1. Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany, Department of Materials Science and Engineering, University of California, Los Angeles, California 90095-1595, Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, and The California NanoSystems Institute, University of California, Los Angeles, California 90095