1. Department of PhotonicsNational Cheng Kung University Tainan 701 Taiwan
2. Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE)University of Duisburg-Essen Universitätsstraße 15 Essen 45141 Germany
3. Department of Physical ChemistryUniversity of Pavia Via Torquato Taramelli 14 Pavia 27100 Italy
4. Hierarchical Green-Energy Materials (Hi-GEM) Research CenterNational Cheng Kung University Tainan 701 Taiwan