[1] Chongqing 2D Mat Inst, Chongqing 400714, Peoples R China
[2] Univ Manchester, Dept Mat, Manchester M13 9PL, Lancs, England
[3] Univ Manchester, Natl Graphene Inst, Manchester M13 9PL, Lancs, England
[4] Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England
[5] Chongqing Univ, Coll Aerosp Engn, Chongqing 400044, Peoples R China
[6] Natl Univ Singapore, Inst Funct Intelligent Mat, Singapore 117544, Singapore