Crystal structures and luminescence properties of Eu²⁺-activated new NaBa_0.5Ca_0.5PO₄ and Na₃Ba₂Ca(PO₄)₃

Abstract

NaBa(1-x)Ca(x)PO4:Eu(2+) were synthesized using polymerizable complex method. New phases were observed at x = 1/3 and 0.5, which were identified by single-crystal XRD analysis as Na3Ba2Ca(PO4)3 and NaBa0.5Ca0.5PO4 with a trigonal system. Though both phases pretend to be solid solutions between NaBaPO4 and NaCaPO4, they have different coordination environments and PO4 orderings. 1 mol% Eu(2+)-activated NaBaPO4, Na3Ba2Ca(PO4)3, and NaBa0.5Ca0.5PO4 exhibited an emission maximum at 435 nm, 458 nm, and 460 nm, respectively. The shift of the emission maximum might be due to a change in the Eu-O bond length.

Exploration of electron–vibrational interaction in the 5d states of Eu2+ ions in ABaPO4 (A = Li, Na, K and Rb) phosphors

“…The experimental data required for estimation of the EVI parameters of ABaPO 4 :Eu 2 + (A = Li, Na, K and Rb) phosphors were derived from the results published by Zhang et al , Kim et al , Lin et al and Song et al . The photoluminescence spectra of all four phosphors were recorded at room temperature and the observed excitation and emission peaks are attributed to the 4f↔5d transitions of Eu 2 + ions.…”

“…NaBaPO 4 crystallizes in a trigonal phase with space group P m1 (space group no. 164) . There are three metal cation sites in NaBaPO 4 wherein, Na + and Ba 2 + occupy the sites with coordination numbers 6 and 12, respectively.…”

“…Crystal structures of (a) LiBaPO 4 :Eu 2 + , (b) NaBaPO 4 :Eu 2 + , (c) KBaPO 4 :Eu 2 + and (d) RbBaPO 4 :Eu 2 + .…”

“…Taking advantage the nature of the emission band, we analyze the electron–vibrational interaction (EVI) parameters of the 5d state of Eu 2 + ions in some ABPO 4 (A = Li, Na, K and Rb; B = Ba) systems. The experimental data required for this analysis are borrowed from earlier reported results for these phosphors .…”

Synthesis, Structure, and Photoluminescence of a Novel Oxynitride BaYSi2O5N Activated by Eu2+ and Ce3+

“…511 Our group succeeded in the development of new compounds capable of hosts for Eu 2+ -activated phosphors with giving a contrast in the ionic radii of constituent ions by substitution of Sr 2+ or Ca 2+ for Ba 2+ in Ba 4 Al 2 S 7 or NaBaPO 4 , respectively. 9,10 On the other hand, oxynitrides are one of the promising host groups for phosphors because some oxynitrides such as SiAlON, Ba 3 Si 6 O 12 N 2 , and their related materials exhibit excellent luminescent properties, especially low thermal quencing. 12 Based on the background described above, we searched for new oxynitride compounds with the concept of contrasts in constituent elements with respects to not only the ionic radii but also oxidation numbers ( Figure S1) .…”