Photoluminescence and Decay Kinetic Studies of Eu3+ Activated Novel Magnesium Tungstate Double Perovskite for Lighting Application.

Abstract

A red emitting luminescent novel double perovskites magnesium tungstate (Mg₃WO₆) activated with Eu³⁺ were prepared and characterized for structural and photoluminescence (PL) properties. The phosphors were prepared using the standard solid-state reaction (SSR) method, with varying Eu³⁺ concentrations ranging from 1 mol% to 4 mol%. All the phosphor under study were thoroughly examined by utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDAX) analysis for structural and morphological aspects. The Rietveld refinement matching of powder XRD patters confirms the Monoclinic crystalline structure of the phosphor under study. Moreover, the crystallite size is computed using Debye-Scherrer (D-S) formulation. The monoclinic crystallized Mg₃WO₆:Eu³⁺ phosphors show agglomerated surface looking like a cluster of particles, which primarily due to the high-temperature calcination. When excited at 278 nm, 396 nm, and 536 nm excitations, the phosphor series doped with Eu³⁺ exhibited standard PL emission of activator ions. Under all three applied excitations, the phosphors displayed red spectral emission with notably high luminescence intensity for which ⁵D₀-⁷F_J (J = 1 and 2) standard transition of Eu³⁺ ions are responsible. The effect of doping and concentration quenching were investigated and discussed. The decay kinetics of the phosphors were examined using PL decay lifetime measurements for λ_ex = 396 nm and λ_em = 616 nm, and corresponding lifetime was determined. Additionally, the PL quantum efficiency, a key parameter for evaluating the potential of the phosphors, was calculated based on the measured PL decay time using Auzel's model. The CIE color coordinates significantly falling within red region of the CIE diagram, confirming standard color emission and related photometric parameters were determined. As a result, the synthesized phosphor series under investigation found capable in their application in light illumination devices.