1. Department
of Chemistry, Brown University, Providence, Rhode Island 02912, United States
2. Materials
Physics and Application Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
3. Department
of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
4. Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
5. School
of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China