Synthesis and Near-Infrared Fluorescent Properties of Nd3+-Yb3+ Co-Doped Lanthanum Phosphate

In the present work, LaPO₄: Ln (Ln = Nd, Yb) samples were prepared via a simple hydrothermal method and characterized by X-ray diffraction, UV-Vis spectrophotometer, and fluorescence spectrophotometer. The XRD patterns show that the crystal structure of samples was lanthanum phosphate phase that belongs to monoclinic system with a space group of P2₁/n. Nd³⁺, as a sensitizer, was excited to ⁴I_9/2 by 808 nm laser diode, and then transfer the energy to Yb³⁺, resulting in the fluorescent emission at 980 nm. This fluorescent emission arises from the ²F_5/2→²F_7/2 transition. And the luminescent intensity depends on the concentration of Yb³⁺ ions. This implies that the concentration quenching is observed in the present work. The optimal Yb³⁺ ions concentration is 4 mol %.