Effects of doping ions on the luminescence performance of terbium doped gadolinium polysulfide phosphor

Abstract Gd2O2S: Tb (GOS) phosphor screen has been widely used in digital X-ray imaging, and so far, numerous studies have been focused on the doping ions to improve the luminescence performance of the GOS phosphors. GOS: Tb, Dy phosphors were synthesized by the solid-state reaction process, and their phase composition, particle size, morphology and luminescence properties were characterized. The results showed that co-doping Dy3+ can promote the luminescence and the optimal doping concentration of Dy3+ ions were about 0.2%, however concentration quenching will occur when the doping concentration exceeded 0.5%. Ta5+ ion was also studied in the GOS: Tb and GOS: Tb; Dy phosphors prepared by the same method. The results showed that when the Ta5+co-doping concentration was 100ppm, the strongest emitted light intensity would be obtained for both phosphors. The photoluminescence spectra revealed a different influencing mechanism of Ta5+ ion comparing to Dy3+, which is by a strong energy transfer between Dy3+ and Tb3+.