1. Institute of Biomedicine and Biotechnology; Shenzhen Institutes of Advanced Technology; Chinese Academy of Sciences; Shenzhen 518055 P. R. China
2. Department of Physics and Materials Science; City University of Hong Kong; Tat Chee Avenue Kowloon Hong Kong P. R. China
3. State Key Laboratory of Optoelectronic Materials and Technologies; School of Physics and Engineering; Sun Yat-sen (Zhongshan) University; Guangzhou 510275 P. R. China
4. School of Advanced Materials; Peking University Shenzhen Graduate School; Shenzhen 518055 P. R. China