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Understanding the Role of Fluorine Groups in Passivating Defects for Perovskite Solar Cells |
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| Authors: | Xiaoqing Jiang Guangyue Yang Bingqian Zhang Linqin Wang Yanfeng Yin Fengshan Zhang Shitao Yu Shiwei Liu Hongkai Bu Zhongmin Zhou Licheng Sun Shuping Pang Xin Guo |
| Institution: | 1. College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China;2. College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China
These authors contributed equally to this work.;3. Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China Shandong Energy Institute, Qingdao, 266101 China Qingdao New Energy Shandong Laboratory, Qingdao, 266101 China College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China These authors contributed equally to this work.;4. Center of Artificial Photosynthesis for Solar Fuels, School of Science, Westlake University, Hangzhou, 310024 Zhejiang, China;5. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China;6. Shandong Huatai Paper Co., Ltd. & Shandong Yellow Triangle Biotechnology Industry Research Institute Co. LTD, Dongying, 257335 China;7. College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042 China;8. Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China |
| Abstract: | Introducing fluorine (F) groups into a passivator plays an important role in enhancing the defect passivation effect for the perovskite film, which is usually attributed to the direct interaction of F and defect states. However, the interaction between electronegative F and electron-rich passivation groups in the same molecule, which may influence the passivation effect, is ignored. We herein report that such interactions can vary the electron cloud distribution around the passivation groups and thus changing their coordination with defect sites. By comparing two fluorinated molecules, heptafluorobutylamine (HFBM) and heptafluorobutyric acid (HFBA), we find that the F/−NH2 interaction in HFBM is stronger than the F/−COOH one in HFBA, inducing weaker passivation ability of HFBM than HFBA. Accordingly, HFBA-based perovskite solar cells (PSCs) provide an efficiency of 24.70 % with excellent long-term stability. Moreover, the efficiency of a large-area perovskite module (14.0 cm2) based on HFBA reaches 21.13 %. Our work offers an insight into understanding an unaware role of the F group in impacting the passivation effect for the perovskite film. |
| Keywords: | Defect Passivation Fluorinated Additive Fluorine Group Intermolecular Interaction Perovskite Solar Cells |