[Preparation of nanocrystal Gd2O3: Eu by EDTA complexing sol-gel process and spectroscopic study].

ABSTRACT

Gd2O3 Eu nanocrystal was synthesized by EDTA complexing sol-gel process at relatively low temperature, in which ethylene-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and disperser respectively. The properties of the nanocrystal were investigated by XRD, SEM, EDS, and fluorescence spectrophotometer. The results show that nanosized, homogenous and pure cubic phase Gd2O3 Eu has been produced after the precursor calcined at 800 degrees C for 2 h. The particles of the Gd2O3 Eu are basically spherical in shape and about 30 nm in size. The main emission peak of Gd2O3 Eu nanocrystal is at 611 nm, resulting in a red emission. Compared with micron scale Gd2O3 Eu phosphors prepared by a conventional method, a clear red shift occurs in the excitation spectrum of Gd2O3 Eu nanocrystal prepared by the present work, and the quenching concentration of Eu has been raised. For this type of nanophosphor, quenching starts at an Eu concentration of 8% (mol%), while a value of 6% was obtained for the conventional one.