1. State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000
2. State School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240
3. Department Novel Materials and Interfaces for Photovoltaic Solar Cells, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin
4. Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210