Investigation of the structure and photoluminescence properties of Eu3+ ion-activated Y6WxMo(1 − x)O12

Abstract

A series of Eu³⁺ ion-activated Y₆W_xMo_{(1 − x)}O₁₂ polycrystalline powders were synthesized using a solid-state reaction. The crystal structure, ultraviolet-visible and photoluminescence spectra of these compounds were characterized. The structural parameters, electronic structure and orbital population of Y₆WO₁₂ and Y₆MoO₁₂ were determined by means of density functional theory calculation. The calculated structural parameters agreed well with the experimental values. Both electronic structures and ultraviolet-visible spectra indicated that the band-gap of Y₆WO₁₂ is larger than that of Y₆MoO₁₂. The WO₆ or MoO₆ groups in the host lattices could be efficiently excited by near-UV or violet light, and then transferred the energy to the activator Eu³⁺ ions, resulting in red light dominated emission. It was shown that the ratio of W to Mo in the host lattice had an impact on the luminescence intensity, the purity of the emission light and the decay lifetime strongly. Compounds Y₆W_xMo_{(1 − x)}O₁₂:Eu could be red-phosphor candidates for WLED devices.