1. College of Chemistry and Materials Science,
The Key Laboratory of Functional Molecular Solids, Ministry of Education,
Anhui Laboratory of Molecular-Based Materials, Centre for Nano Science
and Technology, Anhui Normal University, Wuhu 241000, P. R. China
2. School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
3. Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia