1. Beijing National Laboratory
for Molecular Sciences (BNLMS), Laboratory of New Materials, Key Laboratory
of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
2. Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R.
China
3. Department of Physics
and Key
Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, P.R. China