1. Center
of Innovative Photovoltaic Systems (CIPS), Gifu University, Yanagido
1-1, Gifu, Gifu 501-1193, Japan
2. Research
Center for Organic Electronics (ROEL), Yamagata University, Jonan 4-3-16, Yonezawa, Yamagata 992-8510, Japan
3. Department
of Applied Chemistry, Faculty
of Science, Beijing University of Chemical Technology, Beijing 100029, China
4. Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria