Efficient blue up-conversion luminescence of Tm3+ ions in transparent oxyfluoride glass ceramics containing Pbx Cd1−x F2 nanocrystals

Oxyfluoride glasses were developed in the 30SiO2 · 15AlO1.5 · 28PbF2 · 22CdF2 · (4.8 − y)GdF3 · 0.1NdF3 · yYbF3 · 0.1TmF3 (y = 0, 0.1, 0.2, 0.5, 1, 2, 3, 4 and 4.8) composition, in mol%. X-ray diffraction analysis revealed that heat treatments of the oxyfluoride glasses cause the precipitation of (Nd3+, Yb3 +, Tm3+)-doped fluorite-type Pbx Cd1−x F2 nanocrystals of about 17.8 nm diameter in a glass matrix. Very strong blue up-conversion luminescence which can be assigned to the Tm3+ :1 G 4 →3 H 6 transition under 800 nm excitation was observed in these transparent glass ceramics. The intensity of the blue up-conversion luminescence is strongly dependent on the precipitation of Pbx Cd1−x F2 crystals and the YbF3 concentration. The reasons for the highly efficient Tm3+ up-conversion luminescence are discussed. An energy transfer process and an up-conversion mechanism in the glass and glass ceramics are also proposed.