A novel blue-emitting phosphor LiSrPO4:Eu for white LEDs

A novel blue-emitting phosphor, LiSrPO₄:Eu²⁺, was prepared by the solid-state reaction and X-ray powder diffraction (XRD) analysis confirmed the formation of LiSrPO₄:Eu²⁺. Photoluminescence (PL) results showed that the phosphor can be efficiently excited by UV-visible light from 250 to 440 nm, and exhibited bright blue emission. The effects of the doped-Eu²⁺ concentration in LiSrPO₄:Eu²⁺ on the PL were investigated in detail. The results showed that the relative PL intensity increases with Eu²⁺-concentration increasing until a maximum intensity is reached, and then it decreases due to concentration quenching and a red-shift appears, which are explained satisfactorily with the luminescent theory. Upon excited with 396 nm light, the present synthesized phosphor has higher emission intensity than that from the commercial blue phosphor, BaMgAl₁₀O₁₇:Eu²⁺. Bright blue light-emitting diodes were fabricated by the combination of the synthesized LiSrPO₄:Eu²⁺ with ∼397 nm emitting InGaN-based chips.