1. School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
2. Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of NewYork, Buffalo, New York 14260, United States
3. Department of Chemistry and Research and Education in Energy Environment and Water Institute, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
4. ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010 Australia