Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 84: Glasses and Glas transition (joint session DY/CPP)
CPP 84.8: Vortrag
Freitag, 16. März 2018, 12:00–12:15, BH-N 334
Controlled crystallization of luminescent lithium borate glasses — •A. Charlotte Rimbach1, Juliane Schuppich1, Bernd Ahrens1,2, Franziska Steudel2, and Stefan Schweizer1,2 — 1South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494 Soest — 2Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Lübecker Ring 2, 59494 Soest
Lanthanide-doped borate glasses are promising candidates as frequency-converter for LED applications. The borate glass system provides high transparency in the visible spectral range, good lanthanide ion solubility and high mechanical stability. The lanthanide ions terbium (Tb3+) and europium (Eu3+) show a bright luminescence therein with quantum efficiency values of approx. 60 % (486 nm excitation) and 90 % (396 nm excitation), respectively. However, since the absorption coefficient of the lanthanide ions is low, only a small amount of the excitation light is absorbed resulting in a poor conversion efficiency. To increase the optical absorption by prolonging the optical pathway through multiple scattering within the glass, the as-made luminescent borate glasses are processed to glass ceramics. The focus of this work is on the analysis of the crystallization process by means of differential scanning calorimetry (DSC), in situ x-ray diffraction (XRD) as well as optical spectroscopy and quantum efficiency (QE) measurements.