Synthesis and characterizations of pompon-like Y2O2SO4:Eu3+ phosphors using a UBHP technique based on UAS system

The pompon-like Y2O2SO4:Eu3+ phosphors have been successfully synthesized using a urea-based homogeneous precipitation (UBHP) technique based on urea-ammonium sulfate (UAS) system. Detailed characterizations of the synthetic products were attained by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis and thermo-gravimetry (DTA – TG) and photoluminescence (PL) spectroscopy. SEM observations clearly revealed that morphologies of the synthetic products were controllable by m   values, namely, the molar ratio of SO42− groups to Y3+ ions, and when m = 5, pure pompon-like Y2O2SO4 phosphor with 2 – 3 μm in diameter was obtained. FT-IR and XRD results showed this precursor was composed of amorphous yttrium hydroxyl, carbonate and sulfate groups compound and could be converted into pure Y2O2SO4 phase by calcined at 800 °C for 2 h in air. PL spectra of the Y2O2SO4:Eu3+ phosphors under 268 nm ultraviolet (UV) light excitation showed a red emission at 620 nm as the most prominent peak, which attributes to the 5D0→7F2 transition of Eu3+ ions. The quenching concentration of Eu3+ ions is 5 mol%. The concentration quenching mechanism is the exchange interaction and its corresponding lifetime is 1.85 ms according to the linear fitting result.