Synthesis and characterization of Tb3+/Gd3+ dual-doped multifunctional hydroxyapatite nanoparticles

Abstract Tb 3+ /Gd 3+ dual-doped multifunctional hydroxyapatite (Tb 3+ /Gd 3+ -HAp) nanoparticles with magnetic and luminescent properties were prepared by the co-precipitation method using CaCl 2 and Na 2 HPO 4 ·12H 2 O as raw materials and CTAB as a template in alkaline conditions. The products were characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM). Single hexagonal phase Tb 3+ /Gd 3+ -HAp nanoparticles were obtained by the co-precipitation method and the products were sphere-like morphology with particle sizes ranging from 40 to 100 nm. Crystallinity degree of the products decreased with the Tb 3+ /Gd 3+ substitute increasing. Photoluminescence (PL) and magnetic properties of the products were also investigated. The results show Tb 3+ /Gd 3+ -HAp nanoparticles are endowed with strong luminescence at 544 nm and prominent paramagnetic behavior, allowing their potential applications in biological labeling. Gd 3+ ions sensitize the 5 D 4 - 7 F 5 transition emission of Tb 3+ ions in HAp nanoparticles, and the PL emission intensity increases along with increasing concentration of Gd 3+ ions. Concentration quenching occurs when the Gd 3+ concentration exceeds 10 mol%. The magnetization level of Tb 3+ /Gd 3+ -HAp increased steadily with the doping concentration of Gd 3+ ions.