1. Organic Materials Group, Polymer
Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
2. Department of Materials Science
and Engineering, Graduate School of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8571,
Japan
3. Photovoltaic Materials
Unit, National Institute for Materials Science, 1-2-1 Sengen,
Tsukuba, Ibaraki 305-0047, Japan
4. Materials Analysis Station, National Institute for Materials Science, 1-1 Namiki,
Tsukuba, Ibaraki 305-0044, Japan