1. Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials Bio-Engineering Research Centre (AMBER); Trinity College Dublin; Dublin 2 Ireland
2. School of Chemistry; Trinity College Dublin; Dublin 2 Ireland
3. Department of Materials Science and Engineering; A. J. Drexel Nanomaterials Institute; Drexel University; Philadelphia PA 19104 USA
4. School of Physics; Trinity College Dublin; Dublin 2 Ireland
5. Institute of Physics; EIT 2; Faculty of Electrical Engineering and Information Technology; Universität der Bundeswehr; 85577 Neubiberg, München Germany