Preparation and effect of thermal treatment on Gd2O3:SiO2 nanocomposite

Abstract

Rare earth oxides have been extensively investigated due to their fascinating properties such as enhanced luminescence efficiency, lower lasing threshold, high-performance luminescent devices, drug-carrying vehicle, contrast agent in magnetic resonance imaging (MRI), up-conversion materials, catalysts and time-resolved fluorescence (TRF) labels for biological detection etc. Nanocomposites of silica gadolinium oxide have been successfully synthesized by sol–gel process using hydrochloric acid as a catalyst. Gd ( NO 3)3⋅6 H 2 O and tetraethyl orthosilicate (TEOS) were used as precursors to obtain powdered form of gadolinum oxide:silica ( Gd 2 O 3: SiO 2) composite. The powdered samples having 2.8 mol% Gd 2 O 3 were annealed at 500°C and 900°C temperature for 6 h and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM). The effect of annealing on the phase evolution of the composite system has been discussed in detail. It was found that the sintering of gadolinium precursor plays a pivotal role to obtain crystalline phase of Gd 2 O 3. Cubic phase of gadolinium oxide was developed for annealed sample at 900°C (6 h) with an average grain size ~12 nm.