1. Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
2. Nanoscale Characterization Facility, Singh Center for Nanotechnology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
3. Univ. Grenoble Alpes, CNRS, CEA, INAC-SyMMES, F-38000 Grenoble, France
4. DuPont Co., Wilmington, Delaware 19803, United States
5. Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States