Physicochemical Characterization of the Hybrid Molybdate–Tungstate Materials for Solid-State Lighting

Abstract

A series of trivalent europium-and samarium-doped calcium molybdate−tungstate phosphors were synthesized via the high-temperature solid-state reaction. The composition of the light-emitting materials was planned to consider different matrix content of Mo/W and various concentrations of dopant ions (Eu 3+ /Sm 3+ ) as the inorganic phosphors with tunable visible emission. X-ray powder diffractograms proved the formation of pure and highly crystalline tetragonal crystals with space group I4 1 / a. Images from a scanning electron microscope enable an analysis of the surface morphology of the microparticles and also functionalized polymer materials. The series of phosphors exhibit strong emission in the visible region at 617 nm, corresponding to the electric dipole transition of 5 D 0 → 7 F 2 of Eu 3+ and 646 nm assigned to the 5 D 5/2 → 6 H 9/2 transition typical for Sm 3+ . The emission intensity of CaMoWO 4 :Eu 3+ /Sm 3+ is tuned by changing the concentration of the Sm 3+ dopant, and 1931 Commission International de I'Eclairage (CIE) chromaticity coordinates showed the emission colors in the reddish-orange region under an excitation of 300 nm and in the red range under both 393 and 404 nm wavelengths. The investigated compounds can be used as a potential commercial tunable phosphor for solid-state lighting applications. For this purpose, the luminescent material was placed into the poly(styrene-co-acrylonitrile) and checked for its functionality.