Efficient blue up-conversion luminescence of Tm3+ ions in transparent oxyfluoride glass ceramics containing PbxCd1-xF2 nanocrystals

Oxyfluoride glasses were developed in the 30SiO(2).15AlO(1.5).28PbF(2).22CdF(2).(4.8-y)GdF3.0.1NdF(3).yYbF(3).0.1TmF(3)(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 PbxCd1-xF2 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) --> H-3(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 PbxCd1-xF2 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.