Extensive studies of host lattices and activators in lanthanide phosphors based on efficient synthesis

Uniform and dispersive NaLa(MoO₄)_2-x(WO₄)_x (abbreviated as NLMW): Eu³⁺/Tb³⁺(5 mol%) microspheres were successfully synthesized at low temperature (393 K). The incorporation of Bi³⁺ or Mn²⁺ into CaMoO₄: Eu³⁺ with tetragonal crystalline phase has also been studied. The structure, morphology, and luminescent properties of these powder samples were examined by means of X-ray diffraction (abbreviated as XRD), scanning electron microscopy (abbreviated as SEM), and fluorescent spectrophotometry, respectively. SEM images substantiated that these phosphors have uniform sphere-shaped morphologies. The samples exhibited the characteristic emission of Eu³⁺(⁵D₀ → ⁷F_J)/Tb³⁺(⁵D₄ → ⁷F_J) under ultraviolet excitation. Effects of the ratio of MoO₄/WO₄ on the luminescence behavior were investigated in detail. The MoO₄/WO₄ ratio was optimized as 1/1. The international commission on illumination (abbreviated CIE for its French name) chromaticity coordinates of NLMW: Eu³⁺ and NLMW: Tb³⁺ indicate the emissions were located in the red and green region, which will be beneficial for the potential device fabrication. Encapsulation of Bi³⁺ and Mn²⁺ both can effectively sensitize europium (III) ions, generating stronger red emissions (⁵D₀ → ⁷F_J). - Highlights: • Lanthanide molybdate–tungstates have been synthesized by SMC method. • Regular microspheres have been observed. • Effects of different hosts on the luminescence were investigated.