Synthesis and photoluminescence properties of a novel red-emitting Eu³⁺-doped LiSrGd(WO₄)₃ phosphors

Rare-earth (RE)-doped tungstate LiSrGd_1−x(WO₄)₃:xEu red-emitting phosphors were prepared by traditional high-temperature solid-state reaction method. These samples were characterized by X-ray diffraction, scanning electron microscopy, and photoluminescence (PL). PL spectrum exhibited characteristic luminescent ⁵D₀/⁷F_J (J = 0–4) intra-4f shell Eu³⁺ ion transitions. Eu³⁺-activated LiSrGd(WO₄)₃ phosphors could be excited by near-ultraviolet (NUV) light of 393 nm and blue light of 464 nm and showed excellent red emission lying around 616 nm (⁵D₀ → ⁷F₂). Eu³⁺-doped concentration in LiSrGd_1−x(WO₄)₃:xEu was x = 0.3. Arising temperature to 393 K, the red emission intensity of LiSrGd_1−x(WO₄)₃:xEu phosphor decayed by only 13.57 and 19.53 \(\%\) relative to room temperature, which indicates that the phosphor possesses good temperature stability. The evaluated Commission International de l’Eclairage (CIE) color coordinates of these phosphors were close to the standard red CIE color coordinate published by the National Television Systems Committee. Hence LiSrGd_1−x(WO₄)₃:xEu phosphor is promising with potential for white LED.