Cooperation for development of luminescent oxyfluoride glass ceramics for white LEDs (2015)
This project of the Baltic-German University Liaison Office is supported by the German Academic Exchange Service (DAAD) with funds from the Foreign Office of the Federal Republic Germany.
Project realization time: 01 July – 15 December 2015
Head of the project: Prof. Dr. Uldis Rogulis
German cooperation partner: Prof. Dr. S. Schweizer
Countries and institutions involved in the project:
1. Latvia, Institute of Solid State Physics, University of Latvia
2. Germany, South Westphalia University of Applied Sciences, Soest
Aims of the project:
Glass-ceramics, especially the oxyfluoride based glass-ceramics, are innovative materials which allow to embed the fluoride micro- and nano-crystals in the oxide glass matrix. By an additional doping with definite activators (mostly rare-earth elements), several application possibilities can be achieved:
Glass-ceramics could find applications, for example, as convertors for infrared light, as scintillators, or as phosphors for white LED’s. The additional activator ions could be embedded either in the glass matrix or in the fluoride micro- and nano-crystals. So the luminescence properties of the glass or the glass-ceramics could be correspondingly varied and adjusted.
The quantum-efficiency plays an extraordinary important role for the mentioned above applications. However, up to now mostly only the relative comparison of the luminescence intensities of the samples have been performed. A systematic estimation of the absolute quantum-efficiency should be performed within the guest-visits at the South-Westphalia University of Applied Sciences at the laboratories of prof. S. Schweizer.
The synthesis of the oxyfluoride glasses and glass-ceramics will be performed at the Institute of Solid State Physics, UL in Riga. The obtained samples will be initially analysed by optical techniques in Riga and then proceeded to Soest for investigations of the absolute quantum-efficiency and the phonon-spectra.
The team of prof. S. Schweizer is especially suited to these tasks because prof. Schweizer is a well-known expert in the scientific fields of the phosphors and glass-ceramics and possess the necessary analysis- and measurement-equipment.
Target group involved persons:
ISSP UL – students and scientific co-workers – approx. 30 participants at each of the seminars and approx. 30 participants at each of the guest lessons
Main activities of the project and venues where the project activities will be carried out:
- Synthesis of the samples at the ISSP UL, Riga
- Measurements of the luminescence quantum efficiency, Soest
- Analysis of the results and discussions, choice of the composition of the samples, Soest and Riga
Planned public events and date of the events:
Work group seminars and guest lectures during the visits (in August - September in Riga, and in October, November, December in Soest), presentation and publication of the project results at a the Scientific conference of the University of Latvia, middle of February 2016