Synthesis, photoluminescence and Li+ concentration effect on new reddish phosphor Li2Sr2Al(PO4)3:Sm3+ for white LEDs

Abstract A series of Sm3+ doped Li2Sr2AlP3O12 reddish phosphors have been synthesized by traditional solid-state reaction method. The emission spectrum of Li2Sr2AlP3O12:Sm3+ phosphor is composed of four sharp emission bands at 561, 596, 643 and 705 nm, respectively. We investigated the influence of Sm3+ and Li+ concentration on the luminescent properties of phosphors, among which Li1.98Sr1.96AlP3O12:0.04Sm3+ shows the strongest emission. The phosphors exhibit luminescence quenching as Sm3+ concentration is more than 0.04 mol%, which is due to dipole–dipole interaction among neighbouring Sm3+ ions. Li ions can not only enhance the emission intensity but also extend the luminescence lifetime, which is probably attributed to the suitable Li+ contents that decreases the crystal defects of phosphors. In addition, Sm3+ doped Li2Sr2AlP3O12 phosphor with the chromaticity coordinate (0.59, 0.41) can be demonstrated as a potential reddish luminescence material.