Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 54: Focus Session: Nanophotonic concepts and materials for energy harvesting - Plasmonics, transformation optics, upconversion, and beyond II
HL 54.2: Hauptvortrag
Mittwoch, 18. März 2015, 15:30–16:00, EW 201
Material Design of Luminescent Glasses and Glass Ceramics for White-LED Applications — •Stefan Schweizer1,2, Franziska Steudel2, Sebastian Loos1, Bernd Ahrens1,2, Peter Nolte2, and Florian Wagner1 — 1South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494 Soest — 2Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Mechanics of Materials IWM, Lübecker Ring 2, 59494 Soest
The majority of white light emitting diodes (LED) is based on a blue light emitting diode with a yellow phosphor on top. The phosphor powder, which converts a part of the blue light from the LED into yellow light, is usually embedded in an organic polymer and directly coated onto the LED chip. Heat-induced degradation of the encapsulate, however, results in an efficiency decrease and colour temperature change. Luminescent glasses or glass ceramics might represent an interesting alternative due to their higher thermal and chemical stability. Here, rare-earth single- and double-doped glasses and glass ceramics are investigated for their potential as photon converters. Interestingly, the colour coordinate of the double-doped glass can be varied over a broad spectral range by changing the rare-earth doping ratio accordingly. In addition, double-doping allows for a change in the colour coordinate by using different excitation wavelengths.