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 D-5(4) to F-7(J) (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. (C) 2012 Elsevier B.V. All rights reserved.