Microwave-assisted synthesis and down- and up-conversion luminescent properties of BaYF5:Ln (Ln = Yb/Er, Ce/Tb) nanocrystals.

Hydrophilic BaYF5 nanocrystals have been prepared via a facile and fast microwave-assisted method at low temperature without the assistance of template reagents. The Yb3+/Er3+, Ce3+/Tb3+ doped BaYF5 nanocrystals could be dispersed well in water and alcohol. BaYF5:Ce3+/Tb3+ nanocrystals show bright green luminescence. The existence of the Ce3+ ions can dramatically enhance the luminescence intensity of the Tb3+ ions, due to the efficient energy transfer from Ce3+ to Tb3+ ions. More importantly, when doped with Yb3+/Er3+ ions, the BaYF5 nanocrystals show bright red upconversion luminescence. [ABSTRACT FROM AUTHOR]