1. Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena CA 91125 USA
2. Joint Center for Artificial Photosynthesis; California Institute of Technology; Pasadena CA 91125 USA
3. Department of Physics; University of California San Diego; La Jolla CA 92093 USA
4. Department of Applied Physics and Materials Science; California Institute of Technology; Pasadena CA 91125 USA
5. Beckman Institute Molecular Materials Research Center; California Institute of Technology; Pasadena CA 91125 USA
6. Department of Electrical and Computer Engineering; University of California San Diego; La Jolla CA 92093 USA
7. Kavli Nanoscience Institute; California Institute of Technology; Pasadena CA 91125 USA