Synthesis and photoluminescent characteristics of Dy³⁺ doped Gd₂O₃ phosphors

Pure and dysprosium doped gadolinium oxide nanoparticles for three different concentrations (2, 5 and 10 mol.%) were synthesized by auto-combustion method using citric acid as fuel. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), UV–vis–NIR spectroscopy and photoluminescence (PL) spectroscopy techniques. XRD pattern revealed the crystalline cubic phase with space group Ia3 (Space Group: 206) for both the pure and doped Gd₂O₃ nanoparticles. The metal oxide phase formation and purity of Gd₂O₃ nanoparticles were further confirmed from the FTIR spectra. Morphology of the pure Gd₂O₃ powder is loosely dispersed clusters of tiny particles with microscopic pores, whereas for the doped samples aggregates were broken to form small clusters. Optical absorption measurements were recorded in the UV–vis–NIR wavelength region and the optical band gap variations with dopant concentration were discussed. The PL spectra of pure and Dy³⁺ doped Gd₂O₃ nanoparticles have been studied and the effect of emitted light on the yellow-to-blue intensity ratio (Y/B) of Dy³⁺ emission was demonstrated. (paper)