Regensburg 2010 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 25: Glasses II (joint session of CPP, DF, DY)
DY 25.8: Talk
Thursday, March 25, 2010, 11:30–11:45, H38
Crystallization and structural investigation of Eu-doped fluorozirconate-based glass ceramics. — •Christian Paßlick1, Bernd Ahrens1,2, Bastian Henke1,2, Jacqueline A. Johnson3, and Stefan Schweizer1,2 — 1Centre for Innovation Competence SiLi-nano®, Martin Luther University of Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3, 06120 Halle (Saale) — 2Fraunhofer Center for Silicon Photovoltaics, Walter-Hülse-Str. 1, 06120 Halle (Saale) — 3Department of Materials Science and Engineering, University of Tennessee Space Institute, Tullahoma, TN 37388, USA
A series of Eu-doped fluorozirconate-based glass ceramics has been developed for medical and photovoltaic applications. In the first case, the materials can be used as x-ray scintillators or x-ray storage phosphors, in the latter case as down-converting top layers for highly efficient solar cells. The glasses are based on a modified ZBLAN composition, i.e. a mixture of Zr, Ba, La, Al, and Na fluorides. They are additionally doped with chlorine ions to initiate the growth of BaCl2 nanocrystals upon thermal processing. Eu2+ ions are incorporated into the nanocrystals during the annealing procedure enabling a strong fluorescence upon ultraviolet or x-ray excitation. The nanocrystal size and structural phase depend significantly on the heating conditions and Eu doping level. X-ray diffraction patterns show a structural phase change of the BaCl2 nanocrystals from hexagonal to orthorhombic as annealing temperatures are increased. DSC experiments were performed to obtain activation energies, thermal stability parameters and information on the crystal growth mechanisms.
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