1. School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Materials Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
4. Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Victoria 3010, Australia
6. Department of Materials Science and Engineering, University of California Berkeley, Berkeley, California 94720, United States