1. State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering; University of Science and Technology Beijing; Beijing 100083 P. R. China
2. Department of Materials Science and Engineering, College of Engineering; Peking University; Beijing 100871 P. R. China
3. Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 P. R. China
4. ENN Solar Energy Co., Ltd.; Huaxiang Road 106 Langfang Hebei 065001 P. R. China