Crystal structure and magnetic-dipole emissions of Sr2CaWO6: RE3+ (RE=Dy, Sm and Eu) phosphors

• Published in: Journal of alloys and compounds Vol. 739; pp. 660 - 668
• Main Authors: Song, Xiaoyu, Wang, Xianxian, Xu, Xuewen, Liu, Xin, Ge, Xiaoli, Meng, Fanbin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.03.2018
• Subjects: Double perovskite; Phosphors; Photoluminescence; WLEDs; Double perovskite; WLEDs; Phosphors; Photoluminescence
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.12.302

The Sr2CaWO6: RE3+ (RE = Dy, Sm and Eu) phosphors with the unusual emissions corresponding to the magnetic-dipole (MD) transition were synthesized via a sol-gel process. The crystal structure, electronic properties, photoluminescence excitation and emission spectra, and fluorescence lifetimes of the as-prepared samples were investigated. X-ray diffraction analysis confirmed that Sr2CaWO6 crystallized in the monoclinic structure with the centrosymmetric monoclinic space group (P21/n). The indirect band gap for Sr2CaWO6 was 4.24 eV, which was calculated within the framework of density functional theory (DFT). The phosphors could be excited by the ultra-violet (UV) light at 280 nm, and exhibited characteristic emissions corresponding to the MD transitions for different RE3+ ions. The WO6 groups in the host lattice can absorb UV light efficiently, and then transferred the energy to activator ions. The results indicated that the doped rare earth ions occupied the centrosymmetric site in Sr2CaWO6 lattice. With increasing the concentration of the dopants, the local symmetry of the activator ions can be effectively changed, which resulted in the enhancement of the characteristic emissions dominated by the electric-dipole (ED) transitions of the doped RE3+. The Sr2CaWO6: Sm3+ phosphor exhibited near white emission under radiation of 280 nm. [Display omitted] •The as-prepared Sr2CaWO6 sample crystallizes in the monoclinic structure.•The PL emission of Sr2CaWO6: RE3+ is dominated by MD transitions of RE3+.•The doped RE3+ ions occupy the centrosymmetric sites of Sr2CaWO6 host.•The CIE coordinate of Sr2CaWO6: Sm3+ is (0.36, 0.30).