[1] City Univ Hong Kong, COSDAF, Hong Kong, Hong Kong, Peoples R China
[2] City Univ Hong Kong, Dept Phys & Mat Sci, Hong Kong, Hong Kong, Peoples R China
[3] Soochow Univ, Inst Funct Nano & Soft Mat, Suzhou 215123, Jiangsu, Peoples R China
[4] Soochow Univ, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Suzhou 215123, Jiangsu, Peoples R China
[5] Chinese Acad Sci, Phys Biol Lab, Shanghai Inst Appl Phys, Shanghai 201800, Peoples R China