title: Analysis of thermal and structural properties of germanate glasses co-doped with Yb(3+)/Tb(3+) ions.
abstract: In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb(3+)/Tb(3+)ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800cm(-1) corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O(-)) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621nm corresponding to (5)D4→(7)FJ (J=6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3.
authors.affiliation: Department of Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology, 45D Wiejska Street, 15-351 Bialystok, Poland. Electronic address: j.zmojda@pb.edu.pl.
authors.forename: J
authors.initials: J
authors.lastname: Zmojda
authors.affiliation: Department of Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology, 45D Wiejska Street, 15-351 Bialystok, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kochanowicz
authors.affiliation: Department of Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology, 45D Wiejska Street, 15-351 Bialystok, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Miluski
authors.affiliation: Department of Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology, 45D Wiejska Street, 15-351 Bialystok, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Dorosz
authors.affiliation: Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 30 Mickiewicza Av., 30-059 Krakow, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Jelen
authors.affiliation: Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 30 Mickiewicza Av., 30-059 Krakow, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Sitarz
mesh_terms: D002412:Cations / Q000737:chemistry; D003460:Crystallization; D005857:Germanium / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D007700:Kinetics; D049449:Luminescence; D013059:Spectrum Analysis, Raman; D013725:Terbium / Q000737:chemistry*; D013816:Thermodynamics; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D002412:Cations; D005857:Germanium; D013725:Terbium; C040516:germanium oxide; D015018:Ytterbium
keywords: Co-operative upconversion emission; Germanate glass; Kinetic study; Structural properties; Yb(3+)/Tb(3+)