Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

Pr³⁺-activated barium tungsto-molybdate solid solution phosphor Ba(Mo_1-zW_z)O₄:Pr³⁺ is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr³⁺-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of WO₄ for MoO₄ can significantly enhance its luminescence, which may be due to the fact that Ba(Mo_1-zW_z)O₄:Pr³⁺ owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity, well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white light-emitting diodes (LEDs).