Effect of Mn4+ ions on the structure and luminescence properties of NaY (MoO4)2: Yb3+/Er3+ phosphor

In this work, we prepare a series of phosphor of NaY(MoO4)(2): Yb3+/Er3+Mn4+ using high temperature solid state method, the results of X-ray diffraction (XRD) shows that the doped Yb3+, Er3+ and Mn4+ ions will make lattice be smaller size. The reduction of the binding energy of O-1s XPS is due to the vacancy of O2- ions in the matrix lattice which is brought by the substitution of Mn4+ and Mo6+ ions. Under the laser excitation of 980 nm, the Er3+ ions exhibit strong green up-conversion emission and weak red up-conversion emission at 532, 554 and 658 nm, corresponding to the transitions of H-2(11/2)/S-4(3/2) -> I-4(15/2), F-4(9/2) -> I-4(15/2) of Er3+ ions. The reasons for the high green emission intensity are discussed in detail by analyzing the Raman spectroscopy of NaY (MoO4)(2): Yb3+/Er3+/Mn4+ phosphor. It can be inferred that the emissions at 554 nm and 658 nm are a two-photon process by the relationship between pump power and up-conversion luminescence intensity, and the possible up-conversion emission mechanism has been explored. Meanwhile, the luminescence life of green and red light decreases with the increasing doping concentration of Mn4+ ions. After doping Mn4+ ions, the symmetry of the matrix lattice decreases, and the emission intensity of up-conversion will be greatly improved. The study of this work expands the research scope of traditional conversion materials, and offers reference for the exploration of up-conversion luminescent materials based on transition metals.