Efficient Near-Infrared Down-Conversion in Pr3+-Yb3+ Codoped Glasses and Glass Ceramics Containing LaF3 Nanocrystals

The Pr3+-Yb3+ ion codoped 40SiO(2)-30Al(2)O(3)-18Na(2)O-12LaF(3) glasses were synthesized by a conventional melting-quenching method. Near-infrared downconversion emission with 12% quantum yield has been realized. Transparent glass ceramics containing LaF3 nanocrystals were prepared by heat treatment. X-ray diffraction and scanning electron microscopy results show that fluorides favor the formation of small crystals. Comparing the absorption and emission spectra of the glasses with that of the glass ceramics indicates that the Pr3+ ions are incorporated in priority into the LaF3 crystals, due to the similar crystal lattice. Thus, energy transfer. efficiency cannot be enhanced in the present glass by crystallization. It is suggested that fluorides from TbF3 to LuF3 (including YF3) having the orthorhombic structure in aluminosilicate glass are suitable for incorporating YbF3 during the crystallization process.