A guide to use fluorinated aromatic bulky cations for stable and high-performance 2D/3D perovskite solar cells:The more fluorination the better?

• 作者: Lei Wang Qin Zhou Zilong Zhang Wenbo Li Xiaobing Wang Qing Tian Xiaoyan Yu Ting Sun Jihuai Wu Bao Zhang Peng Gao
• 来源期刊: 能源化学
• 年，卷（期）: 2022,（1）
• 页码范围: 179-189
• 页数: 11页
• 语种: 英文

摘要

While serious stability issues impede the commercialization of perovskite solar cells (PSCs),two-dimensional (2D) perovskites based on fluorinated bulky cations have emerged as more intrinsically stable materials.However,the influence of fluorination degree of the bulky aromatic cation on the per-formance of resulting PSCs has not been scrutinized.Here,2D perovskites (FxPEA)2PbI4 (x =1,2,3,5) are grown in situ on the surface of the three-dimensional (3D) perovskite and demonstrate effective passiva-tion of the surface defects of 3D perovskite.The power conversion efficiency (PCE) of the optimized devices were boosted from 20.75％ for the control device to 21.09％,22.06％,22.74％ and 21.86％ for 2D/BD devices treated with 4-fluorophenethylamine iodide,3,5-difluorophenylethylamine iodide,2,4,5-trifluoroethylphenylethylamine iodide,and 1,2,3,4,5-pentafluorophenylethylamine iodide,respec-tively.We firstly reported two unexplored RP-type layered perovskites with F2PEAI and F3PEAI as bulky cations.The combined experimental and theoretical analysis revealed the reasons behind the various morphology,device performances,dynamic behavior,and humidity stability.The best performing FsPEAl-treated device retaining 95.0％ of its initial PCE under ambient atmosphere (with RH of 60％ ± 5％) without encapsulation for 300 h storage.This work provides useful guidance for selecting flu-orinated bulky cations with different molecular electronic properties,which will play an essential role in further improving the performance/stability of PSCs for the sake of further commercialization.