1. Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
2. Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
3. Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
4. Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, United States
5. Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States