1. Department of Applied Sciences and Technology, North Carolina A&T State University, Greensboro, North Carolina, USA
2. Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland, USA
3. Department of Physics, North Carolina A&T State University Greensboro, Greensboro, North Carolina, USA
4. Department of Chemistry, North Carolina A&T State University, Greensboro, North Carolina, USA
5. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA