Synthesis, Structural and Photophysical Properties of Gd₂O₃:Eu³⁺ Nanostructures Prepared by a Microwave Sintering Process

Abstract

In this paper, we report the obtention of gadolinium oxide doped with europium (Gd 2 O 3 :Eu +3 ) by thermal decomposition of the Gd(OH) 3 :Eu 3+ precursor prepared by the microwave assisted hydrothermal method. These systems were analyzed by thermalgravimetric analyses (TGA/DTA), X-ray diffraction (XRD), structural Rietveld refinement method, fourrier transmission infrared absorbance spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) measurement. XRD patterns, Rietveld refinement analysis and FT-IR confirmed that the Gd(OH) 3 :Eu 3+ precursor crystallize in a hexagonal structure and space group P 6 /m , while the Gd 2 O 3 :Eu 3+ powders annealed in range of 500 ° C and 700 ° C crystallized in a cubic structure with space group Ia-3. FE-SEM images showed that Gd(OH) 3 :Eu 3+ precursor and Gd 2 O 3 :Eu 3+ are composed by aggregated and polydispersed particles structured as nanorods-like morphology. The excitation spectra consisted of an intense broad band with a maximum at 263 nm and the Eu 3+ ions can be excitated via matrix. The emission spectra presented the characteristics transitions of the Eu 3+ ion, whose main emission, , is observed at 612 nm. The photophysical properties indicated that the microwave sintering treatment favored the Eu 3+ ions connected to the O-Gd linkages in the Gd 2 O 3 matrix. Also, the emission in the Gd 2 O 3 :Eu 3+ comes from the energy transfered from the Gd-O linkages to the clusters in the crystalline structure.