1. Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
2. Innovative Center for Flexible Devices (iFLEX)School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
3. Beijing National Laboratory for Molecular SciencesKey Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China