1. Department of Chemistry, Columbia University, New York, New York 10027, United States
2. Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
3. Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
4. Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
5. Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States