1. MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
2. State
Key Laboratory of Mechanics and Control of Mechanical Structures,
College of Materials science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
3. Division
of Physics and Applied Physics, School of Physical and Mathematical
Sciences, Nanyang Technological University, 637371, Singapore