Crystal structure and luminescence properties of a novel single-phase orange-red emitting phosphor Ca(9)La (PO(4))(7):Sm(3+)

Ca(9)La(1−x)(PO(4))(7):xSm(3+) phosphors (0.01 < x < 0.25) were synthesized via high temperature solid-state reaction. Their properties including crystal structure, decay performance, thermal stability and photoluminescence were examined in detail. Phase analysis indicated that the phosphors crystallized in a rhombohedral structure, and the emission spectra of the phosphors consisted of four peaks centered around 570, 607, 653, and 714 nm, attributed to Sm(3+) ions transitions (4)G(5/2) → (6)H(J) (J = 5/2, 7/2, 9/2, and 11/2, respectively). The optimal Sm(3+) doping content was 0.12 mol and the Ca(9)La(PO(4))(7):Sm(3+) phosphor also exhibited better thermal stability compared to other phosphors. In addition, the mechanism behind the energy transfer between Sm(3+) ions was determined to be dipole–dipole interactions as described by Dexter theory. The results indicated that as orange-red phosphors, Ca(9)La (PO(4))(7):Sm(3+) phosphors were promising candidates for being integrated into white light emitting diodes.