Enhancement of luminescence intensity and color purity of MgxZn1-xMoO4:Eu3+, Bi3+ phosphors

ZnMoO4:Eu3+ red phosphors co-doped with Mg2+ and Bi3+ were synthesized using a solid-state reaction. X-ray powder diffraction, scanning electron microscopy, and photoluminescence analysis were used for characterizing the phosphors. The introduction of Mg2+ into a Zn2+ site further enhanced the emission intensity of the D-5(0) -> F-7(2) transition since the asymmetry of a Eu3+ site increased when Zn2+ was substituted by Mg2+. The co-doped Bi3+ efficiently sensitized the emission of Eu3+ and effectively extended the absorption of near-ultraviolet light with wavelengths ranging from 300 to 370 nm. The high color purity of Mg0.10Zn0.84MoO4:Eu-0.05(3+), Bi-0.01(3+) was calculated to be 91.80%. The thermal quenching temperature T-d was about 387 K and the activation energy for thermal quenching was found to be about 0.31 eV for Mg0.10Zn0.84MoO4:Eu-0.05(3+), Bi-0.01(3+), respectively. Moreover, the results revealed that the energy transfer was more effective when the Zn0.95MoO4:Eu-0.05(3+) phosphors were co-doped with Mg2+ ions and Bi3+ ions than those doped only with Mg2+ ions.