[1] Stanford Univ, Dept Chem & Lab Adv Mat, Stanford, CA 94305 USA
[2] Tsinghua Univ, Dept Chem, Key Lab Organ Optoelect & Mol Engn, Beijing 100084, Peoples R China
[3] Nankai Univ, Inst Polymer Chem, Coll Chem, Key Lab Funct Polymer Mat, Tianjin 300071, Peoples R China
[4] Nankai Univ, Inst Polymer Chem, Coll Chem, Ctr Nanoscale Sci & Technol, Tianjin 300071, Peoples R China