1. University of Jyväskylä; Department of Chemistry; Nanoscience Center; P.O. Box 35 40014 Jyväskylä Finland
2. Aalto University; School of Science; Department of Applied Physics; Puumiehenkuja 2 02150 Espoo Finland
3. TOFWERK; Uttigenstrasse 22 3600 Thun Switzerland
4. University of Bonn; Kekulé-Institute of Organic Chemistry and Biochemistry; Gerhard-Domagk-Strasse 1 53121 Bonn Germany