Monodisperse mesocrystals of YF3 and Ce3+/Ln3+ (Ln=Tb, Eu) co-activated YF3: shape control synthesis, luminescent properties, and biocompatibility.

ABSTRACT

A family of monodisperse YF(3), YF(3)Ce(3+) and YF(3)Ce(3+)/Ln(3+) (Ln=Tb, Eu) mesocrystals with a morphology of a hollow spindle can be synthesized by a solvothermal process using yttrium nitrate and NH(4) F as precursors. The effects of reaction time, fluorine source, solvents, and reaction temperature on the synthesis of these mesocrystals have been studied in detail. The results demonstrate that the formation of a hollow spindle-like YF(3) can be ascribed to a nonclassical crystallization process by means of a particle-based reaction route in ethanol. It has been shown that the fluorine sources selected have a remarkable effect on the morphologies and crystalline phases of the final products. Moreover, the luminescent properties of Ln(3+)-doped and Ce(3+)/Ln(3+) -co-doped spindle-like YF(3) mesocrystals were also investigated. It turns out that Ce(3+) is an efficient sensitizer for Ln(3+) in the spindle-like YF(3) mesocrystals. Remarkable fluorescence enhancement was observed in Ce(3+)/Ln(3+) -co-doped YF(3) mesocrystals. The mechanism of the energy transfer and electronic transition between Ce(3+) and Ln(3+) in the host material of YF(3) mesocrystals was also explored. The cytotoxicity study revealed that these YF(3) -based nanocrystals are biocompatible for applications, such as cellular imaging.