1. Key Laboratory for Rubber-Plastics of Ministry of Education/Shandong Province, School of Polymer Science and Technology, Qingdao University of Science and Technology, Qingdao 266042
2. Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100
3. Hybrid Solar Cells, Faculty of Engineering and Natural Sciences, Tampere University, FI-33014 Tampere