Novel red-emitting LiGd(WO4)2:Eu3+ phosphor with high thermal stability and high color purity for application in white light-emitting diodes

Abstract

An excellent light-emitting diodes phosphor must possess effective absorption, high quantum efficiency, high quenching temperatures, and high color purity. Our synthesized LiGd(WO₄)₂:Eu³⁺ materials possess all of these properties. Excitation of these phosphors with ultraviolet radiation yields bright red emission at 617 nm due to the ⁵D₀ → ⁷F₂ transition of Eu³⁺ ions. Compared with different Eu³⁺ doping concentrations, LiGd(WO₄)₂:80%Eu³⁺ phosphor has optimal photoluminescence properties and shows internal quantum efficiency as high as 69%. More impressive is its good thermal stability; when heated up to 150 °C, the LiGd(WO₄)₂:80%Eu³⁺ phosphor still has 81% of its initial emission intensity at room temperature. Furthermore, the LiGd(WO₄)₂:80%Eu³⁺ phosphor shows high purity of red emission with coordinate values (x = 0.656, y = 0.334). The abovementioned results suggest that the LiGd(WO₄)₂:80%Eu³⁺ phosphor can be a suitable red-emitting candidate for ultraviolet-excited white light-emitting diodes.