1. Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
2. Materials Department, University of California, Santa
Barbara, California 93106-5121, United States
3. Institut Charles Gerhardt−Laboratoire
des Agrégats, Interfaces et Matériaux pour l’Energie, CNRS UMR 5253, 34095 Montpellier Cedex 5, France
4. Center for Electron Microscopy and Microanalysis, University of Southern California, Los Angeles, California 90089, United States