Synthesis and optical properties of (Gd1-x,Eux)2O2SO4 nano-phosphors by a novel co-precipitation method

(Gd1-x,Eu-x)(2)O2SO4 nano-phosphors were synthesized by a novel co-precipitation method from commercially available Gd2O3, Eu2O3, H2SO4 and NaOH starting materials. Composition of the precursor is greatly influenced by the molar ratio of NaOH to (Gd1-x,Eu-x)(2)(SO4)(3) (the m value), and the optimal m value was found to be 4. Fourier transform infrared spectrum (FT-IR) and thermal analysis show that the precursor (m = 4) can be transformed into pure (Gd1-x,Eu-x)(2)o(2)SO(4) nano-phosphor by calcining at 900 degrees C for 2 h in air. Transmission electron microscope (TEM) observation shows that the Gd2O2SO4 phosphor particles (m = 4) are quasi-spherical in shape and well dispersed, with a mean particle size of about 30-50 nm. Photoluminescence (PL) spectroscopy reveals that the strongest emission peak is located at 617 nm under 271 nm light excitation, which corresponds to the D-5(0) -> F-7(2) transition of Eu3+ ions. The quenching concentration of Eu3+ ions is 10 mol% and the concentration quenching mechanism is exchange interaction among the Eu3+ ions. Decay study reveals that the D-5(0) -> F-7(2) transition of Eu3+ ions has a single exponential decay behavior. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.