1. Department of Chemistry State University of New York at Binghamton Binghamton NY 13902 USA
2. Materials Science and Engineering Program State University of New York at Binghamton Binghamton NY 13902 USA
3. Center for Functional Nanomaterials Brookhaven National Laboratory Upton NY 11973 USA
4. Present address: College of Environmental Science and Engineering Taiyuan University of Technology Taiyuan Shanxi Province China
5. Analytical and Diagnostics Lab State University of New York at Binghamton Binghamton NY 13902 USA
6. College of Arts & Sciences Microscopy Texas Tech University Lubbock TX 79409 USA
7. Chapel Hill Analytical and Nanofabrication Laboratory University of North Carolina at Chapel Hill Chapel Hill NC 27599 USA