The KEu(WO₄)₂ Red Phosphor Co-doped with Li⁺ and SO₄ ²⁻ for Synergistic Enhancement of High Efficiency and Thermal Stability

Abstract

A series of tungstate red phosphors K_1−xLi _xEu(WO₄)_2−y(SO₄) _y were successfully prepared by sol-gel method, and the effects of the introduction of Li⁺ and SO₄ ²⁻ on the fluorescence intensity and thermal quenching properties of the prepared K_1−xLi _xEu(WO₄)_2−y(SO₄) _y phosphors were investigated. The X-ray diffraction data show that the prepared (Li⁺ and SO₄ ²⁻)-doped KEu(WO₄)₂ phosphors have a monoclinic tetragonal structure. In addition, the emission intensities of all the observed emission peaks change significantly with the increase of Li⁺ doping concentration, especially the intensity of the emission peaks at 615 nm fluctuated significantly and reached the maximum at x = 0.3 and y = 0.2. The K_1−xLi _xEu(WO₄)_2−y(SO₄) _y phosphors are found to have the highest fluorescence intensity at x = 0.3 and y = 0.2. Moreover, the K_0.7Li_0.3Eu(WO₄)_1.8(SO₄)_0.2 phosphor has better thermal quenching properties and luminescence efficiency, and the experimental results indicates that the fluorescence intensity and thermal burst performance of KEu(WO₄)₂ red phosphor could be effectively improved by using low-cost bionic doping of Li⁺ and SO₄ ²⁻.

Keywords

sol-gel / fluorescence / phosphors / KEu(WO₄)₂ / Li⁺ / SO₄ ²⁻

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