title: Rare-earth containing nanocrystal precipitation and up-conversion luminescence in oxyfluoride glasses.
abstract: Rare-earth ion doped oxyfluoride glass with a composition of 25SiO2 x 5GeO2 x 15AIO1.5 x 40PbF2 x 10PbO x (4.9 - x)GdF3 x 0.1HoF3 x xYbF3 (x = 0, 0.1,0.2, 0.5,1,2, 3, and 4) in molar ratio was developed. When the oxyfluoride glasses are heat-treated at the first crystallization temperature, the glasses give transparent glass-ceramics in which rare-earth-containing fluorite-type nanocrystals of about 17.2 nm in diameter uniformly precipitated in the glass matrix. Comparing with the glasses before heat treatment, the glass ceramics exhibit very strong up-conversion luminescence under 980-nm light excitation. Rare-earth-containing nanocrystals were also space selectively precipitated upon laser irradiation in an oxyfluoride glass; the size of precipitated nanocrystals can be controlled by laser power and scan speed. The intensity of the green up-conversion luminescence is strongly dependent on the precipitation of beta-PbF2 nanocrystals and the YbF3 concentration. The reasons for the highly efficient Ho3+ up-conversion luminescence are discussed.
authors.affiliation: Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology, Asahidai 1-1, Nomi, Ishikawa 923-1292, Japan.
authors.forename: Jianbei
authors.initials: J
authors.lastname: Qiu
authors.forename: Akio
authors.initials: A
authors.lastname: Makishima
mesh_terms: D003460:Crystallization / Q000379:methods*; D004735:Energy Transfer; D005461:Fluorine / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D005590:Fractional Precipitation; D005898:Glass / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D007477:Ions; D008027:Light; D049449:Luminescence; D008422:Materials Testing; D008674:Metals, Rare Earth / Q000032:analysis / Q000737:chemistry*; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D010087:Oxides / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D010777:Photochemistry / Q000379:methods; D012666:Semiconductors
chemical_list: D007477:Ions; D008674:Metals, Rare Earth; D010087:Oxides; D005461:Fluorine; C014559:fluorine monoxide