Template-free synthesis of mesoporous NaTbF4 and NaTbF4:Eu nano-rice and their luminescence properties

Abstract

Single-crystalline mesoporous NaTbF₄ nano-rice have been successfully synthesized in large scale by reaction of aqueous Tb³⁺ with sodium fluoride in the presence of ethylenediaminetetraacetic acid (EDTA) at 110 °C for 12 h, which were confirmed by X-ray powder diffraction, energy dispersive X-ray analysis, transmission electron microscopy, scanning electron microscopy, and nitrogen adsorption–desorption isotherms. A mechanism for the formation of the mesoporous nano-rice by an EDTA-directed assembly process accompanied by the localized Ostwald ripening has been proposed based on the observations of time-dependent experiments. In addition, this novel nano-rice can be used as an excellent host lattice for Eu³⁺ ions, in which the luminescence properties of Eu³⁺ would be improved significantly. Our study indicates that the maximum quantum efficiency of NaTbF₄:Eu nano-rice reaches up to 69.9%. This work demonstrates that morphology-controlled synthesis can offer a simple solution to fabricate mesoporous NaTbF₄:Eu nano-rice for technological and biomedical applications.