Synthesis and luminescence characterization of fine gadolinium oxide phosphors for high resolution X-ray imaging

In this work, fine Gd₂O₃:Eu powder was synthesized using a solution-combustion method for high-resolution digital X-ray imaging detectors. The structure of the phosphors was characterized by X-ray diffraction (XRD), high-resolution scanning electron microscopy (HR-SEM). It was possible to obtain fine Gd₂O₃:Eu crystallized particles with an average particle size of only 20 nm. The optical properties investigated were photoluminescence emission and excitation spectra, luminescence decay time, and X-ray conversion efficiency. The emission corresponding to the ⁵D₀→⁷F₂ transition at 610 nm was dominant, and the Eu³⁺ ions substituted well for the Gd³⁺ sites. Quenching starts at an europium concentration of 8% wt, and the strongest X-ray conversion efficiency was achieved at the phosphor with 5% wt. The mean lifetime of synthesized phosphors is 2.3-2.6 ms.