[1] Chinese Acad Sci, Tech Inst Phys & Chem, Lab Org Optoelect Functional Mat & Mol Engn, Nano Org Photoelect Lab, Beijing 100080, Peoples R China
[2] City Univ Hong Kong, Ctr Super Diamond & Adv Film, Dept Phys & Mat Sci, Hong Kong, Hong Kong, Peoples R China
[3] Tsinghua Univ, Tsinghua Foxconn Nanotechnol Res Ctr, Dept Phys, Beijing 100084, Peoples R China