1. Department
of Chemistry, University of California, Berkeley, California 94720, United States
2. Materials
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. The
Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee
149, 22761 Hamburg, Germany
4. Department
of Physics, University of California, Berkeley, California 94720, United States
5. Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
6. Department
of Materials Science and Engineering, University of California, Berkeley, California 94720, United States