1. São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970 São Carlos, SP, Brazil
2. Laboratory of Nanomaterials for Renewable Energy and Artificial Photosynthesis (NanoREAP), Federal University of Rio Grande do Sul (UFRGS), Campus do Vale, Agronomia, Porto Alegre-RS, Brazil
3. School of Engineering and Innovation, The Open University, Milton Keynes, MK7 6AA, UK