1. MOE Key Laboratory of Organic OptoElectronics and Molecular Engineering; Department of Chemistry; Tsinghua University; Beijing 100084 P. R. China
2. Institute for Materials Research; Tohoku University; Sendai 980-8577 Japan
3. Materials Genome Institute; Shanghai University; Shanghai 200444 P. R. China
4. Key Laboratory of Organic Solids; Beijing National Laboratory for Molecular Science (BNLMS); Institute of Chemistry; Chinese Academy of Science; Beijing 100190 P. R. China
5. Collaborative Innovation Center of Chemistry for Energy Materials; Xiamen University; Xiamen 351005 P. R. China