Synthesis and photoluminescence properties of Eu2+-doped olivine Mg2SiO4 blue-emitting phosphor for plant growth

Mg2SiO4:Eu2+ phosphors with olivine structure were prepared by the solid-state reaction under a reducing atmosphere, and their phase composition, crystal structure, microscopic morphology, and photoluminescence properties were investigated. It was suggested that Eu2+ ions occupied the lattice of Mg2+ ions, and a small amount of Eu2+ ions doping (0.05% ~ 0.2%) did not affect the crystal structure and morphology of the Mg2SiO4. The samples were crystallized into ellipsoidal particles with a size of 1–3 μm. The optimal doping concentration of Eu2+ ions in Mg2-xSiO4: xEu2+ phosphors is 0.1%. Upon the excitation of 275 nm ultraviolet light, the Mg2-xSiO4: xEu2+(x = 0.1%) sample exhibited a broad emission band with the maximum emission intensity at 453 nm, which is in the spectral absorption range of chlorophyll A and chlorophyll B, thus enabling the enhancement of the photosynthesis of the plant growth. The emission spectrum of the sample is decomposed into two subbands by the Gaussian method, which corresponds to the 5d-4f transitions of Eu2+ ions occupying the Mg1 and Mg2 lattice sites, respectively. In addition, the fluorescence decay behavior and thermal stability of the Mg2-xSiO4: xEu2+(x = 0.1%) sample were analyzed, and the sample showed good thermal stability.