1. Department of Materials Science and Engineering and A. J. Drexel Nanomaterials Institute Drexel University Philadelphia PA 19104 USA
2. Soochow Institute for Energy and Materials Innovations College of Energy Soochow University Suzhou 215006 China
3. Centre for Clean Energy Technology School of Mathematical and Physical Sciences University of Technology Sydney Sydney NSW Australia
4. Department of Applied Physics and Applied Mathematics Columbia University New York NY 10027 USA
5. Department of Chemistry and Chemical Biology Cornell University Ithaca NY 14853 USA
6. Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton NY 11973 USA