1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
2. Electron Microscopy Center, Argonne National Laboratory, Argonne, Illinois 60439, United States
3. Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616, United States
4. Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
5. Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States
6. Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States