1. Department of Chemistry, University of California, Berkeley, California 94720, United States
2. Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Kavli Energy Nanoscience Institute, Berkeley, California 94720, United States
4. Graduate Group in Applied Science & Technology, University of California, Berkeley, California 94720, United States
5. Graduate Group in Biophysics, University of California, Berkeley, California 94720, United States
6. Howard Hughes Medical Institute and Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, United States