Study on the luminescent properties of Dy3+-doped double perovskite LiYMgWO6 phosphors for WLED applications

In this study, phosphors of LiYMgWO₆:Dy³⁺ were created for the first time using a high-temperature solid-state synthesis technique. The purity of the phases and the chemical composition of the samples were analyzed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), which validated the establishment of pure-phase LiYMgWO₆. Under 352 nm excitation, the Dy³⁺ ions exhibit characteristic emissions originating from the ⁴F_9/2 → (Fang et al., 2018 [6]⁾ H_J/2 (J = 11，13，15) transitions, resulting in blue, yellow, and red emission peaks. The photoluminescence properties were systematically investigated, and the optimal emission intensity was observed at a Dy³⁺ doping concentration of 0.04. The LiYMgWO₆:0.04Dy³⁺ phosphor exhibited a quantum efficiency of 40.7 %, with its emission intensity at 423 K maintaining 46.8 % of the intensity observed at room temperature (298 K). Additionally, a WLED fabricated by combining the synthesized yellow-emitting LiYMgWO₆:Dy³⁺ phosphor with a commercial blue phosphor (BAM: Eu²⁺) achieved a color rendering index (Ra) of 70 under 365 nm excitation. These findings indicate that the LiYMgWO₆:0.04Dy³⁺ yellow phosphor shows great potential as a candidate for UV-excitation WLED devices.