1. Department of Physics and Astronomy; Clemson Nanomaterials Center, COMSET; Clemson University; Clemson SC 29634 USA
2. ABV-Indian Institute of Information Technology and Management; Gwalior 474010 Madhya Pradesh India
3. Department of Chemical Engineering; University of South Carolina; Columbia SC 29208 USA
4. Laboratory of Nano-biophysics; Clemson University; Clemson SC 29634 USA