SEM), simultaneous DSC-TG, X-ray diffraction (XRD), photo luminescent spectroscope (PLS) and thermal luminescent (TL) spectroscope were employed to characterize the phosphor. SrAl_2O_4:Eu~(2+)Dy~(3+) and Sr_4Al_(14)O_(25):Eu~(2+)Dy~(3+) phosphors in nano scale were obtained by calcinating the precipitated precursor at 1200 and 1300 deg C, respectively. Both the low-temperature product SrAl_2O_4:Eu~(2+)Dy~(3+) and the high-temperature product Sr_4Al_(14)O_(25):Eu~(2+)Dy~(3+) showed photoluminescence upon UV illumination with an emission peak at 480 and 505 nm, respectively. When compared to the powder obtained in conventional method, the nano sized powders revealed a blue shift in emission spectrum due to the decrease in grain size. Those two phosphors showed long persistent afterglow, and the Sr_4Al_(14)O_(25):Eu~(2+)Dy~(3+) phosphor exhibited better afterglow property than SrAl_2O_4:Eu~(2+)Dy~(3+) phosphor due to a deeper trap level and a higher trap concentration formed in the host material.