Synthesis and luminescence properties of red long-lasting phosphor Y2O2S:Eu3+, Mg2+, Ti4+ nanoparticles

We report an effective method to synthesize Y2O2S:Eu3+, Mg2+, Ti4+ nanoparticles. Tube-like Y(OH)3 were firstly synthesized by hydrothermal method to serve as the precursor. Nanocrystalline long-lasting phosphor Y2O2S:Eu3+, Mg2+, Ti4+ was obtained by calcinating the precursor with co-activators and S powder. XRD investigation shows a pure phase of Y2O2S, indicating no other impurity phase appeared. SEM and TEM observation reveals that the precursor synthesized via a hydrothermal routine has tube-like structure and the final phosphor reveals a hexagonal shape. The fine nanoparticles which have the particle size ranging from 30 to 50 nm show uniform size and well-dispersed distribution. From the spectrum, the main emission peaks are ascribed to Eu3+ ions transition from 5DJ (J = 0, 1, 2) to 7FJ (J = 0, 1, 2, 3, 4). After irradiation by 325 nm for 10 min, the Y2O2S:Eu3+, Mg2+, Ti4+ long-lasting phosphor shows very bright red afterglow and the longest could last for more than 1 h even after the irradiation source had been removed. It is considered that the long-lasting phosphorescence is due to the contribution from the electron traps with suitable trap depth.