Manipulate energy transport via fluorinated spacers towards record-efficiency 2D Dion-Jacobson CsPbI<sub>3</sub> solar cells

Journal article (2022)

Authors

Yutian Lei Lanzhou University
Zhen-Hua Li Lanzhou University
H. Wang Photovoltaic Materials and Devices - EEMCS
Qian Wang Lanzhou University
Guoqiang Peng Lanzhou University
Youkui Xu Lanzhou University
Haihua Zhang Tianjin University
Gang Wang Ningbo University
Liming Ding National Center for Nanoscience and Technology (NCNST)
Zhiwen Jin Lanzhou University
Research Group
Photovoltaic Materials and Devices (EEMCS) (TU Delft)
Copyright: © 2022 Yutian Lei, Zhen-Hua Li, H. Wang, Qian Wang, Guoqiang Peng, Youkui Xu, Haihua Zhang, Gang Wang, Liming Ding, Zhiwen Jin
DOI
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https://doi.org/10.1016/j.scib.2022.05.019
Interaction Dion-Jacobson CsPbI Energy transport Fluorinated spacers
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Published Date

2022

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Electrical Sustainable Energy

Research Group

Photovoltaic Materials and Devices

Abstract

Two-dimensional (2D) Dion-Jacobson (D-J)-type cesium lead iodide CsPbI
3 perform remarkably in terms of stability. However, the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells (PSCs). Herein, starting from the considerable structural diversity of organic spacers, we engineer 2D CsPbI
3 with fine-tuning functionalities. Specifically, for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI
3, and successfully applied it into construction of high-performance PSCs. Compared with constitutive 1,4-diaminobenzene (PDA), the fluorinated 2-fluorobenzene-1,4-diamine (F-PDA) component greatly expands the dipole moment from 0.59D to 3.47D, which reduces the exciton binding energy of the system. A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in (F-PDA)Cs
n–
1Pb
nI
3
n+
1. The results show that (F-PDA)Cs
n–
1Pb
nI
3
n+
1 demonstrates more significant charge transfer between organic and inorganic layers than (PDA)Cs
n–
1Pb
nI
3
n+
1, and it is confirmed in the femtosecond transient absorption experiment. Moreover, the interactions of the fluorinated spacer with the [PbI
6]
4
– plane effectively manipulate the crystallization quality, and thus the ion migration and defect formation of target 2D CsPbI
3 are inhibited. As a result, we obtained a record power conversion efficiency (PCE) beyond 15% for 2D D-J (F-PDA)Cs
3Pb
4I
13 (n = 4) PSCs with significantly improved environmental stability compared with the three-dimensional (3D) counterparts.