1. National Renewable Energy Laboratory, Golden, Colorado 80401, United States
2. Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
3. Materials Science & Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
4. Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
5. Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
6. Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, California 92697, United States
7. Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States