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

Abstract Green-emitting (La 1− x − y M x Tb y )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 Tb 3+ . The oxychloride phosphors exhibit typical emission peaks assigned to the transition from 5 D 4 to 7 F J ( J = 6, 5, 4, and 3) of Tb 3+ , and the luminescence emission intensity was successfully enhanced by doping divalent alkaline earth metal ions (M = Mg 2+ , Ca 2+ , and Sr 2+ ) into La 3+ sites of the host LaOCl lattice. The highest green emission intensity was obtained for (La 0.88 Ca 0.05 Tb 0.07 )OCl, of which the relative emission intensity was 75% of that for a commercial green-emitting (La 0.52 Ce 0.31 Tb 0.17 )PO 4 phosphor.