Near infrared and charge transfer luminescence of trivalent ytterbium in KLa(PO_(3))_(4) powders

摘要

The polycrystalline powders of condensed polyphosphates KLa_(1-x)Yb_(x)(PO_(3))_(4) (x velence 5, 10, 15,20percent) with linear chain were prepared by solid-state reaction. These samples were characterized by X-ray diffraction, FTIR and Raman scattering spectroscopies. The obtained powders are formed by single monoclinic phase of type III of condensed polyphosphate KLa(PO_(3))_(4) (KLP) crystallized with P2_(1) space group. Lattice parameters varied as a function of the ytterbium concentration. As the Yb~(3+) concentration increased, the crystal lattice parameters were decreased. For the first time, near infrared (NIR) and UV-Visible spectroscopy of Yb~(3+) in KLa(PO_(3))_(4) powders, at room temperature, are carried out. In the IR range, a broad band relative to the fundamental ~(2)F_(5/2) -> ~(2)F_(7/2) emission was registered. In the UV-Visible spectra, two bands typical of the Yb~(3+) charge transfer band (CTB) luminescence are observed. The registered decay times of these two emission types showed low sensibility to the Yb~(3+) concentration in KLa(PO_(3))_(4).