1. Department of Mechanical Engineering and Materials Science Yale University New Haven CT 06511 USA
2. Energy Sciences Institute Yale West Campus West Haven CT 06525 USA
3. Materials Theory Division Department of Physics and Astronomy Uppsala University Box 516 75120 Uppsala Sweden
4. Shaanxi Key Laboratory of Optical Information Technology Northwestern Polytechnical University Xi'an 710072 China
5. Chemistry Department Brookhaven National Laboratory Upton NY 11973 USA
6. Department of Chemistry Yale University New Haven CT 06511 USA
7. College of Chemistry and Molecular Engineering Peking University Beijing 100871 P. R. China
8. Department of Electrical Engineering Yale University New Haven CT 06511 USA