1. Institute of Molecular Plus, Key Laboratory of Organic Integrated Circuits, Ministry of Education &Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, Tianjin University, Tianjin 300072, China
2. Department of Chemistry and Centre for Processable Electronics, Imperial College London, W12 0BZ, UK
3. School of Chemistry and Chemical Engineering, Shanghai Key Lab of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
4. School of Materials Science and Engineering and Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin 300350, China
5. ExxonMobil Technology and Engineering Company, Annandale, New Jersey 08801, USA