1. Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
2. Molecular
Materials and Nanosystems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
3. Dutch Institute for Fundamental Energy Research, De Zaale 20, 5612
AJ Eindhoven, The Netherlands