1. Department of Electrical Engineering and Computer Science Center for Advanced Photovoltaics South Dakota State University Brookings SD 57007 USA
2. Department of Materials Chemistry Huzhou University Huzhou Zhejiang 313000 China
3. Department of Applied Chemistry School of Science Northwestern Polytechnical University Xi'an 710072 China
4. Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion Department of Applied Chemistry Tianjin University of Technology Tianjin 300384 China
5. Sichuan Research Center of New Materials Institute of Chemical Materials China Academy of Engineering Physics Chengdu 610207 China