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Enhancing Charge Transport of 2D Perovskite Passivation Agent for Wide‐Bandgap Perovskite Solar Cells Beyond 21%
Author(s) -
Ye Jiselle Y.,
Tong Jinhui,
Hu Jun,
Xiao Chuanxiao,
Lu Haipeng,
Dunfield Sean P.,
Kim Dong Hoe,
Chen Xihan,
Larson Bryon W.,
Hao Ji,
Wang Kang,
Zhao Qian,
Chen Zheng,
Hu Huamin,
You Wei,
Berry Joseph J.,
Zhang Fei,
Zhu Kai
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.202000082
Subject(s) - perovskite (structure) , passivation , band gap , materials science , binding energy , energy conversion efficiency , exciton , charge carrier , chemical engineering , nanotechnology , crystallography , chemistry , optoelectronics , layer (electronics) , condensed matter physics , physics , nuclear physics , engineering
The replacement of a small amount of organic cations with bulkier organic spacer cations in the perovskite precursor solution to form a 2D perovskite passivation agent (2D‐PPA) in 3D perovskite thin films has recently become a promising strategy for developing perovskite solar cells (PSCs) with long‐term stability and high efficiency. However, the long, bulky organic cations often form a barrier, hindering charge transport. Herein, for the first time, 2D‐PPA engineering based on wide‐bandgap (≈1.68 eV) perovskites are reported. Pentafluorophenethylammonium (F5PEA + ) is introduced to partially replace phenylethylammonium (PEA + ) as the 2D‐PPA, forming a strong noncovalent interaction between the two bulky cations. The charge transport across and within the planes of pure 2D perovskites, based on mixed ammoniums, increases by a factor of five and three compared with that of mono‐cation 2D perovskites, respectively. The perovskite films based on mixed‐ammonium (F5PEA + ‐PEA + ) 2D‐PPA exhibit similar surface morphology and crystal structure, but longer carrier lifetime, lower exciton binding energy, less trap density and higher conductivity, in comparison with those using mono‐cation (PEA + ) 2D‐PPA. The performance of PSCs based on mixed‐cation 2D‐PPA is enhanced from 19.58% to 21.10% along with improved stability, which is the highest performance for reported wide‐bandgap PSCs.