Europium activated gadolinium sulfide nanoparticles

Abstract

In the present work, we report the synthesis and characterization of Eu³⁺ doped Gd₂S₃ nanoparticles, a potential candidate for T₁-weighted MRI contrast agents and molecular markers. Eu³⁺ doped Gd_2(1−x)S₃:Eu_x (x = 0.0, 0.02, 0.04 and 0.06) were synthesized by a chemical route by varying the Eu concentration. X-ray diffraction and scanning electron microscopy were performed to extract the information about structure and surface morphology of prepared nanoparticles, respectively. The oxidation state of the Eu ions was elucidated from X-ray absorption near edge structure (XANES) spectra, which indicate the presence of only Eu³⁺ ions without any signature of Eu²⁺ ions. 120 MeV Ag⁹⁺ ions were used for ionoluminescence (IL) measurements to study the optical properties. The IL results show that the luminescence intensity increases with increasing Eu doping and no saturation or degradation of the luminescence were observed for the as-prepared nanoparticles. The nanoparticles doped with 2 and 4% Eu showed an increase in the IL intensity initially before decreasing to saturation at higher fluences. On the other hand, IL intensity from 6% doped samples decreased exponentially and saturated at higher fluences.