Disentangling Electronic and Lattice Contributions to Transient Absorption in Metal Halide Perovskites: A First-Principles Study of CH3NH3PbBr3.
- 1Department of Physics and CSMB, Humboldt-Universität zu Berlin, 12489Berlin, Germany.
- 2Distributed Algorithms and Supercomputing Department, 14195Berlin, Germany.
- 3European Theoretical Spectroscopy Facility (ETSF), Ecole Polytechnique, 91120Palaiseau, France.
Abstract
Soft lattices combined with strong electron-phonon coupling in metal halide perovskites result in a complex interplay between electronic and lattice degrees of freedom. This interplay complicates the interpretation of time-resolved spectroscopic signals, such as transient absorption spectra. Here, we develop a first-principles approach that combines a nonequilibrium extension of the Bethe-Salpeter equation with ab initio molecular dynamics to resolve the origin of transient absorption. This approach can quantitatively disentangle electronic and thermal lattice contributions across femtosecond-to-picosecond time scales. Exemplified with CH3NH3PbBr3, we find that on the femtosecond scale, both X-ray and optical transient absorption spectra are dominated by electronic contributions: Photoinduced Coulomb screening weakens the effective electron-hole interaction and blueshifts the excitonic resonances, whereas Pauli blocking is negligible in the X-ray region but non-negligible in the optical one. On the picosecond scale, thermal lattice contributions become essential, with distinct mechanisms dominating different spectral regions: Lattice vibrations lead to spectral redistribution in the X-ray transient absorption spectrum, whereas lattice expansion blueshifts the optical transient absorption spectrum.
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BibTeX
@article{qiao2026disentangling,
title = {{Disentangling Electronic and Lattice Contributions to Transient Absorption in Metal Halide Perovskites: A First-Principles Study of CH3NH3PbBr3.}},
author = {Lu Qiao and Ronaldo Rodrigues Pela and Claudia Draxl},
journal = {Journal of the American Chemical Society},
year = {2026},
month = oct,
doi = {10.1021/jacs.6c14114},
url = {https://europepmc.org/article/MED/42913530},
note = {CC BY},
}
RIS
TY - JOUR
TI - Disentangling Electronic and Lattice Contributions to Transient Absorption in Metal Halide Perovskites: A First-Principles Study of CH3NH3PbBr3.
AU - Lu Qiao
AU - Ronaldo Rodrigues Pela
AU - Claudia Draxl
PY - 2026
DA - 2026/10/01
JO - Journal of the American Chemical Society
DO - 10.1021/jacs.6c14114
UR - https://europepmc.org/article/MED/42913530
AB - Soft lattices combined with strong electron-phonon coupling in metal halide perovskites result in a complex interplay between electronic and lattice degrees of freedom. This interplay complicates the interpretation of time-resolved spectroscopic signals, such as transient absorption spectra. Here, we develop a first-principles approach that combines a nonequilibrium extension of the Bethe-Salpeter equation with ab initio molecular dynamics to resolve the origin of transient absorption. This approach can quantitatively disentangle electronic and thermal lattice contributions across femtosecond-to-picosecond time scales. Exemplified with CH3NH3PbBr3, we find that on the femtosecond scale, both X-ray and optical transient absorption spectra are dominated by electronic contributions: Photoinduced Coulomb screening weakens the effective electron-hole interaction and blueshifts the excitonic resonances, whereas Pauli blocking is negligible in the X-ray region but non-negligible in the optical one. On the picosecond scale, thermal lattice contributions become essential, with distinct mechanisms dominating different spectral regions: Lattice vibrations lead to spectral redistribution in the X-ray transient absorption spectrum, whereas lattice expansion blueshifts the optical transient absorption spectrum.
SN - 0002-7863
SN - 1520-5126
ER -