Green-emitting (La,M,Tb)OCl (M = Mg, Ca, and Sr) phosphors

Green-emitting (La1−x−yMxTby)OCl (0 ⩽ x ⩽ 0.13, 0.03 ⩽ y ⩽ 0.15, M = Mg, Ca, and Sr) single phase phosphors were synthesized using a liquid-phase method and their photoluminescence properties were characterized. The excitation spectrum consisted of a strong broad band from 220 to 290 nm, which corresponds to the 4f–5d transition of Tb3+. The oxychloride phosphors exhibit typical emission peaks assigned to the transition from 5D4 to 7FJ (J = 6, 5, 4, and 3) of Tb3+, and the luminescence emission intensity was successfully enhanced by doping divalent alkaline earth metal ions (M = Mg2+, Ca2+, and Sr2+) into La3+ sites of the host LaOCl lattice. The highest green emission intensity was obtained for (La0.88Ca0.05Tb0.07)OCl, of which the relative emission intensity was 75% of that for a commercial green-emitting (La0.52Ce0.31Tb0.17)PO4 phosphor.

► Green-emitting (La,M,Tb)OCl (M = Mg, Ca, and Sr) phosphors were synthesized by a liquid-phase method.
► The luminescence emission intensity was successfully enhanced by doping alkaline earth metal ions into the host lattice.
► The highest emission intensity was obtained for (La0.88Ca0.05Tb0.07)OCl.
► The relative emission intensity of (La0.88Ca0.05Tb0.07)OCl was 75% of that for a commercial (La0.52Ce0.31Tb0.17)PO4 phosphor.