Microwave-assisted combustion synthesis of (GdxY2-x) O3:Eu3+ nanoparticles

Abstract

(GdxY2-x)O3:Eu3+ nanoparticles were synthesized from stoichiometric metal nitrates mixture (oxidizer) and glycine (fuel) by microwave-assisted combustion method. (GdxY2-x)O3:Eu3+ nanoparticles were fully crystalized in solution combustion step by microwave irradiation. These nanoparticles were thermally treated at 300, 500, 700, 900, and 1100 ˚C for about 30 min to release the combustion-induced stresses. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray (EDX), and photoluminescence spectroscopy (PL) techniques. Based on the XRD spectra, the as-synthesized sample was crystalline and single-phase. The crystallinity of nanoparticles was further improved after additional thermal treatment. The main PL peaks intensity (PLI) at 612 nm and 590 nm (relating to 5D0-7F2 electric bipolar and 5D0-7F1 magnetic dipole transitions, respectively) were increased upon thermal treatment above 300˚C. The PLI was increased about twice of the as-synthesized sample upon thermal treatment at 1000 ˚C. The Chromaticity coordinates diagram of the emission were evaluated based on the 1931 CIE chromaticity diagram. TEM images confirmed the grain growth from ~25 nm to over 100 nm after thermal treatment. The substitution of Eu3+ instead of Y3+ was also confirmed by EDX point analysis in 3% (GdxY2-x) O3: Eu+3 structure. Crystallographic planes and the crystallinity of the as-synthesized samples were investigated using SAED patterns.