1. School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, United States
2. Department of Physics and Astronomy, University of Maine, Orono, Maine 04469, United States
3. National Renewable Energy Laboratory, Golden, Colorado 80401, United States
4. Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
5. Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States
6. Department of Materials Science and Engineering, University of Central Florida, Orlando, Florida 32816, United States