1. Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
2. Spectroscopy
Laboratory for Functional π-Electronic Systems and Department
of Chemistry, Yonsei University, Seoul 120-749, Korea
3. Department of Materials Science & Engineering, National University of Singapore, Singapore 119260, Singapore
4. Graduate
School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma 630-0192, Japan
5. Division
of Physical Science and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
6. Institute of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way, Innovis, #08-03, Singapore 117602, Singapore