1. Institute
of Chemistry, the Chinese Academy of Sciences, Bei Yi Jie 2, Zhong Guan Cun, Beijing 100190, China
2. Department of Physics and Materials Science & Centre for Functional Photonics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong S.A.R.
3. Clean
Energy and Nanotechnology (CLEAN) Laboratory, School of Energy and
Environment, City University of Hong Kong, Hong Kong S.A.R.