Hydrothermal Synthesis and Optical Properties of Magneto-Optical Na3FeF6:Tb3+ Octahedral Particles.

Zhiguo Zhao,Xue Li

doi:10.3390/ma13020320

Abstract

Sodium iron hexafluoride (Na3FeF6), as a colorless iron fluoride, is expected to be an ideal host for rare earth ions to realize magneto-optical bi-functionality. Herein, monodispersed terbium ions (Tb3+) doped Na3FeF6 particles are successfully synthesized by a facile one-pot hydrothermal process. X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM) reveal that the Tb3+ doped Na3FeF6 micro-particles with regular octahedral shape can be assigned to a monoclinic crystal structure (space group P21/c). Under ultraviolet light excitation, the Na3FeF6:Tb3+ octahedral particles given orange-red light emission originated from the 5D4→7FJ transitions of the Tb3+ ions. In addition, the magnetism measurement indicates that Na3FeF6:Tb3+ octahedral particles are paramagnetic with high magnetization at room temperature. Therefore, the Na3FeF6:Tb3+ powders may find potential applications in the biomedical field as magnetic-optical bi-functional materials.

Highlights

Bi-functional materials with distinct magnetic and fluorescent properties have received considerable attention [1,2] due to their potential applications in magnetic resonance imaging [3], targeted drug delivery [4], sensors [5,6], optical isolators [7,8,9], high accuracy communication [10], and aircraft guidance [11]
The diffraction peaks of all samples clearly match that of the standard pattern of Na3 AlF6 (JCPDS no. 12-0907), indicating the structure of obtained samples is isomorphic with cryolite-like structures (Na3 AlF6 and Na3 CrF6 ) that belongs to the space group P21/c [24,25,26]
Na1 site is located at the distorted octahedral site of (NaF6 ), Na2 site is located at the bi-pyramid site of (NaF5 ), and the Na3 site is located at the distorted tetrahedral site of (NaF4 )

Summary

Introduction

Bi-functional materials with distinct magnetic and fluorescent (luminescent) properties have received considerable attention [1,2] due to their potential applications in magnetic resonance imaging [3], targeted drug delivery [4], sensors [5,6], optical isolators [7,8,9], high accuracy communication [10], and aircraft guidance [11]. Great efforts have been devoted to the design and fabrication of magneto-optical bi-functional systems based on RE-doped up-conversion or down-conversion materials, such as Gd2 O3 : Er3+ /Yb3+ [16], GdPO4 : Eu3+ [17], YVO4 : Er3+ [18], Tb0.94 Pr0.06 VO4 [19] and NaYF4 : Yb, Ho [20]. Materials 2020, 13, 320 core-shell structures is complicated, and more importantly, magnetic oxide, Fe3 O4 , strongly absorbs visible light and quenches fluorescence of the RE ions [23]. The investigation of the magnetic property reveals that the Na3 FeF6 :Tb3+ particles are paramagnetic at room temperature These results indicate that Na3 FeF6 :Tb3+ particles might be promising as a new platform for exploiting magnetic-optical functionalities

Materials and Methods

Characterization

Results and Discussion

Ultraviolet-visible

Conclusions