Morphology and upconversion luminescence of NaYbF4:Tm3+ nanocrystals modified by Gd3+ ions

Hexagonal Tm3+ and Gd3+ doped NaYbF4 nanodisks and nanorods were synthesized through the hydrothermal approach. The dissolution–reconstruction mechanism plays an important role in the growth progress. With the introduction of Gd3+ ions, the morphological shapes of NaYbF4 were modified to be uniform. Under 980 nm excitation, the Tm3+ ions doped into NaYbF4 samples emitted ultraviolet fluorescence 288 nm (1I6 → 3H6), 344 nm (1I6 → 3F4), 360 nm (1D2 → 3H6) and blue fluorescence 450 nm (1D2 → 3F4), 473 nm (1G4 → 3H6), which were modified and enhanced by Gd3+ ions. We reported a new method to modify simultaneously morphology and luminescence of the Tm3+-doped NaYbF4 by introducing Gd3+ ions.

► Tm3+ and Gd3+ doped NaYbF4 nanodisks and nanorods were synthesized through the hydrothermal approach. ► Morphology of NaYbF4 nanodisks and nanorods was modified by introducing Gd3+ ions. ► Upconversion luminescence of Tm3+ ions was modified and enhanced by Gd3+ ions, simultaneously. ► Upconversion mechanisms of Yb3+–Tm3+–Gd3+ system in NaYbF4 nanocrystals were discussed.