Photoluminescent properties of Eu3+, Tb3+ activated M3Ln(PO4)3 (M = Sr, Ca; Ln = Y, La, Gd) phosphors derived from hybrid precursors

Ternary orthophosphates M3Ln(PO4)3 doped with Eu3+, Tb3+ were prepared via an in situ chemical co-precipitation technology, and the assembly process of hybrid precursors were as follows: using rare-earth coordination polymers with salicylic acid as precursors and composing with the polyvinyl alcohol (PVA) as dispersing media. Their microstructure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The emission spectra exhibited strong luminescence of 5D0 → 7F2 at 609 nm, indicating that the Eu3+ located in a noncentrosymmetric position in Eu-doped M3Ln (PO4)3 matrix. Besides this, the values of red to orange emission intensities for Eu3+ in Sr3Gd (PO4)3 strongly depend on the doping concentration.