[1] Yunnan Univ, Natl Ctr Int Res Photoelect & Energy Mat, Sch Mat & Energy, Kunming 650091, Peoples R China
[2] Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China
[3] Yunnan Univ, Ctr Optoelect Engn Res, Dept Phys, Kunming 650091, Peoples R China
[4] Nanjing Univ, Ecomat & Renewable Energy Res Ctr ERERC, Coll Engn & Appl Sci, Nanjing 210093, Peoples R China