Facile synthesis and luminescence properties of highly uniform YF3:Ln3+ (Ln = Eu, Tb, Ce, Dy) nanocrystals in ionic liquids

Uniform YF3 nanocrystals were prepared through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route in a imidazolium ionic liquids (1-octyl-3-methylimidazolium hexafluorophosphate) with the ionic liquids acting as both reagents and templates. The partial hydrolysis of PF6− was utilized to introduce a fluoride source. X-ray diffraction (XRD), field emission scanning microscopy (FE-SEM) and transmission electron microscopy (TEM) have been used to study the morphologies and crystal structure. The detailed growth mechanism of the YF3 nanocrystals was researched. Furthermore, under ultraviolet exaltation, the phosphor of YF3:Eu3+ and YF3:Tb3+ shows red and green emission, corresponding to 5D0–7F1 transition of Eu3+ and 5D4–7F5 transition of Tb3+. The emission spectrum of YF3:Ce3+ phosphor exhibits one dissymmetrical band extending from 350 to 500 nm with a maximum at about 383 nm. A bright fluorescent yellow emission at 574 nm and blue emission at 487 nm were observed in the YF3:Dy3+. These novel nanocrystals could be potentially used in biolabels and light emitting diodes (LEDs).