1. Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-0033, Japan, Hewlett-Packard Japan, Limited, 2-2-24 Higashishinagawa, Shinagawa-ku, Tokyo, 140-8641 Japan, and Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan