1. State Key Laboratory of Terahertz and Millimeter Waves and Department of Materials Science & Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
2. Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
3. Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, China
4. Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China