Na3Sm(PO4)2: (3+1)-dimensional commensurately modulated structure model and photoluminescence properties

Abstract For the first time, we determined the detailed crystal structure of Na 3 Sm(PO 4 ) 2 using single crystal X-ray diffraction and established the commensurately modulated structure model using the superspace formalism. The structure adopts a (3+1)-dimensional superspace group Pca 2 1 (0 β 0)000 with the modulation vector q=1/3b*. At the same time, the photoluminescent properties of Na 3 Sm(PO 4 ) 2 sintered at different temperatures between 800 and 1200°C were studied. Under near-UV excitation (402 nm), Na 3 Sm(PO 4 ) 2 shows intense characteristic emission bands of Sm 3+ (561, 596, 642 nm) with the CIE coordinate of (0.5709, 0.4282), corresponding to orange color. The excitation spectrum covers a wide range from 350 nm to 470 nm, which indicates that Na 3 Sm(PO 4 ) 2 can be efficiently activated by near-UV or visuable LED ship.