1. Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
2. Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916, USA
3. Min H. Kao Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee 37996, USA
4. Institute for Advanced Materials & Manufacturing, University of Tennessee, Knoxville, Tennessee 37996, USA
5. Department of Physics, Brown University, Providence, Rhode Island 02912, USA