Preparation of LaPO 4 :Ce 3+ ,Tb 3+ nanophosphors by mixed co-precipitation process and their photoluminescence properties

Abstract Nanosized Ce 3+ and Tb 3+ co-doped LaPO 4 phosphors were synthesized by a mixed co-precipitation method using oxalic acid (H 2 C 2 O 4 ·2H 2 O) and ammonium dibasic phosphate ((NH 4 ) 2 HPO 4 ) as the precipitants. The morphology, crystal structure and photoluminescence properties of the synthesized LaPO 4 :Ce 3+ ,Tb 3+ phosphors were investigated by thermo-gravimetry and differential scanning colorimetry, X-ray diffraction, scanning electron microscope, and photoluminescence emission spectra methods. The results showed that the pure phase of lanthanum orthophosphate can be formed with a lower calcining temperature compared to that of the traditional solid-state reaction method. LaPO 4 phosphors doped with 20 mol% Tb 3+ and 40 mol% Ce 3+ , which were calcined at 900 °C for 1 h, reached the maximum emission intensity under 265 nm excitation. The most prominent emission was at 543 nm, which corresponded to the 5 D 4 → 7 F 5 transition of Tb 3+ ions.