| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1646684 | Materials Letters | 2012 | 4 Pages |
Highly crystalline NaYF4:Ln3+ (Ln=Yb, Er, Tm) crystals with honeycomb structure were successfully synthesized for the first time by using a mixed NaCl–KCl flux cooling method at a holding temperature of 800 °C for 2 h in air. The results indicated that the crystals of NaYF4:Ln3+ belonged to hexagonal system and three-dimensional open pores had an average diameter of 1 μm interconnected with each other. Upon 980 nm laser diode excitation, yellow green and sky blue upconversion fluorescences of β-NaYF4:20%Yb3+, 2%Er3+ crystals and β-NaYF4:20%Yb3+, 0.5%Tm3+ crystals, which was caused by two- or three-photon upconversion processes, was observed clearly.
► Honeycomb-like β-NaYF4 crystals were successfully synthesized for the first time. ►The mixed NaCl–KCl flux cooling method was adopted. ►The yellow green and sky blue upconversion fluorescences can be observed clearly.
