Volume 62, Issue 29 e202304486
Research Article

Rashba Band Splitting and Bulk Photovoltaic Effect Induced by Halogen Bonds in Hybrid Layered Perovskites

Jie Xue

Jie Xue

Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China

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Yuling Huang

Yuling Huang

SUSTech Energy Institute for Carbon Neutrality, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, 518055 P. R. China

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Dr. Yang Liu

Dr. Yang Liu

Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 P. R. China

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Zhongwei Chen

Zhongwei Chen

Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China

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Dr. Herman H.-Y. Sung

Dr. Herman H.-Y. Sung

Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China

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Prof. Dr. Ian D. Williams

Prof. Dr. Ian D. Williams

Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China

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Prof. Dr. Zonglong Zhu

Prof. Dr. Zonglong Zhu

Department of Chemistry, City University of Hong Kong, Kowloon, 999077 Hong Kong Hong Kong

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Prof. Dr. Lingling Mao

Corresponding Author

Prof. Dr. Lingling Mao

Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 P. R. China

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Prof. Dr. Xihan Chen

Corresponding Author

Prof. Dr. Xihan Chen

SUSTech Energy Institute for Carbon Neutrality, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, 518055 P. R. China

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Prof. Dr. Haipeng Lu

Corresponding Author

Prof. Dr. Haipeng Lu

Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China

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First published: 17 May 2023
Citations: 9

Graphical Abstract

We reported a new series of 2D perovskites featuring thickness-dependent hydrogen and halogen bonding interactions. The strength of non-covalent interaction has a direct impact on the structure symmetry and optoelectronic properties. Stronger halogen interaction leads to centrosymmetry, whereas weaker halogen bonds give rise to non-centrosymmetric structures, Rashba splitting, suppressed radiative recombination, and bulk photovoltaic effect.

Abstract

Non-covalent interactions play an essential role in directing the self-assembly of hybrid organic–inorganic crystals. In hybrid halide perovskites, hydrogen bonding has been the paramount non-covalent interaction. Here, we show another non-covalent interaction, namely, the halogen bond interaction, that directs a symmetry-breaking assembly in a new series of two-dimensional (2D) perovskites (ICH2CH2NH3)2(CH3NH3)n−1PbnI3n+1 (n is the layer thickness, n=1–4). Structural analysis shows that the halogen bond strength varies with the layer thickness. For the odd number (n=1, 3) layered perovskites, stronger halogen interaction leads to centrosymmetric structures, whereas for the n=2 layered perovskites, weaker halogen bonds result in non-centrosymmetric structures. Transient reflection spectroscopy shows a suppressed radiative recombination rate (k2≈0) and prolonged spin lifetime for n=2 structure, suggesting an enhanced Rashba band splitting effect. The structural asymmetry is further confirmed with a reversible bulk photovoltaic effect. Our work provides a new design strategy to enable hybrid perovskites with emerging properties and functionalities associated with structural asymmetry.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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