Bond Polarizability as a Probe of Local Crystal Fields in Hybrid Lead-Halide Perovskites.

Abstract
A rotating organic cation and a dynamically disordered soft inorganic cage are the hallmark features of organic-inorganic lead-halide perovskites. Understanding the interplay between these two subsystems is a challenging problem, but it is this coupling that is widely conjectured to be responsible for the unique behavior of photocarriers in these materials. In this work, we use the fact that the polarizability of the organic cation strongly depends on the ambient electrostatic environment to put the molecule forward as a sensitive probe of the local crystal fields inside the lattice cell. We measure the average polarizability of the C/N-H bond stretching mode by means of infrared spectroscopy, which allows us to deduce the character of the motion of the cation molecule, find the magnitude of the local crystal field, and place an estimate on the strength of the hydrogen bond between the hydrogen and halide atoms. Our results pave the way for understanding electric fields in lead-halide perovskites using infrared bond spectroscopy.

Citation
Wei, Y., Volosniev, A. G., Lorenc, D., Zhumekenov, A. A., Bakr, O. M., Lemeshko, M., & Alpichshev, Z. (2023). Bond Polarizability as a Probe of Local Crystal Fields in Hybrid Lead-Halide Perovskites. The Journal of Physical Chemistry Letters, 6309–6314. https://doi.org/10.1021/acs.jpclett.3c01158

Acknowledgements
We thank Bingqing Cheng and Hong-Zhou Ye for valuable discussions; Y.W.’s work at IST Austria was supported through ISTernship summer internship program funded by OeAD-GmbH; D.L. and Z.A. acknowledge support by IST Austria (ISTA); M.L. acknowledges support by the European Research Council (ERC) Starting Grant No. 801770 (ANGULON). A.A.Z. and O.M.B. acknowledge support by KAUST.

Publisher
arXiv

Journal
The journal of physical chemistry letters

DOI
10.1021/acs.jpclett.3c01158

PubMed ID
37405449

arXiv
2304.14198

Additional Links
https://pubs.acs.org/doi/10.1021/acs.jpclett.3c01158

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