1. Chemistry Department, Federal University of Paraná, Curitiba 81531-980, Brazil
2. Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz, Eggenstein-Leopoldshafen 76344, Germany
3. Department of Physics, Federal University of Pelotas, P.O. Box 354, Pelotas, Rio Grande do Sul 96010-900, Brazil
4. Institute of Physics and International Center of Physics, University of Brasília, Brasília 70910900, Brazil