1. Department of Chemical and Biological Engineering University of Colorado Boulder Boulder CO 80303 USA
2. Department of Chemistry Stanford University Stanford CA 94305 USA
3. Department of Materials Science and Engineering Stanford University Stanford CA 94305 USA
4. Department of Physics University of Colorado Boulder Boulder CO 80309 USA
5. Renewable and Sustainable Energy Institute: National Renewable Energy Laboratory and University of Colorado at Boulder Boulder CO 80303 USA
6. Materials Science and Engineering Program University of Colorado Boulder Boulder CO 80303 USA
7. Department of Chemistry University of Nevada Reno Reno NV 89503 USA
8. National Renewable Energy Laboratory Golden CO 80401 USA