1. Department of Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, 81377 Munich, Germany
2. Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
3. Lumileds Phosphor Center Aachen, Lumileds Germany GmbH, Philipsstrasse 8, 52068 Aachen, Germany