1. University of Duisburg-Essen; Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE) Universitätsstr. 5-7; 45117 Essen (Germany)
2. Institute of Inorganic Chemistry; University of Bonn Römerstr. 164; 53117 Bonn (Germany)
3. Werkstoffe der Elektrotechnik and Center for Nanointegration Duisburg-Essen (CENIDE); University of Duisburg-Essen Bismarckstraße 81; BA 47057 Duisburg (Germany)