Effects of doped-Li+ and -Eu3+ ions content on structure and luminescent properties of LixSr1−2x(MoO4):Eu3+x red-emitting phosphors for white LEDs

Eu3+-activated molybdate-based red-emitting phosphors of LixSr1−2x(MoO4):Eu3+x with various doped-ions contents (x = 0.1–0.5) were synthesized by the organic gel-thermal decomposition process and their structure and photoluminescence properties were investigated. The as-synthesized phosphors are characterized with a scheelite structure and almost tetragonal-dipyramidal morphology. With the doped-ions content increasing from (x=) 0.1 to 0.5 in LixSr1−2x(MoO4):Eu3+x, the lattice cell reduces and the grain growth is basically suppressed during the calcination process owing to the hybrid ions substitution. These LixSr1−2x(MoO4):Eu3+x phosphors can be effectively excited by ultraviolet light (396 nm) and blue light (466 nm), which are well suitable for current commercial near-UV and blue LEDs. The excitation intensity and emission intensity for LixSr1−2x(MoO4):Eu3+x phosphors exhibit an increasing trend with the doped-ions content, and two maximum values are located at x = 0.25 and 0.45 respectively, which are coincident with two minimum average grain sizes about 76 nm (x = 0.25) and 58 nm (x = 0.45) calculated by the X-ray diffraction analysis. The measured chromaticity coordinates for LixSr1−2x(MoO4):Eu3+x phosphors with a high doped-ions content (x = 0.25–0.50) are completely consistent with the National Television System Committee (NTSC) standard requirement.

LixSr1−2x(MoO4):Eu3+x red-emitting phosphors with micrometer size and without particle aggregation prepared by the organic gel-thermal decomposition process can be effectively excited by ultraviolet light (396 nm) and blue light (466 nm) and their chromaticity coordinates are consistent with the NTSC standard values.Figure optionsDownload as PowerPoint slideHighlights
► LixSr1−2x(MoO4):Eu3+x red-emitting phosphors with micrometer sizes were prepared.
► Their structure and luminescent property can be tuned by Li+ and Eu3+ ions doping.
► These phosphors can be effectively excited by ultraviolet light and blue light.
► Their chromaticity coordinates are consistent with the NTSC standard values.