Publication date: Oct 25, 2021
The development of next generation perovskite-based optoelectronic devices relies critically on the understanding of the interaction between charge carriers and the polar lattice in out-of-equilibrium conditions. While it has become increasingly evident for CsPbBr3 perovskites that the Pb-Br framework flexibility plays a key role in their light-activated functionality, the corresponding local structural rearrangement has not yet been unambiguously identified. In this work, we demonstrate that the photoinduced lattice changes in the system are due to a specific polaronic distortion, associated with the activation of a longitudinal optical phonon mode at 18 meV by electron-phonon coupling, and we quantify the associated structural changes with atomic-level precision. Key to this achievement is the combination of time-resolved and temperature-dependent studies at Br K-edge and Pb L3-edge X-ray absorption with refined ab-initio simulations, which fully account for the screened core-hole final state effects on the X-ray absorption spectra. From the temporal kinetics, we show that carrier recombination reversibly unlocks the structural deformation at both Br and Pb sites. The comparison with the temperature-dependent XAS results rules out thermal effects as the primary source of distortion of the Pb-Br bonding motif during photoexcitation. Our work provides a comprehensive description of the CsPbBr3 perovskites photophysics, offering novel insights on the light-induced response of the system and its exceptional optoelectronic properties.
No Explore or Discover sections associated with this archive record.
File name | Size | Description |
---|---|---|
README.txt
MD5md5:d3da6c183f4f560df3652bc2fc0f9640
|
5.8 KiB | Description of files and data inside the archive dataset.tar.gz |
dataset.tar.gz
MD5md5:13657aee2e61fb8f401e9bd6aa307799
|
81.4 MiB | Archive containing the raw data to reproduce the results and the figures reported in the publication |
2021.167 (version v1) [This version] | Oct 25, 2021 | DOI10.24435/materialscloud:2p-e8 |