Hydrothermal synthesis and photoluminescence properties of Gd2O2SO4:Eu~(3+) spherical phosphor

摘要

Gd2O2SO4:Eu~(3+) spherical phosphor was successfully synthesized through a simple hydrothermal synthesis routine from commercially available Gd2(SO4)3·8H2O, Eu2(SO4)3·8H2O and urea as the starting materials. The as-synthesized products were characterized by XRD, SEM, FT-IR, DTA-TG-DTG and photoluminescence (PL) spectra. It is found that the phase and morphologies of the precursors are strongly dependent on m value, namely, the molar ratio of urea to Gd2(SO4)3. The optimal m value is 2. DTA-TG-DTG, FT-IR and XRD analyses show that the optimal precursor is composed of amorphous Gd2(OH)2CO3SO4·H2O phase and can be converted into pure Gd2O2SO4 phase at a temperature higher than 800 °C for 2 h in air. SEM observation shows that the pure Gd2O2SO4 phosphor particles are spherical in shape and well dispersed, with a particle size range of about 1-3 μm. PL spectra reveal that the strongest emission peak for Gd2O2SO4:Eu~(3+) spherical phosphor is located at 620 nm under 270 nm light excitation, which corresponds to the ~5D0 → ~7F2 transition of Eu~(3+) ions. The quenching concentration of Eu~(3+) ions is 15 mol% and the concentration quenching mechanism is the exchange interaction for the ~5D0 → ~7F2 transition of Eu~(3+) ions. KPhosphor;; Chemical synthesis;; Crystal growth;; Luminescence