1. Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
2. Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen 518060, China
3. College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China
4. Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
5. Institute of Photovoltaics/Department of Materials Science and Engineering, Nanchang University, Nanchang 330031, China