1. Institute of Nanotechnology, CNR-NANOTEC, via Amendola 122/D and c/o Department of Chemistry, University of Bari, via Orabona 4, 70126 Bari, Italy
2. Departamento de Física Aplicada, Universidad de Cantabria, Avda. de los Castros s/n, 39005 Santander, Spain
3. MINT Didactics of Physics, Linz School of Education, University of Linz, Linz, Austria
4. Tyndall National Institute-University College Cork, Lee Maltings, Dyke Parade, Cork, Ireland
5. Institute of Physics, University of Muenster, Heisenbergstr. 11, 48149 Muenster, Germany