1. Department of Chemistry and
Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1969, United States
2. Department of Materials Science
and Engineering, University of Delaware, Newark, Delaware 19716-1501, United States
3. Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547,
United States
4. California NanoSystems Institute, Los Angeles, California 90095, United States
5. WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba,
Ibaraki 305-0040, Japan