Eu3+/ Tb3+ - Doped Lnpo4 and Lnpo4. Nh2o (Ln = Y, Gd) Nanowires/Nanorods/Nanoparticles: Synthesis and Characterization

Abstract

A novel polymeric method was applied in the synthesis of nanoscaled luminesecent lanthanide orthophosphates powders. In this method, N, N – dimethyllformamide solvent was adopted, which plays an important role in the formation of the gel. Subsequently, the gel was heat – treated at different temperature to yield Tb 3+ /Eu 3+ - doped LnPO 4 and LnPO 4 .nH 2 O (5 mol %) with various morphologies. Their structure, morphology, composition, thermal behavior, and photoluminescence of as – synthesized products were analyzed by X – ray diffration (XRD), thermogravimetric and differential thermal analysis (TG/DSC), Fourier transform infrared spectroscopy (FT – IR), transmission electron microscopic (TEM) and photoluminescence (PL) spectra. The results indicate that the structure, morphology and luminescent properties of the compounds can be changed during the heat treatment process. Under calcinating at lower temperature, both products present hexagonal hydrated lanthanide orthophosphate nanowires with diameter of 5 ～ 10 nm and a length of about 1 ～ 2 μm. While at the higher temperature, the tetragonal YPO 4 and monoclinic GdPO 4 has been obtained, showing the nanoparticle – like and naorod – like morphologies, respectively. This method can be expected to be a candidate for the synthesis of nanoscaled rare earth orthophosphates materials.

Keywords: orthophosphate, hydrate, luminescence, N, N - dimethylformamide, nanowires