[1] Chinese Acad Sci, Ningbo Inst Mat Technol & Engn, Ningbo 315201, Peoples R China
[2] Univ Chinese Acad Sci, Ctr Mat Sci & Optoelect Engn, Beijing 100049, Peoples R China
[3] Jiangsu Collaborat Innovat Ctr Photovolta Sci & E, Changzhou 213164, Peoples R China