Real-time observation of the buildup of polaron in α-FAPbI3

Xingyu Yue; Chunwei Wang; Bo Zhang; Zeyu Zhang; Zhuang Xiong; Xinzhi Zu; Zhengzheng Liu; Zhiping Hu; George Omololu Odunmbaku; Yujie Zheng; Kuan Sun; Juan Du

doi:10.1038/s41467-023-36652-4

Real-time observation of the buildup of polaron in α-FAPbI₃

Nat Commun. 2023 Feb 17;14(1):917. doi: 10.1038/s41467-023-36652-4.

Authors

Xingyu Yue^#^{1

2

3}, Chunwei Wang^#^{1

3

4}, Bo Zhang^#⁵, Zeyu Zhang^{6

7

8}, Zhuang Xiong⁵, Xinzhi Zu^{1

2

3}, Zhengzheng Liu^{1

2

3}, Zhiping Hu², George Omololu Odunmbaku⁵, Yujie Zheng⁵, Kuan Sun⁹, Juan Du^{10

11

12}

Affiliations

¹ State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai, 201800, China.
² School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China.
³ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
⁴ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
⁵ MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials & Devices Joint Laboratory, School of Energy & Power Engineering, Chongqing University, Chongqing, 400044, China.
⁶ State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai, 201800, China. zhangzeyu@ucas.ac.cn.
⁷ School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China. zhangzeyu@ucas.ac.cn.
⁸ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. zhangzeyu@ucas.ac.cn.
⁹ MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials & Devices Joint Laboratory, School of Energy & Power Engineering, Chongqing University, Chongqing, 400044, China. kuan.sun@cqu.edu.cn.
¹⁰ State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai, 201800, China. dujuan@siom.ac.cn.
¹¹ School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China. dujuan@siom.ac.cn.
¹² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. dujuan@siom.ac.cn.

^# Contributed equally.

Abstract

The formation of polaron, i.e., the strong coupling process between the carrier and lattice, is considered to play a crucial role in benefiting the photoelectric performance of hybrid organic-inorganic halide perovskites. However, direct observation of the dynamical formation of polarons occurring at time scales within hundreds of femtoseconds remains a technical challenge. Here, by terahertz emission spectroscopy, we demonstrate the real-time observation of polaron formation process in FAPbI₃ films. Two different polaron resonances interpreted with the anharmonic coupling emission model have been studied: P1 at ~1 THz relates to the inorganic sublattice vibration mode and the P2 at ~0.4 THz peak relates to the FA⁺ cation rotation mode. Moreover, P2 could be further strengthened than P1 by pumping the hot carriers to the higher sub-conduction band. Our observations could open a door for THz emission spectroscopy to be a powerful tool in studying polaron formation dynamics in perovskites.

Grants and funding

92050203, 61905264, 61875211, 62005296/National Science Foundation of China | Key Programme