1. Key Lab of Organic Optoelectronics Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 China
2. State Key Laboratory of Fine Chemicals School of Chemistry Dalian University of Technology Dalian 116024 China
3. School of Engineering Brown University Providence RI 02912 USA
4. Energy Materials and Surface Sciences Unit Okinawa Institute of Science and Technology Graduate University Okinawa 904‐0495 Japan
5. Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China