1. Department of Chemistry, University of California, Berkeley, California 94720, United States
2. California Research Alliance (CARA), BASF Corporation, Berkeley, California 94720, United States
3. BASF Corporation, Ludwigshafen am Rhein 67056, Germany
4. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
6. Kavli Energy NanoSciences Institute, Berkeley, California 94720, United States