1. Molecular Sciences Research Center, University of Puerto Rico, San Juan, Puerto Rico 00926-2614, United States
2. Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico 00925-2537, United States
3. Department of Biology, College of Natural Sciences, University of Puerto Rico, Rio Piedras
Campus, San Juan, Puerto Rico 00925-2537, United States
4. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
5. Department of Physics, Howell Science Complex, East Carolina University, Greenville, North Carolina 27858, United States
6. Department of Physics, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico 00925-2537, United States