Investigation on the Luminescence of Ln3+ (Ln = Eu, Gd, and Dy) in Hexagonal KCaR(PO4)2 Phosphates (R = Gd, Y)

Abstract

The optical properties of Ln3+ ions (Ln = Gd, Eu and Dy) in KCaR (PO4)2 (R = Gd, Y) are studied in detail. It is found that no striking concentration quenching for Gd3+ and Eu3+ activators occurred in hexagonal KCaR(PO4)2 when exciting into their f → f transitions, viz., via Gd3+ 274 nm and Eu3+ 394 nm, respectively. Energy transfer from Gd3+ to Eu3+ or Dy3+ ions via Gd3+ are very efficient. The concentration quenching of Dy3+ emission based on KCaGd(PO4)2 was very strong on account of its cross relaxation. The concentration dependence of Eu3+ and Dy3+ emission sensitized by Gd3+ is also reported. The interactions between Ln3+ in KCaR(PO4)2 were mainly d‐d or exchange interactions.

Synthesis and characterization of Eu3+ activated hexagonal ABaGd(PO4)2 (A+=Li, Na, or K) phosphates

“…Besides these lines, two emission lines at higher wavelength side due to 5D 0 ---> 7F 3 and 5Do---> 7F4 transitions were also observed, respectively. These results are consistent with the earlier reported results, except for the non-appearance of line for 5Do ~ 7Fo transition in the emission spectrum, as had been reported by Shaolong Tie et al (1995). For the DE site symmetry of the Eu 3+ ions in a hexagonal phosphate, three lines for each transitions, 5D o + 7F!…”

Synthesis of GdVO4 : Bi,Eu Red Phosphor by Combustion Process

“…The 5 D 0 3 7 F 2 emission line of Eu 3 splits into three components at 609, 615 and 619 nm due to lowering of local site symmetry of Eu 3 ions. These results are consistent with the earlier reported emission results [35]. The splitting of various emission lines was also reported in Eu 3 doped MgSiO 3 gel and attributed to the lowering of local site symmetry of Eu 3 ions [36].…”

Synthesis and crystal structure of NaCuIn(PO4)2

“…In addition, the structures of certain members of this phosphate family are similar to those of the zeolite-ABW structural type (Badri et al, 2014). When the trivalent cation is lanthanum or yttrium, the crystal structures KM II La(PO 4 ) 2 (M II = Mg or Zn) are isotypes of the monazite monoclinic structure of LaPO 4 with space-group type P2 1 /n (Pan et al, 2006;Tie et al, 1995), while KMgY(PO 4 ) 2 turns out to be an isotype of the xenotime structure YPO 4 adopting a tetragonal symmetry with space-group type I4 1 /amd (Tie et al, 1996).…”

“…Transition-metal phosphates have been the subject of intensive research as a result of their interesting physical properties and potential applications in wide-ranging fields such as catalysis, electrochemistry, luminescence (Tie et al, 1995;Pan et al, 2006;Yang et al, 2016) and ion exchange (Cheetham et al, 1999;Han et al, 2015;Manos et al, 2005Manos et al, , 2007Plabst et al, 2009;Stadie et al, 2017). In these materials, the anionic framework is built up from PO 4 tetrahedra linked to different kinds of transition metal (TM) coordination polyhedra of the form [TMO n ] (n = 4, 5 and 6), leading to a large variety of crystal structure families.…”