Solid-state synthesis, characterization and luminescent properties of Eu 3+-doped gadolinium tungstate and molybdate phosphors: Gd (2−x)MO 6:Eu x3+ ( M=W, Mo)

Abstract

Red phosphors gadolinium tungstate and molybdate with the formula Gd (2− x ) MO 6:Eu x 3+ ( M=Mo, W) were successfully synthesized by the solid-state reaction at 900 and 1300 °C for 4 h, respectively. The products were characterized by an X-ray powder diffractometer (XRD), TG–DSC, FT-IR, PL, UV–vis and SEM. Room-temperature photoluminescence indicated that the as-prepared Gd (2− x ) MO 6:Eu x 3+ ( M=Mo, W) had a strong red emission, which is due to the characteristic transitions of Eu 3+ ( 5 D 0→ 7 F J , J=0, 1, 2, 3, 4) for these phosphors. Meanwhile, the 5 D 0→ 7 F 2 is in the dominant position. The emission quantum efficiency of Eu 3+ in the Gd (2− x ) MO 6:Eu x 3+ ( M=Mo, W) system has been investigated. The XRD results indicate that both Gd 2WO 6 and Gd 2MoO 6 belong to the monoclinic system with space group C2/ c [A. Bril, G. Blasse, J. Chem. Phys. 45 (1966) 2350–2356] and I2/ a [A. Bril, G. Blasse, J. Chem. Phys. 45 (1966) 2350–2356], respectively. SEM images indicate that the shape of Gd 1.96WO 6:Eu 0.04 3+ is aggregated small particles with a mean diameter of about 300 nm, and the shape of Gd 1.96MoO 6:Eu 0.04 3+ is block-like structures.