1. Ningbo Institute of Materials Technology and Engineering
2. Chinese Academy of Sciences
3. Ningbo 315201
4. P. R. China
5. Center of Materials Science and Optoelectronics Engineering
6. CAS Key Laboratory of Nanosystem and Hierarchical Fabrication
7. CAS Center for Excellence in Nanoscience
8. National Center for Nanoscience and Technology
9. Beijing 100190
10. China