Real-time observation of the buildup of polaron in α-FAPbI 3

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 a...

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Published inNature communications Vol. 14; no. 1; p. 917
Main Authors Yue, Xingyu, Wang, Chunwei, Zhang, Bo, Zhang, Zeyu, Xiong, Zhuang, Zu, Xinzhi, Liu, Zhengzheng, Hu, Zhiping, Odunmbaku, George Omololu, Zheng, Yujie, Sun, Kuan, Du, Juan
Format Journal Article
LanguageEnglish
Published England 17.02.2023
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Summary: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 FAPbI 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.
ISSN:2041-1723