microwave-assisted combustion synthesis of (gdxy2-x) o3:eu3+ nanoparticles

Dxy2-x)o3:eu^3+ nanoparticles were synthesized from stoichiometric metal nitrates mixture (oxidizer) and glycine (fuel) by microwave-assisted combustion method. (gdxy2-x)o3:eu^3+ 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 and 590 nm (relating to ^5d˚-7f2 electric bipolar and ^5d˚-^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 eu^3+ instead of y^3+ or gd^3+ was also confirmed by edx point analysis in (gdxy2-x)o3:eu^3+ structure. crystallographic planes of the synthesized samples were investigated using saed patterns. crystallinity of samples with increasing the heat-treatment temperature was promoted. also afm images confirm the enhancement of particles size with increasing temperature.