Intense upconversion in novel transparent NaLuF4:Tb3+, Yb3+ glass–ceramics

• Transparent NaLuF4:Tb3+–Yb3+ glass–ceramics were fabricated for the first time.
• Samples exhibit intense characteristic emissions of Tb3+ and Yb3+ ionic pairs.
• Greatly enhanced emission indicates the incorporation of Tb3+, Yb3+ into NaLuF4.

Novel Tb3+–Yb3+ co-doped transparent glass–ceramics containing NaLuF4 nanocrystals were successfully fabricated by melt-quenching technique for the first time. The structural and luminescent properties were investigated by XRD, TEM, absorption and upconversion spectra systemically. All samples exhibit intense characteristic emissions of Tb3+ (5D4 → 7FJ (J = 3–5) and 5D3 → 7FJ (J = 4–6)) and cooperative luminescence of Yb3+ ion pairs (476 nm) excited by 980 nm laser. The dramatically enhanced upconversion in glass–ceramics suggests that most rare earth ions have preferentially entered into NaLuF4 nanocrystals with lower phonon energy after crystallization. Our results indicate NaLuF4 based transparent glass–ceramics may be excellent hosts for rare earth ions doping.