A facile co-precipitation synthesis and luminescence properties of red-emitting la₂o₂so₄: X%eu³⁺ nanophosphors

A series of Eu³⁺ ions activated La₂ O₂ SO₄ nanophosphors had been prepared successfully by a facial co-precipitation route followed by a subsequent calcination treatment. The commercial Eu₂ O₃, La₂ O₃, HNO₃, (NH₄ )₂ SO₄ and NH₃·H₂ O were used as the raw materials. The structural analyses and luminescence properties of as-prepared products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and photoluminescence (PL) spectra. Pure La₂ O₂ SO₄ quasi-sphere nanoparticles with an average diameter of 40 nm were successfully prepared by calcining the precursor at 800^o C for 2 h in air. PL results reveal that the strongest red emission peak is centred at 617 nm upon 393 nm light excitation, corresponding to the⁵ D₀ →⁷ F₂ transition of Eu³⁺ ions. Its quenching concentration is 9 mol%, which can be attributed to the exchange interaction among Eu³⁺ ions and the corresponding decay process shows a double exponential decay behavior, with 0.310 μs for t₁ and 1.419 μs for t₂.