1. INM – Leibniz Institute for New Materials 66123 Saarbrücken Germany
2. ARC Centre of Excellence in Exciton Science School of Chemistry The University of Sydney Sydney 2006 Australia
3. Department of Chemistry Saarland University 66123 Saarbrücken Germany
4. The University of Sydney Nano Institute The University of Sydney Sydney 2006 Australia
5. Department of Physics Saarland University 66123 Saarbrücken Germany