Synthesis and luminescence properties of Y2O2S:Dy3+, Mg2+, Ti4+phosphors prepared by sol–gel process

Y2O2S:Dy3+, Mg2+, Ti4+ white-light long-lasting phosphors were synthesized by sol–gel method. Y2O2S:Dy3+, Mg2+, Ti4+ phosphors were characterized by X-ray diffraction, photoluminescence spectroscopy and thermally stimulated spectrometry. The results showed that the samples calcined at different temperatures from 900 °C to 1200 °C were composed of the pure Y2O2S phase. Under 359 nm UV excitation, the phosphor presented white luminescence due to mixing of the dominating emissions centered at 488 nm (blue) and 579 nm (yellow), corresponding to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+, respectively. Both the fluorescence intensity and afterglow time reached the largest values in the phosphor calcined at 1200 °C and the afterglow time could last for over 65 min (≥1 mcd/m2) when the excited source was cut off.