1. Department of Material Science and Engineering, Stanford University School of Engineering, Stanford, California 94305, United States
2. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
4. Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
5. Kavli Energy Nanoscience Institute, Berkeley, California 94720, United States
6. Department of Physics, Stanford University, Stanford, California 94305, United States
7. Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
8. Department of Radiology, Stanford University School of Medicine, Stanford, California 94305, United States