1. Department of Applied Physics The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong P. R. China
2. Department of Chemistry Hong Kong Baptist University Kowloon Tong Kowloon Hong Kong P. R. China
3. Research Institute of Intelligent Wearable Systems The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong P. R. China