Synthesis and Luminescence Investigation of Eu³⁺ Doped Ca₂KZn₂V₃O₁₂ Phosphors: A Potential Material for WLEDs Applications

Abstract

A series of white light emitting Ca₂KZn_2–xV₃O₁₂:xEu³⁺ (x = 0.1, 0.2, 0.3, 0.4 and 0.5) phosphor samples were successfully synthesized by the traditional solid-state reaction method. The powder X-ray diffraction (XRD) patterns of the as-prepared sample reveal the high degree of crystallinity of the cubical structure with $Ia\overline{3}d$ space group and without any other phase formation. Fourier transform infrared (FTIR) spectra confirmed the occurrence of characteristic vibrational bands of garnet vanadate. The optical diffuse reflectance spectra consisting of broad band absorption in the ultraviolet (UV) region and the sharp absorption in the visible region were ascribing to the charge transfer between ligand–metal in the VO₄ tetrahedral group and Eu³⁺ ions. Under the UV and near-UV excitation wavelengths, the broad band emission and the sharp emission were ascribing to the host material charge transfer of the VO₄ tetrahedral group and f-f transitions of the rare-earth Eu³⁺ ions respectively. Ultimately, through the doping concentration optimization, a high Color Rendering Index (CRI) and excellent Correlated Color Temperature (CCT) were achieved with cool white emission. Therefore, the contribution of Ca₂KZn_1.8Eu_0.2V₃O₁₂ phosphor was significant to phosphor-converted white light emitting device (WLEDs) excited with near ultraviolet.