Long lasting behavior of Gd2O2S:Eu3+ phosphor synthesized by hydrothermal routine

This paper reports the detailed preparation process and afterglow properties of Eu3+ activated long lasting Gd2O2S phosphor by hydrothermal routine. Rod-like Gd(OH)3 were firstly synthesized by hydrothermal method to serve as the precursor. Long lasting Gd2O2S:Eu3+,Ti4+,Mg2+ phosphor was obtained by calcinating the precursor with co-activators and S powder. It was found from the results that the hydrothermally prepared Gd(OH)3 revealed a rod-like morphology, while the calcinated Gd2O2S:Eu3+,Ti4+,Mg2+ phosphor showed a round granular shape. The morphological change can be explained by the etching effect of the melt that was formed by the carbonate and S powder during the high temperature calcination. The obtained Gd2O2S:Eu3+,Ti4+,Mg2+ phosphor produced a red emission upon 243 nm UV excitation, which is a typical emission of Eu3+ from 5Dj to 7Fj states. Long lasting behavior was observed after the UV source was switched off, due to the formation of electron traps with suitable trap depth within the matrix by the codoped Ti4+ and Mg2+ ions.