Rare earth doped NaYF4 nanorods: Synthesis and up-conversion luminescence spanning deep-ultraviolet to near-infrared regions

• NaYF4 nanorods were successfully synthesized using oleic acid as stabilizing agent.
• The size of nanorods could be tuned by controlling the concentration of Gd3+.
• Under 980 nm excitation, the UV to the NIR multiple UC emissions were observed.
• This kind of nanorods will have application in multichannel fluorescent label.

Yb3+/Er3+/Tm3+/Gd3+ co-doped NaYF4 nanorods were synthesized by a facile hydrothermal treatment method using oleic acid as stabilizing agent. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and luminescence spectroscopy. The samples show a hexagonal phase structure and rod-like morphology. The size of the products is varied by controlling the concentration of Gd3+. Under 980 nm excitation, multiple up-conversion (UC) emissions spanning the deep-ultraviolet (UV) to the near-infrared (NIR) were observed. The possible UC mechanisms were also discussed. The as-prepared nanorods showed potential applications in multichannel fluorescent label.