Changes of Tb Emission by Non-radiative Energy Transfer from Dy in Gd2O2S:Tb Phosphor

In this study, the Gd 2 O 2 S:Tb 1.5 Dy x =0.3,0.6,0.9 nanophosphor were synthesized by the homogenous precipitation method followed with a sulfur reaction. The fluorescence of Gd 2 O 2 S:Tb 1.5 ,Dy nanophosphors, and the energy transfer between dysprosium (Dy) and Tb have been studied. Although, the two weak emissions of Dy were observed, the terbium (Tb) emission was increased due to energy transfer from Dy ions to Tb ions. The results illustrated that the co-activator of Dy had a significant influence on the spectral properties of the Gd 2 O 2 S:Tb 1.5 nanophosphor with an optimal amount of Dy (0.3 mol%). Moreover, Gd 2 O 2 S:Tb 1.5 and Gd 2 O 2 S:Tb 1.5 ,Dy nanophosphors screens were prepared with 10 mg/cm 2 coating thickness. The scintillation properties of these screens have been investigated. We found a Gd 2 O 2 S:Tb 1.5 ,Dy 0.3 scintillator can be employed in x-ray imaging applications.