1. CAS Key Laboratory of Nano-Bio Interface, i -Lab; Suzhou Institute of Nano-Tech and Nano-Bionics; Chinese Academy of Sciences; 398 Ruoshui Road Suzhou 215123 Jiangsu P. R. China
2. Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics; Collaborative Innovation Center for Optoelectronic Science and Technology and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province; Shenzhen University; Shenzhen 518060 P. R. China
3. Institute of Functional Nano and Soft Materials (FUNSOM); Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices; Soochow University; 199 Ren'ai Road Suzhou 215123 Jiangsu P. R. China
4. College of Chemistry and Chemical Engineering; Yangzhou University; Yangzhou 225002 P. R. China
5. Key Laboratory of Organic Synthesis of Jiangsu Province; College of Chemistry; Chemical Engineering and Materials Science; Dushu Lake Campus; Soochow University; Suzhou 215123 P. R. China
6. Department of Materials Science and Engineering; Faculty of Engineering; Monash University; Clayton 3800 Victoria Australia
7. Department of Physics; Tsinghua University; Beijing 100084 P. R. China