Structure twinning and photoluminescence properties of sodium dysprosium phosphate Na3Dy(PO4)2

• Published in: Journal of materials science. Materials in electronics Vol. 29; no. 2; pp. 1664 - 1671
• Main Authors: Nie, Cong-Kui, Zhao, Dan, Duan, Pei-Gao, Fan, Yun-Chang, Zhang, Lei, Zhang, Rui-Juan
• Format: Journal Article
• Language: English
• Published: New York Springer US 2018; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromaticity; Crystal structure; Crystallography; Decay; Dysprosium; Emission spectra; Excitation; Excitation spectra; Exponential functions; Lanthanide phosphates; Materials Science; Molten salts; Optical and Electronic Materials; Phosphates; Photoluminescence; Radiation; Rare earth phosphates; Raw materials; Single crystals; Sintering (powder metallurgy); Twinning
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-017-8079-8

Rare-earth phosphate with the general formula Na 3 Ln(PO 4 ) 2 (Ln = lanthanoids) have been known as good luminescent materials for a long time, but their crystal structures have not been recognized completely. In this work, compound Na 3 Dy(PO 4 ) 2 was prepared using molten salt (flux) method and was structurally determined on X-ray single-crystal diffraction for the first time. Interestingly, its structure solution was complicated by non-merohedral twinning, whose twin law can be characterized by a 180° rotation about the (1 0 0) direction of reciprocal lattice. Furthermore, the excitation and emission spectra, decay time and CIE chromaticity index of Na 3 Dy(PO 4 ) 2 were studied. Under near-UV light excitation (350 nm), the powdered Na 3 Dy(PO 4 ) 2 sintered at 1000 °C shows the strongest emission at around 484 and 574 nm, which originates from the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transformations of Dy 3+ ion, respectively. The decay curve at 350 nm was measured and the decay curve can be well fitted by bi-exponential function, which can be explained by two crystallographic sites of Dy atom in the structure.