In this work, La₂O₂S:Eu³⁺ nanophosphor was successfully synthesized through a combination method of co-precipitation and following reduction step, using commercial available lanthanum sulfate octahydrate, europium nitrate hexahydrate and ammonia water as experimental raw materials. Fourier transform infrared spectroscopy (FTIR) results showed that the precursor contains OH^- and SO₄^2- groups. X-ray diffraction (XRD) exhibited that the composition of the precursor is La₂(OH)₄SO₄·2H₂O. After calcination at 800 ^oC in muffle furnace for 2 h, the precursor was transformed into the La₂O₂SO₄ phase and then reduced to pure La₂O₂S phase at 800 ^oC for 1h under a reducing atmosphere. Differential scanning calorimetry/thermogravimetry (DSC/TG) analysis further confirmed that the removal of crystal water and dehydroxylation process from La₂(OH)₄SO₄·2H₂O to La₂O₂SO₄. Field-emission scanning electron microscopy (FESEM) observations displayed that the morphologies of La₂(OH)₄SO₄·2H₂O and La₂O₂SO₄ are lamellar structures, while after reduction treatment, the produced La₂O₂S possesses a rice ear-like shape with particle size of 20-50 nm. Photoluminescence (PL) spectra revealed that the La₂O₂S:Eu³⁺ nanophosphor displays excellent photoluminescent properties, with the main emission peak at 624 nm after photoexcitation at 254 nm, a good CIE coordinate of (0.6669, 0.3214), a short lifetime of 1.60 ms and an appropriate CCT value of 3951 K

Keywords: La₂O₂SO₄/La₂O₂S, Rice ear-like morphology, Co-precipitation method, Reduction treatment, Photoluminescence