1. Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials; Hubei Key Laboratory of Ferro- & Piezoelectric Materials and Devices; Faculty of Physics & Electronic Science; Hubei University; Wuhan 430062 P. R. China
2. School of Chemistry; Monash University; Clayton VIC 3800 Australia
3. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore