Energy transfer and upconversion emission of Er3+/Tb3+/Yb3+ co-doped transparent glass-ceramics containing Ba2LaF7 nanocrystals under heat treatment

• We prepared UC of Er–Tb–Yb co-doped glass-ceramics containing Ba2LaF7 nanocrystals.
• The UC emission intensity in the glass-ceramics has enhanced after heat treatment.
• There was possibly an energy transition process from Tb3+ to Er3+ ions.
• The UC emission intensity increases and reaches its maximum at 2.5Yb3+ concentration.

Transparent glass-ceramics SiO2–AlF3–BaF2–TiO2–LaF3 (SABTL) containing Ba2LaF7 nanocrystals were successfully prepared by heat treatment process through conventional melting method. The crystal size in the glass-ceramics increased gradually under the changing of heat treatment temperatures and times, which was confirmed by the results of XRD, TEM measurements. The intensity of the blue, green and red upconversion luminescence around 490 nm, 525 nm, 546 nm, 657 nm which originate from the transitions 5D4 → 7FJ (J = 6 and 5) of Tb3+ ions and (2H11/2, 4S3/2, 4F9/2) → 4I15/2 transitions of Er3+ ions, respectively, were strongly observed after heat treatment under 980 nm laser diode excitation. The intensity of upconversion luminescence was increased gradually with the increase of Yb3+ concentrations and reaches its maximum at 2.5 mol%. The upconversion luminescence and energy transfer process between Tb3+, Yb3+ and Er3+ ions in the glass-ceramics were discussed.