Salt-assisted size-controlled synthesis and luminescence studies of single phase CaWO₄:Dy³⁺: an insight into its morphological evolution, energy transfer and colour evaluation

Abstract

The size of the particles of CaWO4:Dy3+ increases with the addition of NH4Cl/KCl electrolyte and enhances its luminescence.

Crystal structure, optical spectroscopy and energy transfer properties in NaZnPO4:Ce3+, Tb3+ phosphors for UV-based LEDs

“…† In this host, the Zn site with the 4e Wyckoff position which creates high stress in the lattice. There exist three kinds of Zn 2+ cation sites (Zn 10 , Zn 14 , and Zn 19 ) and three positions of Na + sites: Na (6), Na (7), and Na (18) with a coordination number (CN), CN ¼ 6 for Na (6) and Na (7) and CN ¼ 8 for Na (18). The interatomic distances of P-O, Zn-O, and the Na-O for the NZPO sample are listed in Table S3.…”

“…[1][2][3][4] Rare earth (RE 3+ ), transition metals, and Bi 3+ -activated phosphors have been extensively investigated due to their unique luminescence performance. [5][6][7][8][9] RE ions can emit fascinating colors thanks to their special 4f shell conguration. Different excitation energies and almost all of the visible light spectrum from violet to red can be obtained by combining different RE ions and varying the ratio of dopants.…”

Understanding the Doping Chemistry of High Oxidation States in Scheelite CaWO4 by Hydrothermal Conditions

“…That is, CaWO 4 can absorb medium ultraviolet light of ∼250 nm and emit blue light of ∼420 nm. On the other hand, the chemical and physical properties of scheelite are stable, showing the merits of a wide band gap and low phonon energy essential for application as a potential luminescent host material. , For those lanthanide ions of trivalent states higher than Ca 2+ in the host lattice, the energy-level transitions are extremely sensitive to the surrounding crystal field environment, and the change of symmetry will have a powerful influence on its luminescence. Among trivalent lanthanide ions, Eu 3+ is widely used as a structural probe owing to the fact that it has stable luminescence properties in the visible-light region, and energy-level transitions (f → f transitions) in the 4f shell (similar structural probe roles could also be applied for other rare-earth ions like Dy 3+ and Sm 3+ ). , In particular, for this work, the detailed reasons for selecting Eu 3+ as the probe for the local structure are the following: Firstly, the emission peak of the excited state 5 D 0 de-excited and decayed to the ground state 7 F 0 will not be split due to the influence of the crystal field, which is very helpful for the interpretation of the experimental results.…”