1. Karlsruhe Institute of Technology (KIT); Institut für Anorganische Chemie; Engesserstraße 15 D-76131 Karlsruhe Germany
2. National Synchrotron Radiation Research Center; Hsinchu 30076 Taiwan
3. Department of Opto-Electronic Engineering; National Dong Hwa University; Hualien 97401 Taiwan
4. Department of Chemical Engineering; National Taiwan University; Taipei 10617 Taiwan
5. Institute of Atomic and Molecular Sciences; Academia Sinica; Taipei 10617 Taiwan
6. Center for Condensed Matter Sciences; National Taiwan University; Taipei 10617 Taiwan