1. Department of Organic Materials Science, Yamagata University 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
2. Hodogaya Chemical Co., Ltd. 1-9-2, Higashi-Shimbashi, Minato-ku, Tokyo 105-0021, Japan
3. Research Center for Organic Electronics (ROEL), Yamagata University 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan