1. Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
2. Materials
Department, University of California, Santa Barbara, California 93106, United States
3. Department
of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER)
Center, Northwestern University, Evanston, Illinois 60208, United States
4. Department
of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
5. Institute
of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece
6. Physics
Department, National Technical University of Athens, 15780 Zografou, Athens, Greece