1. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
2. Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
3. Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
4. Department of Physics, University of California, Santa Cruz, California 95064, United States