1. Department of Chemistry; Faculty of Science; Chulalongkorn University; Bangkok 10330 Thailand
2. Semiconductor Physics; Institute of Physics; Chemnitz University of Technology; Chemnitz 09126 Germany
3. Linz Institute for Organic Solar Cells (LIOS), Institute of Physical Chemistry; Johannes Kepler University; Linz 4040 Austria
4. Institute of Inorganic Chemistry; Johannes Kepler University; Linz 4040 Austria
5. Zentrum für Oberflächen und Nanoanalytik (ZONA); Johannes Kepler University; Linz 4040 Austria