1. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
2. Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China
3. Department of Materials Science and Engineering University of Tennessee Knoxville TN 37996 USA
4. Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA
5. Department of Materials Science and Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea
6. Bredesen Center for Interdisciplinary Research and Graduate Education University of Tennessee Knoxville TN 37966 USA
7. Materials Sciences and Technology Division Oak Ridge National Laboratory Oak Ridge TN 37830 USA
8. Center for Multidimensional Carbon Materials Institute for Basic Science (IBS) Ulsan 44919 Republic of Korea