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

Abstract (Gd 1− x ,Eu x ) 2 O 2 SO 4 nano-phosphors were synthesized by a novel co-precipitation method from commercially available Gd 2 O 3 , Eu 2 O 3 , H 2 SO 4 and NaOH starting materials. Composition of the precursor is greatly influenced by the molar ratio of NaOH to (Gd 1− x ,Eu x ) 2 (SO 4 ) 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 (Gd 1− x ,Eu x ) 2 O 2 SO 4 nano-phosphor by calcining at 900 °C for 2 h in air. Transmission electron microscope (TEM) observation shows that the Gd 2 O 2 SO 4 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 5 D 0 → 7 F 2 transition of Eu 3+ ions. The quenching concentration of Eu 3+ ions is 10 mol% and the concentration quenching mechanism is exchange interaction among the Eu 3+ ions. Decay study reveals that the 5 D 0 → 7 F 2 transition of Eu 3+ ions has a single exponential decay behavior.