Boosting exciton mobility approaching Mott-Ioffe-Regel limit in Ruddlesden-Popper perovskites by anchoring the organic cation

Yiyang Gong; Shuai Yue; Yin Liang; Wenna Du; Tieyuan Bian; Chuanxiu Jiang; Xiaotian Bao; Shuai Zhang; Mingzhu Long; Guofu Zhou; Jun Yin; Shibin Deng; Qing Zhang; Bo Wu; Xinfeng Liu

doi:10.1038/s41467-024-45740-y

Boosting exciton mobility approaching Mott-Ioffe-Regel limit in Ruddlesden-Popper perovskites by anchoring the organic cation

Nat Commun. 2024 Feb 29;15(1):1893. doi: 10.1038/s41467-024-45740-y.

Authors

Yiyang Gong^{1

2

3}, Shuai Yue^{2

3}, Yin Liang⁴, Wenna Du^{2

3}, Tieyuan Bian⁵, Chuanxiu Jiang^{2

3}, Xiaotian Bao², Shuai Zhang^{2

3}, Mingzhu Long¹, Guofu Zhou¹, Jun Yin⁵, Shibin Deng^{6

7}, Qing Zhang⁸, Bo Wu^{9

10}, Xinfeng Liu^{11

12}

Affiliations

¹ South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China.
² CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China.
³ University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
⁴ School of Materials Science and Engineering, Peking University, Beijing, 100871, P.R. China.
⁵ Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P.R. China.
⁶ Ultrafast Electron Microscopy Laboratory, School of Physics, Nankai University, Tianjin, 300071, P.R. China.
⁷ The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin, 300071, P.R. China.
⁸ School of Materials Science and Engineering, Peking University, Beijing, 100871, P.R. China. Q_zhang@pku.edu.cn.
⁹ South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China. bowu@m.scnu.edu.cn.
¹⁰ CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China. bowu@m.scnu.edu.cn.
¹¹ CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China. liuxf@nanoctr.cn.
¹² University of Chinese Academy of Sciences, Beijing, 100049, P.R. China. liuxf@nanoctr.cn.

Abstract

Exciton transport in two-dimensional Ruddlesden-Popper perovskite plays a pivotal role for their optoelectronic performance. However, a clear photophysical picture of exciton transport is still lacking due to strong confinement effects and intricate exciton-phonon interactions in an organic-inorganic hybrid lattice. Herein, we present a systematical study on exciton transport in (BA)₂(MA)_n-1Pb_nI_3n+1 Ruddlesden-Popper perovskites using time-resolved photoluminescence microscopy. We reveal that the free exciton mobilities in exfoliated thin flakes can be improved from around 8 cm² V^-1 s^-1 to 280 cm²V^-1s^-1 by anchoring the soft butyl ammonium cation with a polymethyl methacrylate network at the surface. The mobility of the latter is close to the theoretical limit of Mott-Ioffe-Regel criterion. Combining optical measurements and theoretical studies, it is unveiled that the polymethyl methacrylate network significantly improve the lattice rigidity resulting in the decrease of deformation potential scattering and lattice fluctuation at the surface few layers. Our work elucidates the origin of high exciton mobility in Ruddlesden-Popper perovskites and opens up avenues to regulate exciton transport in two-dimensional materials.

Abstract

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