1. Key Laboratory of Chemical Engineering Process and Technology for High-Efficiency Conversion, School of Chemistry and Material Sciences, Heilongjiang University, Harbin, P. R. China
2. Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Wisconsin, USA
3. Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, P. R. China
4. Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin, P. R. China
5. Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, P. R. China