[1] Tsing Hua Univ, Dept Chem, Beijing 100084, Peoples R China
[2] Korea Univ, Dept Chem, Seoul 136701, South Korea
[3] Korea Univ, Ctr Electro & Photorespons Mol, Seoul 136701, South Korea
[4] Elect & Telecommun Res Inst, Taejon 305350, South Korea
[5] Samsung Adv Inst Technol, Analyt Engn Ctr, Suwon 440600, South Korea