1. Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
2. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
3. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
5. The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
6. Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States