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Ligand‐Modulated Excess PbI 2 Nanosheets for Highly Efficient and Stable Perovskite Solar Cells
Author(s) -
Wang Huanhuan,
Wang Zaiwei,
Yang Zhen,
Xu Yuzeng,
Ding Yi,
Tan Liguo,
Yi Chenyi,
Zhang Zhuang,
Meng Ke,
Chen Gang,
Zhao Ying,
Luo Yongsong,
Zhang Xiaodan,
Hagfeldt Anders,
Luo Jingshan
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202000865
Subject(s) - perovskite (structure) , materials science , passivation , energy conversion efficiency , nanocrystal , halide , iodide , grain boundary , ligand (biochemistry) , carrier lifetime , chemical engineering , grain size , layer (electronics) , nanotechnology , optoelectronics , inorganic chemistry , silicon , composite material , microstructure , chemistry , biochemistry , receptor , engineering
Abstract Excess lead iodide (PbI 2 ), as a defect passivation material in perovskite films, contributes to the longer carrier lifetime and reduced halide vacancies for high‐efficiency perovskite solar cells. However, the random distribution of excess PbI 2 also leads to accelerated degradation of the perovskite layer. Inspired by nanocrystal synthesis, here, a universal ligand‐modulation technology is developed to modulate the shape and distribution of excess PbI 2 in perovskite films. By adding certain ligands, perovskite films with vertically distributed PbI 2 nanosheets between the grain boundaries are successfully achieved, which reduces the nonradiative recombination and trap density of the perovskite layer. Thus, the power conversion efficiency of the modulated device increases from 20% to 22% compared to the control device. In addition, benefiting from the vertical distribution of excess PbI 2 and the hydrophobic nature of the surface ligands, the modulated devices exhibit much longer stability, retaining 72% of their initial efficiency after 360 h constant illumination under maximum power point tracking measurement.