1. National Renewable Energy Laboratory, Golden Colorado 80401, United States
2. Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States
3. Materials Science and Engineering, University of Colorado, Boulder, Colorado 80309, United States
4. Department of Applied Physics, Stanford University, Stanford, California 94305, United States
5. Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States