Gd₂O₂S:Eu³⁺ Nanophosphors: Microwave Synthesis and X-ray Imaging Detector Application

Red-emitting Gd₂O₂S:Eu³⁺ nanophosphors were successfully prepared using a microwave irradiation method followed by hydrogenation treatment. The optimum calcination temperature (900 ºC) was determined by thermogravimetric-differential scanning calorimetry. The X-ray diffraction results showed that all the samples consisted of the pure hexagonal Gd₂O₂S:Eu³⁺ phase. The field emission scanning electron microscopy images showed that the Gd₂O₂S:Eu³⁺ nanophosphors were spherical, and their average particle diameter increased parallel with the microwave irradiation power. The photoluminescence spectra (under 325-nm excitation) of the samples exhibited red emission corresponding to the ⁵D₀→⁷F₂ transition of Eu³⁺ ions. A Gd₂O₂S:Eu³⁺ nanophosphor screen film was fabricated using the particle-binder sedimentation method. The result shows that the luminance of the Gd₂O₂S:Eu³⁺ nanophosphor screen film increased with an increase in the X-ray energy. Hence, this film would become one of the potential candidate for future imaging applications.

Keywords:
Gd₂O₂S:Eu³⁺ nanophosphors; microwave; luminescent; imaging detector