1. Department of Chemistry, University of California, Berkeley, California 94720, United States
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
4. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
5. Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
6. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
7. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States