1. Department of Chemistry, University of Missouri−Columbia, Columbia, Missouri 65211, United States
2. Key Laboratory of Chemical Biology, Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
3. School of Chemical Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
4. Institute of Chemical Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, United Kingdom
5. Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
6. Institute of Carbon-Based Thin Film Electronics, Peking University, Shanxi, Taiyuan 030012, China