1. Molecular Materials, Department of Applied Physics, Aalto University School of Science and Technology (previously Helsinki University of Technology), P.O. Box 15100, 00076 Aalto, Finland
2. Department of Chemistry, University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece
3. Polymeric and Organic Materials Department, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan