1. Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
2. JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o OPERA, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
3. Innovative Organic Device Laboratory, Institute of Systems, Information Technologies and Nanotechnologies (ISIT), 744 Motooka, Nishi, Fukuoka 819-0395, Japan
4. Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106-9510, USA
5. International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan