1. Hebei Key Lab of Optic‐electronic Information and Materials, College of Physics Science and Technology, Hebei UniversityBaoding 071002China
2. State Key Laboratory of Photovoltaic Materials & Technology, Yingli Green Energy Holding Co., Ltd.Baoding 071051China
3. Institute of New Energy Technology, College of Information Science and Technology, Jinan UniversityGuangzhou 510632China